source: vbox/trunk/src/VBox/VMM/VMMR0/HMVMXR0.cpp@ 94439

/* $Id: HMVMXR0.cpp 94011 2022-03-01 05:28:19Z vboxsync $ */
/** @file
 * HM VMX (Intel VT-x) - Host Context Ring-0.
 */

/*
 * Copyright (C) 2012-2022 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 */


/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#define LOG_GROUP LOG_GROUP_HM
#define VMCPU_INCL_CPUM_GST_CTX
#include <iprt/x86.h>
#include <iprt/asm-amd64-x86.h>
#include <iprt/thread.h>
#include <iprt/mem.h>
#include <iprt/mp.h>

#include <VBox/vmm/pdmapi.h>
#include <VBox/vmm/dbgf.h>
#include <VBox/vmm/iem.h>
#include <VBox/vmm/iom.h>
#include <VBox/vmm/tm.h>
#include <VBox/vmm/em.h>
#include <VBox/vmm/gim.h>
#include <VBox/vmm/apic.h>
#include "HMInternal.h"
#include <VBox/vmm/vmcc.h>
#include <VBox/vmm/hmvmxinline.h>
#include "HMVMXR0.h"
#include "VMXInternal.h"
#include "dtrace/VBoxVMM.h"


/*********************************************************************************************************************************
*   Defined Constants And Macros                                                                                                 *
*********************************************************************************************************************************/
#ifdef DEBUG_ramshankar
# define HMVMX_ALWAYS_SAVE_GUEST_RFLAGS
# define HMVMX_ALWAYS_SAVE_RO_GUEST_STATE
# define HMVMX_ALWAYS_SAVE_FULL_GUEST_STATE
# define HMVMX_ALWAYS_SYNC_FULL_GUEST_STATE
# define HMVMX_ALWAYS_CLEAN_TRANSIENT
# define HMVMX_ALWAYS_CHECK_GUEST_STATE
# define HMVMX_ALWAYS_TRAP_ALL_XCPTS
# define HMVMX_ALWAYS_TRAP_PF
# define HMVMX_ALWAYS_FLUSH_TLB
# define HMVMX_ALWAYS_SWAP_EFER
#endif


/*********************************************************************************************************************************
*   Structures and Typedefs                                                                                                      *
*********************************************************************************************************************************/
/**
 * VMX page allocation information.
 */
typedef struct
{
    uint32_t    fValid;       /**< Whether to allocate this page (e.g, based on a CPU feature). */
    uint32_t    uPadding0;    /**< Padding to ensure array of these structs are aligned to a multiple of 8. */
    PRTHCPHYS   pHCPhys;      /**< Where to store the host-physical address of the allocation. */
    PRTR0PTR    ppVirt;       /**< Where to store the host-virtual address of the allocation. */
} VMXPAGEALLOCINFO;
/** Pointer to VMX page-allocation info. */
typedef VMXPAGEALLOCINFO *PVMXPAGEALLOCINFO;
/** Pointer to a const VMX page-allocation info. */
typedef const VMXPAGEALLOCINFO *PCVMXPAGEALLOCINFO;
AssertCompileSizeAlignment(VMXPAGEALLOCINFO, 8);


/*********************************************************************************************************************************
*   Internal Functions                                                                                                           *
*********************************************************************************************************************************/
static bool     hmR0VmxShouldSwapEferMsr(PCVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient);
static int      hmR0VmxExitHostNmi(PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo);


/**
 * Checks if the given MSR is part of the lastbranch-from-IP MSR stack.
 * @returns @c true if it's part of LBR stack, @c false otherwise.
 *
 * @param   pVM         The cross context VM structure.
 * @param   idMsr       The MSR.
 * @param   pidxMsr     Where to store the index of the MSR in the LBR MSR array.
 *                      Optional, can be NULL.
 *
 * @remarks Must only be called when LBR is enabled.
 */
DECL_FORCE_INLINE(bool) hmR0VmxIsLbrBranchFromMsr(PCVMCC pVM, uint32_t idMsr, uint32_t *pidxMsr)
{
    Assert(pVM->hmr0.s.vmx.fLbr);
    Assert(pVM->hmr0.s.vmx.idLbrFromIpMsrFirst);
    uint32_t const cLbrStack = pVM->hmr0.s.vmx.idLbrFromIpMsrLast - pVM->hmr0.s.vmx.idLbrFromIpMsrFirst + 1;
    uint32_t const idxMsr    = idMsr - pVM->hmr0.s.vmx.idLbrFromIpMsrFirst;
    if (idxMsr < cLbrStack)
    {
        if (pidxMsr)
            *pidxMsr = idxMsr;
        return true;
    }
    return false;
}


/**
 * Checks if the given MSR is part of the lastbranch-to-IP MSR stack.
 * @returns @c true if it's part of LBR stack, @c false otherwise.
 *
 * @param   pVM         The cross context VM structure.
 * @param   idMsr       The MSR.
 * @param   pidxMsr     Where to store the index of the MSR in the LBR MSR array.
 *                      Optional, can be NULL.
 *
 * @remarks Must only be called when LBR is enabled and when lastbranch-to-IP MSRs
 *          are supported by the CPU (see hmR0VmxSetupLbrMsrRange).
 */
DECL_FORCE_INLINE(bool) hmR0VmxIsLbrBranchToMsr(PCVMCC pVM, uint32_t idMsr, uint32_t *pidxMsr)
{
    Assert(pVM->hmr0.s.vmx.fLbr);
    if (pVM->hmr0.s.vmx.idLbrToIpMsrFirst)
    {
        uint32_t const cLbrStack = pVM->hmr0.s.vmx.idLbrToIpMsrLast - pVM->hmr0.s.vmx.idLbrToIpMsrFirst + 1;
        uint32_t const idxMsr    = idMsr - pVM->hmr0.s.vmx.idLbrToIpMsrFirst;
        if (idxMsr < cLbrStack)
        {
            if (pidxMsr)
                *pidxMsr = idxMsr;
            return true;
        }
    }
    return false;
}


/**
 * Gets the active (in use) VMCS info. object for the specified VCPU.
 *
 * This is either the guest or nested-guest VMCS info. and need not necessarily
 * pertain to the "current" VMCS (in the VMX definition of the term). For instance,
 * if the VM-entry failed due to an invalid-guest state, we may have "cleared" the
 * current VMCS while returning to ring-3. However, the VMCS info. object for that
 * VMCS would still be active and returned here so that we could dump the VMCS
 * fields to ring-3 for diagnostics. This function is thus only used to
 * distinguish between the nested-guest or guest VMCS.
 *
 * @returns The active VMCS information.
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @thread  EMT.
 * @remarks This function may be called with preemption or interrupts disabled!
 */
DECLINLINE(PVMXVMCSINFO) hmGetVmxActiveVmcsInfo(PVMCPUCC pVCpu)
{
    if (!pVCpu->hmr0.s.vmx.fSwitchedToNstGstVmcs)
        return &pVCpu->hmr0.s.vmx.VmcsInfo;
    return &pVCpu->hmr0.s.vmx.VmcsInfoNstGst;
}


/**
 * Returns whether the VM-exit MSR-store area differs from the VM-exit MSR-load
 * area.
 *
 * @returns @c true if it's different, @c false otherwise.
 * @param   pVmcsInfo   The VMCS info. object.
 */
DECL_FORCE_INLINE(bool) hmR0VmxIsSeparateExitMsrStoreAreaVmcs(PCVMXVMCSINFO pVmcsInfo)
{
    return RT_BOOL(   pVmcsInfo->pvGuestMsrStore != pVmcsInfo->pvGuestMsrLoad
                   && pVmcsInfo->pvGuestMsrStore);
}


/**
 * Sets the given Processor-based VM-execution controls.
 *
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   uProcCtls       The Processor-based VM-execution controls to set.
 */
static void hmR0VmxSetProcCtlsVmcs(PVMXTRANSIENT pVmxTransient, uint32_t uProcCtls)
{
    PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
    if ((pVmcsInfo->u32ProcCtls & uProcCtls) != uProcCtls)
    {
        pVmcsInfo->u32ProcCtls |= uProcCtls;
        int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC, pVmcsInfo->u32ProcCtls);
        AssertRC(rc);
    }
}


/**
 * Removes the given Processor-based VM-execution controls.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   uProcCtls       The Processor-based VM-execution controls to remove.
 *
 * @remarks When executing a nested-guest, this will not remove any of the specified
 *          controls if the nested hypervisor has set any one of them.
 */
static void hmR0VmxRemoveProcCtlsVmcs(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient, uint32_t uProcCtls)
{
    PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
    if (pVmcsInfo->u32ProcCtls & uProcCtls)
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        if (   !pVmxTransient->fIsNestedGuest
            || !CPUMIsGuestVmxProcCtlsSet(&pVCpu->cpum.GstCtx, uProcCtls))
#else
        NOREF(pVCpu);
        if (!pVmxTransient->fIsNestedGuest)
#endif
        {
            pVmcsInfo->u32ProcCtls &= ~uProcCtls;
            int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC, pVmcsInfo->u32ProcCtls);
            AssertRC(rc);
        }
    }
}


/**
 * Sets the TSC offset for the current VMCS.
 *
 * @param   uTscOffset  The TSC offset to set.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static void hmR0VmxSetTscOffsetVmcs(PVMXVMCSINFO pVmcsInfo, uint64_t uTscOffset)
{
    if (pVmcsInfo->u64TscOffset != uTscOffset)
    {
        int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_TSC_OFFSET_FULL, uTscOffset);
        AssertRC(rc);
        pVmcsInfo->u64TscOffset = uTscOffset;
    }
}


/**
 * Loads the VMCS specified by the VMCS info. object.
 *
 * @returns VBox status code.
 * @param   pVmcsInfo       The VMCS info. object.
 *
 * @remarks Can be called with interrupts disabled.
 */
static int hmR0VmxLoadVmcs(PVMXVMCSINFO pVmcsInfo)
{
    Assert(pVmcsInfo->HCPhysVmcs != 0 && pVmcsInfo->HCPhysVmcs != NIL_RTHCPHYS);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    int rc = VMXLoadVmcs(pVmcsInfo->HCPhysVmcs);
    if (RT_SUCCESS(rc))
        pVmcsInfo->fVmcsState |= VMX_V_VMCS_LAUNCH_STATE_CURRENT;
    return rc;
}


/**
 * Clears the VMCS specified by the VMCS info. object.
 *
 * @returns VBox status code.
 * @param   pVmcsInfo   The VMCS info. object.
 *
 * @remarks Can be called with interrupts disabled.
 */
static int hmR0VmxClearVmcs(PVMXVMCSINFO pVmcsInfo)
{
    Assert(pVmcsInfo->HCPhysVmcs != 0 && pVmcsInfo->HCPhysVmcs != NIL_RTHCPHYS);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    int rc = VMXClearVmcs(pVmcsInfo->HCPhysVmcs);
    if (RT_SUCCESS(rc))
        pVmcsInfo->fVmcsState = VMX_V_VMCS_LAUNCH_STATE_CLEAR;
    return rc;
}


/**
 * Checks whether the MSR belongs to the set of guest MSRs that we restore
 * lazily while leaving VT-x.
 *
 * @returns true if it does, false otherwise.
 * @param   pVCpu   The cross context virtual CPU structure.
 * @param   idMsr   The MSR to check.
 */
static bool hmR0VmxIsLazyGuestMsr(PCVMCPUCC pVCpu, uint32_t idMsr)
{
    if (pVCpu->CTX_SUFF(pVM)->hmr0.s.fAllow64BitGuests)
    {
        switch (idMsr)
        {
            case MSR_K8_LSTAR:
            case MSR_K6_STAR:
            case MSR_K8_SF_MASK:
            case MSR_K8_KERNEL_GS_BASE:
                return true;
        }
    }
    return false;
}


/**
 * Loads a set of guests MSRs to allow read/passthru to the guest.
 *
 * The name of this function is slightly confusing. This function does NOT
 * postpone loading, but loads the MSR right now. "hmR0VmxLazy" is simply a
 * common prefix for functions dealing with "lazy restoration" of the shared
 * MSRs.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxLazyLoadGuestMsrs(PVMCPUCC pVCpu)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

    Assert(pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_SAVED_HOST);
    if (pVCpu->CTX_SUFF(pVM)->hmr0.s.fAllow64BitGuests)
    {
        /*
         * If the guest MSRs are not loaded -and- if all the guest MSRs are identical
         * to the MSRs on the CPU (which are the saved host MSRs, see assertion above) then
         * we can skip a few MSR writes.
         *
         * Otherwise, it implies either 1. they're not loaded, or 2. they're loaded but the
         * guest MSR values in the guest-CPU context might be different to what's currently
         * loaded in the CPU. In either case, we need to write the new guest MSR values to the
         * CPU, see @bugref{8728}.
         */
        PCCPUMCTX pCtx = &pVCpu->cpum.GstCtx;
        if (   !(pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST)
            && pCtx->msrKERNELGSBASE == pVCpu->hmr0.s.vmx.u64HostMsrKernelGsBase
            && pCtx->msrLSTAR        == pVCpu->hmr0.s.vmx.u64HostMsrLStar
            && pCtx->msrSTAR         == pVCpu->hmr0.s.vmx.u64HostMsrStar
            && pCtx->msrSFMASK       == pVCpu->hmr0.s.vmx.u64HostMsrSfMask)
        {
#ifdef VBOX_STRICT
            Assert(ASMRdMsr(MSR_K8_KERNEL_GS_BASE) == pCtx->msrKERNELGSBASE);
            Assert(ASMRdMsr(MSR_K8_LSTAR)          == pCtx->msrLSTAR);
            Assert(ASMRdMsr(MSR_K6_STAR)           == pCtx->msrSTAR);
            Assert(ASMRdMsr(MSR_K8_SF_MASK)        == pCtx->msrSFMASK);
#endif
        }
        else
        {
            ASMWrMsr(MSR_K8_KERNEL_GS_BASE, pCtx->msrKERNELGSBASE);
            ASMWrMsr(MSR_K8_LSTAR,          pCtx->msrLSTAR);
            ASMWrMsr(MSR_K6_STAR,           pCtx->msrSTAR);
            /* The system call flag mask register isn't as benign and accepting of all
               values as the above, so mask it to avoid #GP'ing on corrupted input. */
            Assert(!(pCtx->msrSFMASK & ~(uint64_t)UINT32_MAX));
            ASMWrMsr(MSR_K8_SF_MASK,        pCtx->msrSFMASK & UINT32_MAX);
        }
    }
    pVCpu->hmr0.s.vmx.fLazyMsrs |= VMX_LAZY_MSRS_LOADED_GUEST;
}


/**
 * Checks if the specified guest MSR is part of the VM-entry MSR-load area.
 *
 * @returns @c true if found, @c false otherwise.
 * @param   pVmcsInfo   The VMCS info. object.
 * @param   idMsr       The MSR to find.
 */
static bool hmR0VmxIsAutoLoadGuestMsr(PCVMXVMCSINFO pVmcsInfo, uint32_t idMsr)
{
    PCVMXAUTOMSR   pMsrs = (PCVMXAUTOMSR)pVmcsInfo->pvGuestMsrLoad;
    uint32_t const cMsrs = pVmcsInfo->cEntryMsrLoad;
    Assert(pMsrs);
    Assert(sizeof(*pMsrs) * cMsrs <= X86_PAGE_4K_SIZE);
    for (uint32_t i = 0; i < cMsrs; i++)
    {
        if (pMsrs[i].u32Msr == idMsr)
            return true;
    }
    return false;
}


/**
 * Performs lazy restoration of the set of host MSRs if they were previously
 * loaded with guest MSR values.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 * @remarks The guest MSRs should have been saved back into the guest-CPU
 *          context by hmR0VmxImportGuestState()!!!
 */
static void hmR0VmxLazyRestoreHostMsrs(PVMCPUCC pVCpu)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

    if (pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST)
    {
        Assert(pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_SAVED_HOST);
        if (pVCpu->CTX_SUFF(pVM)->hmr0.s.fAllow64BitGuests)
        {
            ASMWrMsr(MSR_K8_LSTAR,          pVCpu->hmr0.s.vmx.u64HostMsrLStar);
            ASMWrMsr(MSR_K6_STAR,           pVCpu->hmr0.s.vmx.u64HostMsrStar);
            ASMWrMsr(MSR_K8_SF_MASK,        pVCpu->hmr0.s.vmx.u64HostMsrSfMask);
            ASMWrMsr(MSR_K8_KERNEL_GS_BASE, pVCpu->hmr0.s.vmx.u64HostMsrKernelGsBase);
        }
    }
    pVCpu->hmr0.s.vmx.fLazyMsrs &= ~(VMX_LAZY_MSRS_LOADED_GUEST | VMX_LAZY_MSRS_SAVED_HOST);
}


/**
 * Sets pfnStartVm to the best suited variant.
 *
 * This must be called whenever anything changes relative to the hmR0VmXStartVm
 * variant selection:
 *      - pVCpu->hm.s.fLoadSaveGuestXcr0
 *      - HM_WSF_IBPB_ENTRY in pVCpu->hmr0.s.fWorldSwitcher
 *      - HM_WSF_IBPB_EXIT  in pVCpu->hmr0.s.fWorldSwitcher
 *      - Perhaps: CPUMIsGuestFPUStateActive() (windows only)
 *      - Perhaps: CPUMCTX.fXStateMask (windows only)
 *
 * We currently ASSUME that neither HM_WSF_IBPB_ENTRY nor HM_WSF_IBPB_EXIT
 * cannot be changed at runtime.
 */
static void hmR0VmxUpdateStartVmFunction(PVMCPUCC pVCpu)
{
    static const struct CLANGWORKAROUND { PFNHMVMXSTARTVM pfn; } s_aHmR0VmxStartVmFunctions[] =
    {
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_SansL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_SansL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_SansL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_SansL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_WithL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_WithL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_WithL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_WithL1dEntry_SansMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_SansL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_SansL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_SansL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_SansL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_WithL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_WithL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_WithL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_WithL1dEntry_WithMdsEntry_SansIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_SansL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_SansL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_SansL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_SansL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_WithL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_WithL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_WithL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_WithL1dEntry_SansMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_SansL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_SansL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_SansL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_SansL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_SansIbpbEntry_WithL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_SansIbpbEntry_WithL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_SansXcr0_WithIbpbEntry_WithL1dEntry_WithMdsEntry_WithIbpbExit },
        { hmR0VmxStartVm_WithXcr0_WithIbpbEntry_WithL1dEntry_WithMdsEntry_WithIbpbExit },
    };
    uintptr_t const idx = (pVCpu->hmr0.s.fLoadSaveGuestXcr0                 ?  1 : 0)
                        | (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_IBPB_ENTRY ?  2 : 0)
                        | (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_L1D_ENTRY  ?  4 : 0)
                        | (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_MDS_ENTRY  ?  8 : 0)
                        | (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_IBPB_EXIT  ? 16 : 0);
    PFNHMVMXSTARTVM const pfnStartVm = s_aHmR0VmxStartVmFunctions[idx].pfn;
    if (pVCpu->hmr0.s.vmx.pfnStartVm != pfnStartVm)
        pVCpu->hmr0.s.vmx.pfnStartVm = pfnStartVm;
}


/**
 * Pushes a 2-byte value onto the real-mode (in virtual-8086 mode) guest's
 * stack.
 *
 * @returns Strict VBox status code (i.e. informational status codes too).
 * @retval  VINF_EM_RESET if pushing a value to the stack caused a triple-fault.
 * @param   pVCpu   The cross context virtual CPU structure.
 * @param   uValue  The value to push to the guest stack.
 */
static VBOXSTRICTRC hmR0VmxRealModeGuestStackPush(PVMCPUCC pVCpu, uint16_t uValue)
{
    /*
     * The stack limit is 0xffff in real-on-virtual 8086 mode. Real-mode with weird stack limits cannot be run in
     * virtual 8086 mode in VT-x. See Intel spec. 26.3.1.2 "Checks on Guest Segment Registers".
     * See Intel Instruction reference for PUSH and Intel spec. 22.33.1 "Segment Wraparound".
     */
    PCPUMCTX pCtx = &pVCpu->cpum.GstCtx;
    if (pCtx->sp == 1)
        return VINF_EM_RESET;
    pCtx->sp -= sizeof(uint16_t);       /* May wrap around which is expected behaviour. */
    int rc = PGMPhysSimpleWriteGCPhys(pVCpu->CTX_SUFF(pVM), pCtx->ss.u64Base + pCtx->sp, &uValue, sizeof(uint16_t));
    AssertRC(rc);
    return rc;
}


/**
 * Wrapper around VMXWriteVmcs16 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxWriteVmcs16(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint16_t u16Val)
{
    RT_NOREF(pVCpu);
    return VMXWriteVmcs16(uFieldEnc, u16Val);
}


/**
 * Wrapper around VMXWriteVmcs32 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxWriteVmcs32(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint32_t u32Val)
{
    RT_NOREF(pVCpu);
    return VMXWriteVmcs32(uFieldEnc, u32Val);
}


/**
 * Wrapper around VMXWriteVmcs64 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxWriteVmcs64(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint64_t u64Val)
{
    RT_NOREF(pVCpu);
    return VMXWriteVmcs64(uFieldEnc, u64Val);
}


/**
 * Wrapper around VMXReadVmcs16 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxReadVmcs16(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint16_t *pu16Val)
{
    RT_NOREF(pVCpu);
    return VMXReadVmcs16(uFieldEnc, pu16Val);
}


/**
 * Wrapper around VMXReadVmcs32 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxReadVmcs32(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint32_t *pu32Val)
{
    RT_NOREF(pVCpu);
    return VMXReadVmcs32(uFieldEnc, pu32Val);
}


/**
 * Wrapper around VMXReadVmcs64 taking a pVCpu parameter so VCC doesn't complain about
 * unreferenced local parameters in the template code...
 */
DECL_FORCE_INLINE(int) hmR0VmxReadVmcs64(PCVMCPUCC pVCpu, uint32_t uFieldEnc, uint64_t *pu64Val)
{
    RT_NOREF(pVCpu);
    return VMXReadVmcs64(uFieldEnc, pu64Val);
}


/*
 * Instantiate the code we share with the NEM darwin backend.
 */
#define VCPU_2_VMXSTATE(a_pVCpu)            (a_pVCpu)->hm.s
#define VCPU_2_VMXSTATS(a_pVCpu)            (a_pVCpu)->hm.s

#define VM_IS_VMX_UNRESTRICTED_GUEST(a_pVM) (a_pVM)->hmr0.s.vmx.fUnrestrictedGuest
#define VM_IS_VMX_NESTED_PAGING(a_pVM)      (a_pVM)->hmr0.s.fNestedPaging
#define VM_IS_VMX_PREEMPT_TIMER_USED(a_pVM) (a_pVM)->hmr0.s.vmx.fUsePreemptTimer
#define VM_IS_VMX_LBR(a_pVM)                (a_pVM)->hmr0.s.vmx.fLbr

#define VMX_VMCS_WRITE_16(a_pVCpu, a_FieldEnc, a_Val) hmR0VmxWriteVmcs16((a_pVCpu), (a_FieldEnc), (a_Val))
#define VMX_VMCS_WRITE_32(a_pVCpu, a_FieldEnc, a_Val) hmR0VmxWriteVmcs32((a_pVCpu), (a_FieldEnc), (a_Val))
#define VMX_VMCS_WRITE_64(a_pVCpu, a_FieldEnc, a_Val) hmR0VmxWriteVmcs64((a_pVCpu), (a_FieldEnc), (a_Val))
#define VMX_VMCS_WRITE_NW(a_pVCpu, a_FieldEnc, a_Val) hmR0VmxWriteVmcs64((a_pVCpu), (a_FieldEnc), (a_Val))

#define VMX_VMCS_READ_16(a_pVCpu, a_FieldEnc, a_pVal) hmR0VmxReadVmcs16((a_pVCpu), (a_FieldEnc), (a_pVal))
#define VMX_VMCS_READ_32(a_pVCpu, a_FieldEnc, a_pVal) hmR0VmxReadVmcs32((a_pVCpu), (a_FieldEnc), (a_pVal))
#define VMX_VMCS_READ_64(a_pVCpu, a_FieldEnc, a_pVal) hmR0VmxReadVmcs64((a_pVCpu), (a_FieldEnc), (a_pVal))
#define VMX_VMCS_READ_NW(a_pVCpu, a_FieldEnc, a_pVal) hmR0VmxReadVmcs64((a_pVCpu), (a_FieldEnc), (a_pVal))

#include "../VMMAll/VMXAllTemplate.cpp.h"

#undef VMX_VMCS_WRITE_16
#undef VMX_VMCS_WRITE_32
#undef VMX_VMCS_WRITE_64
#undef VMX_VMCS_WRITE_NW

#undef VMX_VMCS_READ_16
#undef VMX_VMCS_READ_32
#undef VMX_VMCS_READ_64
#undef VMX_VMCS_READ_NW

#undef VM_IS_VMX_PREEMPT_TIMER_USED
#undef VM_IS_VMX_NESTED_PAGING
#undef VM_IS_VMX_UNRESTRICTED_GUEST
#undef VCPU_2_VMXSTATS
#undef VCPU_2_VMXSTATE


/**
 * Updates the VM's last error record.
 *
 * If there was a VMX instruction error, reads the error data from the VMCS and
 * updates VCPU's last error record as well.
 *
 * @param   pVCpu   The cross context virtual CPU structure of the calling EMT.
 *                  Can be NULL if @a rc is not VERR_VMX_UNABLE_TO_START_VM or
 *                  VERR_VMX_INVALID_VMCS_FIELD.
 * @param   rc      The error code.
 */
static void hmR0VmxUpdateErrorRecord(PVMCPUCC pVCpu, int rc)
{
    if (   rc == VERR_VMX_INVALID_VMCS_FIELD
        || rc == VERR_VMX_UNABLE_TO_START_VM)
    {
        AssertPtrReturnVoid(pVCpu);
        VMXReadVmcs32(VMX_VMCS32_RO_VM_INSTR_ERROR, &pVCpu->hm.s.vmx.LastError.u32InstrError);
    }
    pVCpu->CTX_SUFF(pVM)->hm.s.ForR3.rcInit = rc;
}


/**
 * Enters VMX root mode operation on the current CPU.
 *
 * @returns VBox status code.
 * @param   pHostCpu        The HM physical-CPU structure.
 * @param   pVM             The cross context VM structure. Can be
 *                          NULL, after a resume.
 * @param   HCPhysCpuPage   Physical address of the VMXON region.
 * @param   pvCpuPage       Pointer to the VMXON region.
 */
static int hmR0VmxEnterRootMode(PHMPHYSCPU pHostCpu, PVMCC pVM, RTHCPHYS HCPhysCpuPage, void *pvCpuPage)
{
    Assert(pHostCpu);
    Assert(HCPhysCpuPage && HCPhysCpuPage != NIL_RTHCPHYS);
    Assert(RT_ALIGN_T(HCPhysCpuPage, _4K, RTHCPHYS) == HCPhysCpuPage);
    Assert(pvCpuPage);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    if (pVM)
    {
        /* Write the VMCS revision identifier to the VMXON region. */
        *(uint32_t *)pvCpuPage = RT_BF_GET(g_HmMsrs.u.vmx.u64Basic, VMX_BF_BASIC_VMCS_ID);
    }

    /* Paranoid: Disable interrupts as, in theory, interrupt handlers might mess with CR4. */
    RTCCUINTREG const fEFlags = ASMIntDisableFlags();

    /* Enable the VMX bit in CR4 if necessary. */
    RTCCUINTREG const uOldCr4 = SUPR0ChangeCR4(X86_CR4_VMXE, RTCCUINTREG_MAX);

    /* Record whether VMXE was already prior to us enabling it above. */
    pHostCpu->fVmxeAlreadyEnabled = RT_BOOL(uOldCr4 & X86_CR4_VMXE);

    /* Enter VMX root mode. */
    int rc = VMXEnable(HCPhysCpuPage);
    if (RT_FAILURE(rc))
    {
        /* Restore CR4.VMXE if it was not set prior to our attempt to set it above. */
        if (!pHostCpu->fVmxeAlreadyEnabled)
            SUPR0ChangeCR4(0 /* fOrMask */, ~(uint64_t)X86_CR4_VMXE);

        if (pVM)
            pVM->hm.s.ForR3.vmx.HCPhysVmxEnableError = HCPhysCpuPage;
    }

    /* Restore interrupts. */
    ASMSetFlags(fEFlags);
    return rc;
}


/**
 * Exits VMX root mode operation on the current CPU.
 *
 * @returns VBox status code.
 * @param   pHostCpu        The HM physical-CPU structure.
 */
static int hmR0VmxLeaveRootMode(PHMPHYSCPU pHostCpu)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /* Paranoid: Disable interrupts as, in theory, interrupts handlers might mess with CR4. */
    RTCCUINTREG const fEFlags = ASMIntDisableFlags();

    /* If we're for some reason not in VMX root mode, then don't leave it. */
    RTCCUINTREG const uHostCr4 = ASMGetCR4();

    int rc;
    if (uHostCr4 & X86_CR4_VMXE)
    {
        /* Exit VMX root mode and clear the VMX bit in CR4. */
        VMXDisable();

        /* Clear CR4.VMXE only if it was clear prior to use setting it. */
        if (!pHostCpu->fVmxeAlreadyEnabled)
            SUPR0ChangeCR4(0 /* fOrMask */, ~(uint64_t)X86_CR4_VMXE);

        rc = VINF_SUCCESS;
    }
    else
        rc = VERR_VMX_NOT_IN_VMX_ROOT_MODE;

    /* Restore interrupts. */
    ASMSetFlags(fEFlags);
    return rc;
}


/**
 * Allocates pages specified as specified by an array of VMX page allocation info
 * objects.
 *
 * The pages contents are zero'd after allocation.
 *
 * @returns VBox status code.
 * @param   phMemObj        Where to return the handle to the allocation.
 * @param   paAllocInfo     The pointer to the first element of the VMX
 *                          page-allocation info object array.
 * @param   cEntries        The number of elements in the @a paAllocInfo array.
 */
static int hmR0VmxPagesAllocZ(PRTR0MEMOBJ phMemObj, PVMXPAGEALLOCINFO paAllocInfo, uint32_t cEntries)
{
    *phMemObj = NIL_RTR0MEMOBJ;

    /* Figure out how many pages to allocate. */
    uint32_t cPages = 0;
    for (uint32_t iPage = 0; iPage < cEntries; iPage++)
        cPages += !!paAllocInfo[iPage].fValid;

    /* Allocate the pages. */
    if (cPages)
    {
        size_t const cbPages = cPages << HOST_PAGE_SHIFT;
        int rc = RTR0MemObjAllocPage(phMemObj, cbPages, false /* fExecutable */);
        if (RT_FAILURE(rc))
            return rc;

        /* Zero the contents and assign each page to the corresponding VMX page-allocation entry. */
        void *pvFirstPage = RTR0MemObjAddress(*phMemObj);
        RT_BZERO(pvFirstPage, cbPages);

        uint32_t iPage = 0;
        for (uint32_t i = 0; i < cEntries; i++)
            if (paAllocInfo[i].fValid)
            {
                RTHCPHYS const HCPhysPage = RTR0MemObjGetPagePhysAddr(*phMemObj, iPage);
                void          *pvPage     = (void *)((uintptr_t)pvFirstPage + (iPage << X86_PAGE_4K_SHIFT));
                Assert(HCPhysPage && HCPhysPage != NIL_RTHCPHYS);
                AssertPtr(pvPage);

                Assert(paAllocInfo[iPage].pHCPhys);
                Assert(paAllocInfo[iPage].ppVirt);
                *paAllocInfo[iPage].pHCPhys = HCPhysPage;
                *paAllocInfo[iPage].ppVirt  = pvPage;

                /* Move to next page. */
                ++iPage;
            }

        /* Make sure all valid (requested) pages have been assigned. */
        Assert(iPage == cPages);
    }
    return VINF_SUCCESS;
}


/**
 * Frees pages allocated using hmR0VmxPagesAllocZ.
 *
 * @param   phMemObj    Pointer to the memory object handle.  Will be set to
 *                      NIL.
 */
DECL_FORCE_INLINE(void) hmR0VmxPagesFree(PRTR0MEMOBJ phMemObj)
{
    /* We can cleanup wholesale since it's all one allocation. */
    if (*phMemObj != NIL_RTR0MEMOBJ)
    {
        RTR0MemObjFree(*phMemObj, true /* fFreeMappings */);
        *phMemObj = NIL_RTR0MEMOBJ;
    }
}


/**
 * Initializes a VMCS info. object.
 *
 * @param   pVmcsInfo           The VMCS info. object.
 * @param   pVmcsInfoShared     The VMCS info. object shared with ring-3.
 */
static void hmR0VmxVmcsInfoInit(PVMXVMCSINFO pVmcsInfo, PVMXVMCSINFOSHARED pVmcsInfoShared)
{
    RT_ZERO(*pVmcsInfo);
    RT_ZERO(*pVmcsInfoShared);

    pVmcsInfo->pShared             = pVmcsInfoShared;
    Assert(pVmcsInfo->hMemObj == NIL_RTR0MEMOBJ);
    pVmcsInfo->HCPhysVmcs          = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysShadowVmcs    = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysMsrBitmap     = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysGuestMsrLoad  = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysGuestMsrStore = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysHostMsrLoad   = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysVirtApic      = NIL_RTHCPHYS;
    pVmcsInfo->HCPhysEPTP          = NIL_RTHCPHYS;
    pVmcsInfo->u64VmcsLinkPtr      = NIL_RTHCPHYS;
    pVmcsInfo->idHostCpuState      = NIL_RTCPUID;
    pVmcsInfo->idHostCpuExec       = NIL_RTCPUID;
}


/**
 * Frees the VT-x structures for a VMCS info. object.
 *
 * @param   pVmcsInfo           The VMCS info. object.
 * @param   pVmcsInfoShared     The VMCS info. object shared with ring-3.
 */
static void hmR0VmxVmcsInfoFree(PVMXVMCSINFO pVmcsInfo, PVMXVMCSINFOSHARED pVmcsInfoShared)
{
    hmR0VmxPagesFree(&pVmcsInfo->hMemObj);
    hmR0VmxVmcsInfoInit(pVmcsInfo, pVmcsInfoShared);
}


/**
 * Allocates the VT-x structures for a VMCS info. object.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmcsInfo       The VMCS info. object.
 * @param   fIsNstGstVmcs   Whether this is a nested-guest VMCS.
 *
 * @remarks The caller is expected to take care of any and all allocation failures.
 *          This function will not perform any cleanup for failures half-way
 *          through.
 */
static int hmR0VmxAllocVmcsInfo(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo, bool fIsNstGstVmcs)
{
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);

    bool const fMsrBitmaps = RT_BOOL(g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_MSR_BITMAPS);
    bool const fShadowVmcs = !fIsNstGstVmcs ? pVM->hmr0.s.vmx.fUseVmcsShadowing : pVM->cpum.ro.GuestFeatures.fVmxVmcsShadowing;
    Assert(!pVM->cpum.ro.GuestFeatures.fVmxVmcsShadowing);  /* VMCS shadowing is not yet exposed to the guest. */
    VMXPAGEALLOCINFO aAllocInfo[] =
    {
        { true,        0 /* Unused */, &pVmcsInfo->HCPhysVmcs,         &pVmcsInfo->pvVmcs         },
        { true,        0 /* Unused */, &pVmcsInfo->HCPhysGuestMsrLoad, &pVmcsInfo->pvGuestMsrLoad },
        { true,        0 /* Unused */, &pVmcsInfo->HCPhysHostMsrLoad,  &pVmcsInfo->pvHostMsrLoad  },
        { fMsrBitmaps, 0 /* Unused */, &pVmcsInfo->HCPhysMsrBitmap,    &pVmcsInfo->pvMsrBitmap    },
        { fShadowVmcs, 0 /* Unused */, &pVmcsInfo->HCPhysShadowVmcs,   &pVmcsInfo->pvShadowVmcs   },
    };

    int rc = hmR0VmxPagesAllocZ(&pVmcsInfo->hMemObj, &aAllocInfo[0], RT_ELEMENTS(aAllocInfo));
    if (RT_FAILURE(rc))
        return rc;

    /*
     * We use the same page for VM-entry MSR-load and VM-exit MSR store areas.
     * Because they contain a symmetric list of guest MSRs to load on VM-entry and store on VM-exit.
     */
    AssertCompile(RT_ELEMENTS(aAllocInfo) > 0);
    Assert(pVmcsInfo->HCPhysGuestMsrLoad != NIL_RTHCPHYS);
    pVmcsInfo->pvGuestMsrStore     = pVmcsInfo->pvGuestMsrLoad;
    pVmcsInfo->HCPhysGuestMsrStore = pVmcsInfo->HCPhysGuestMsrLoad;

    /*
     * Get the virtual-APIC page rather than allocating them again.
     */
    if (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_TPR_SHADOW)
    {
        if (!fIsNstGstVmcs)
        {
            if (PDMHasApic(pVM))
            {
                rc = APICGetApicPageForCpu(pVCpu, &pVmcsInfo->HCPhysVirtApic, (PRTR0PTR)&pVmcsInfo->pbVirtApic, NULL /*pR3Ptr*/);
                if (RT_FAILURE(rc))
                    return rc;
                Assert(pVmcsInfo->pbVirtApic);
                Assert(pVmcsInfo->HCPhysVirtApic && pVmcsInfo->HCPhysVirtApic != NIL_RTHCPHYS);
            }
        }
        else
        {
            pVmcsInfo->pbVirtApic     = &pVCpu->cpum.GstCtx.hwvirt.vmx.abVirtApicPage[0];
            pVmcsInfo->HCPhysVirtApic = GVMMR0ConvertGVMPtr2HCPhys(pVM, pVmcsInfo->pbVirtApic);
            Assert(pVmcsInfo->HCPhysVirtApic && pVmcsInfo->HCPhysVirtApic != NIL_RTHCPHYS);
        }
    }

    return VINF_SUCCESS;
}


/**
 * Free all VT-x structures for the VM.
 *
 * @returns IPRT status code.
 * @param   pVM     The cross context VM structure.
 */
static void hmR0VmxStructsFree(PVMCC pVM)
{
    hmR0VmxPagesFree(&pVM->hmr0.s.vmx.hMemObj);
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    if (pVM->hmr0.s.vmx.fUseVmcsShadowing)
    {
        RTMemFree(pVM->hmr0.s.vmx.paShadowVmcsFields);
        pVM->hmr0.s.vmx.paShadowVmcsFields = NULL;
        RTMemFree(pVM->hmr0.s.vmx.paShadowVmcsRoFields);
        pVM->hmr0.s.vmx.paShadowVmcsRoFields = NULL;
    }
#endif

    for (VMCPUID idCpu = 0; idCpu < pVM->cCpus; idCpu++)
    {
        PVMCPUCC pVCpu = VMCC_GET_CPU(pVM, idCpu);
        hmR0VmxVmcsInfoFree(&pVCpu->hmr0.s.vmx.VmcsInfo, &pVCpu->hm.s.vmx.VmcsInfo);
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        if (pVM->cpum.ro.GuestFeatures.fVmx)
            hmR0VmxVmcsInfoFree(&pVCpu->hmr0.s.vmx.VmcsInfoNstGst, &pVCpu->hm.s.vmx.VmcsInfoNstGst);
#endif
    }
}


/**
 * Allocate all VT-x structures for the VM.
 *
 * @returns IPRT status code.
 * @param   pVM     The cross context VM structure.
 *
 * @remarks This functions will cleanup on memory allocation failures.
 */
static int hmR0VmxStructsAlloc(PVMCC pVM)
{
    /*
     * Sanity check the VMCS size reported by the CPU as we assume 4KB allocations.
     * The VMCS size cannot be more than 4096 bytes.
     *
     * See Intel spec. Appendix A.1 "Basic VMX Information".
     */
    uint32_t const cbVmcs = RT_BF_GET(g_HmMsrs.u.vmx.u64Basic, VMX_BF_BASIC_VMCS_SIZE);
    if (cbVmcs <= X86_PAGE_4K_SIZE)
    { /* likely */ }
    else
    {
        VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_INVALID_VMCS_SIZE;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /*
     * Allocate per-VM VT-x structures.
     */
    bool const fVirtApicAccess   = RT_BOOL(g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS);
    bool const fUseVmcsShadowing = pVM->hmr0.s.vmx.fUseVmcsShadowing;
    VMXPAGEALLOCINFO aAllocInfo[] =
    {
        { fVirtApicAccess,   0 /* Unused */, &pVM->hmr0.s.vmx.HCPhysApicAccess,    (PRTR0PTR)&pVM->hmr0.s.vmx.pbApicAccess },
        { fUseVmcsShadowing, 0 /* Unused */, &pVM->hmr0.s.vmx.HCPhysVmreadBitmap,  &pVM->hmr0.s.vmx.pvVmreadBitmap         },
        { fUseVmcsShadowing, 0 /* Unused */, &pVM->hmr0.s.vmx.HCPhysVmwriteBitmap, &pVM->hmr0.s.vmx.pvVmwriteBitmap        },
#ifdef VBOX_WITH_CRASHDUMP_MAGIC
        { true,              0 /* Unused */, &pVM->hmr0.s.vmx.HCPhysScratch,       (PRTR0PTR)&pVM->hmr0.s.vmx.pbScratch    },
#endif
    };

    int rc = hmR0VmxPagesAllocZ(&pVM->hmr0.s.vmx.hMemObj, &aAllocInfo[0], RT_ELEMENTS(aAllocInfo));
    if (RT_SUCCESS(rc))
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        /* Allocate the shadow VMCS-fields array. */
        if (fUseVmcsShadowing)
        {
            Assert(!pVM->hmr0.s.vmx.cShadowVmcsFields);
            Assert(!pVM->hmr0.s.vmx.cShadowVmcsRoFields);
            pVM->hmr0.s.vmx.paShadowVmcsFields   = (uint32_t *)RTMemAllocZ(sizeof(g_aVmcsFields));
            pVM->hmr0.s.vmx.paShadowVmcsRoFields = (uint32_t *)RTMemAllocZ(sizeof(g_aVmcsFields));
            if (!pVM->hmr0.s.vmx.paShadowVmcsFields || !pVM->hmr0.s.vmx.paShadowVmcsRoFields)
                rc = VERR_NO_MEMORY;
        }
#endif

        /*
         * Allocate per-VCPU VT-x structures.
         */
        for (VMCPUID idCpu = 0; idCpu < pVM->cCpus && RT_SUCCESS(rc); idCpu++)
        {
            /* Allocate the guest VMCS structures. */
            PVMCPUCC pVCpu = VMCC_GET_CPU(pVM, idCpu);
            rc = hmR0VmxAllocVmcsInfo(pVCpu, &pVCpu->hmr0.s.vmx.VmcsInfo, false /* fIsNstGstVmcs */);

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
            /* Allocate the nested-guest VMCS structures, when the VMX feature is exposed to the guest. */
            if (pVM->cpum.ro.GuestFeatures.fVmx && RT_SUCCESS(rc))
                rc = hmR0VmxAllocVmcsInfo(pVCpu, &pVCpu->hmr0.s.vmx.VmcsInfoNstGst, true /* fIsNstGstVmcs */);
#endif
        }
        if (RT_SUCCESS(rc))
            return VINF_SUCCESS;
    }
    hmR0VmxStructsFree(pVM);
    return rc;
}


/**
 * Pre-initializes non-zero fields in VMX structures that will be allocated.
 *
 * @param   pVM     The cross context VM structure.
 */
static void hmR0VmxStructsInit(PVMCC pVM)
{
    /* Paranoia. */
    Assert(pVM->hmr0.s.vmx.pbApicAccess == NULL);
#ifdef VBOX_WITH_CRASHDUMP_MAGIC
    Assert(pVM->hmr0.s.vmx.pbScratch == NULL);
#endif

    /*
     * Initialize members up-front so we can cleanup en masse on allocation failures.
     */
#ifdef VBOX_WITH_CRASHDUMP_MAGIC
    pVM->hmr0.s.vmx.HCPhysScratch       = NIL_RTHCPHYS;
#endif
    pVM->hmr0.s.vmx.HCPhysApicAccess    = NIL_RTHCPHYS;
    pVM->hmr0.s.vmx.HCPhysVmreadBitmap  = NIL_RTHCPHYS;
    pVM->hmr0.s.vmx.HCPhysVmwriteBitmap = NIL_RTHCPHYS;
    for (VMCPUID idCpu = 0; idCpu < pVM->cCpus; idCpu++)
    {
        PVMCPUCC pVCpu = VMCC_GET_CPU(pVM, idCpu);
        hmR0VmxVmcsInfoInit(&pVCpu->hmr0.s.vmx.VmcsInfo,       &pVCpu->hm.s.vmx.VmcsInfo);
        hmR0VmxVmcsInfoInit(&pVCpu->hmr0.s.vmx.VmcsInfoNstGst, &pVCpu->hm.s.vmx.VmcsInfoNstGst);
    }
}

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
/**
 * Returns whether an MSR at the given MSR-bitmap offset is intercepted or not.
 *
 * @returns @c true if the MSR is intercepted, @c false otherwise.
 * @param   pbMsrBitmap     The MSR bitmap.
 * @param   offMsr          The MSR byte offset.
 * @param   iBit            The bit offset from the byte offset.
 */
DECLINLINE(bool) hmR0VmxIsMsrBitSet(uint8_t const *pbMsrBitmap, uint16_t offMsr, int32_t iBit)
{
    Assert(offMsr + (iBit >> 3) <= X86_PAGE_4K_SIZE);
    return ASMBitTest(pbMsrBitmap + offMsr, iBit);
}
#endif

/**
 * Sets the permission bits for the specified MSR in the given MSR bitmap.
 *
 * If the passed VMCS is a nested-guest VMCS, this function ensures that the
 * read/write intercept is cleared from the MSR bitmap used for hardware-assisted
 * VMX execution of the nested-guest, only if nested-guest is also not intercepting
 * the read/write access of this MSR.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmcsInfo       The VMCS info. object.
 * @param   fIsNstGstVmcs   Whether this is a nested-guest VMCS.
 * @param   idMsr           The MSR value.
 * @param   fMsrpm          The MSR permissions (see VMXMSRPM_XXX). This must
 *                          include both a read -and- a write permission!
 *
 * @sa      CPUMGetVmxMsrPermission.
 * @remarks Can be called with interrupts disabled.
 */
static void hmR0VmxSetMsrPermission(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo, bool fIsNstGstVmcs, uint32_t idMsr, uint32_t fMsrpm)
{
    uint8_t *pbMsrBitmap = (uint8_t *)pVmcsInfo->pvMsrBitmap;
    Assert(pbMsrBitmap);
    Assert(VMXMSRPM_IS_FLAG_VALID(fMsrpm));

    /*
     * MSR-bitmap Layout:
     *   Byte index            MSR range            Interpreted as
     * 0x000 - 0x3ff    0x00000000 - 0x00001fff    Low MSR read bits.
     * 0x400 - 0x7ff    0xc0000000 - 0xc0001fff    High MSR read bits.
     * 0x800 - 0xbff    0x00000000 - 0x00001fff    Low MSR write bits.
     * 0xc00 - 0xfff    0xc0000000 - 0xc0001fff    High MSR write bits.
     *
     * A bit corresponding to an MSR within the above range causes a VM-exit
     * if the bit is 1 on executions of RDMSR/WRMSR.  If an MSR falls out of
     * the MSR range, it always cause a VM-exit.
     *
     * See Intel spec. 24.6.9 "MSR-Bitmap Address".
     */
    uint16_t const offBitmapRead  = 0;
    uint16_t const offBitmapWrite = 0x800;
    uint16_t       offMsr;
    int32_t        iBit;
    if (idMsr <= UINT32_C(0x00001fff))
    {
        offMsr = 0;
        iBit   = idMsr;
    }
    else if (idMsr - UINT32_C(0xc0000000) <= UINT32_C(0x00001fff))
    {
        offMsr = 0x400;
        iBit   = idMsr - UINT32_C(0xc0000000);
    }
    else
        AssertMsgFailedReturnVoid(("Invalid MSR %#RX32\n", idMsr));

    /*
     * Set the MSR read permission.
     */
    uint16_t const offMsrRead = offBitmapRead + offMsr;
    Assert(offMsrRead + (iBit >> 3) < offBitmapWrite);
    if (fMsrpm & VMXMSRPM_ALLOW_RD)
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        bool const fClear = !fIsNstGstVmcs ? true
                          : !hmR0VmxIsMsrBitSet(pVCpu->cpum.GstCtx.hwvirt.vmx.abMsrBitmap, offMsrRead, iBit);
#else
        RT_NOREF2(pVCpu, fIsNstGstVmcs);
        bool const fClear = true;
#endif
        if (fClear)
            ASMBitClear(pbMsrBitmap + offMsrRead, iBit);
    }
    else
        ASMBitSet(pbMsrBitmap + offMsrRead, iBit);

    /*
     * Set the MSR write permission.
     */
    uint16_t const offMsrWrite = offBitmapWrite + offMsr;
    Assert(offMsrWrite + (iBit >> 3) < X86_PAGE_4K_SIZE);
    if (fMsrpm & VMXMSRPM_ALLOW_WR)
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        bool const fClear = !fIsNstGstVmcs ? true
                          : !hmR0VmxIsMsrBitSet(pVCpu->cpum.GstCtx.hwvirt.vmx.abMsrBitmap, offMsrWrite, iBit);
#else
        RT_NOREF2(pVCpu, fIsNstGstVmcs);
        bool const fClear = true;
#endif
        if (fClear)
            ASMBitClear(pbMsrBitmap + offMsrWrite, iBit);
    }
    else
        ASMBitSet(pbMsrBitmap + offMsrWrite, iBit);
}


/**
 * Updates the VMCS with the number of effective MSRs in the auto-load/store MSR
 * area.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 * @param   cMsrs       The number of MSRs.
 */
static int hmR0VmxSetAutoLoadStoreMsrCount(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo, uint32_t cMsrs)
{
    /* Shouldn't ever happen but there -is- a number. We're well within the recommended 512. */
    uint32_t const cMaxSupportedMsrs = VMX_MISC_MAX_MSRS(g_HmMsrs.u.vmx.u64Misc);
    if (RT_LIKELY(cMsrs < cMaxSupportedMsrs))
    {
        /* Commit the MSR counts to the VMCS and update the cache. */
        if (pVmcsInfo->cEntryMsrLoad != cMsrs)
        {
            int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_ENTRY_MSR_LOAD_COUNT, cMsrs);   AssertRC(rc);
            rc     = VMXWriteVmcs32(VMX_VMCS32_CTRL_EXIT_MSR_STORE_COUNT, cMsrs);   AssertRC(rc);
            rc     = VMXWriteVmcs32(VMX_VMCS32_CTRL_EXIT_MSR_LOAD_COUNT,  cMsrs);   AssertRC(rc);
            pVmcsInfo->cEntryMsrLoad = cMsrs;
            pVmcsInfo->cExitMsrStore = cMsrs;
            pVmcsInfo->cExitMsrLoad  = cMsrs;
        }
        return VINF_SUCCESS;
    }

    LogRel(("Auto-load/store MSR count exceeded! cMsrs=%u MaxSupported=%u\n", cMsrs, cMaxSupportedMsrs));
    pVCpu->hm.s.u32HMError = VMX_UFC_INSUFFICIENT_GUEST_MSR_STORAGE;
    return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
}


/**
 * Adds a new (or updates the value of an existing) guest/host MSR
 * pair to be swapped during the world-switch as part of the
 * auto-load/store MSR area in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   idMsr           The MSR.
 * @param   uGuestMsrValue  Value of the guest MSR.
 * @param   fSetReadWrite   Whether to set the guest read/write access of this
 *                          MSR (thus not causing a VM-exit).
 * @param   fUpdateHostMsr  Whether to update the value of the host MSR if
 *                          necessary.
 */
static int hmR0VmxAddAutoLoadStoreMsr(PVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient, uint32_t idMsr, uint64_t uGuestMsrValue,
                                      bool fSetReadWrite, bool fUpdateHostMsr)
{
    PVMXVMCSINFO  pVmcsInfo     = pVmxTransient->pVmcsInfo;
    bool const      fIsNstGstVmcs = pVmxTransient->fIsNestedGuest;
    PVMXAUTOMSR     pGuestMsrLoad = (PVMXAUTOMSR)pVmcsInfo->pvGuestMsrLoad;
    uint32_t        cMsrs         = pVmcsInfo->cEntryMsrLoad;
    uint32_t        i;

    /* Paranoia. */
    Assert(pGuestMsrLoad);

#ifndef DEBUG_bird
    LogFlowFunc(("pVCpu=%p idMsr=%#RX32 uGuestMsrValue=%#RX64\n", pVCpu, idMsr, uGuestMsrValue));
#endif

    /* Check if the MSR already exists in the VM-entry MSR-load area. */
    for (i = 0; i < cMsrs; i++)
    {
        if (pGuestMsrLoad[i].u32Msr == idMsr)
            break;
    }

    bool fAdded = false;
    if (i == cMsrs)
    {
        /* The MSR does not exist, bump the MSR count to make room for the new MSR. */
        ++cMsrs;
        int rc = hmR0VmxSetAutoLoadStoreMsrCount(pVCpu, pVmcsInfo, cMsrs);
        AssertMsgRCReturn(rc, ("Insufficient space to add MSR to VM-entry MSR-load/store area %u\n", idMsr), rc);

        /* Set the guest to read/write this MSR without causing VM-exits. */
        if (   fSetReadWrite
            && (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS))
            hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, fIsNstGstVmcs, idMsr, VMXMSRPM_ALLOW_RD_WR);

        Log4Func(("Added MSR %#RX32, cMsrs=%u\n", idMsr, cMsrs));
        fAdded = true;
    }

    /* Update the MSR value for the newly added or already existing MSR. */
    pGuestMsrLoad[i].u32Msr   = idMsr;
    pGuestMsrLoad[i].u64Value = uGuestMsrValue;

    /* Create the corresponding slot in the VM-exit MSR-store area if we use a different page. */
    if (hmR0VmxIsSeparateExitMsrStoreAreaVmcs(pVmcsInfo))
    {
        PVMXAUTOMSR pGuestMsrStore = (PVMXAUTOMSR)pVmcsInfo->pvGuestMsrStore;
        pGuestMsrStore[i].u32Msr   = idMsr;
        pGuestMsrStore[i].u64Value = uGuestMsrValue;
    }

    /* Update the corresponding slot in the host MSR area. */
    PVMXAUTOMSR pHostMsr = (PVMXAUTOMSR)pVmcsInfo->pvHostMsrLoad;
    Assert(pHostMsr != pVmcsInfo->pvGuestMsrLoad);
    Assert(pHostMsr != pVmcsInfo->pvGuestMsrStore);
    pHostMsr[i].u32Msr = idMsr;

    /*
     * Only if the caller requests to update the host MSR value AND we've newly added the
     * MSR to the host MSR area do we actually update the value. Otherwise, it will be
     * updated by hmR0VmxUpdateAutoLoadHostMsrs().
     *
     * We do this for performance reasons since reading MSRs may be quite expensive.
     */
    if (fAdded)
    {
        if (fUpdateHostMsr)
        {
            Assert(!VMMRZCallRing3IsEnabled(pVCpu));
            Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
            pHostMsr[i].u64Value = ASMRdMsr(idMsr);
        }
        else
        {
            /* Someone else can do the work. */
            pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs = false;
        }
    }
    return VINF_SUCCESS;
}


/**
 * Removes a guest/host MSR pair to be swapped during the world-switch from the
 * auto-load/store MSR area in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   idMsr           The MSR.
 */
static int hmR0VmxRemoveAutoLoadStoreMsr(PVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient, uint32_t idMsr)
{
    PVMXVMCSINFO  pVmcsInfo     = pVmxTransient->pVmcsInfo;
    bool const      fIsNstGstVmcs = pVmxTransient->fIsNestedGuest;
    PVMXAUTOMSR     pGuestMsrLoad = (PVMXAUTOMSR)pVmcsInfo->pvGuestMsrLoad;
    uint32_t        cMsrs         = pVmcsInfo->cEntryMsrLoad;

#ifndef DEBUG_bird
    LogFlowFunc(("pVCpu=%p idMsr=%#RX32\n", pVCpu, idMsr));
#endif

    for (uint32_t i = 0; i < cMsrs; i++)
    {
        /* Find the MSR. */
        if (pGuestMsrLoad[i].u32Msr == idMsr)
        {
            /*
             * If it's the last MSR, we only need to reduce the MSR count.
             * If it's -not- the last MSR, copy the last MSR in place of it and reduce the MSR count.
             */
            if (i < cMsrs - 1)
            {
                /* Remove it from the VM-entry MSR-load area. */
                pGuestMsrLoad[i].u32Msr   = pGuestMsrLoad[cMsrs - 1].u32Msr;
                pGuestMsrLoad[i].u64Value = pGuestMsrLoad[cMsrs - 1].u64Value;

                /* Remove it from the VM-exit MSR-store area if it's in a different page. */
                if (hmR0VmxIsSeparateExitMsrStoreAreaVmcs(pVmcsInfo))
                {
                    PVMXAUTOMSR pGuestMsrStore = (PVMXAUTOMSR)pVmcsInfo->pvGuestMsrStore;
                    Assert(pGuestMsrStore[i].u32Msr == idMsr);
                    pGuestMsrStore[i].u32Msr   = pGuestMsrStore[cMsrs - 1].u32Msr;
                    pGuestMsrStore[i].u64Value = pGuestMsrStore[cMsrs - 1].u64Value;
                }

                /* Remove it from the VM-exit MSR-load area. */
                PVMXAUTOMSR pHostMsr = (PVMXAUTOMSR)pVmcsInfo->pvHostMsrLoad;
                Assert(pHostMsr[i].u32Msr == idMsr);
                pHostMsr[i].u32Msr   = pHostMsr[cMsrs - 1].u32Msr;
                pHostMsr[i].u64Value = pHostMsr[cMsrs - 1].u64Value;
            }

            /* Reduce the count to reflect the removed MSR and bail. */
            --cMsrs;
            break;
        }
    }

    /* Update the VMCS if the count changed (meaning the MSR was found and removed). */
    if (cMsrs != pVmcsInfo->cEntryMsrLoad)
    {
        int rc = hmR0VmxSetAutoLoadStoreMsrCount(pVCpu, pVmcsInfo, cMsrs);
        AssertRCReturn(rc, rc);

        /* We're no longer swapping MSRs during the world-switch, intercept guest read/writes to them. */
        if (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS)
            hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, fIsNstGstVmcs, idMsr, VMXMSRPM_EXIT_RD | VMXMSRPM_EXIT_WR);

        Log4Func(("Removed MSR %#RX32, cMsrs=%u\n", idMsr, cMsrs));
        return VINF_SUCCESS;
    }

    return VERR_NOT_FOUND;
}


/**
 * Updates the value of all host MSRs in the VM-exit MSR-load area.
 *
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxUpdateAutoLoadHostMsrs(PCVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo)
{
    RT_NOREF(pVCpu);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    PVMXAUTOMSR pHostMsrLoad = (PVMXAUTOMSR)pVmcsInfo->pvHostMsrLoad;
    uint32_t const cMsrs     = pVmcsInfo->cExitMsrLoad;
    Assert(pHostMsrLoad);
    Assert(sizeof(*pHostMsrLoad) * cMsrs <= X86_PAGE_4K_SIZE);
    LogFlowFunc(("pVCpu=%p cMsrs=%u\n", pVCpu, cMsrs));
    for (uint32_t i = 0; i < cMsrs; i++)
    {
        /*
         * Performance hack for the host EFER MSR. We use the cached value rather than re-read it.
         * Strict builds will catch mismatches in hmR0VmxCheckAutoLoadStoreMsrs(). See @bugref{7368}.
         */
        if (pHostMsrLoad[i].u32Msr == MSR_K6_EFER)
            pHostMsrLoad[i].u64Value = g_uHmVmxHostMsrEfer;
        else
            pHostMsrLoad[i].u64Value = ASMRdMsr(pHostMsrLoad[i].u32Msr);
    }
}


/**
 * Saves a set of host MSRs to allow read/write passthru access to the guest and
 * perform lazy restoration of the host MSRs while leaving VT-x.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxLazySaveHostMsrs(PVMCPUCC pVCpu)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /*
     * Note: If you're adding MSRs here, make sure to update the MSR-bitmap accesses in hmR0VmxSetupVmcsProcCtls().
     */
    if (!(pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_SAVED_HOST))
    {
        Assert(!(pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST));  /* Guest MSRs better not be loaded now. */
        if (pVCpu->CTX_SUFF(pVM)->hmr0.s.fAllow64BitGuests)
        {
            pVCpu->hmr0.s.vmx.u64HostMsrLStar        = ASMRdMsr(MSR_K8_LSTAR);
            pVCpu->hmr0.s.vmx.u64HostMsrStar         = ASMRdMsr(MSR_K6_STAR);
            pVCpu->hmr0.s.vmx.u64HostMsrSfMask       = ASMRdMsr(MSR_K8_SF_MASK);
            pVCpu->hmr0.s.vmx.u64HostMsrKernelGsBase = ASMRdMsr(MSR_K8_KERNEL_GS_BASE);
        }
        pVCpu->hmr0.s.vmx.fLazyMsrs |= VMX_LAZY_MSRS_SAVED_HOST;
    }
}


#ifdef VBOX_STRICT

/**
 * Verifies that our cached host EFER MSR value has not changed since we cached it.
 *
 * @param   pVmcsInfo   The VMCS info. object.
 */
static void hmR0VmxCheckHostEferMsr(PCVMXVMCSINFO pVmcsInfo)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    if (pVmcsInfo->u32ExitCtls & VMX_EXIT_CTLS_LOAD_EFER_MSR)
    {
        uint64_t const uHostEferMsr      = ASMRdMsr(MSR_K6_EFER);
        uint64_t const uHostEferMsrCache = g_uHmVmxHostMsrEfer;
        uint64_t       uVmcsEferMsrVmcs;
        int rc = VMXReadVmcs64(VMX_VMCS64_HOST_EFER_FULL, &uVmcsEferMsrVmcs);
        AssertRC(rc);

        AssertMsgReturnVoid(uHostEferMsr == uVmcsEferMsrVmcs,
                            ("EFER Host/VMCS mismatch! host=%#RX64 vmcs=%#RX64\n", uHostEferMsr, uVmcsEferMsrVmcs));
        AssertMsgReturnVoid(uHostEferMsr == uHostEferMsrCache,
                            ("EFER Host/Cache mismatch! host=%#RX64 cache=%#RX64\n", uHostEferMsr, uHostEferMsrCache));
    }
}


/**
 * Verifies whether the guest/host MSR pairs in the auto-load/store area in the
 * VMCS are correct.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmcsInfo       The VMCS info. object.
 * @param   fIsNstGstVmcs   Whether this is a nested-guest VMCS.
 */
static void hmR0VmxCheckAutoLoadStoreMsrs(PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo, bool fIsNstGstVmcs)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /* Read the various MSR-area counts from the VMCS. */
    uint32_t cEntryLoadMsrs;
    uint32_t cExitStoreMsrs;
    uint32_t cExitLoadMsrs;
    int rc = VMXReadVmcs32(VMX_VMCS32_CTRL_ENTRY_MSR_LOAD_COUNT, &cEntryLoadMsrs);  AssertRC(rc);
    rc     = VMXReadVmcs32(VMX_VMCS32_CTRL_EXIT_MSR_STORE_COUNT, &cExitStoreMsrs);  AssertRC(rc);
    rc     = VMXReadVmcs32(VMX_VMCS32_CTRL_EXIT_MSR_LOAD_COUNT,  &cExitLoadMsrs);   AssertRC(rc);

    /* Verify all the MSR counts are the same. */
    Assert(cEntryLoadMsrs == cExitStoreMsrs);
    Assert(cExitStoreMsrs == cExitLoadMsrs);
    uint32_t const cMsrs = cExitLoadMsrs;

    /* Verify the MSR counts do not exceed the maximum count supported by the hardware. */
    Assert(cMsrs < VMX_MISC_MAX_MSRS(g_HmMsrs.u.vmx.u64Misc));

    /* Verify the MSR counts are within the allocated page size. */
    Assert(sizeof(VMXAUTOMSR) * cMsrs <= X86_PAGE_4K_SIZE);

    /* Verify the relevant contents of the MSR areas match. */
    PCVMXAUTOMSR pGuestMsrLoad  = (PCVMXAUTOMSR)pVmcsInfo->pvGuestMsrLoad;
    PCVMXAUTOMSR pGuestMsrStore = (PCVMXAUTOMSR)pVmcsInfo->pvGuestMsrStore;
    PCVMXAUTOMSR pHostMsrLoad   = (PCVMXAUTOMSR)pVmcsInfo->pvHostMsrLoad;
    bool const   fSeparateExitMsrStorePage = hmR0VmxIsSeparateExitMsrStoreAreaVmcs(pVmcsInfo);
    for (uint32_t i = 0; i < cMsrs; i++)
    {
        /* Verify that the MSRs are paired properly and that the host MSR has the correct value. */
        if (fSeparateExitMsrStorePage)
        {
            AssertMsgReturnVoid(pGuestMsrLoad->u32Msr == pGuestMsrStore->u32Msr,
                                ("GuestMsrLoad=%#RX32 GuestMsrStore=%#RX32 cMsrs=%u\n",
                                 pGuestMsrLoad->u32Msr, pGuestMsrStore->u32Msr, cMsrs));
        }

        AssertMsgReturnVoid(pHostMsrLoad->u32Msr == pGuestMsrLoad->u32Msr,
                            ("HostMsrLoad=%#RX32 GuestMsrLoad=%#RX32 cMsrs=%u\n",
                             pHostMsrLoad->u32Msr, pGuestMsrLoad->u32Msr, cMsrs));

        uint64_t const u64HostMsr = ASMRdMsr(pHostMsrLoad->u32Msr);
        AssertMsgReturnVoid(pHostMsrLoad->u64Value == u64HostMsr,
                            ("u32Msr=%#RX32 VMCS Value=%#RX64 ASMRdMsr=%#RX64 cMsrs=%u\n",
                             pHostMsrLoad->u32Msr, pHostMsrLoad->u64Value, u64HostMsr, cMsrs));

        /* Verify that cached host EFER MSR matches what's loaded on the CPU. */
        bool const fIsEferMsr = RT_BOOL(pHostMsrLoad->u32Msr == MSR_K6_EFER);
        AssertMsgReturnVoid(!fIsEferMsr || u64HostMsr == g_uHmVmxHostMsrEfer,
                            ("Cached=%#RX64 ASMRdMsr=%#RX64 cMsrs=%u\n", g_uHmVmxHostMsrEfer, u64HostMsr, cMsrs));

        /* Verify that the accesses are as expected in the MSR bitmap for auto-load/store MSRs. */
        if (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS)
        {
            uint32_t const fMsrpm = CPUMGetVmxMsrPermission(pVmcsInfo->pvMsrBitmap, pGuestMsrLoad->u32Msr);
            if (fIsEferMsr)
            {
                AssertMsgReturnVoid((fMsrpm & VMXMSRPM_EXIT_RD), ("Passthru read for EFER MSR!?\n"));
                AssertMsgReturnVoid((fMsrpm & VMXMSRPM_EXIT_WR), ("Passthru write for EFER MSR!?\n"));
            }
            else
            {
                /* Verify LBR MSRs (used only for debugging) are intercepted. We don't passthru these MSRs to the guest yet. */
                PCVMCC pVM = pVCpu->CTX_SUFF(pVM);
                if (   pVM->hmr0.s.vmx.fLbr
                    && (   hmR0VmxIsLbrBranchFromMsr(pVM, pGuestMsrLoad->u32Msr, NULL /* pidxMsr */)
                        || hmR0VmxIsLbrBranchToMsr(pVM, pGuestMsrLoad->u32Msr, NULL /* pidxMsr */)
                        || pGuestMsrLoad->u32Msr == pVM->hmr0.s.vmx.idLbrTosMsr))
                {
                    AssertMsgReturnVoid((fMsrpm & VMXMSRPM_MASK) == VMXMSRPM_EXIT_RD_WR,
                                        ("u32Msr=%#RX32 cMsrs=%u Passthru read/write for LBR MSRs!\n",
                                         pGuestMsrLoad->u32Msr, cMsrs));
                }
                else if (!fIsNstGstVmcs)
                {
                    AssertMsgReturnVoid((fMsrpm & VMXMSRPM_MASK) == VMXMSRPM_ALLOW_RD_WR,
                                        ("u32Msr=%#RX32 cMsrs=%u No passthru read/write!\n", pGuestMsrLoad->u32Msr, cMsrs));
                }
                else
                {
                    /*
                     * A nested-guest VMCS must -also- allow read/write passthrough for the MSR for us to
                     * execute a nested-guest with MSR passthrough.
                     *
                     * Check if the nested-guest MSR bitmap allows passthrough, and if so, assert that we
                     * allow passthrough too.
                     */
                    void const *pvMsrBitmapNstGst = pVCpu->cpum.GstCtx.hwvirt.vmx.abMsrBitmap;
                    Assert(pvMsrBitmapNstGst);
                    uint32_t const fMsrpmNstGst = CPUMGetVmxMsrPermission(pvMsrBitmapNstGst, pGuestMsrLoad->u32Msr);
                    AssertMsgReturnVoid(fMsrpm == fMsrpmNstGst,
                                        ("u32Msr=%#RX32 cMsrs=%u Permission mismatch fMsrpm=%#x fMsrpmNstGst=%#x!\n",
                                         pGuestMsrLoad->u32Msr, cMsrs, fMsrpm, fMsrpmNstGst));
                }
            }
        }

        /* Move to the next MSR. */
        pHostMsrLoad++;
        pGuestMsrLoad++;
        pGuestMsrStore++;
    }
}

#endif /* VBOX_STRICT */

/**
 * Flushes the TLB using EPT.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure of the calling
 *                          EMT.  Can be NULL depending on @a enmTlbFlush.
 * @param   pVmcsInfo       The VMCS info. object. Can be NULL depending on @a
 *                          enmTlbFlush.
 * @param   enmTlbFlush     Type of flush.
 *
 * @remarks Caller is responsible for making sure this function is called only
 *          when NestedPaging is supported and providing @a enmTlbFlush that is
 *          supported by the CPU.
 * @remarks Can be called with interrupts disabled.
 */
static void hmR0VmxFlushEpt(PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo, VMXTLBFLUSHEPT enmTlbFlush)
{
    uint64_t au64Descriptor[2];
    if (enmTlbFlush == VMXTLBFLUSHEPT_ALL_CONTEXTS)
        au64Descriptor[0] = 0;
    else
    {
        Assert(pVCpu);
        Assert(pVmcsInfo);
        au64Descriptor[0] = pVmcsInfo->HCPhysEPTP;
    }
    au64Descriptor[1] = 0;                       /* MBZ. Intel spec. 33.3 "VMX Instructions" */

    int rc = VMXR0InvEPT(enmTlbFlush, &au64Descriptor[0]);
    AssertMsg(rc == VINF_SUCCESS, ("VMXR0InvEPT %#x %#RHp failed. rc=%Rrc\n", enmTlbFlush, au64Descriptor[0], rc));

    if (   RT_SUCCESS(rc)
        && pVCpu)
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushNestedPaging);
}


/**
 * Flushes the TLB using VPID.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure of the calling
 *                          EMT.  Can be NULL depending on @a enmTlbFlush.
 * @param   enmTlbFlush     Type of flush.
 * @param   GCPtr           Virtual address of the page to flush (can be 0 depending
 *                          on @a enmTlbFlush).
 *
 * @remarks Can be called with interrupts disabled.
 */
static void hmR0VmxFlushVpid(PVMCPUCC pVCpu, VMXTLBFLUSHVPID enmTlbFlush, RTGCPTR GCPtr)
{
    Assert(pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fVpid);

    uint64_t au64Descriptor[2];
    if (enmTlbFlush == VMXTLBFLUSHVPID_ALL_CONTEXTS)
    {
        au64Descriptor[0] = 0;
        au64Descriptor[1] = 0;
    }
    else
    {
        AssertPtr(pVCpu);
        AssertMsg(pVCpu->hmr0.s.uCurrentAsid != 0, ("VMXR0InvVPID: invalid ASID %lu\n", pVCpu->hmr0.s.uCurrentAsid));
        AssertMsg(pVCpu->hmr0.s.uCurrentAsid <= UINT16_MAX, ("VMXR0InvVPID: invalid ASID %lu\n", pVCpu->hmr0.s.uCurrentAsid));
        au64Descriptor[0] = pVCpu->hmr0.s.uCurrentAsid;
        au64Descriptor[1] = GCPtr;
    }

    int rc = VMXR0InvVPID(enmTlbFlush, &au64Descriptor[0]);
    AssertMsg(rc == VINF_SUCCESS,
              ("VMXR0InvVPID %#x %u %RGv failed with %Rrc\n", enmTlbFlush, pVCpu ? pVCpu->hmr0.s.uCurrentAsid : 0, GCPtr, rc));

    if (   RT_SUCCESS(rc)
        && pVCpu)
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushAsid);
    NOREF(rc);
}


/**
 * Invalidates a guest page by guest virtual address. Only relevant for EPT/VPID,
 * otherwise there is nothing really to invalidate.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 * @param   GCVirt  Guest virtual address of the page to invalidate.
 */
VMMR0DECL(int) VMXR0InvalidatePage(PVMCPUCC pVCpu, RTGCPTR GCVirt)
{
    AssertPtr(pVCpu);
    LogFlowFunc(("pVCpu=%p GCVirt=%RGv\n", pVCpu, GCVirt));

    if (!VMCPU_FF_IS_SET(pVCpu, VMCPU_FF_TLB_FLUSH))
    {
        /*
         * We must invalidate the guest TLB entry in either case, we cannot ignore it even for
         * the EPT case. See @bugref{6043} and @bugref{6177}.
         *
         * Set the VMCPU_FF_TLB_FLUSH force flag and flush before VM-entry in hmR0VmxFlushTLB*()
         * as this function maybe called in a loop with individual addresses.
         */
        PVMCC pVM = pVCpu->CTX_SUFF(pVM);
        if (pVM->hmr0.s.vmx.fVpid)
        {
            if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID_INDIV_ADDR)
            {
                hmR0VmxFlushVpid(pVCpu, VMXTLBFLUSHVPID_INDIV_ADDR, GCVirt);
                STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbInvlpgVirt);
            }
            else
                VMCPU_FF_SET(pVCpu, VMCPU_FF_TLB_FLUSH);
        }
        else if (pVM->hmr0.s.fNestedPaging)
            VMCPU_FF_SET(pVCpu, VMCPU_FF_TLB_FLUSH);
    }

    return VINF_SUCCESS;
}


/**
 * Dummy placeholder for tagged-TLB flush handling before VM-entry. Used in the
 * case where neither EPT nor VPID is supported by the CPU.
 *
 * @param   pHostCpu    The HM physical-CPU structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 *
 * @remarks Called with interrupts disabled.
 */
static void hmR0VmxFlushTaggedTlbNone(PHMPHYSCPU pHostCpu, PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);
    AssertPtr(pHostCpu);

    VMCPU_FF_CLEAR(pVCpu, VMCPU_FF_TLB_FLUSH);

    Assert(pHostCpu->idCpu != NIL_RTCPUID);
    pVCpu->hmr0.s.idLastCpu     = pHostCpu->idCpu;
    pVCpu->hmr0.s.cTlbFlushes   = pHostCpu->cTlbFlushes;
    pVCpu->hmr0.s.fForceTLBFlush  = false;
    return;
}


/**
 * Flushes the tagged-TLB entries for EPT+VPID CPUs as necessary.
 *
 * @param   pHostCpu    The HM physical-CPU structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 *
 * @remarks  All references to "ASID" in this function pertains to "VPID" in Intel's
 *           nomenclature. The reason is, to avoid confusion in compare statements
 *           since the host-CPU copies are named "ASID".
 *
 * @remarks  Called with interrupts disabled.
 */
static void hmR0VmxFlushTaggedTlbBoth(PHMPHYSCPU pHostCpu, PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo)
{
#ifdef VBOX_WITH_STATISTICS
    bool fTlbFlushed = false;
# define HMVMX_SET_TAGGED_TLB_FLUSHED()       do { fTlbFlushed = true; } while (0)
# define HMVMX_UPDATE_FLUSH_SKIPPED_STAT()    do { \
                                                if (!fTlbFlushed) \
                                                    STAM_COUNTER_INC(&pVCpu->hm.s.StatNoFlushTlbWorldSwitch); \
                                              } while (0)
#else
# define HMVMX_SET_TAGGED_TLB_FLUSHED()       do { } while (0)
# define HMVMX_UPDATE_FLUSH_SKIPPED_STAT()    do { } while (0)
#endif

    AssertPtr(pVCpu);
    AssertPtr(pHostCpu);
    Assert(pHostCpu->idCpu != NIL_RTCPUID);

    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    AssertMsg(pVM->hmr0.s.fNestedPaging && pVM->hmr0.s.vmx.fVpid,
              ("hmR0VmxFlushTaggedTlbBoth cannot be invoked unless NestedPaging & VPID are enabled."
               "fNestedPaging=%RTbool fVpid=%RTbool", pVM->hmr0.s.fNestedPaging, pVM->hmr0.s.vmx.fVpid));

    /*
     * Force a TLB flush for the first world-switch if the current CPU differs from the one we
     * ran on last. If the TLB flush count changed, another VM (VCPU rather) has hit the ASID
     * limit while flushing the TLB or the host CPU is online after a suspend/resume, so we
     * cannot reuse the current ASID anymore.
     */
    if (   pVCpu->hmr0.s.idLastCpu   != pHostCpu->idCpu
        || pVCpu->hmr0.s.cTlbFlushes != pHostCpu->cTlbFlushes)
    {
        ++pHostCpu->uCurrentAsid;
        if (pHostCpu->uCurrentAsid >= g_uHmMaxAsid)
        {
            pHostCpu->uCurrentAsid = 1;            /* Wraparound to 1; host uses 0. */
            pHostCpu->cTlbFlushes++;               /* All VCPUs that run on this host CPU must use a new VPID. */
            pHostCpu->fFlushAsidBeforeUse = true;  /* All VCPUs that run on this host CPU must flush their new VPID before use. */
        }

        pVCpu->hmr0.s.uCurrentAsid = pHostCpu->uCurrentAsid;
        pVCpu->hmr0.s.idLastCpu    = pHostCpu->idCpu;
        pVCpu->hmr0.s.cTlbFlushes  = pHostCpu->cTlbFlushes;

        /*
         * Flush by EPT when we get rescheduled to a new host CPU to ensure EPT-only tagged mappings are also
         * invalidated. We don't need to flush-by-VPID here as flushing by EPT covers it. See @bugref{6568}.
         */
        hmR0VmxFlushEpt(pVCpu, pVmcsInfo, pVM->hmr0.s.vmx.enmTlbFlushEpt);
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbWorldSwitch);
        HMVMX_SET_TAGGED_TLB_FLUSHED();
        VMCPU_FF_CLEAR(pVCpu, VMCPU_FF_TLB_FLUSH);
    }
    else if (VMCPU_FF_TEST_AND_CLEAR(pVCpu, VMCPU_FF_TLB_FLUSH))    /* Check for explicit TLB flushes. */
    {
        /*
         * Changes to the EPT paging structure by VMM requires flushing-by-EPT as the CPU
         * creates guest-physical (ie. only EPT-tagged) mappings while traversing the EPT
         * tables when EPT is in use. Flushing-by-VPID will only flush linear (only
         * VPID-tagged) and combined (EPT+VPID tagged) mappings but not guest-physical
         * mappings, see @bugref{6568}.
         *
         * See Intel spec. 28.3.2 "Creating and Using Cached Translation Information".
         */
        hmR0VmxFlushEpt(pVCpu, pVmcsInfo, pVM->hmr0.s.vmx.enmTlbFlushEpt);
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlb);
        HMVMX_SET_TAGGED_TLB_FLUSHED();
    }
    else if (pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb)
    {
        /*
         * The nested-guest specifies its own guest-physical address to use as the APIC-access
         * address which requires flushing the TLB of EPT cached structures.
         *
         * See Intel spec. 28.3.3.4 "Guidelines for Use of the INVEPT Instruction".
         */
        hmR0VmxFlushEpt(pVCpu, pVmcsInfo, pVM->hmr0.s.vmx.enmTlbFlushEpt);
        pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb = false;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbNstGst);
        HMVMX_SET_TAGGED_TLB_FLUSHED();
    }


    pVCpu->hmr0.s.fForceTLBFlush = false;
    HMVMX_UPDATE_FLUSH_SKIPPED_STAT();

    Assert(pVCpu->hmr0.s.idLastCpu == pHostCpu->idCpu);
    Assert(pVCpu->hmr0.s.cTlbFlushes == pHostCpu->cTlbFlushes);
    AssertMsg(pVCpu->hmr0.s.cTlbFlushes == pHostCpu->cTlbFlushes,
              ("Flush count mismatch for cpu %d (%u vs %u)\n", pHostCpu->idCpu, pVCpu->hmr0.s.cTlbFlushes, pHostCpu->cTlbFlushes));
    AssertMsg(pHostCpu->uCurrentAsid >= 1 && pHostCpu->uCurrentAsid < g_uHmMaxAsid,
              ("Cpu[%u] uCurrentAsid=%u cTlbFlushes=%u pVCpu->idLastCpu=%u pVCpu->cTlbFlushes=%u\n", pHostCpu->idCpu,
               pHostCpu->uCurrentAsid, pHostCpu->cTlbFlushes, pVCpu->hmr0.s.idLastCpu, pVCpu->hmr0.s.cTlbFlushes));
    AssertMsg(pVCpu->hmr0.s.uCurrentAsid >= 1 && pVCpu->hmr0.s.uCurrentAsid < g_uHmMaxAsid,
              ("Cpu[%u] pVCpu->uCurrentAsid=%u\n", pHostCpu->idCpu, pVCpu->hmr0.s.uCurrentAsid));

    /* Update VMCS with the VPID. */
    int rc  = VMXWriteVmcs16(VMX_VMCS16_VPID, pVCpu->hmr0.s.uCurrentAsid);
    AssertRC(rc);

#undef HMVMX_SET_TAGGED_TLB_FLUSHED
}


/**
 * Flushes the tagged-TLB entries for EPT CPUs as necessary.
 *
 * @param   pHostCpu    The HM physical-CPU structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 *
 * @remarks Called with interrupts disabled.
 */
static void hmR0VmxFlushTaggedTlbEpt(PHMPHYSCPU pHostCpu, PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo)
{
    AssertPtr(pVCpu);
    AssertPtr(pHostCpu);
    Assert(pHostCpu->idCpu != NIL_RTCPUID);
    AssertMsg(pVCpu->CTX_SUFF(pVM)->hmr0.s.fNestedPaging, ("hmR0VmxFlushTaggedTlbEpt cannot be invoked without NestedPaging."));
    AssertMsg(!pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fVpid, ("hmR0VmxFlushTaggedTlbEpt cannot be invoked with VPID."));

    /*
     * Force a TLB flush for the first world-switch if the current CPU differs from the one we ran on last.
     * A change in the TLB flush count implies the host CPU is online after a suspend/resume.
     */
    if (   pVCpu->hmr0.s.idLastCpu   != pHostCpu->idCpu
        || pVCpu->hmr0.s.cTlbFlushes != pHostCpu->cTlbFlushes)
    {
        pVCpu->hmr0.s.fForceTLBFlush = true;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbWorldSwitch);
    }

    /* Check for explicit TLB flushes. */
    if (VMCPU_FF_TEST_AND_CLEAR(pVCpu, VMCPU_FF_TLB_FLUSH))
    {
        pVCpu->hmr0.s.fForceTLBFlush = true;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlb);
    }

    /* Check for TLB flushes while switching to/from a nested-guest. */
    if (pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb)
    {
        pVCpu->hmr0.s.fForceTLBFlush = true;
        pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb = false;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbNstGst);
    }

    pVCpu->hmr0.s.idLastCpu = pHostCpu->idCpu;
    pVCpu->hmr0.s.cTlbFlushes = pHostCpu->cTlbFlushes;

    if (pVCpu->hmr0.s.fForceTLBFlush)
    {
        hmR0VmxFlushEpt(pVCpu, pVmcsInfo, pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.enmTlbFlushEpt);
        pVCpu->hmr0.s.fForceTLBFlush = false;
    }
}


/**
 * Flushes the tagged-TLB entries for VPID CPUs as necessary.
 *
 * @param   pHostCpu    The HM physical-CPU structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 *
 * @remarks Called with interrupts disabled.
 */
static void hmR0VmxFlushTaggedTlbVpid(PHMPHYSCPU pHostCpu, PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);
    AssertPtr(pHostCpu);
    Assert(pHostCpu->idCpu != NIL_RTCPUID);
    AssertMsg(pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fVpid, ("hmR0VmxFlushTlbVpid cannot be invoked without VPID."));
    AssertMsg(!pVCpu->CTX_SUFF(pVM)->hmr0.s.fNestedPaging, ("hmR0VmxFlushTlbVpid cannot be invoked with NestedPaging"));

    /*
     * Force a TLB flush for the first world switch if the current CPU differs from the one we
     * ran on last. If the TLB flush count changed, another VM (VCPU rather) has hit the ASID
     * limit while flushing the TLB or the host CPU is online after a suspend/resume, so we
     * cannot reuse the current ASID anymore.
     */
    if (   pVCpu->hmr0.s.idLastCpu != pHostCpu->idCpu
        || pVCpu->hmr0.s.cTlbFlushes != pHostCpu->cTlbFlushes)
    {
        pVCpu->hmr0.s.fForceTLBFlush = true;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbWorldSwitch);
    }

    /* Check for explicit TLB flushes. */
    if (VMCPU_FF_TEST_AND_CLEAR(pVCpu, VMCPU_FF_TLB_FLUSH))
    {
        /*
         * If we ever support VPID flush combinations other than ALL or SINGLE-context (see
         * hmR0VmxSetupTaggedTlb()) we would need to explicitly flush in this case (add an
         * fExplicitFlush = true here and change the pHostCpu->fFlushAsidBeforeUse check below to
         * include fExplicitFlush's too) - an obscure corner case.
         */
        pVCpu->hmr0.s.fForceTLBFlush = true;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlb);
    }

    /* Check for TLB flushes while switching to/from a nested-guest. */
    if (pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb)
    {
        pVCpu->hmr0.s.fForceTLBFlush = true;
        pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb = false;
        STAM_COUNTER_INC(&pVCpu->hm.s.StatFlushTlbNstGst);
    }

    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    pVCpu->hmr0.s.idLastCpu = pHostCpu->idCpu;
    if (pVCpu->hmr0.s.fForceTLBFlush)
    {
        ++pHostCpu->uCurrentAsid;
        if (pHostCpu->uCurrentAsid >= g_uHmMaxAsid)
        {
            pHostCpu->uCurrentAsid        = 1;     /* Wraparound to 1; host uses 0 */
            pHostCpu->cTlbFlushes++;               /* All VCPUs that run on this host CPU must use a new VPID. */
            pHostCpu->fFlushAsidBeforeUse = true;  /* All VCPUs that run on this host CPU must flush their new VPID before use. */
        }

        pVCpu->hmr0.s.fForceTLBFlush = false;
        pVCpu->hmr0.s.cTlbFlushes    = pHostCpu->cTlbFlushes;
        pVCpu->hmr0.s.uCurrentAsid   = pHostCpu->uCurrentAsid;
        if (pHostCpu->fFlushAsidBeforeUse)
        {
            if (pVM->hmr0.s.vmx.enmTlbFlushVpid == VMXTLBFLUSHVPID_SINGLE_CONTEXT)
                hmR0VmxFlushVpid(pVCpu, VMXTLBFLUSHVPID_SINGLE_CONTEXT, 0 /* GCPtr */);
            else if (pVM->hmr0.s.vmx.enmTlbFlushVpid == VMXTLBFLUSHVPID_ALL_CONTEXTS)
            {
                hmR0VmxFlushVpid(pVCpu, VMXTLBFLUSHVPID_ALL_CONTEXTS, 0 /* GCPtr */);
                pHostCpu->fFlushAsidBeforeUse = false;
            }
            else
            {
                /* hmR0VmxSetupTaggedTlb() ensures we never get here. Paranoia. */
                AssertMsgFailed(("Unsupported VPID-flush context type.\n"));
            }
        }
    }

    AssertMsg(pVCpu->hmr0.s.cTlbFlushes == pHostCpu->cTlbFlushes,
              ("Flush count mismatch for cpu %d (%u vs %u)\n", pHostCpu->idCpu, pVCpu->hmr0.s.cTlbFlushes, pHostCpu->cTlbFlushes));
    AssertMsg(pHostCpu->uCurrentAsid >= 1 && pHostCpu->uCurrentAsid < g_uHmMaxAsid,
              ("Cpu[%u] uCurrentAsid=%u cTlbFlushes=%u pVCpu->idLastCpu=%u pVCpu->cTlbFlushes=%u\n", pHostCpu->idCpu,
               pHostCpu->uCurrentAsid, pHostCpu->cTlbFlushes, pVCpu->hmr0.s.idLastCpu, pVCpu->hmr0.s.cTlbFlushes));
    AssertMsg(pVCpu->hmr0.s.uCurrentAsid >= 1 && pVCpu->hmr0.s.uCurrentAsid < g_uHmMaxAsid,
              ("Cpu[%u] pVCpu->uCurrentAsid=%u\n", pHostCpu->idCpu, pVCpu->hmr0.s.uCurrentAsid));

    int rc  = VMXWriteVmcs16(VMX_VMCS16_VPID, pVCpu->hmr0.s.uCurrentAsid);
    AssertRC(rc);
}


/**
 * Flushes the guest TLB entry based on CPU capabilities.
 *
 * @param   pHostCpu    The HM physical-CPU structure.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 *
 * @remarks Called with interrupts disabled.
 */
static void hmR0VmxFlushTaggedTlb(PHMPHYSCPU pHostCpu, PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
#ifdef HMVMX_ALWAYS_FLUSH_TLB
    VMCPU_FF_SET(pVCpu, VMCPU_FF_TLB_FLUSH);
#endif
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    switch (pVM->hmr0.s.vmx.enmTlbFlushType)
    {
        case VMXTLBFLUSHTYPE_EPT_VPID: hmR0VmxFlushTaggedTlbBoth(pHostCpu, pVCpu, pVmcsInfo); break;
        case VMXTLBFLUSHTYPE_EPT:      hmR0VmxFlushTaggedTlbEpt(pHostCpu, pVCpu, pVmcsInfo);  break;
        case VMXTLBFLUSHTYPE_VPID:     hmR0VmxFlushTaggedTlbVpid(pHostCpu, pVCpu);            break;
        case VMXTLBFLUSHTYPE_NONE:     hmR0VmxFlushTaggedTlbNone(pHostCpu, pVCpu);            break;
        default:
            AssertMsgFailed(("Invalid flush-tag function identifier\n"));
            break;
    }
    /* Don't assert that VMCPU_FF_TLB_FLUSH should no longer be pending. It can be set by other EMTs. */
}


/**
 * Sets up the appropriate tagged TLB-flush level and handler for flushing guest
 * TLB entries from the host TLB before VM-entry.
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 */
static int hmR0VmxSetupTaggedTlb(PVMCC pVM)
{
    /*
     * Determine optimal flush type for nested paging.
     * We cannot ignore EPT if no suitable flush-types is supported by the CPU as we've already setup
     * unrestricted guest execution (see hmR3InitFinalizeR0()).
     */
    if (pVM->hmr0.s.fNestedPaging)
    {
        if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVEPT)
        {
            if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVEPT_SINGLE_CONTEXT)
                pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_SINGLE_CONTEXT;
            else if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVEPT_ALL_CONTEXTS)
                pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_ALL_CONTEXTS;
            else
            {
                /* Shouldn't happen. EPT is supported but no suitable flush-types supported. */
                pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_NOT_SUPPORTED;
                VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_EPT_FLUSH_TYPE_UNSUPPORTED;
                return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
            }

            /* Make sure the write-back cacheable memory type for EPT is supported. */
            if (RT_UNLIKELY(!(g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_MEMTYPE_WB)))
            {
                pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_NOT_SUPPORTED;
                VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_EPT_MEM_TYPE_NOT_WB;
                return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
            }

            /* EPT requires a page-walk length of 4. */
            if (RT_UNLIKELY(!(g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_PAGE_WALK_LENGTH_4)))
            {
                pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_NOT_SUPPORTED;
                VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_EPT_PAGE_WALK_LENGTH_UNSUPPORTED;
                return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
            }
        }
        else
        {
            /* Shouldn't happen. EPT is supported but INVEPT instruction is not supported. */
            pVM->hmr0.s.vmx.enmTlbFlushEpt = VMXTLBFLUSHEPT_NOT_SUPPORTED;
            VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_EPT_INVEPT_UNAVAILABLE;
            return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
        }
    }

    /*
     * Determine optimal flush type for VPID.
     */
    if (pVM->hmr0.s.vmx.fVpid)
    {
        if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID)
        {
            if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID_SINGLE_CONTEXT)
                pVM->hmr0.s.vmx.enmTlbFlushVpid = VMXTLBFLUSHVPID_SINGLE_CONTEXT;
            else if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID_ALL_CONTEXTS)
                pVM->hmr0.s.vmx.enmTlbFlushVpid = VMXTLBFLUSHVPID_ALL_CONTEXTS;
            else
            {
                /* Neither SINGLE nor ALL-context flush types for VPID is supported by the CPU. Ignore VPID capability. */
                if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID_INDIV_ADDR)
                    LogRelFunc(("Only INDIV_ADDR supported. Ignoring VPID.\n"));
                if (g_HmMsrs.u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVVPID_SINGLE_CONTEXT_RETAIN_GLOBALS)
                    LogRelFunc(("Only SINGLE_CONTEXT_RETAIN_GLOBALS supported. Ignoring VPID.\n"));
                pVM->hmr0.s.vmx.enmTlbFlushVpid = VMXTLBFLUSHVPID_NOT_SUPPORTED;
                pVM->hmr0.s.vmx.fVpid           = false;
            }
        }
        else
        {
            /*  Shouldn't happen. VPID is supported but INVVPID is not supported by the CPU. Ignore VPID capability. */
            Log4Func(("VPID supported without INVEPT support. Ignoring VPID.\n"));
            pVM->hmr0.s.vmx.enmTlbFlushVpid = VMXTLBFLUSHVPID_NOT_SUPPORTED;
            pVM->hmr0.s.vmx.fVpid           = false;
        }
    }

    /*
     * Setup the handler for flushing tagged-TLBs.
     */
    if (pVM->hmr0.s.fNestedPaging && pVM->hmr0.s.vmx.fVpid)
        pVM->hmr0.s.vmx.enmTlbFlushType = VMXTLBFLUSHTYPE_EPT_VPID;
    else if (pVM->hmr0.s.fNestedPaging)
        pVM->hmr0.s.vmx.enmTlbFlushType = VMXTLBFLUSHTYPE_EPT;
    else if (pVM->hmr0.s.vmx.fVpid)
        pVM->hmr0.s.vmx.enmTlbFlushType = VMXTLBFLUSHTYPE_VPID;
    else
        pVM->hmr0.s.vmx.enmTlbFlushType = VMXTLBFLUSHTYPE_NONE;


    /*
     * Copy out the result to ring-3.
     */
    pVM->hm.s.ForR3.vmx.fVpid           = pVM->hmr0.s.vmx.fVpid;
    pVM->hm.s.ForR3.vmx.enmTlbFlushType = pVM->hmr0.s.vmx.enmTlbFlushType;
    pVM->hm.s.ForR3.vmx.enmTlbFlushEpt  = pVM->hmr0.s.vmx.enmTlbFlushEpt;
    pVM->hm.s.ForR3.vmx.enmTlbFlushVpid = pVM->hmr0.s.vmx.enmTlbFlushVpid;
    return VINF_SUCCESS;
}


/**
 * Sets up the LBR MSR ranges based on the host CPU.
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 *
 * @sa nemR3DarwinSetupLbrMsrRange
 */
static int hmR0VmxSetupLbrMsrRange(PVMCC pVM)
{
    Assert(pVM->hmr0.s.vmx.fLbr);
    uint32_t idLbrFromIpMsrFirst;
    uint32_t idLbrFromIpMsrLast;
    uint32_t idLbrToIpMsrFirst;
    uint32_t idLbrToIpMsrLast;
    uint32_t idLbrTosMsr;

    /*
     * Determine the LBR MSRs supported for this host CPU family and model.
     *
     * See Intel spec. 17.4.8 "LBR Stack".
     * See Intel "Model-Specific Registers" spec.
     */
    uint32_t const uFamilyModel = (pVM->cpum.ro.HostFeatures.uFamily << 8)
                                | pVM->cpum.ro.HostFeatures.uModel;
    switch (uFamilyModel)
    {
        case 0x0f01: case 0x0f02:
            idLbrFromIpMsrFirst = MSR_P4_LASTBRANCH_0;
            idLbrFromIpMsrLast  = MSR_P4_LASTBRANCH_3;
            idLbrToIpMsrFirst   = 0x0;
            idLbrToIpMsrLast    = 0x0;
            idLbrTosMsr         = MSR_P4_LASTBRANCH_TOS;
            break;

        case 0x065c: case 0x065f: case 0x064e: case 0x065e: case 0x068e:
        case 0x069e: case 0x0655: case 0x0666: case 0x067a: case 0x0667:
        case 0x066a: case 0x066c: case 0x067d: case 0x067e:
            idLbrFromIpMsrFirst = MSR_LASTBRANCH_0_FROM_IP;
            idLbrFromIpMsrLast  = MSR_LASTBRANCH_31_FROM_IP;
            idLbrToIpMsrFirst   = MSR_LASTBRANCH_0_TO_IP;
            idLbrToIpMsrLast    = MSR_LASTBRANCH_31_TO_IP;
            idLbrTosMsr         = MSR_LASTBRANCH_TOS;
            break;

        case 0x063d: case 0x0647: case 0x064f: case 0x0656: case 0x063c:
        case 0x0645: case 0x0646: case 0x063f: case 0x062a: case 0x062d:
        case 0x063a: case 0x063e: case 0x061a: case 0x061e: case 0x061f:
        case 0x062e: case 0x0625: case 0x062c: case 0x062f:
            idLbrFromIpMsrFirst = MSR_LASTBRANCH_0_FROM_IP;
            idLbrFromIpMsrLast  = MSR_LASTBRANCH_15_FROM_IP;
            idLbrToIpMsrFirst   = MSR_LASTBRANCH_0_TO_IP;
            idLbrToIpMsrLast    = MSR_LASTBRANCH_15_TO_IP;
            idLbrTosMsr         = MSR_LASTBRANCH_TOS;
            break;

        case 0x0617: case 0x061d: case 0x060f:
            idLbrFromIpMsrFirst = MSR_CORE2_LASTBRANCH_0_FROM_IP;
            idLbrFromIpMsrLast  = MSR_CORE2_LASTBRANCH_3_FROM_IP;
            idLbrToIpMsrFirst   = MSR_CORE2_LASTBRANCH_0_TO_IP;
            idLbrToIpMsrLast    = MSR_CORE2_LASTBRANCH_3_TO_IP;
            idLbrTosMsr         = MSR_CORE2_LASTBRANCH_TOS;
            break;

        /* Atom and related microarchitectures we don't care about:
        case 0x0637: case 0x064a: case 0x064c: case 0x064d: case 0x065a:
        case 0x065d: case 0x061c: case 0x0626: case 0x0627: case 0x0635:
        case 0x0636: */
        /* All other CPUs: */
        default:
        {
            LogRelFunc(("Could not determine LBR stack size for the CPU model %#x\n", uFamilyModel));
            VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_LBR_STACK_SIZE_UNKNOWN;
            return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
        }
    }

    /*
     * Validate.
     */
    uint32_t const cLbrStack = idLbrFromIpMsrLast - idLbrFromIpMsrFirst + 1;
    PCVMCPU pVCpu0 = VMCC_GET_CPU_0(pVM);
    AssertCompile(   RT_ELEMENTS(pVCpu0->hm.s.vmx.VmcsInfo.au64LbrFromIpMsr)
                  == RT_ELEMENTS(pVCpu0->hm.s.vmx.VmcsInfo.au64LbrToIpMsr));
    if (cLbrStack > RT_ELEMENTS(pVCpu0->hm.s.vmx.VmcsInfo.au64LbrFromIpMsr))
    {
        LogRelFunc(("LBR stack size of the CPU (%u) exceeds our buffer size\n", cLbrStack));
        VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_LBR_STACK_SIZE_OVERFLOW;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }
    NOREF(pVCpu0);

    /*
     * Update the LBR info. to the VM struct. for use later.
     */
    pVM->hmr0.s.vmx.idLbrTosMsr = idLbrTosMsr;

    pVM->hm.s.ForR3.vmx.idLbrFromIpMsrFirst = pVM->hmr0.s.vmx.idLbrFromIpMsrFirst = idLbrFromIpMsrFirst;
    pVM->hm.s.ForR3.vmx.idLbrFromIpMsrLast  = pVM->hmr0.s.vmx.idLbrFromIpMsrLast  = idLbrFromIpMsrLast;

    pVM->hm.s.ForR3.vmx.idLbrToIpMsrFirst   = pVM->hmr0.s.vmx.idLbrToIpMsrFirst   = idLbrToIpMsrFirst;
    pVM->hm.s.ForR3.vmx.idLbrToIpMsrLast    = pVM->hmr0.s.vmx.idLbrToIpMsrLast    = idLbrToIpMsrLast;
    return VINF_SUCCESS;
}


#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
/**
 * Sets up the shadow VMCS fields arrays.
 *
 * This function builds arrays of VMCS fields to sync the shadow VMCS later while
 * executing the guest.
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 */
static int hmR0VmxSetupShadowVmcsFieldsArrays(PVMCC pVM)
{
    /*
     * Paranoia. Ensure we haven't exposed the VMWRITE-All VMX feature to the guest
     * when the host does not support it.
     */
    bool const fGstVmwriteAll = pVM->cpum.ro.GuestFeatures.fVmxVmwriteAll;
    if (   !fGstVmwriteAll
        || (g_HmMsrs.u.vmx.u64Misc & VMX_MISC_VMWRITE_ALL))
    { /* likely. */ }
    else
    {
        LogRelFunc(("VMX VMWRITE-All feature exposed to the guest but host CPU does not support it!\n"));
        VMCC_GET_CPU_0(pVM)->hm.s.u32HMError = VMX_UFC_GST_HOST_VMWRITE_ALL;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    uint32_t const cVmcsFields = RT_ELEMENTS(g_aVmcsFields);
    uint32_t       cRwFields   = 0;
    uint32_t       cRoFields   = 0;
    for (uint32_t i = 0; i < cVmcsFields; i++)
    {
        VMXVMCSFIELD VmcsField;
        VmcsField.u = g_aVmcsFields[i];

        /*
         * We will be writing "FULL" (64-bit) fields while syncing the shadow VMCS.
         * Therefore, "HIGH" (32-bit portion of 64-bit) fields must not be included
         * in the shadow VMCS fields array as they would be redundant.
         *
         * If the VMCS field depends on a CPU feature that is not exposed to the guest,
         * we must not include it in the shadow VMCS fields array. Guests attempting to
         * VMREAD/VMWRITE such VMCS fields would cause a VM-exit and we shall emulate
         * the required behavior.
         */
        if (   VmcsField.n.fAccessType == VMX_VMCSFIELD_ACCESS_FULL
            && CPUMIsGuestVmxVmcsFieldValid(pVM, VmcsField.u))
        {
            /*
             * Read-only fields are placed in a separate array so that while syncing shadow
             * VMCS fields later (which is more performance critical) we can avoid branches.
             *
             * However, if the guest can write to all fields (including read-only fields),
             * we treat it a as read/write field. Otherwise, writing to these fields would
             * cause a VMWRITE instruction error while syncing the shadow VMCS.
             */
            if (   fGstVmwriteAll
                || !VMXIsVmcsFieldReadOnly(VmcsField.u))
                pVM->hmr0.s.vmx.paShadowVmcsFields[cRwFields++] = VmcsField.u;
            else
                pVM->hmr0.s.vmx.paShadowVmcsRoFields[cRoFields++] = VmcsField.u;
        }
    }

    /* Update the counts. */
    pVM->hmr0.s.vmx.cShadowVmcsFields   = cRwFields;
    pVM->hmr0.s.vmx.cShadowVmcsRoFields = cRoFields;
    return VINF_SUCCESS;
}


/**
 * Sets up the VMREAD and VMWRITE bitmaps.
 *
 * @param   pVM     The cross context VM structure.
 */
static void hmR0VmxSetupVmreadVmwriteBitmaps(PVMCC pVM)
{
    /*
     * By default, ensure guest attempts to access any VMCS fields cause VM-exits.
     */
    uint32_t const cbBitmap        = X86_PAGE_4K_SIZE;
    uint8_t       *pbVmreadBitmap  = (uint8_t *)pVM->hmr0.s.vmx.pvVmreadBitmap;
    uint8_t       *pbVmwriteBitmap = (uint8_t *)pVM->hmr0.s.vmx.pvVmwriteBitmap;
    ASMMemFill32(pbVmreadBitmap,  cbBitmap, UINT32_C(0xffffffff));
    ASMMemFill32(pbVmwriteBitmap, cbBitmap, UINT32_C(0xffffffff));

    /*
     * Skip intercepting VMREAD/VMWRITE to guest read/write fields in the
     * VMREAD and VMWRITE bitmaps.
     */
    {
        uint32_t const *paShadowVmcsFields = pVM->hmr0.s.vmx.paShadowVmcsFields;
        uint32_t const  cShadowVmcsFields  = pVM->hmr0.s.vmx.cShadowVmcsFields;
        for (uint32_t i = 0; i < cShadowVmcsFields; i++)
        {
            uint32_t const uVmcsField = paShadowVmcsFields[i];
            Assert(!(uVmcsField & VMX_VMCSFIELD_RSVD_MASK));
            Assert(uVmcsField >> 3 < cbBitmap);
            ASMBitClear(pbVmreadBitmap  + (uVmcsField >> 3), uVmcsField & 7);
            ASMBitClear(pbVmwriteBitmap + (uVmcsField >> 3), uVmcsField & 7);
        }
    }

    /*
     * Skip intercepting VMREAD for guest read-only fields in the VMREAD bitmap
     * if the host supports VMWRITE to all supported VMCS fields.
     */
    if (g_HmMsrs.u.vmx.u64Misc & VMX_MISC_VMWRITE_ALL)
    {
        uint32_t const *paShadowVmcsRoFields = pVM->hmr0.s.vmx.paShadowVmcsRoFields;
        uint32_t const  cShadowVmcsRoFields  = pVM->hmr0.s.vmx.cShadowVmcsRoFields;
        for (uint32_t i = 0; i < cShadowVmcsRoFields; i++)
        {
            uint32_t const uVmcsField = paShadowVmcsRoFields[i];
            Assert(!(uVmcsField & VMX_VMCSFIELD_RSVD_MASK));
            Assert(uVmcsField >> 3 < cbBitmap);
            ASMBitClear(pbVmreadBitmap + (uVmcsField >> 3), uVmcsField & 7);
        }
    }
}
#endif /* VBOX_WITH_NESTED_HWVIRT_VMX */


/**
 * Sets up the virtual-APIC page address for the VMCS.
 *
 * @param   pVmcsInfo   The VMCS info. object.
 */
DECLINLINE(void) hmR0VmxSetupVmcsVirtApicAddr(PCVMXVMCSINFO pVmcsInfo)
{
    RTHCPHYS const HCPhysVirtApic = pVmcsInfo->HCPhysVirtApic;
    Assert(HCPhysVirtApic != NIL_RTHCPHYS);
    Assert(!(HCPhysVirtApic & 0xfff));                       /* Bits 11:0 MBZ. */
    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_VIRT_APIC_PAGEADDR_FULL, HCPhysVirtApic);
    AssertRC(rc);
}


/**
 * Sets up the MSR-bitmap address for the VMCS.
 *
 * @param   pVmcsInfo   The VMCS info. object.
 */
DECLINLINE(void) hmR0VmxSetupVmcsMsrBitmapAddr(PCVMXVMCSINFO pVmcsInfo)
{
    RTHCPHYS const HCPhysMsrBitmap = pVmcsInfo->HCPhysMsrBitmap;
    Assert(HCPhysMsrBitmap != NIL_RTHCPHYS);
    Assert(!(HCPhysMsrBitmap & 0xfff));                      /* Bits 11:0 MBZ. */
    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_MSR_BITMAP_FULL, HCPhysMsrBitmap);
    AssertRC(rc);
}


/**
 * Sets up the APIC-access page address for the VMCS.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 */
DECLINLINE(void) hmR0VmxSetupVmcsApicAccessAddr(PVMCPUCC pVCpu)
{
    RTHCPHYS const HCPhysApicAccess = pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.HCPhysApicAccess;
    Assert(HCPhysApicAccess != NIL_RTHCPHYS);
    Assert(!(HCPhysApicAccess & 0xfff));                     /* Bits 11:0 MBZ. */
    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_APIC_ACCESSADDR_FULL, HCPhysApicAccess);
    AssertRC(rc);
}

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX

/**
 * Sets up the VMREAD bitmap address for the VMCS.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 */
DECLINLINE(void) hmR0VmxSetupVmcsVmreadBitmapAddr(PVMCPUCC pVCpu)
{
    RTHCPHYS const HCPhysVmreadBitmap = pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.HCPhysVmreadBitmap;
    Assert(HCPhysVmreadBitmap != NIL_RTHCPHYS);
    Assert(!(HCPhysVmreadBitmap & 0xfff));                     /* Bits 11:0 MBZ. */
    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_VMREAD_BITMAP_FULL, HCPhysVmreadBitmap);
    AssertRC(rc);
}


/**
 * Sets up the VMWRITE bitmap address for the VMCS.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 */
DECLINLINE(void) hmR0VmxSetupVmcsVmwriteBitmapAddr(PVMCPUCC pVCpu)
{
    RTHCPHYS const HCPhysVmwriteBitmap = pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.HCPhysVmwriteBitmap;
    Assert(HCPhysVmwriteBitmap != NIL_RTHCPHYS);
    Assert(!(HCPhysVmwriteBitmap & 0xfff));                     /* Bits 11:0 MBZ. */
    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_VMWRITE_BITMAP_FULL, HCPhysVmwriteBitmap);
    AssertRC(rc);
}

#endif

/**
 * Sets up the VM-entry MSR load, VM-exit MSR-store and VM-exit MSR-load addresses
 * in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVmcsInfo   The VMCS info. object.
 */
DECLINLINE(int) hmR0VmxSetupVmcsAutoLoadStoreMsrAddrs(PVMXVMCSINFO pVmcsInfo)
{
    RTHCPHYS const HCPhysGuestMsrLoad = pVmcsInfo->HCPhysGuestMsrLoad;
    Assert(HCPhysGuestMsrLoad != NIL_RTHCPHYS);
    Assert(!(HCPhysGuestMsrLoad & 0xf));                     /* Bits 3:0 MBZ. */

    RTHCPHYS const HCPhysGuestMsrStore = pVmcsInfo->HCPhysGuestMsrStore;
    Assert(HCPhysGuestMsrStore != NIL_RTHCPHYS);
    Assert(!(HCPhysGuestMsrStore & 0xf));                    /* Bits 3:0 MBZ. */

    RTHCPHYS const HCPhysHostMsrLoad = pVmcsInfo->HCPhysHostMsrLoad;
    Assert(HCPhysHostMsrLoad != NIL_RTHCPHYS);
    Assert(!(HCPhysHostMsrLoad & 0xf));                      /* Bits 3:0 MBZ. */

    int rc = VMXWriteVmcs64(VMX_VMCS64_CTRL_ENTRY_MSR_LOAD_FULL, HCPhysGuestMsrLoad);   AssertRC(rc);
    rc     = VMXWriteVmcs64(VMX_VMCS64_CTRL_EXIT_MSR_STORE_FULL, HCPhysGuestMsrStore);  AssertRC(rc);
    rc     = VMXWriteVmcs64(VMX_VMCS64_CTRL_EXIT_MSR_LOAD_FULL,  HCPhysHostMsrLoad);    AssertRC(rc);
    return VINF_SUCCESS;
}


/**
 * Sets up MSR permissions in the MSR bitmap of a VMCS info. object.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmcsInfo       The VMCS info. object.
 */
static void hmR0VmxSetupVmcsMsrPermissions(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
    Assert(pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS);

    /*
     * By default, ensure guest attempts to access any MSR cause VM-exits.
     * This shall later be relaxed for specific MSRs as necessary.
     *
     * Note: For nested-guests, the entire bitmap will be merged prior to
     * executing the nested-guest using hardware-assisted VMX and hence there
     * is no need to perform this operation. See hmR0VmxMergeMsrBitmapNested.
     */
    Assert(pVmcsInfo->pvMsrBitmap);
    ASMMemFill32(pVmcsInfo->pvMsrBitmap, X86_PAGE_4K_SIZE, UINT32_C(0xffffffff));

    /*
     * The guest can access the following MSRs (read, write) without causing
     * VM-exits; they are loaded/stored automatically using fields in the VMCS.
     */
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_SYSENTER_CS,  VMXMSRPM_ALLOW_RD_WR);
    hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_SYSENTER_ESP, VMXMSRPM_ALLOW_RD_WR);
    hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_SYSENTER_EIP, VMXMSRPM_ALLOW_RD_WR);
    hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K8_GS_BASE,        VMXMSRPM_ALLOW_RD_WR);
    hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K8_FS_BASE,        VMXMSRPM_ALLOW_RD_WR);

    /*
     * The IA32_PRED_CMD and IA32_FLUSH_CMD MSRs are write-only and has no state
     * associated with then. We never need to intercept access (writes need to be
     * executed without causing a VM-exit, reads will #GP fault anyway).
     *
     * The IA32_SPEC_CTRL MSR is read/write and has state. We allow the guest to
     * read/write them. We swap the guest/host MSR value using the
     * auto-load/store MSR area.
     */
    if (pVM->cpum.ro.GuestFeatures.fIbpb)
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_PRED_CMD,  VMXMSRPM_ALLOW_RD_WR);
    if (pVM->cpum.ro.GuestFeatures.fFlushCmd)
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_FLUSH_CMD, VMXMSRPM_ALLOW_RD_WR);
    if (pVM->cpum.ro.GuestFeatures.fIbrs)
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_IA32_SPEC_CTRL, VMXMSRPM_ALLOW_RD_WR);

    /*
     * Allow full read/write access for the following MSRs (mandatory for VT-x)
     * required for 64-bit guests.
     */
    if (pVM->hmr0.s.fAllow64BitGuests)
    {
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K8_LSTAR,          VMXMSRPM_ALLOW_RD_WR);
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K6_STAR,           VMXMSRPM_ALLOW_RD_WR);
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K8_SF_MASK,        VMXMSRPM_ALLOW_RD_WR);
        hmR0VmxSetMsrPermission(pVCpu, pVmcsInfo, false, MSR_K8_KERNEL_GS_BASE, VMXMSRPM_ALLOW_RD_WR);
    }

    /*
     * IA32_EFER MSR is always intercepted, see @bugref{9180#c37}.
     */
#ifdef VBOX_STRICT
    Assert(pVmcsInfo->pvMsrBitmap);
    uint32_t const fMsrpmEfer = CPUMGetVmxMsrPermission(pVmcsInfo->pvMsrBitmap, MSR_K6_EFER);
    Assert(fMsrpmEfer == VMXMSRPM_EXIT_RD_WR);
#endif
}


/**
 * Sets up pin-based VM-execution controls in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static int hmR0VmxSetupVmcsPinCtls(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    uint32_t       fVal = g_HmMsrs.u.vmx.PinCtls.n.allowed0;      /* Bits set here must always be set. */
    uint32_t const fZap = g_HmMsrs.u.vmx.PinCtls.n.allowed1;      /* Bits cleared here must always be cleared. */

    fVal |= VMX_PIN_CTLS_EXT_INT_EXIT                        /* External interrupts cause a VM-exit. */
         |  VMX_PIN_CTLS_NMI_EXIT;                           /* Non-maskable interrupts (NMIs) cause a VM-exit. */

    if (g_HmMsrs.u.vmx.PinCtls.n.allowed1 & VMX_PIN_CTLS_VIRT_NMI)
        fVal |= VMX_PIN_CTLS_VIRT_NMI;                       /* Use virtual NMIs and virtual-NMI blocking features. */

    /* Enable the VMX-preemption timer. */
    if (pVM->hmr0.s.vmx.fUsePreemptTimer)
    {
        Assert(g_HmMsrs.u.vmx.PinCtls.n.allowed1 & VMX_PIN_CTLS_PREEMPT_TIMER);
        fVal |= VMX_PIN_CTLS_PREEMPT_TIMER;
    }

#if 0
    /* Enable posted-interrupt processing. */
    if (pVM->hm.s.fPostedIntrs)
    {
        Assert(g_HmMsrs.u.vmx.PinCtls.n.allowed1  & VMX_PIN_CTLS_POSTED_INT);
        Assert(g_HmMsrs.u.vmx.ExitCtls.n.allowed1 & VMX_EXIT_CTLS_ACK_EXT_INT);
        fVal |= VMX_PIN_CTLS_POSTED_INT;
    }
#endif

    if ((fVal & fZap) != fVal)
    {
        LogRelFunc(("Invalid pin-based VM-execution controls combo! Cpu=%#RX32 fVal=%#RX32 fZap=%#RX32\n",
                    g_HmMsrs.u.vmx.PinCtls.n.allowed0, fVal, fZap));
        pVCpu->hm.s.u32HMError = VMX_UFC_CTRL_PIN_EXEC;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /* Commit it to the VMCS and update our cache. */
    int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PIN_EXEC, fVal);
    AssertRC(rc);
    pVmcsInfo->u32PinCtls = fVal;

    return VINF_SUCCESS;
}


/**
 * Sets up secondary processor-based VM-execution controls in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static int hmR0VmxSetupVmcsProcCtls2(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    uint32_t       fVal = g_HmMsrs.u.vmx.ProcCtls2.n.allowed0;    /* Bits set here must be set in the VMCS. */
    uint32_t const fZap = g_HmMsrs.u.vmx.ProcCtls2.n.allowed1;    /* Bits cleared here must be cleared in the VMCS. */

    /* WBINVD causes a VM-exit. */
    if (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_WBINVD_EXIT)
        fVal |= VMX_PROC_CTLS2_WBINVD_EXIT;

    /* Enable EPT (aka nested-paging). */
    if (pVM->hmr0.s.fNestedPaging)
        fVal |= VMX_PROC_CTLS2_EPT;

    /* Enable the INVPCID instruction if we expose it to the guest and is supported
       by the hardware. Without this, guest executing INVPCID would cause a #UD. */
    if (   pVM->cpum.ro.GuestFeatures.fInvpcid
        && (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_INVPCID))
        fVal |= VMX_PROC_CTLS2_INVPCID;

    /* Enable VPID. */
    if (pVM->hmr0.s.vmx.fVpid)
        fVal |= VMX_PROC_CTLS2_VPID;

    /* Enable unrestricted guest execution. */
    if (pVM->hmr0.s.vmx.fUnrestrictedGuest)
        fVal |= VMX_PROC_CTLS2_UNRESTRICTED_GUEST;

#if 0
    if (pVM->hm.s.fVirtApicRegs)
    {
        /* Enable APIC-register virtualization. */
        Assert(g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_APIC_REG_VIRT);
        fVal |= VMX_PROC_CTLS2_APIC_REG_VIRT;

        /* Enable virtual-interrupt delivery. */
        Assert(g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_VIRT_INTR_DELIVERY);
        fVal |= VMX_PROC_CTLS2_VIRT_INTR_DELIVERY;
    }
#endif

    /* Virtualize-APIC accesses if supported by the CPU. The virtual-APIC page is
       where the TPR shadow resides. */
    /** @todo VIRT_X2APIC support, it's mutually exclusive with this. So must be
     *        done dynamically. */
    if (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS)
    {
        fVal |= VMX_PROC_CTLS2_VIRT_APIC_ACCESS;
        hmR0VmxSetupVmcsApicAccessAddr(pVCpu);
   }

    /* Enable the RDTSCP instruction if we expose it to the guest and is supported
       by the hardware. Without this, guest executing RDTSCP would cause a #UD. */
    if (   pVM->cpum.ro.GuestFeatures.fRdTscP
        && (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_RDTSCP))
        fVal |= VMX_PROC_CTLS2_RDTSCP;

    /* Enable Pause-Loop exiting. */
    if (   (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_PAUSE_LOOP_EXIT)
        && pVM->hm.s.vmx.cPleGapTicks
        && pVM->hm.s.vmx.cPleWindowTicks)
    {
        fVal |= VMX_PROC_CTLS2_PAUSE_LOOP_EXIT;

        int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PLE_GAP, pVM->hm.s.vmx.cPleGapTicks);          AssertRC(rc);
        rc     = VMXWriteVmcs32(VMX_VMCS32_CTRL_PLE_WINDOW, pVM->hm.s.vmx.cPleWindowTicks);    AssertRC(rc);
    }

    if ((fVal & fZap) != fVal)
    {
        LogRelFunc(("Invalid secondary processor-based VM-execution controls combo! cpu=%#RX32 fVal=%#RX32 fZap=%#RX32\n",
                    g_HmMsrs.u.vmx.ProcCtls2.n.allowed0, fVal, fZap));
        pVCpu->hm.s.u32HMError = VMX_UFC_CTRL_PROC_EXEC2;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /* Commit it to the VMCS and update our cache. */
    int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC2, fVal);
    AssertRC(rc);
    pVmcsInfo->u32ProcCtls2 = fVal;

    return VINF_SUCCESS;
}


/**
 * Sets up processor-based VM-execution controls in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static int hmR0VmxSetupVmcsProcCtls(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    uint32_t       fVal = g_HmMsrs.u.vmx.ProcCtls.n.allowed0;     /* Bits set here must be set in the VMCS. */
    uint32_t const fZap = g_HmMsrs.u.vmx.ProcCtls.n.allowed1;     /* Bits cleared here must be cleared in the VMCS. */

    fVal |= VMX_PROC_CTLS_HLT_EXIT                                    /* HLT causes a VM-exit. */
         |  VMX_PROC_CTLS_USE_TSC_OFFSETTING                          /* Use TSC-offsetting. */
         |  VMX_PROC_CTLS_MOV_DR_EXIT                                 /* MOV DRx causes a VM-exit. */
         |  VMX_PROC_CTLS_UNCOND_IO_EXIT                              /* All IO instructions cause a VM-exit. */
         |  VMX_PROC_CTLS_RDPMC_EXIT                                  /* RDPMC causes a VM-exit. */
         |  VMX_PROC_CTLS_MONITOR_EXIT                                /* MONITOR causes a VM-exit. */
         |  VMX_PROC_CTLS_MWAIT_EXIT;                                 /* MWAIT causes a VM-exit. */

    /* We toggle VMX_PROC_CTLS_MOV_DR_EXIT later, check if it's not -always- needed to be set or clear. */
    if (   !(g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_MOV_DR_EXIT)
        ||  (g_HmMsrs.u.vmx.ProcCtls.n.allowed0 & VMX_PROC_CTLS_MOV_DR_EXIT))
    {
        pVCpu->hm.s.u32HMError = VMX_UFC_CTRL_PROC_MOV_DRX_EXIT;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /* Without nested paging, INVLPG (also affects INVPCID) and MOV CR3 instructions should cause VM-exits. */
    if (!pVM->hmr0.s.fNestedPaging)
    {
        Assert(!pVM->hmr0.s.vmx.fUnrestrictedGuest);
        fVal |= VMX_PROC_CTLS_INVLPG_EXIT
             |  VMX_PROC_CTLS_CR3_LOAD_EXIT
             |  VMX_PROC_CTLS_CR3_STORE_EXIT;
    }

    /* Use TPR shadowing if supported by the CPU. */
    if (   PDMHasApic(pVM)
        && (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_TPR_SHADOW))
    {
        fVal |= VMX_PROC_CTLS_USE_TPR_SHADOW;                /* CR8 reads from the Virtual-APIC page. */
                                                             /* CR8 writes cause a VM-exit based on TPR threshold. */
        Assert(!(fVal & VMX_PROC_CTLS_CR8_STORE_EXIT));
        Assert(!(fVal & VMX_PROC_CTLS_CR8_LOAD_EXIT));
        hmR0VmxSetupVmcsVirtApicAddr(pVmcsInfo);
    }
    else
    {
        /* Some 32-bit CPUs do not support CR8 load/store exiting as MOV CR8 is
           invalid on 32-bit Intel CPUs. Set this control only for 64-bit guests. */
        if (pVM->hmr0.s.fAllow64BitGuests)
            fVal |= VMX_PROC_CTLS_CR8_STORE_EXIT             /* CR8 reads cause a VM-exit. */
                 |  VMX_PROC_CTLS_CR8_LOAD_EXIT;             /* CR8 writes cause a VM-exit. */
    }

    /* Use MSR-bitmaps if supported by the CPU. */
    if (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_MSR_BITMAPS)
    {
        fVal |= VMX_PROC_CTLS_USE_MSR_BITMAPS;
        hmR0VmxSetupVmcsMsrBitmapAddr(pVmcsInfo);
    }

    /* Use the secondary processor-based VM-execution controls if supported by the CPU. */
    if (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_SECONDARY_CTLS)
        fVal |= VMX_PROC_CTLS_USE_SECONDARY_CTLS;

    if ((fVal & fZap) != fVal)
    {
        LogRelFunc(("Invalid processor-based VM-execution controls combo! cpu=%#RX32 fVal=%#RX32 fZap=%#RX32\n",
                    g_HmMsrs.u.vmx.ProcCtls.n.allowed0, fVal, fZap));
        pVCpu->hm.s.u32HMError = VMX_UFC_CTRL_PROC_EXEC;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /* Commit it to the VMCS and update our cache. */
    int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC, fVal);
    AssertRC(rc);
    pVmcsInfo->u32ProcCtls = fVal;

    /* Set up MSR permissions that don't change through the lifetime of the VM. */
    if (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS)
        hmR0VmxSetupVmcsMsrPermissions(pVCpu, pVmcsInfo);

    /* Set up secondary processor-based VM-execution controls if the CPU supports it. */
    if (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_SECONDARY_CTLS)
        return hmR0VmxSetupVmcsProcCtls2(pVCpu, pVmcsInfo);

    /* Sanity check, should not really happen. */
    if (RT_LIKELY(!pVM->hmr0.s.vmx.fUnrestrictedGuest))
    { /* likely */ }
    else
    {
        pVCpu->hm.s.u32HMError = VMX_UFC_INVALID_UX_COMBO;
        return VERR_HM_UNSUPPORTED_CPU_FEATURE_COMBO;
    }

    /* Old CPUs without secondary processor-based VM-execution controls would end up here. */
    return VINF_SUCCESS;
}


/**
 * Sets up miscellaneous (everything other than Pin, Processor and secondary
 * Processor-based VM-execution) control fields in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static int hmR0VmxSetupVmcsMiscCtls(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    if (pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fUseVmcsShadowing)
    {
        hmR0VmxSetupVmcsVmreadBitmapAddr(pVCpu);
        hmR0VmxSetupVmcsVmwriteBitmapAddr(pVCpu);
    }
#endif

    Assert(pVmcsInfo->u64VmcsLinkPtr == NIL_RTHCPHYS);
    int rc = VMXWriteVmcs64(VMX_VMCS64_GUEST_VMCS_LINK_PTR_FULL, NIL_RTHCPHYS);
    AssertRC(rc);

    rc = hmR0VmxSetupVmcsAutoLoadStoreMsrAddrs(pVmcsInfo);
    if (RT_SUCCESS(rc))
    {
        uint64_t const u64Cr0Mask = vmxHCGetFixedCr0Mask(pVCpu);
        uint64_t const u64Cr4Mask = vmxHCGetFixedCr4Mask(pVCpu);

        rc = VMXWriteVmcsNw(VMX_VMCS_CTRL_CR0_MASK, u64Cr0Mask);    AssertRC(rc);
        rc = VMXWriteVmcsNw(VMX_VMCS_CTRL_CR4_MASK, u64Cr4Mask);    AssertRC(rc);

        pVmcsInfo->u64Cr0Mask = u64Cr0Mask;
        pVmcsInfo->u64Cr4Mask = u64Cr4Mask;

        if (pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fLbr)
        {
            rc = VMXWriteVmcsNw(VMX_VMCS64_GUEST_DEBUGCTL_FULL, MSR_IA32_DEBUGCTL_LBR);
            AssertRC(rc);
        }
        return VINF_SUCCESS;
    }
    else
        LogRelFunc(("Failed to initialize VMCS auto-load/store MSR addresses. rc=%Rrc\n", rc));
    return rc;
}


/**
 * Sets up the initial exception bitmap in the VMCS based on static conditions.
 *
 * We shall setup those exception intercepts that don't change during the
 * lifetime of the VM here. The rest are done dynamically while loading the
 * guest state.
 *
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static void hmR0VmxSetupVmcsXcptBitmap(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo)
{
    /*
     * The following exceptions are always intercepted:
     *
     * #AC - To prevent the guest from hanging the CPU and for dealing with
     *       split-lock detecting host configs.
     * #DB - To maintain the DR6 state even when intercepting DRx reads/writes and
     *       recursive #DBs can cause a CPU hang.
     * #PF - To sync our shadow page tables when nested-paging is not used.
     */
    bool const fNestedPaging = pVCpu->CTX_SUFF(pVM)->hmr0.s.fNestedPaging;
    uint32_t const uXcptBitmap = RT_BIT(X86_XCPT_AC)
                               | RT_BIT(X86_XCPT_DB)
                               | (fNestedPaging ? 0 : RT_BIT(X86_XCPT_PF));

    /* Commit it to the VMCS. */
    int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_EXCEPTION_BITMAP, uXcptBitmap);
    AssertRC(rc);

    /* Update our cache of the exception bitmap. */
    pVmcsInfo->u32XcptBitmap = uXcptBitmap;
}


#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
/**
 * Sets up the VMCS for executing a nested-guest using hardware-assisted VMX.
 *
 * @returns VBox status code.
 * @param   pVmcsInfo   The VMCS info. object.
 */
static int hmR0VmxSetupVmcsCtlsNested(PVMXVMCSINFO pVmcsInfo)
{
    Assert(pVmcsInfo->u64VmcsLinkPtr == NIL_RTHCPHYS);
    int rc = VMXWriteVmcs64(VMX_VMCS64_GUEST_VMCS_LINK_PTR_FULL, NIL_RTHCPHYS);
    AssertRC(rc);

    rc = hmR0VmxSetupVmcsAutoLoadStoreMsrAddrs(pVmcsInfo);
    if (RT_SUCCESS(rc))
    {
        if (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_MSR_BITMAPS)
            hmR0VmxSetupVmcsMsrBitmapAddr(pVmcsInfo);

        /* Paranoia - We've not yet initialized these, they shall be done while merging the VMCS. */
        Assert(!pVmcsInfo->u64Cr0Mask);
        Assert(!pVmcsInfo->u64Cr4Mask);
        return VINF_SUCCESS;
    }
    LogRelFunc(("Failed to set up the VMCS link pointer in the nested-guest VMCS. rc=%Rrc\n", rc));
    return rc;
}
#endif


/**
 * Selector FNHMSVMVMRUN implementation.
 */
static DECLCALLBACK(int) hmR0VmxStartVmSelector(PVMXVMCSINFO pVmcsInfo, PVMCPUCC pVCpu, bool fResume)
{
    hmR0VmxUpdateStartVmFunction(pVCpu);
    return pVCpu->hmr0.s.vmx.pfnStartVm(pVmcsInfo, pVCpu, fResume);
}


/**
 * Sets up the VMCS for executing a guest (or nested-guest) using hardware-assisted
 * VMX.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmcsInfo       The VMCS info. object.
 * @param   fIsNstGstVmcs   Whether this is a nested-guest VMCS.
 */
static int hmR0VmxSetupVmcs(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo, bool fIsNstGstVmcs)
{
    Assert(pVmcsInfo->pvVmcs);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /* Set the CPU specified revision identifier at the beginning of the VMCS structure. */
    *(uint32_t *)pVmcsInfo->pvVmcs = RT_BF_GET(g_HmMsrs.u.vmx.u64Basic, VMX_BF_BASIC_VMCS_ID);
    const char * const pszVmcs     = fIsNstGstVmcs ? "nested-guest VMCS" : "guest VMCS";

    LogFlowFunc(("\n"));

    /*
     * Initialize the VMCS using VMCLEAR before loading the VMCS.
     * See Intel spec. 31.6 "Preparation And Launching A Virtual Machine".
     */
    int rc = hmR0VmxClearVmcs(pVmcsInfo);
    if (RT_SUCCESS(rc))
    {
        rc = hmR0VmxLoadVmcs(pVmcsInfo);
        if (RT_SUCCESS(rc))
        {
            /*
             * Initialize the hardware-assisted VMX execution handler for guest and nested-guest VMCS.
             * The host is always 64-bit since we no longer support 32-bit hosts.
             * Currently we have just a single handler for all guest modes as well, see @bugref{6208#c73}.
             */
            if (!fIsNstGstVmcs)
            {
                rc = hmR0VmxSetupVmcsPinCtls(pVCpu, pVmcsInfo);
                if (RT_SUCCESS(rc))
                {
                    rc = hmR0VmxSetupVmcsProcCtls(pVCpu, pVmcsInfo);
                    if (RT_SUCCESS(rc))
                    {
                        rc = hmR0VmxSetupVmcsMiscCtls(pVCpu, pVmcsInfo);
                        if (RT_SUCCESS(rc))
                        {
                            hmR0VmxSetupVmcsXcptBitmap(pVCpu, pVmcsInfo);
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
                            /*
                             * If a shadow VMCS is allocated for the VMCS info. object, initialize the
                             * VMCS revision ID and shadow VMCS indicator bit. Also, clear the VMCS
                             * making it fit for use when VMCS shadowing is later enabled.
                             */
                            if (pVmcsInfo->pvShadowVmcs)
                            {
                                VMXVMCSREVID VmcsRevId;
                                VmcsRevId.u = RT_BF_GET(g_HmMsrs.u.vmx.u64Basic, VMX_BF_BASIC_VMCS_ID);
                                VmcsRevId.n.fIsShadowVmcs = 1;
                                *(uint32_t *)pVmcsInfo->pvShadowVmcs = VmcsRevId.u;
                                rc = vmxHCClearShadowVmcs(pVmcsInfo);
                                if (RT_SUCCESS(rc))
                                { /* likely */ }
                                else
                                    LogRelFunc(("Failed to initialize shadow VMCS. rc=%Rrc\n", rc));
                            }
#endif
                        }
                        else
                            LogRelFunc(("Failed to setup miscellaneous controls. rc=%Rrc\n", rc));
                    }
                    else
                        LogRelFunc(("Failed to setup processor-based VM-execution controls. rc=%Rrc\n", rc));
                }
                else
                    LogRelFunc(("Failed to setup pin-based controls. rc=%Rrc\n", rc));
            }
            else
            {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
                rc = hmR0VmxSetupVmcsCtlsNested(pVmcsInfo);
                if (RT_SUCCESS(rc))
                { /* likely */ }
                else
                    LogRelFunc(("Failed to initialize nested-guest VMCS. rc=%Rrc\n", rc));
#else
                AssertFailed();
#endif
            }
        }
        else
            LogRelFunc(("Failed to load the %s. rc=%Rrc\n", rc, pszVmcs));
    }
    else
        LogRelFunc(("Failed to clear the %s. rc=%Rrc\n", rc, pszVmcs));

    /* Sync any CPU internal VMCS data back into our VMCS in memory. */
    if (RT_SUCCESS(rc))
    {
        rc = hmR0VmxClearVmcs(pVmcsInfo);
        if (RT_SUCCESS(rc))
        { /* likely */ }
        else
            LogRelFunc(("Failed to clear the %s post setup. rc=%Rrc\n", rc, pszVmcs));
    }

    /*
     * Update the last-error record both for failures and success, so we
     * can propagate the status code back to ring-3 for diagnostics.
     */
    hmR0VmxUpdateErrorRecord(pVCpu, rc);
    NOREF(pszVmcs);
    return rc;
}


/**
 * Does global VT-x initialization (called during module initialization).
 *
 * @returns VBox status code.
 */
VMMR0DECL(int) VMXR0GlobalInit(void)
{
#ifdef HMVMX_USE_FUNCTION_TABLE
    AssertCompile(VMX_EXIT_MAX + 1 == RT_ELEMENTS(g_aVMExitHandlers));
# ifdef VBOX_STRICT
    for (unsigned i = 0; i < RT_ELEMENTS(g_aVMExitHandlers); i++)
        Assert(g_aVMExitHandlers[i].pfn);
# endif
#endif
    return VINF_SUCCESS;
}


/**
 * Does global VT-x termination (called during module termination).
 */
VMMR0DECL(void) VMXR0GlobalTerm()
{
    /* Nothing to do currently. */
}


/**
 * Sets up and activates VT-x on the current CPU.
 *
 * @returns VBox status code.
 * @param   pHostCpu        The HM physical-CPU structure.
 * @param   pVM             The cross context VM structure.  Can be
 *                          NULL after a host resume operation.
 * @param   pvCpuPage       Pointer to the VMXON region (can be NULL if @a
 *                          fEnabledByHost is @c true).
 * @param   HCPhysCpuPage   Physical address of the VMXON region (can be 0 if
 *                          @a fEnabledByHost is @c true).
 * @param   fEnabledByHost  Set if SUPR0EnableVTx() or similar was used to
 *                          enable VT-x on the host.
 * @param   pHwvirtMsrs     Pointer to the hardware-virtualization MSRs.
 */
VMMR0DECL(int) VMXR0EnableCpu(PHMPHYSCPU pHostCpu, PVMCC pVM, void *pvCpuPage, RTHCPHYS HCPhysCpuPage, bool fEnabledByHost,
                              PCSUPHWVIRTMSRS pHwvirtMsrs)
{
    AssertPtr(pHostCpu);
    AssertPtr(pHwvirtMsrs);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /* Enable VT-x if it's not already enabled by the host. */
    if (!fEnabledByHost)
    {
        int rc = hmR0VmxEnterRootMode(pHostCpu, pVM, HCPhysCpuPage, pvCpuPage);
        if (RT_FAILURE(rc))
            return rc;
    }

    /*
     * Flush all EPT tagged-TLB entries (in case VirtualBox or any other hypervisor have been
     * using EPTPs) so we don't retain any stale guest-physical mappings which won't get
     * invalidated when flushing by VPID.
     */
    if (pHwvirtMsrs->u.vmx.u64EptVpidCaps & MSR_IA32_VMX_EPT_VPID_CAP_INVEPT_ALL_CONTEXTS)
    {
        hmR0VmxFlushEpt(NULL /* pVCpu */, NULL /* pVmcsInfo */, VMXTLBFLUSHEPT_ALL_CONTEXTS);
        pHostCpu->fFlushAsidBeforeUse = false;
    }
    else
        pHostCpu->fFlushAsidBeforeUse = true;

    /* Ensure each VCPU scheduled on this CPU gets a new VPID on resume. See @bugref{6255}. */
    ++pHostCpu->cTlbFlushes;

    return VINF_SUCCESS;
}


/**
 * Deactivates VT-x on the current CPU.
 *
 * @returns VBox status code.
 * @param   pHostCpu        The HM physical-CPU structure.
 * @param   pvCpuPage       Pointer to the VMXON region.
 * @param   HCPhysCpuPage   Physical address of the VMXON region.
 *
 * @remarks This function should never be called when SUPR0EnableVTx() or
 *          similar was used to enable VT-x on the host.
 */
VMMR0DECL(int) VMXR0DisableCpu(PHMPHYSCPU pHostCpu, void *pvCpuPage, RTHCPHYS HCPhysCpuPage)
{
    RT_NOREF2(pvCpuPage, HCPhysCpuPage);

    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    return hmR0VmxLeaveRootMode(pHostCpu);
}


/**
 * Does per-VM VT-x initialization.
 *
 * @returns VBox status code.
 * @param   pVM             The cross context VM structure.
 */
VMMR0DECL(int) VMXR0InitVM(PVMCC pVM)
{
    AssertPtr(pVM);
    LogFlowFunc(("pVM=%p\n", pVM));

    hmR0VmxStructsInit(pVM);
    int rc = hmR0VmxStructsAlloc(pVM);
    if (RT_FAILURE(rc))
    {
        LogRelFunc(("Failed to allocated VMX structures. rc=%Rrc\n", rc));
        return rc;
    }

    /* Setup the crash dump page. */
#ifdef VBOX_WITH_CRASHDUMP_MAGIC
    strcpy((char *)pVM->hmr0.s.vmx.pbScratch, "SCRATCH Magic");
    *(uint64_t *)(pVM->hmr0.s.vmx.pbScratch + 16) = UINT64_C(0xdeadbeefdeadbeef);
#endif
    return VINF_SUCCESS;
}


/**
 * Does per-VM VT-x termination.
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 */
VMMR0DECL(int) VMXR0TermVM(PVMCC pVM)
{
    AssertPtr(pVM);
    LogFlowFunc(("pVM=%p\n", pVM));

#ifdef VBOX_WITH_CRASHDUMP_MAGIC
    if (pVM->hmr0.s.vmx.pbScratch)
        RT_BZERO(pVM->hmr0.s.vmx.pbScratch, X86_PAGE_4K_SIZE);
#endif
    hmR0VmxStructsFree(pVM);
    return VINF_SUCCESS;
}


/**
 * Sets up the VM for execution using hardware-assisted VMX.
 * This function is only called once per-VM during initialization.
 *
 * @returns VBox status code.
 * @param   pVM     The cross context VM structure.
 */
VMMR0DECL(int) VMXR0SetupVM(PVMCC pVM)
{
    AssertPtr(pVM);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    LogFlowFunc(("pVM=%p\n", pVM));

    /*
     * At least verify if VMX is enabled, since we can't check if we're in VMX root mode or not
     * without causing a #GP.
     */
    RTCCUINTREG const uHostCr4 = ASMGetCR4();
    if (RT_LIKELY(uHostCr4 & X86_CR4_VMXE))
    { /* likely */ }
    else
        return VERR_VMX_NOT_IN_VMX_ROOT_MODE;

    /*
     * Check that nested paging is supported if enabled and copy over the flag to the
     * ring-0 only structure.
     */
    bool const fNestedPaging = pVM->hm.s.fNestedPagingCfg;
    AssertReturn(   !fNestedPaging
                 || (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_EPT), /** @todo use a ring-0 copy of ProcCtls2.n.allowed1 */
                 VERR_INCOMPATIBLE_CONFIG);
    pVM->hmr0.s.fNestedPaging = fNestedPaging;
    pVM->hmr0.s.fAllow64BitGuests = pVM->hm.s.fAllow64BitGuestsCfg;

    /*
     * Without unrestricted guest execution, pRealModeTSS and pNonPagingModeEPTPageTable *must*
     * always be allocated. We no longer support the highly unlikely case of unrestricted guest
     * without pRealModeTSS, see hmR3InitFinalizeR0Intel().
     */
    bool const fUnrestrictedGuest = pVM->hm.s.vmx.fUnrestrictedGuestCfg;
    AssertReturn(   !fUnrestrictedGuest
                || (   (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_UNRESTRICTED_GUEST)
                    && fNestedPaging),
                    VERR_INCOMPATIBLE_CONFIG);
    if (   !fUnrestrictedGuest
        &&  (   !pVM->hm.s.vmx.pNonPagingModeEPTPageTable
             || !pVM->hm.s.vmx.pRealModeTSS))
    {
        LogRelFunc(("Invalid real-on-v86 state.\n"));
        return VERR_INTERNAL_ERROR;
    }
    pVM->hmr0.s.vmx.fUnrestrictedGuest = fUnrestrictedGuest;

    /* Initialize these always, see hmR3InitFinalizeR0().*/
    pVM->hm.s.ForR3.vmx.enmTlbFlushEpt  = pVM->hmr0.s.vmx.enmTlbFlushEpt  = VMXTLBFLUSHEPT_NONE;
    pVM->hm.s.ForR3.vmx.enmTlbFlushVpid = pVM->hmr0.s.vmx.enmTlbFlushVpid = VMXTLBFLUSHVPID_NONE;

    /* Setup the tagged-TLB flush handlers. */
    int rc = hmR0VmxSetupTaggedTlb(pVM);
    if (RT_FAILURE(rc))
    {
        LogRelFunc(("Failed to setup tagged TLB. rc=%Rrc\n", rc));
        return rc;
    }

    /* Determine LBR capabilities. */
    pVM->hmr0.s.vmx.fLbr = pVM->hm.s.vmx.fLbrCfg;
    if (pVM->hmr0.s.vmx.fLbr)
    {
        rc = hmR0VmxSetupLbrMsrRange(pVM);
        if (RT_FAILURE(rc))
        {
            LogRelFunc(("Failed to setup LBR MSR range. rc=%Rrc\n", rc));
            return rc;
        }
    }

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /* Setup the shadow VMCS fields array and VMREAD/VMWRITE bitmaps. */
    if (pVM->hmr0.s.vmx.fUseVmcsShadowing)
    {
        rc = hmR0VmxSetupShadowVmcsFieldsArrays(pVM);
        if (RT_SUCCESS(rc))
            hmR0VmxSetupVmreadVmwriteBitmaps(pVM);
        else
        {
            LogRelFunc(("Failed to setup shadow VMCS fields arrays. rc=%Rrc\n", rc));
            return rc;
        }
    }
#endif

    for (VMCPUID idCpu = 0; idCpu < pVM->cCpus; idCpu++)
    {
        PVMCPUCC pVCpu = VMCC_GET_CPU(pVM, idCpu);
        Log4Func(("pVCpu=%p idCpu=%RU32\n", pVCpu, pVCpu->idCpu));

        pVCpu->hmr0.s.vmx.pfnStartVm = hmR0VmxStartVmSelector;

        rc = hmR0VmxSetupVmcs(pVCpu, &pVCpu->hmr0.s.vmx.VmcsInfo,  false /* fIsNstGstVmcs */);
        if (RT_SUCCESS(rc))
        {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
            if (pVM->cpum.ro.GuestFeatures.fVmx)
            {
                rc = hmR0VmxSetupVmcs(pVCpu, &pVCpu->hmr0.s.vmx.VmcsInfoNstGst, true /* fIsNstGstVmcs */);
                if (RT_SUCCESS(rc))
                { /* likely */ }
                else
                {
                    LogRelFunc(("Nested-guest VMCS setup failed. rc=%Rrc\n", rc));
                    return rc;
                }
            }
#endif
        }
        else
        {
            LogRelFunc(("VMCS setup failed. rc=%Rrc\n", rc));
            return rc;
        }
    }

    return VINF_SUCCESS;
}


/**
 * Saves the host control registers (CR0, CR3, CR4) into the host-state area in
 * the VMCS.
 * @returns CR4 for passing along to hmR0VmxExportHostSegmentRegs.
 */
static uint64_t hmR0VmxExportHostControlRegs(void)
{
    int rc = VMXWriteVmcsNw(VMX_VMCS_HOST_CR0, ASMGetCR0());    AssertRC(rc);
    rc     = VMXWriteVmcsNw(VMX_VMCS_HOST_CR3, ASMGetCR3());    AssertRC(rc);
    uint64_t uHostCr4 = ASMGetCR4();
    rc     = VMXWriteVmcsNw(VMX_VMCS_HOST_CR4, uHostCr4);       AssertRC(rc);
    return uHostCr4;
}


/**
 * Saves the host segment registers and GDTR, IDTR, (TR, GS and FS bases) into
 * the host-state area in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   uHostCr4    The host CR4 value.
 */
static int hmR0VmxExportHostSegmentRegs(PVMCPUCC pVCpu, uint64_t uHostCr4)
{
    /*
     * If we've executed guest code using hardware-assisted VMX, the host-state bits
     * will be messed up. We should -not- save the messed up state without restoring
     * the original host-state, see @bugref{7240}.
     *
     * This apparently can happen (most likely the FPU changes), deal with it rather than
     * asserting. Was observed booting Solaris 10u10 32-bit guest.
     */
    if (pVCpu->hmr0.s.vmx.fRestoreHostFlags > VMX_RESTORE_HOST_REQUIRED)
    {
        Log4Func(("Restoring Host State: fRestoreHostFlags=%#RX32 HostCpuId=%u\n", pVCpu->hmr0.s.vmx.fRestoreHostFlags,
                  pVCpu->idCpu));
        VMXRestoreHostState(pVCpu->hmr0.s.vmx.fRestoreHostFlags, &pVCpu->hmr0.s.vmx.RestoreHost);
        pVCpu->hmr0.s.vmx.fRestoreHostFlags = 0;
    }

    /*
     * Get all the host info.
     * ASSUME it is safe to use rdfsbase and friends if the CR4.FSGSBASE bit is set
     * without also checking the cpuid bit.
     */
    uint32_t fRestoreHostFlags;
#if RT_INLINE_ASM_EXTERNAL
    if (uHostCr4 & X86_CR4_FSGSBASE)
    {
        hmR0VmxExportHostSegmentRegsAsmHlp(&pVCpu->hmr0.s.vmx.RestoreHost, true /*fHaveFsGsBase*/);
        fRestoreHostFlags = VMX_RESTORE_HOST_CAN_USE_WRFSBASE_AND_WRGSBASE;
    }
    else
    {
        hmR0VmxExportHostSegmentRegsAsmHlp(&pVCpu->hmr0.s.vmx.RestoreHost, false /*fHaveFsGsBase*/);
        fRestoreHostFlags = 0;
    }
    RTSEL uSelES = pVCpu->hmr0.s.vmx.RestoreHost.uHostSelES;
    RTSEL uSelDS = pVCpu->hmr0.s.vmx.RestoreHost.uHostSelDS;
    RTSEL uSelFS = pVCpu->hmr0.s.vmx.RestoreHost.uHostSelFS;
    RTSEL uSelGS = pVCpu->hmr0.s.vmx.RestoreHost.uHostSelGS;
#else
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR = ASMGetTR();
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelSS = ASMGetSS();
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelCS = ASMGetCS();
    ASMGetGDTR((PRTGDTR)&pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr);
    ASMGetIDTR((PRTIDTR)&pVCpu->hmr0.s.vmx.RestoreHost.HostIdtr);
    if (uHostCr4 & X86_CR4_FSGSBASE)
    {
        pVCpu->hmr0.s.vmx.RestoreHost.uHostFSBase = ASMGetFSBase();
        pVCpu->hmr0.s.vmx.RestoreHost.uHostGSBase = ASMGetGSBase();
        fRestoreHostFlags = VMX_RESTORE_HOST_CAN_USE_WRFSBASE_AND_WRGSBASE;
    }
    else
    {
        pVCpu->hmr0.s.vmx.RestoreHost.uHostFSBase = ASMRdMsr(MSR_K8_FS_BASE);
        pVCpu->hmr0.s.vmx.RestoreHost.uHostGSBase = ASMRdMsr(MSR_K8_GS_BASE);
        fRestoreHostFlags = 0;
    }
    RTSEL uSelES, uSelDS, uSelFS, uSelGS;
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelDS = uSelDS = ASMGetDS();
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelES = uSelES = ASMGetES();
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelFS = uSelFS = ASMGetFS();
    pVCpu->hmr0.s.vmx.RestoreHost.uHostSelGS = uSelGS = ASMGetGS();
#endif

    /*
     * Determine if the host segment registers are suitable for VT-x. Otherwise use zero to
     * gain VM-entry and restore them before we get preempted.
     *
     * See Intel spec. 26.2.3 "Checks on Host Segment and Descriptor-Table Registers".
     */
    RTSEL const uSelAll = uSelFS | uSelGS | uSelES | uSelDS;
    if (uSelAll & (X86_SEL_RPL | X86_SEL_LDT))
    {
        if (!(uSelAll & X86_SEL_LDT))
        {
#define VMXLOCAL_ADJUST_HOST_SEG(a_Seg, a_uVmcsVar) \
                do { \
                    (a_uVmcsVar) = pVCpu->hmr0.s.vmx.RestoreHost.uHostSel##a_Seg; \
                    if ((a_uVmcsVar) & X86_SEL_RPL) \
                    { \
                        fRestoreHostFlags |= VMX_RESTORE_HOST_SEL_##a_Seg; \
                        (a_uVmcsVar) = 0; \
                    } \
                } while (0)
            VMXLOCAL_ADJUST_HOST_SEG(DS, uSelDS);
            VMXLOCAL_ADJUST_HOST_SEG(ES, uSelES);
            VMXLOCAL_ADJUST_HOST_SEG(FS, uSelFS);
            VMXLOCAL_ADJUST_HOST_SEG(GS, uSelGS);
#undef VMXLOCAL_ADJUST_HOST_SEG
        }
        else
        {
#define VMXLOCAL_ADJUST_HOST_SEG(a_Seg, a_uVmcsVar) \
                do { \
                    (a_uVmcsVar) = pVCpu->hmr0.s.vmx.RestoreHost.uHostSel##a_Seg; \
                    if ((a_uVmcsVar) & (X86_SEL_RPL | X86_SEL_LDT)) \
                    { \
                        if (!((a_uVmcsVar) & X86_SEL_LDT)) \
                            fRestoreHostFlags |= VMX_RESTORE_HOST_SEL_##a_Seg; \
                        else \
                        { \
                            uint32_t const fAttr = ASMGetSegAttr(a_uVmcsVar); \
                            if ((fAttr & X86_DESC_P) && fAttr != UINT32_MAX) \
                                fRestoreHostFlags |= VMX_RESTORE_HOST_SEL_##a_Seg; \
                        } \
                        (a_uVmcsVar) = 0; \
                    } \
                } while (0)
            VMXLOCAL_ADJUST_HOST_SEG(DS, uSelDS);
            VMXLOCAL_ADJUST_HOST_SEG(ES, uSelES);
            VMXLOCAL_ADJUST_HOST_SEG(FS, uSelFS);
            VMXLOCAL_ADJUST_HOST_SEG(GS, uSelGS);
#undef VMXLOCAL_ADJUST_HOST_SEG
        }
    }

    /* Verification based on Intel spec. 26.2.3 "Checks on Host Segment and Descriptor-Table Registers"  */
    Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR & X86_SEL_RPL)); Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR & X86_SEL_LDT)); Assert(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR);
    Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelCS & X86_SEL_RPL)); Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelCS & X86_SEL_LDT)); Assert(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelCS);
    Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelSS & X86_SEL_RPL)); Assert(!(pVCpu->hmr0.s.vmx.RestoreHost.uHostSelSS & X86_SEL_LDT));
    Assert(!(uSelDS & X86_SEL_RPL)); Assert(!(uSelDS & X86_SEL_LDT));
    Assert(!(uSelES & X86_SEL_RPL)); Assert(!(uSelES & X86_SEL_LDT));
    Assert(!(uSelFS & X86_SEL_RPL)); Assert(!(uSelFS & X86_SEL_LDT));
    Assert(!(uSelGS & X86_SEL_RPL)); Assert(!(uSelGS & X86_SEL_LDT));

    /*
     * Determine if we need to manually need to restore the GDTR and IDTR limits as VT-x zaps
     * them to the maximum limit (0xffff) on every VM-exit.
     */
    if (pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.cb != 0xffff)
        fRestoreHostFlags |= VMX_RESTORE_HOST_GDTR;

    /*
     * IDT limit is effectively capped at 0xfff. (See Intel spec. 6.14.1 "64-Bit Mode IDT" and
     * Intel spec. 6.2 "Exception and Interrupt Vectors".)  Therefore if the host has the limit
     * as 0xfff, VT-x bloating the limit to 0xffff shouldn't cause any different CPU behavior.
     * However, several hosts either insists on 0xfff being the limit (Windows Patch Guard) or
     * uses the limit for other purposes (darwin puts the CPU ID in there but botches sidt
     * alignment in at least one consumer).  So, we're only allowing the IDTR.LIMIT to be left
     * at 0xffff on hosts where we are sure it won't cause trouble.
     */
#if defined(RT_OS_LINUX) || defined(RT_OS_SOLARIS)
    if (pVCpu->hmr0.s.vmx.RestoreHost.HostIdtr.cb <  0x0fff)
#else
    if (pVCpu->hmr0.s.vmx.RestoreHost.HostIdtr.cb != 0xffff)
#endif
        fRestoreHostFlags |= VMX_RESTORE_HOST_IDTR;

    /*
     * Host TR base. Verify that TR selector doesn't point past the GDT. Masking off the TI
     * and RPL bits is effectively what the CPU does for "scaling by 8". TI is always 0 and
     * RPL should be too in most cases.
     */
    RTSEL const uSelTR = pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR;
    AssertMsgReturn((uSelTR | X86_SEL_RPL_LDT) <= pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.cb,
                    ("TR selector exceeds limit. TR=%RTsel cbGdt=%#x\n", uSelTR, pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.cb),
                    VERR_VMX_INVALID_HOST_STATE);

    PCX86DESCHC pDesc = (PCX86DESCHC)(pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.uAddr + (uSelTR & X86_SEL_MASK));
    uintptr_t const uTRBase = X86DESC64_BASE(pDesc);

    /*
     * VT-x unconditionally restores the TR limit to 0x67 and type to 11 (32-bit busy TSS) on
     * all VM-exits. The type is the same for 64-bit busy TSS[1]. The limit needs manual
     * restoration if the host has something else. Task switching is not supported in 64-bit
     * mode[2], but the limit still matters as IOPM is supported in 64-bit mode. Restoring the
     * limit lazily while returning to ring-3 is safe because IOPM is not applicable in ring-0.
     *
     * [1] See Intel spec. 3.5 "System Descriptor Types".
     * [2] See Intel spec. 7.2.3 "TSS Descriptor in 64-bit mode".
     */
    Assert(pDesc->System.u4Type == 11);
    if (   pDesc->System.u16LimitLow != 0x67
        || pDesc->System.u4LimitHigh)
    {
        fRestoreHostFlags |= VMX_RESTORE_HOST_SEL_TR;

        /* If the host has made GDT read-only, we would need to temporarily toggle CR0.WP before writing the GDT. */
        if (g_fHmHostKernelFeatures & SUPKERNELFEATURES_GDT_READ_ONLY)
            fRestoreHostFlags |= VMX_RESTORE_HOST_GDT_READ_ONLY;
        if (g_fHmHostKernelFeatures & SUPKERNELFEATURES_GDT_NEED_WRITABLE)
        {
            /* The GDT is read-only but the writable GDT is available. */
            fRestoreHostFlags |= VMX_RESTORE_HOST_GDT_NEED_WRITABLE;
            pVCpu->hmr0.s.vmx.RestoreHost.HostGdtrRw.cb = pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.cb;
            int rc = SUPR0GetCurrentGdtRw(&pVCpu->hmr0.s.vmx.RestoreHost.HostGdtrRw.uAddr);
            AssertRCReturn(rc, rc);
        }
    }

    pVCpu->hmr0.s.vmx.fRestoreHostFlags = fRestoreHostFlags;

    /*
     * Do all the VMCS updates in one block to assist nested virtualization.
     */
    int rc;
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_CS_SEL,  pVCpu->hmr0.s.vmx.RestoreHost.uHostSelCS);       AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_SS_SEL,  pVCpu->hmr0.s.vmx.RestoreHost.uHostSelSS);       AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_DS_SEL,  uSelDS);                                         AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_ES_SEL,  uSelES);                                         AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_FS_SEL,  uSelFS);                                         AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_GS_SEL,  uSelGS);                                         AssertRC(rc);
    rc = VMXWriteVmcs16(VMX_VMCS16_HOST_TR_SEL,  pVCpu->hmr0.s.vmx.RestoreHost.uHostSelTR);       AssertRC(rc);
    rc = VMXWriteVmcsNw(VMX_VMCS_HOST_GDTR_BASE, pVCpu->hmr0.s.vmx.RestoreHost.HostGdtr.uAddr);   AssertRC(rc);
    rc = VMXWriteVmcsNw(VMX_VMCS_HOST_IDTR_BASE, pVCpu->hmr0.s.vmx.RestoreHost.HostIdtr.uAddr);   AssertRC(rc);
    rc = VMXWriteVmcsNw(VMX_VMCS_HOST_TR_BASE,   uTRBase);                                        AssertRC(rc);
    rc = VMXWriteVmcsNw(VMX_VMCS_HOST_FS_BASE,   pVCpu->hmr0.s.vmx.RestoreHost.uHostFSBase);      AssertRC(rc);
    rc = VMXWriteVmcsNw(VMX_VMCS_HOST_GS_BASE,   pVCpu->hmr0.s.vmx.RestoreHost.uHostGSBase);      AssertRC(rc);

    return VINF_SUCCESS;
}


/**
 * Exports certain host MSRs in the VM-exit MSR-load area and some in the
 * host-state area of the VMCS.
 *
 * These MSRs will be automatically restored on the host after every successful
 * VM-exit.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxExportHostMsrs(PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);

    /*
     * Save MSRs that we restore lazily (due to preemption or transition to ring-3)
     * rather than swapping them on every VM-entry.
     */
    hmR0VmxLazySaveHostMsrs(pVCpu);

    /*
     * Host Sysenter MSRs.
     */
    int rc = VMXWriteVmcs32(VMX_VMCS32_HOST_SYSENTER_CS, ASMRdMsr_Low(MSR_IA32_SYSENTER_CS));   AssertRC(rc);
    rc     = VMXWriteVmcsNw(VMX_VMCS_HOST_SYSENTER_ESP,  ASMRdMsr(MSR_IA32_SYSENTER_ESP));      AssertRC(rc);
    rc     = VMXWriteVmcsNw(VMX_VMCS_HOST_SYSENTER_EIP,  ASMRdMsr(MSR_IA32_SYSENTER_EIP));      AssertRC(rc);

    /*
     * Host EFER MSR.
     *
     * If the CPU supports the newer VMCS controls for managing EFER, use it. Otherwise it's
     * done as part of auto-load/store MSR area in the VMCS, see hmR0VmxExportGuestMsrs().
     */
    if (g_fHmVmxSupportsVmcsEfer)
    {
        rc = VMXWriteVmcs64(VMX_VMCS64_HOST_EFER_FULL, g_uHmVmxHostMsrEfer);
        AssertRC(rc);
    }

    /** @todo IA32_PERF_GLOBALCTRL, IA32_PAT also see
     *        hmR0VmxExportGuestEntryExitCtls(). */
}


/**
 * Figures out if we need to swap the EFER MSR which is particularly expensive.
 *
 * We check all relevant bits. For now, that's everything besides LMA/LME, as
 * these two bits are handled by VM-entry, see hmR0VMxExportGuestEntryExitCtls().
 *
 * @returns true if we need to load guest EFER, false otherwise.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks Requires EFER, CR4.
 * @remarks No-long-jump zone!!!
 */
static bool hmR0VmxShouldSwapEferMsr(PCVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient)
{
#ifdef HMVMX_ALWAYS_SWAP_EFER
    RT_NOREF2(pVCpu, pVmxTransient);
    return true;
#else
    PCCPUMCTX pCtx = &pVCpu->cpum.GstCtx;
    uint64_t const u64HostEfer  = g_uHmVmxHostMsrEfer;
    uint64_t const u64GuestEfer = pCtx->msrEFER;

# ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /*
     * For nested-guests, we shall honor swapping the EFER MSR when requested by
     * the nested-guest.
     */
    if (   pVmxTransient->fIsNestedGuest
        && (   CPUMIsGuestVmxEntryCtlsSet(pCtx, VMX_ENTRY_CTLS_LOAD_EFER_MSR)
            || CPUMIsGuestVmxExitCtlsSet(pCtx, VMX_EXIT_CTLS_SAVE_EFER_MSR)
            || CPUMIsGuestVmxExitCtlsSet(pCtx, VMX_EXIT_CTLS_LOAD_EFER_MSR)))
        return true;
# else
    RT_NOREF(pVmxTransient);
#endif

    /*
     * For 64-bit guests, if EFER.SCE bit differs, we need to swap the EFER MSR
     * to ensure that the guest's SYSCALL behaviour isn't broken, see @bugref{7386}.
     */
    if (   CPUMIsGuestInLongModeEx(pCtx)
        && (u64GuestEfer & MSR_K6_EFER_SCE) != (u64HostEfer & MSR_K6_EFER_SCE))
        return true;

    /*
     * If the guest uses PAE and EFER.NXE bit differs, we need to swap the EFER MSR
     * as it affects guest paging. 64-bit paging implies CR4.PAE as well.
     *
     * See Intel spec. 4.5 "IA-32e Paging".
     * See Intel spec. 4.1.1 "Three Paging Modes".
     *
     * Verify that we always intercept CR4.PAE and CR0.PG bits, so we don't need to
     * import CR4 and CR0 from the VMCS here as those bits are always up to date.
     */
    Assert(vmxHCGetFixedCr4Mask(pVCpu) & X86_CR4_PAE);
    Assert(vmxHCGetFixedCr0Mask(pVCpu) & X86_CR0_PG);
    if (   (pCtx->cr4 & X86_CR4_PAE)
        && (pCtx->cr0 & X86_CR0_PG))
    {
        /*
         * If nested paging is not used, verify that the guest paging mode matches the
         * shadow paging mode which is/will be placed in the VMCS (which is what will
         * actually be used while executing the guest and not the CR4 shadow value).
         */
        AssertMsg(   pVCpu->CTX_SUFF(pVM)->hmr0.s.fNestedPaging
                  || pVCpu->hm.s.enmShadowMode == PGMMODE_PAE
                  || pVCpu->hm.s.enmShadowMode == PGMMODE_PAE_NX
                  || pVCpu->hm.s.enmShadowMode == PGMMODE_AMD64
                  || pVCpu->hm.s.enmShadowMode == PGMMODE_AMD64_NX,
                  ("enmShadowMode=%u\n", pVCpu->hm.s.enmShadowMode));
        if ((u64GuestEfer & MSR_K6_EFER_NXE) != (u64HostEfer & MSR_K6_EFER_NXE))
        {
            /* Verify that the host is NX capable. */
            Assert(pVCpu->CTX_SUFF(pVM)->cpum.ro.HostFeatures.fNoExecute);
            return true;
        }
    }

    return false;
#endif
}


/**
 * Exports the guest's RSP into the guest-state area in the VMCS.
 *
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxExportGuestRsp(PVMCPUCC pVCpu)
{
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_RSP)
    {
        HMVMX_CPUMCTX_ASSERT(pVCpu, CPUMCTX_EXTRN_RSP);

        int rc = VMXWriteVmcsNw(VMX_VMCS_GUEST_RSP, pVCpu->cpum.GstCtx.rsp);
        AssertRC(rc);

        ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_RSP);
        Log4Func(("rsp=%#RX64\n", pVCpu->cpum.GstCtx.rsp));
    }
}


/**
 * Exports the guest hardware-virtualization state.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static int hmR0VmxExportGuestHwvirtState(PVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient)
{
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_HWVIRT)
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        /*
         * Check if the VMX feature is exposed to the guest and if the host CPU supports
         * VMCS shadowing.
         */
        if (pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fUseVmcsShadowing)
        {
            /*
             * If the nested hypervisor has loaded a current VMCS and is in VMX root mode,
             * copy the nested hypervisor's current VMCS into the shadow VMCS and enable
             * VMCS shadowing to skip intercepting some or all VMREAD/VMWRITE VM-exits.
             *
             * We check for VMX root mode here in case the guest executes VMXOFF without
             * clearing the current VMCS pointer and our VMXOFF instruction emulation does
             * not clear the current VMCS pointer.
             */
            PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
            if (   CPUMIsGuestInVmxRootMode(&pVCpu->cpum.GstCtx)
                && !CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx)
                && CPUMIsGuestVmxCurrentVmcsValid(&pVCpu->cpum.GstCtx))
            {
                /* Paranoia. */
                Assert(!pVmxTransient->fIsNestedGuest);

                /*
                 * For performance reasons, also check if the nested hypervisor's current VMCS
                 * was newly loaded or modified before copying it to the shadow VMCS.
                 */
                if (!pVCpu->hm.s.vmx.fCopiedNstGstToShadowVmcs)
                {
                    int rc = vmxHCCopyNstGstToShadowVmcs(pVCpu, pVmcsInfo);
                    AssertRCReturn(rc, rc);
                    pVCpu->hm.s.vmx.fCopiedNstGstToShadowVmcs = true;
                }
                vmxHCEnableVmcsShadowing(pVCpu, pVmcsInfo);
            }
            else
                vmxHCDisableVmcsShadowing(pVCpu, pVmcsInfo);
        }
#else
        NOREF(pVmxTransient);
#endif
        ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_HWVIRT);
    }
    return VINF_SUCCESS;
}


/**
 * Exports the guest debug registers into the guest-state area in the VMCS.
 * The guest debug bits are partially shared with the host (e.g. DR6, DR0-3).
 *
 * This also sets up whether \#DB and MOV DRx accesses cause VM-exits.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static int hmR0VmxExportSharedDebugState(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /** @todo NSTVMX: Figure out what we want to do with nested-guest instruction
     *        stepping. */
    PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
    if (pVmxTransient->fIsNestedGuest)
    {
        int rc = VMXWriteVmcsNw(VMX_VMCS_GUEST_DR7, CPUMGetGuestDR7(pVCpu));
        AssertRC(rc);

        /*
         * We don't want to always intercept MOV DRx for nested-guests as it causes
         * problems when the nested hypervisor isn't intercepting them, see @bugref{10080}.
         * Instead, they are strictly only requested when the nested hypervisor intercepts
         * them -- handled while merging VMCS controls.
         *
         * If neither the outer nor the nested-hypervisor is intercepting MOV DRx,
         * then the nested-guest debug state should be actively loaded on the host so that
         * nested-guest reads its own debug registers without causing VM-exits.
         */
        if (   !(pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_MOV_DR_EXIT)
            && !CPUMIsGuestDebugStateActive(pVCpu))
            CPUMR0LoadGuestDebugState(pVCpu, true /* include DR6 */);
        return VINF_SUCCESS;
    }

#ifdef VBOX_STRICT
    /* Validate. Intel spec. 26.3.1.1 "Checks on Guest Controls Registers, Debug Registers, MSRs" */
    if (pVmcsInfo->u32EntryCtls & VMX_ENTRY_CTLS_LOAD_DEBUG)
    {
        /* Validate. Intel spec. 17.2 "Debug Registers", recompiler paranoia checks. */
        Assert((pVCpu->cpum.GstCtx.dr[7] & (X86_DR7_MBZ_MASK | X86_DR7_RAZ_MASK)) == 0);
        Assert((pVCpu->cpum.GstCtx.dr[7] & X86_DR7_RA1_MASK) == X86_DR7_RA1_MASK);
    }
#endif

    bool     fSteppingDB      = false;
    bool     fInterceptMovDRx = false;
    uint32_t uProcCtls        = pVmcsInfo->u32ProcCtls;
    if (pVCpu->hm.s.fSingleInstruction)
    {
        /* If the CPU supports the monitor trap flag, use it for single stepping in DBGF and avoid intercepting #DB. */
        if (g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_MONITOR_TRAP_FLAG)
        {
            uProcCtls |= VMX_PROC_CTLS_MONITOR_TRAP_FLAG;
            Assert(fSteppingDB == false);
        }
        else
        {
            pVCpu->cpum.GstCtx.eflags.u32 |= X86_EFL_TF;
            pVCpu->hm.s.fCtxChanged |= HM_CHANGED_GUEST_RFLAGS;
            pVCpu->hmr0.s.fClearTrapFlag = true;
            fSteppingDB = true;
        }
    }

    uint64_t u64GuestDr7;
    if (   fSteppingDB
        || (CPUMGetHyperDR7(pVCpu) & X86_DR7_ENABLED_MASK))
    {
        /*
         * Use the combined guest and host DRx values found in the hypervisor register set
         * because the hypervisor debugger has breakpoints active or someone is single stepping
         * on the host side without a monitor trap flag.
         *
         * Note! DBGF expects a clean DR6 state before executing guest code.
         */
        if (!CPUMIsHyperDebugStateActive(pVCpu))
        {
            CPUMR0LoadHyperDebugState(pVCpu, true /* include DR6 */);
            Assert(CPUMIsHyperDebugStateActive(pVCpu));
            Assert(!CPUMIsGuestDebugStateActive(pVCpu));
        }

        /* Update DR7 with the hypervisor value (other DRx registers are handled by CPUM one way or another). */
        u64GuestDr7 = CPUMGetHyperDR7(pVCpu);
        pVCpu->hmr0.s.fUsingHyperDR7 = true;
        fInterceptMovDRx = true;
    }
    else
    {
        /*
         * If the guest has enabled debug registers, we need to load them prior to
         * executing guest code so they'll trigger at the right time.
         */
        HMVMX_CPUMCTX_ASSERT(pVCpu, CPUMCTX_EXTRN_DR7);
        if (pVCpu->cpum.GstCtx.dr[7] & (X86_DR7_ENABLED_MASK | X86_DR7_GD))
        {
            if (!CPUMIsGuestDebugStateActive(pVCpu))
            {
                CPUMR0LoadGuestDebugState(pVCpu, true /* include DR6 */);
                Assert(CPUMIsGuestDebugStateActive(pVCpu));
                Assert(!CPUMIsHyperDebugStateActive(pVCpu));
                STAM_COUNTER_INC(&pVCpu->hm.s.StatDRxArmed);
            }
            Assert(!fInterceptMovDRx);
        }
        else if (!CPUMIsGuestDebugStateActive(pVCpu))
        {
            /*
             * If no debugging enabled, we'll lazy load DR0-3.  Unlike on AMD-V, we
             * must intercept #DB in order to maintain a correct DR6 guest value, and
             * because we need to intercept it to prevent nested #DBs from hanging the
             * CPU, we end up always having to intercept it. See hmR0VmxSetupVmcsXcptBitmap().
             */
            fInterceptMovDRx = true;
        }

        /* Update DR7 with the actual guest value. */
        u64GuestDr7 = pVCpu->cpum.GstCtx.dr[7];
        pVCpu->hmr0.s.fUsingHyperDR7 = false;
    }

    if (fInterceptMovDRx)
        uProcCtls |= VMX_PROC_CTLS_MOV_DR_EXIT;
    else
        uProcCtls &= ~VMX_PROC_CTLS_MOV_DR_EXIT;

    /*
     * Update the processor-based VM-execution controls with the MOV-DRx intercepts and the
     * monitor-trap flag and update our cache.
     */
    if (uProcCtls != pVmcsInfo->u32ProcCtls)
    {
        int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC, uProcCtls);
        AssertRC(rc);
        pVmcsInfo->u32ProcCtls = uProcCtls;
    }

    /*
     * Update guest DR7.
     */
    int rc = VMXWriteVmcsNw(VMX_VMCS_GUEST_DR7, u64GuestDr7);
    AssertRC(rc);

    /*
     * If we have forced EFLAGS.TF to be set because we're single-stepping in the hypervisor debugger,
     * we need to clear interrupt inhibition if any as otherwise it causes a VM-entry failure.
     *
     * See Intel spec. 26.3.1.5 "Checks on Guest Non-Register State".
     */
    if (fSteppingDB)
    {
        Assert(pVCpu->hm.s.fSingleInstruction);
        Assert(pVCpu->cpum.GstCtx.eflags.Bits.u1TF);

        uint32_t fIntrState = 0;
        rc = VMXReadVmcs32(VMX_VMCS32_GUEST_INT_STATE, &fIntrState);
        AssertRC(rc);

        if (fIntrState & (VMX_VMCS_GUEST_INT_STATE_BLOCK_STI | VMX_VMCS_GUEST_INT_STATE_BLOCK_MOVSS))
        {
            fIntrState &= ~(VMX_VMCS_GUEST_INT_STATE_BLOCK_STI | VMX_VMCS_GUEST_INT_STATE_BLOCK_MOVSS);
            rc = VMXWriteVmcs32(VMX_VMCS32_GUEST_INT_STATE, fIntrState);
            AssertRC(rc);
        }
    }

    return VINF_SUCCESS;
}


/**
 * Exports certain guest MSRs into the VM-entry MSR-load and VM-exit MSR-store
 * areas.
 *
 * These MSRs will automatically be loaded to the host CPU on every successful
 * VM-entry and stored from the host CPU on every successful VM-exit.
 *
 * We creates/updates MSR slots for the host MSRs in the VM-exit MSR-load area. The
 * actual host MSR values are not- updated here for performance reasons. See
 * hmR0VmxExportHostMsrs().
 *
 * We also exports the guest sysenter MSRs into the guest-state area in the VMCS.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static int hmR0VmxExportGuestMsrs(PVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient)
{
    AssertPtr(pVCpu);
    AssertPtr(pVmxTransient);

    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    PCCPUMCTX pCtx = &pVCpu->cpum.GstCtx;

    /*
     * MSRs that we use the auto-load/store MSR area in the VMCS.
     * For 64-bit hosts, we load/restore them lazily, see hmR0VmxLazyLoadGuestMsrs(),
     * nothing to do here. The host MSR values are updated when it's safe in
     * hmR0VmxLazySaveHostMsrs().
     *
     * For nested-guests, the guests MSRs from the VM-entry MSR-load area are already
     * loaded (into the guest-CPU context) by the VMLAUNCH/VMRESUME instruction
     * emulation. The merged MSR permission bitmap will ensure that we get VM-exits
     * for any MSR that are not part of the lazy MSRs so we do not need to place
     * those MSRs into the auto-load/store MSR area. Nothing to do here.
     */
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_VMX_GUEST_AUTO_MSRS)
    {
        /* No auto-load/store MSRs currently. */
        ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_VMX_GUEST_AUTO_MSRS);
    }

    /*
     * Guest Sysenter MSRs.
     */
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_SYSENTER_MSR_MASK)
    {
        HMVMX_CPUMCTX_ASSERT(pVCpu, CPUMCTX_EXTRN_SYSENTER_MSRS);

        if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_SYSENTER_CS_MSR)
        {
            int rc = VMXWriteVmcs32(VMX_VMCS32_GUEST_SYSENTER_CS, pCtx->SysEnter.cs);
            AssertRC(rc);
            ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_SYSENTER_CS_MSR);
        }

        if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_SYSENTER_EIP_MSR)
        {
            int rc = VMXWriteVmcsNw(VMX_VMCS_GUEST_SYSENTER_EIP, pCtx->SysEnter.eip);
            AssertRC(rc);
            ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_SYSENTER_EIP_MSR);
        }

        if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_SYSENTER_ESP_MSR)
        {
            int rc = VMXWriteVmcsNw(VMX_VMCS_GUEST_SYSENTER_ESP, pCtx->SysEnter.esp);
            AssertRC(rc);
            ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_SYSENTER_ESP_MSR);
        }
    }

    /*
     * Guest/host EFER MSR.
     */
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_EFER_MSR)
    {
        /* Whether we are using the VMCS to swap the EFER MSR must have been
           determined earlier while exporting VM-entry/VM-exit controls. */
        Assert(!(ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_VMX_ENTRY_EXIT_CTLS));
        HMVMX_CPUMCTX_ASSERT(pVCpu, CPUMCTX_EXTRN_EFER);

        if (hmR0VmxShouldSwapEferMsr(pVCpu, pVmxTransient))
        {
            /*
             * EFER.LME is written by software, while EFER.LMA is set by the CPU to (CR0.PG & EFER.LME).
             * This means a guest can set EFER.LME=1 while CR0.PG=0 and EFER.LMA can remain 0.
             * VT-x requires that "IA-32e mode guest" VM-entry control must be identical to EFER.LMA
             * and to CR0.PG. Without unrestricted execution, CR0.PG (used for VT-x, not the shadow)
             * must always be 1. This forces us to effectively clear both EFER.LMA and EFER.LME until
             * the guest has also set CR0.PG=1. Otherwise, we would run into an invalid-guest state
             * during VM-entry.
             */
            uint64_t uGuestEferMsr = pCtx->msrEFER;
            if (!pVM->hmr0.s.vmx.fUnrestrictedGuest)
            {
                if (!(pCtx->msrEFER & MSR_K6_EFER_LMA))
                    uGuestEferMsr &= ~MSR_K6_EFER_LME;
                else
                    Assert((pCtx->msrEFER & (MSR_K6_EFER_LMA | MSR_K6_EFER_LME)) == (MSR_K6_EFER_LMA | MSR_K6_EFER_LME));
            }

            /*
             * If the CPU supports VMCS controls for swapping EFER, use it. Otherwise, we have no option
             * but to use the auto-load store MSR area in the VMCS for swapping EFER. See @bugref{7368}.
             */
            if (g_fHmVmxSupportsVmcsEfer)
            {
                int rc = VMXWriteVmcs64(VMX_VMCS64_GUEST_EFER_FULL, uGuestEferMsr);
                AssertRC(rc);
            }
            else
            {
                /*
                 * We shall use the auto-load/store MSR area only for loading the EFER MSR but we must
                 * continue to intercept guest read and write accesses to it, see @bugref{7386#c16}.
                 */
                int rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, MSR_K6_EFER, uGuestEferMsr,
                                                    false /* fSetReadWrite */, false /* fUpdateHostMsr */);
                AssertRCReturn(rc, rc);
            }

            Log4Func(("efer=%#RX64 shadow=%#RX64\n", uGuestEferMsr, pCtx->msrEFER));
        }
        else if (!g_fHmVmxSupportsVmcsEfer)
            hmR0VmxRemoveAutoLoadStoreMsr(pVCpu, pVmxTransient, MSR_K6_EFER);

        ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_EFER_MSR);
    }

    /*
     * Other MSRs.
     */
    if (ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged) & HM_CHANGED_GUEST_OTHER_MSRS)
    {
        /* Speculation Control (R/W). */
        HMVMX_CPUMCTX_ASSERT(pVCpu, HM_CHANGED_GUEST_OTHER_MSRS);
        if (pVM->cpum.ro.GuestFeatures.fIbrs)
        {
            int rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, MSR_IA32_SPEC_CTRL, CPUMGetGuestSpecCtrl(pVCpu),
                                                false /* fSetReadWrite */, false /* fUpdateHostMsr */);
            AssertRCReturn(rc, rc);
        }

        /* Last Branch Record. */
        if (pVM->hmr0.s.vmx.fLbr)
        {
            PVMXVMCSINFOSHARED const pVmcsInfoShared = pVmxTransient->pVmcsInfo->pShared;
            uint32_t const idFromIpMsrStart = pVM->hmr0.s.vmx.idLbrFromIpMsrFirst;
            uint32_t const idToIpMsrStart   = pVM->hmr0.s.vmx.idLbrToIpMsrFirst;
            uint32_t const cLbrStack        = pVM->hmr0.s.vmx.idLbrFromIpMsrLast - pVM->hmr0.s.vmx.idLbrFromIpMsrFirst + 1;
            Assert(cLbrStack <= 32);
            for (uint32_t i = 0; i < cLbrStack; i++)
            {
                int rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, idFromIpMsrStart + i,
                                                    pVmcsInfoShared->au64LbrFromIpMsr[i],
                                                    false /* fSetReadWrite */, false /* fUpdateHostMsr */);
                AssertRCReturn(rc, rc);

                /* Some CPUs don't have a Branch-To-IP MSR (P4 and related Xeons). */
                if (idToIpMsrStart != 0)
                {
                    rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, idToIpMsrStart + i,
                                                    pVmcsInfoShared->au64LbrToIpMsr[i],
                                                    false /* fSetReadWrite */, false /* fUpdateHostMsr */);
                    AssertRCReturn(rc, rc);
                }
            }

            /* Add LBR top-of-stack MSR (which contains the index to the most recent record). */
            int rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, pVM->hmr0.s.vmx.idLbrTosMsr,
                                                pVmcsInfoShared->u64LbrTosMsr, false /* fSetReadWrite */,
                                                false /* fUpdateHostMsr */);
            AssertRCReturn(rc, rc);
        }

        ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~HM_CHANGED_GUEST_OTHER_MSRS);
    }

    return VINF_SUCCESS;
}


/**
 * Wrapper for running the guest code in VT-x.
 *
 * @returns VBox status code, no informational status codes.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
DECLINLINE(int) hmR0VmxRunGuest(PVMCPUCC pVCpu, PCVMXTRANSIENT pVmxTransient)
{
    /* Mark that HM is the keeper of all guest-CPU registers now that we're going to execute guest code. */
    pVCpu->cpum.GstCtx.fExtrn |= HMVMX_CPUMCTX_EXTRN_ALL | CPUMCTX_EXTRN_KEEPER_HM;

    PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
    bool const   fResumeVM = RT_BOOL(pVmcsInfo->fVmcsState & VMX_V_VMCS_LAUNCH_STATE_LAUNCHED);
#ifdef VBOX_WITH_STATISTICS
    if (fResumeVM)
        STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxVmResume);
    else
        STAM_COUNTER_INC(&pVCpu->hm.s.StatVmxVmLaunch);
#endif
    int rc = pVCpu->hmr0.s.vmx.pfnStartVm(pVmcsInfo, pVCpu, fResumeVM);
    AssertMsg(rc <= VINF_SUCCESS, ("%Rrc\n", rc));
    return rc;
}


/**
 * Reports world-switch error and dumps some useful debug info.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   rcVMRun         The return code from VMLAUNCH/VMRESUME.
 * @param   pVmxTransient   The VMX-transient structure (only
 *                          exitReason updated).
 */
static void hmR0VmxReportWorldSwitchError(PVMCPUCC pVCpu, int rcVMRun, PVMXTRANSIENT pVmxTransient)
{
    Assert(pVCpu);
    Assert(pVmxTransient);
    HMVMX_ASSERT_PREEMPT_SAFE(pVCpu);

    Log4Func(("VM-entry failure: %Rrc\n", rcVMRun));
    switch (rcVMRun)
    {
        case VERR_VMX_INVALID_VMXON_PTR:
            AssertFailed();
            break;
        case VINF_SUCCESS:                  /* VMLAUNCH/VMRESUME succeeded but VM-entry failed... yeah, true story. */
        case VERR_VMX_UNABLE_TO_START_VM:   /* VMLAUNCH/VMRESUME itself failed. */
        {
            int rc = VMXReadVmcs32(VMX_VMCS32_RO_EXIT_REASON, &pVCpu->hm.s.vmx.LastError.u32ExitReason);
            rc    |= VMXReadVmcs32(VMX_VMCS32_RO_VM_INSTR_ERROR, &pVCpu->hm.s.vmx.LastError.u32InstrError);
            AssertRC(rc);
            vmxHCReadExitQualVmcs(pVCpu, pVmxTransient);

            pVCpu->hm.s.vmx.LastError.idEnteredCpu = pVCpu->hmr0.s.idEnteredCpu;
            /* LastError.idCurrentCpu was already updated in hmR0VmxPreRunGuestCommitted().
               Cannot do it here as we may have been long preempted. */

#ifdef VBOX_STRICT
                PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
                Log4(("uExitReason        %#RX32 (VmxTransient %#RX16)\n", pVCpu->hm.s.vmx.LastError.u32ExitReason,
                     pVmxTransient->uExitReason));
                Log4(("Exit Qualification %#RX64\n", pVmxTransient->uExitQual));
                Log4(("InstrError         %#RX32\n", pVCpu->hm.s.vmx.LastError.u32InstrError));
                if (pVCpu->hm.s.vmx.LastError.u32InstrError <= HMVMX_INSTR_ERROR_MAX)
                    Log4(("InstrError Desc.  \"%s\"\n", g_apszVmxInstrErrors[pVCpu->hm.s.vmx.LastError.u32InstrError]));
                else
                    Log4(("InstrError Desc.    Range exceeded %u\n", HMVMX_INSTR_ERROR_MAX));
                Log4(("Entered host CPU   %u\n", pVCpu->hm.s.vmx.LastError.idEnteredCpu));
                Log4(("Current host CPU   %u\n", pVCpu->hm.s.vmx.LastError.idCurrentCpu));

                static struct
                {
                    /** Name of the field to log. */
                    const char     *pszName;
                    /** The VMCS field. */
                    uint32_t        uVmcsField;
                    /** Whether host support of this field needs to be checked. */
                    bool            fCheckSupport;
                } const s_aVmcsFields[] =
                {
                    { "VMX_VMCS32_CTRL_PIN_EXEC",                 VMX_VMCS32_CTRL_PIN_EXEC,                   false  },
                    { "VMX_VMCS32_CTRL_PROC_EXEC",                VMX_VMCS32_CTRL_PROC_EXEC,                  false  },
                    { "VMX_VMCS32_CTRL_PROC_EXEC2",               VMX_VMCS32_CTRL_PROC_EXEC2,                 true   },
                    { "VMX_VMCS32_CTRL_ENTRY",                    VMX_VMCS32_CTRL_ENTRY,                      false  },
                    { "VMX_VMCS32_CTRL_EXIT",                     VMX_VMCS32_CTRL_EXIT,                       false  },
                    { "VMX_VMCS32_CTRL_CR3_TARGET_COUNT",         VMX_VMCS32_CTRL_CR3_TARGET_COUNT,           false  },
                    { "VMX_VMCS32_CTRL_ENTRY_INTERRUPTION_INFO",  VMX_VMCS32_CTRL_ENTRY_INTERRUPTION_INFO,    false  },
                    { "VMX_VMCS32_CTRL_ENTRY_EXCEPTION_ERRCODE",  VMX_VMCS32_CTRL_ENTRY_EXCEPTION_ERRCODE,    false  },
                    { "VMX_VMCS32_CTRL_ENTRY_INSTR_LENGTH",       VMX_VMCS32_CTRL_ENTRY_INSTR_LENGTH,         false  },
                    { "VMX_VMCS32_CTRL_TPR_THRESHOLD",            VMX_VMCS32_CTRL_TPR_THRESHOLD,              false  },
                    { "VMX_VMCS32_CTRL_EXIT_MSR_STORE_COUNT",     VMX_VMCS32_CTRL_EXIT_MSR_STORE_COUNT,       false  },
                    { "VMX_VMCS32_CTRL_EXIT_MSR_LOAD_COUNT",      VMX_VMCS32_CTRL_EXIT_MSR_LOAD_COUNT,        false  },
                    { "VMX_VMCS32_CTRL_ENTRY_MSR_LOAD_COUNT",     VMX_VMCS32_CTRL_ENTRY_MSR_LOAD_COUNT,       false  },
                    { "VMX_VMCS32_CTRL_EXCEPTION_BITMAP",         VMX_VMCS32_CTRL_EXCEPTION_BITMAP,           false  },
                    { "VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MASK",     VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MASK,       false  },
                    { "VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MATCH",    VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MATCH,      false  },
                    { "VMX_VMCS_CTRL_CR0_MASK",                   VMX_VMCS_CTRL_CR0_MASK,                     false  },
                    { "VMX_VMCS_CTRL_CR0_READ_SHADOW",            VMX_VMCS_CTRL_CR0_READ_SHADOW,              false  },
                    { "VMX_VMCS_CTRL_CR4_MASK",                   VMX_VMCS_CTRL_CR4_MASK,                     false  },
                    { "VMX_VMCS_CTRL_CR4_READ_SHADOW",            VMX_VMCS_CTRL_CR4_READ_SHADOW,              false  },
                    { "VMX_VMCS64_CTRL_EPTP_FULL",                VMX_VMCS64_CTRL_EPTP_FULL,                  true   },
                    { "VMX_VMCS_GUEST_RIP",                       VMX_VMCS_GUEST_RIP,                         false  },
                    { "VMX_VMCS_GUEST_RSP",                       VMX_VMCS_GUEST_RSP,                         false  },
                    { "VMX_VMCS_GUEST_RFLAGS",                    VMX_VMCS_GUEST_RFLAGS,                      false  },
                    { "VMX_VMCS16_VPID",                          VMX_VMCS16_VPID,                            true,  },
                    { "VMX_VMCS_HOST_CR0",                        VMX_VMCS_HOST_CR0,                          false  },
                    { "VMX_VMCS_HOST_CR3",                        VMX_VMCS_HOST_CR3,                          false  },
                    { "VMX_VMCS_HOST_CR4",                        VMX_VMCS_HOST_CR4,                          false  },
                    /* The order of selector fields below are fixed! */
                    { "VMX_VMCS16_HOST_ES_SEL",                   VMX_VMCS16_HOST_ES_SEL,                     false  },
                    { "VMX_VMCS16_HOST_CS_SEL",                   VMX_VMCS16_HOST_CS_SEL,                     false  },
                    { "VMX_VMCS16_HOST_SS_SEL",                   VMX_VMCS16_HOST_SS_SEL,                     false  },
                    { "VMX_VMCS16_HOST_DS_SEL",                   VMX_VMCS16_HOST_DS_SEL,                     false  },
                    { "VMX_VMCS16_HOST_FS_SEL",                   VMX_VMCS16_HOST_FS_SEL,                     false  },
                    { "VMX_VMCS16_HOST_GS_SEL",                   VMX_VMCS16_HOST_GS_SEL,                     false  },
                    { "VMX_VMCS16_HOST_TR_SEL",                   VMX_VMCS16_HOST_TR_SEL,                     false  },
                    /* End of ordered selector fields. */
                    { "VMX_VMCS_HOST_TR_BASE",                    VMX_VMCS_HOST_TR_BASE,                      false  },
                    { "VMX_VMCS_HOST_GDTR_BASE",                  VMX_VMCS_HOST_GDTR_BASE,                    false  },
                    { "VMX_VMCS_HOST_IDTR_BASE",                  VMX_VMCS_HOST_IDTR_BASE,                    false  },
                    { "VMX_VMCS32_HOST_SYSENTER_CS",              VMX_VMCS32_HOST_SYSENTER_CS,                false  },
                    { "VMX_VMCS_HOST_SYSENTER_EIP",               VMX_VMCS_HOST_SYSENTER_EIP,                 false  },
                    { "VMX_VMCS_HOST_SYSENTER_ESP",               VMX_VMCS_HOST_SYSENTER_ESP,                 false  },
                    { "VMX_VMCS_HOST_RSP",                        VMX_VMCS_HOST_RSP,                          false  },
                    { "VMX_VMCS_HOST_RIP",                        VMX_VMCS_HOST_RIP,                          false  }
                };

                RTGDTR      HostGdtr;
                ASMGetGDTR(&HostGdtr);

                uint32_t const cVmcsFields = RT_ELEMENTS(s_aVmcsFields);
                for (uint32_t i = 0; i < cVmcsFields; i++)
                {
                    uint32_t const uVmcsField = s_aVmcsFields[i].uVmcsField;

                    bool fSupported;
                    if (!s_aVmcsFields[i].fCheckSupport)
                        fSupported = true;
                    else
                    {
                        PVMCC pVM = pVCpu->CTX_SUFF(pVM);
                        switch (uVmcsField)
                        {
                            case VMX_VMCS64_CTRL_EPTP_FULL:  fSupported = pVM->hmr0.s.fNestedPaging;    break;
                            case VMX_VMCS16_VPID:            fSupported = pVM->hmr0.s.vmx.fVpid;          break;
                            case VMX_VMCS32_CTRL_PROC_EXEC2:
                                fSupported = RT_BOOL(pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_SECONDARY_CTLS);
                                break;
                            default:
                                AssertMsgFailedReturnVoid(("Failed to provide VMCS field support for %#RX32\n", uVmcsField));
                        }
                    }

                    if (fSupported)
                    {
                        uint8_t const uWidth = RT_BF_GET(uVmcsField, VMX_BF_VMCSFIELD_WIDTH);
                        switch (uWidth)
                        {
                            case VMX_VMCSFIELD_WIDTH_16BIT:
                            {
                                uint16_t u16Val;
                                rc = VMXReadVmcs16(uVmcsField, &u16Val);
                                AssertRC(rc);
                                Log4(("%-40s = %#RX16\n", s_aVmcsFields[i].pszName, u16Val));

                                if (   uVmcsField >= VMX_VMCS16_HOST_ES_SEL
                                    && uVmcsField <= VMX_VMCS16_HOST_TR_SEL)
                                {
                                    if (u16Val < HostGdtr.cbGdt)
                                    {
                                        /* Order of selectors in s_apszSel is fixed and matches the order in s_aVmcsFields. */
                                        static const char * const s_apszSel[] = { "Host ES", "Host CS", "Host SS", "Host DS",
                                                                                  "Host FS", "Host GS", "Host TR" };
                                        uint8_t const idxSel = RT_BF_GET(uVmcsField, VMX_BF_VMCSFIELD_INDEX);
                                        Assert(idxSel < RT_ELEMENTS(s_apszSel));
                                        PCX86DESCHC pDesc = (PCX86DESCHC)(HostGdtr.pGdt + (u16Val & X86_SEL_MASK));
                                        hmR0DumpDescriptor(pDesc, u16Val, s_apszSel[idxSel]);
                                    }
                                    else
                                        Log4(("  Selector value exceeds GDT limit!\n"));
                                }
                                break;
                            }

                            case VMX_VMCSFIELD_WIDTH_32BIT:
                            {
                                uint32_t u32Val;
                                rc = VMXReadVmcs32(uVmcsField, &u32Val);
                                AssertRC(rc);
                                Log4(("%-40s = %#RX32\n", s_aVmcsFields[i].pszName, u32Val));
                                break;
                            }

                            case VMX_VMCSFIELD_WIDTH_64BIT:
                            case VMX_VMCSFIELD_WIDTH_NATURAL:
                            {
                                uint64_t u64Val;
                                rc = VMXReadVmcs64(uVmcsField, &u64Val);
                                AssertRC(rc);
                                Log4(("%-40s = %#RX64\n", s_aVmcsFields[i].pszName, u64Val));
                                break;
                            }
                        }
                    }
                }

                Log4(("MSR_K6_EFER            = %#RX64\n", ASMRdMsr(MSR_K6_EFER)));
                Log4(("MSR_K8_CSTAR           = %#RX64\n", ASMRdMsr(MSR_K8_CSTAR)));
                Log4(("MSR_K8_LSTAR           = %#RX64\n", ASMRdMsr(MSR_K8_LSTAR)));
                Log4(("MSR_K6_STAR            = %#RX64\n", ASMRdMsr(MSR_K6_STAR)));
                Log4(("MSR_K8_SF_MASK         = %#RX64\n", ASMRdMsr(MSR_K8_SF_MASK)));
                Log4(("MSR_K8_KERNEL_GS_BASE  = %#RX64\n", ASMRdMsr(MSR_K8_KERNEL_GS_BASE)));
#endif /* VBOX_STRICT */
            break;
        }

        default:
            /* Impossible */
            AssertMsgFailed(("hmR0VmxReportWorldSwitchError %Rrc (%#x)\n", rcVMRun, rcVMRun));
            break;
    }
}


/**
 * Sets up the usage of TSC-offsetting and updates the VMCS.
 *
 * If offsetting is not possible, cause VM-exits on RDTSC(P)s. Also sets up the
 * VMX-preemption timer.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   idCurrentCpu    The current CPU number.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxUpdateTscOffsettingAndPreemptTimer(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient, RTCPUID idCurrentCpu)
{
    bool         fOffsettedTsc;
    bool         fParavirtTsc;
    uint64_t     uTscOffset;
    PVMCC        pVM       = pVCpu->CTX_SUFF(pVM);
    PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);

    if (pVM->hmr0.s.vmx.fUsePreemptTimer)
    {
        /* The TMCpuTickGetDeadlineAndTscOffset function is expensive (calling it on
           every entry slowed down the bs2-test1 CPUID testcase by ~33% (on an 10980xe). */
        uint64_t cTicksToDeadline;
        if (   idCurrentCpu == pVCpu->hmr0.s.idLastCpu
            && TMVirtualSyncIsCurrentDeadlineVersion(pVM, pVCpu->hmr0.s.vmx.uTscDeadlineVersion))
        {
            STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatVmxPreemptionReusingDeadline);
            fOffsettedTsc = TMCpuTickCanUseRealTSC(pVM, pVCpu, &uTscOffset, &fParavirtTsc);
            cTicksToDeadline = pVCpu->hmr0.s.vmx.uTscDeadline - SUPReadTsc();
            if ((int64_t)cTicksToDeadline > 0)
            { /* hopefully */ }
            else
            {
                STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatVmxPreemptionReusingDeadlineExpired);
                cTicksToDeadline = 0;
            }
        }
        else
        {
            STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatVmxPreemptionRecalcingDeadline);
            cTicksToDeadline = TMCpuTickGetDeadlineAndTscOffset(pVM, pVCpu, &uTscOffset, &fOffsettedTsc, &fParavirtTsc,
                                                                &pVCpu->hmr0.s.vmx.uTscDeadline,
                                                                &pVCpu->hmr0.s.vmx.uTscDeadlineVersion);
            pVCpu->hmr0.s.vmx.uTscDeadline += cTicksToDeadline;
            if (cTicksToDeadline >= 128)
            { /* hopefully */ }
            else
                STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatVmxPreemptionRecalcingDeadlineExpired);
        }

        /* Make sure the returned values have sane upper and lower boundaries. */
        uint64_t const u64CpuHz = SUPGetCpuHzFromGipBySetIndex(g_pSUPGlobalInfoPage, pVCpu->iHostCpuSet);
        cTicksToDeadline   = RT_MIN(cTicksToDeadline, u64CpuHz / 64);      /* 1/64th of a second,  15.625ms. */ /** @todo r=bird: Once real+virtual timers move to separate thread, we can raise the upper limit (16ms isn't much). ASSUMES working poke cpu function. */
        cTicksToDeadline   = RT_MAX(cTicksToDeadline, u64CpuHz / 32678);   /* 1/32768th of a second,  ~30us. */
        cTicksToDeadline >>= pVM->hm.s.vmx.cPreemptTimerShift;

        /** @todo r=ramshankar: We need to find a way to integrate nested-guest
         *        preemption timers here. We probably need to clamp the preemption timer,
         *        after converting the timer value to the host. */
        uint32_t const cPreemptionTickCount = (uint32_t)RT_MIN(cTicksToDeadline, UINT32_MAX - 16);
        int rc = VMXWriteVmcs32(VMX_VMCS32_PREEMPT_TIMER_VALUE, cPreemptionTickCount);
        AssertRC(rc);
    }
    else
        fOffsettedTsc = TMCpuTickCanUseRealTSC(pVM, pVCpu, &uTscOffset, &fParavirtTsc);

    if (fParavirtTsc)
    {
        /* Currently neither Hyper-V nor KVM need to update their paravirt. TSC
           information before every VM-entry, hence disable it for performance sake. */
#if 0
        int rc = GIMR0UpdateParavirtTsc(pVM, 0 /* u64Offset */);
        AssertRC(rc);
#endif
        STAM_COUNTER_INC(&pVCpu->hm.s.StatTscParavirt);
    }

    if (   fOffsettedTsc
        && RT_LIKELY(!pVCpu->hmr0.s.fDebugWantRdTscExit))
    {
        if (pVmxTransient->fIsNestedGuest)
            uTscOffset = CPUMApplyNestedGuestTscOffset(pVCpu, uTscOffset);
        hmR0VmxSetTscOffsetVmcs(pVmcsInfo, uTscOffset);
        hmR0VmxRemoveProcCtlsVmcs(pVCpu, pVmxTransient, VMX_PROC_CTLS_RDTSC_EXIT);
    }
    else
    {
        /* We can't use TSC-offsetting (non-fixed TSC, warp drive active etc.), VM-exit on RDTSC(P). */
        hmR0VmxSetProcCtlsVmcs(pVmxTransient, VMX_PROC_CTLS_RDTSC_EXIT);
    }
}


/**
 * Worker for VMXR0ImportStateOnDemand.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object.
 * @param   fWhat       What to import, CPUMCTX_EXTRN_XXX.
 */
static int hmR0VmxImportGuestState(PVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfo, uint64_t fWhat)
{
    int      rc   = VINF_SUCCESS;
    PVMCC    pVM  = pVCpu->CTX_SUFF(pVM);
    PCPUMCTX pCtx = &pVCpu->cpum.GstCtx;
    uint32_t u32Val;

    /*
     * Note! This is hack to workaround a mysterious BSOD observed with release builds
     *       on Windows 10 64-bit hosts. Profile and debug builds are not affected and
     *       neither are other host platforms.
     *
     *       Committing this temporarily as it prevents BSOD.
     *
     * Update: This is very likely a compiler optimization bug, see @bugref{9180}.
     */
#ifdef RT_OS_WINDOWS
    if (pVM == 0 || pVM == (void *)(uintptr_t)-1)
        return VERR_HM_IPE_1;
#endif

    STAM_PROFILE_ADV_START(&pVCpu->hm.s.StatImportGuestState, x);

    /*
     * We disable interrupts to make the updating of the state and in particular
     * the fExtrn modification atomic wrt to preemption hooks.
     */
    RTCCUINTREG const fEFlags = ASMIntDisableFlags();

    fWhat &= pCtx->fExtrn;
    if (fWhat)
    {
        do
        {
            if (fWhat & CPUMCTX_EXTRN_RIP)
                vmxHCImportGuestRip(pVCpu);

            if (fWhat & CPUMCTX_EXTRN_RFLAGS)
                vmxHCImportGuestRFlags(pVCpu, pVmcsInfo);

            if (fWhat & (CPUMCTX_EXTRN_INHIBIT_INT | CPUMCTX_EXTRN_INHIBIT_NMI))
                vmxHCImportGuestIntrState(pVCpu, pVmcsInfo);

            if (fWhat & CPUMCTX_EXTRN_RSP)
            {
                rc = VMXReadVmcsNw(VMX_VMCS_GUEST_RSP, &pCtx->rsp);
                AssertRC(rc);
            }

            if (fWhat & CPUMCTX_EXTRN_SREG_MASK)
            {
                PVMXVMCSINFOSHARED pVmcsInfoShared = pVmcsInfo->pShared;
                bool const fRealOnV86Active = pVmcsInfoShared->RealMode.fRealOnV86Active;
                if (fWhat & CPUMCTX_EXTRN_CS)
                {
                    vmxHCImportGuestSegReg(pVCpu, X86_SREG_CS);
                    vmxHCImportGuestRip(pVCpu);
                    if (fRealOnV86Active)
                        pCtx->cs.Attr.u = pVmcsInfoShared->RealMode.AttrCS.u;
                    EMHistoryUpdatePC(pVCpu, pCtx->cs.u64Base + pCtx->rip, true /* fFlattened */);
                }
                if (fWhat & CPUMCTX_EXTRN_SS)
                {
                    vmxHCImportGuestSegReg(pVCpu, X86_SREG_SS);
                    if (fRealOnV86Active)
                        pCtx->ss.Attr.u = pVmcsInfoShared->RealMode.AttrSS.u;
                }
                if (fWhat & CPUMCTX_EXTRN_DS)
                {
                    vmxHCImportGuestSegReg(pVCpu, X86_SREG_DS);
                    if (fRealOnV86Active)
                        pCtx->ds.Attr.u = pVmcsInfoShared->RealMode.AttrDS.u;
                }
                if (fWhat & CPUMCTX_EXTRN_ES)
                {
                    vmxHCImportGuestSegReg(pVCpu, X86_SREG_ES);
                    if (fRealOnV86Active)
                        pCtx->es.Attr.u = pVmcsInfoShared->RealMode.AttrES.u;
                }
                if (fWhat & CPUMCTX_EXTRN_FS)
                {
                    vmxHCImportGuestSegReg(pVCpu, X86_SREG_FS);
                    if (fRealOnV86Active)
                        pCtx->fs.Attr.u = pVmcsInfoShared->RealMode.AttrFS.u;
                }
                if (fWhat & CPUMCTX_EXTRN_GS)
                {
                    vmxHCImportGuestSegReg(pVCpu, X86_SREG_GS);
                    if (fRealOnV86Active)
                        pCtx->gs.Attr.u = pVmcsInfoShared->RealMode.AttrGS.u;
                }
            }

            if (fWhat & CPUMCTX_EXTRN_TABLE_MASK)
            {
                if (fWhat & CPUMCTX_EXTRN_LDTR)
                    vmxHCImportGuestLdtr(pVCpu);

                if (fWhat & CPUMCTX_EXTRN_GDTR)
                {
                    rc = VMXReadVmcsNw(VMX_VMCS_GUEST_GDTR_BASE,    &pCtx->gdtr.pGdt);  AssertRC(rc);
                    rc = VMXReadVmcs32(VMX_VMCS32_GUEST_GDTR_LIMIT, &u32Val);           AssertRC(rc);
                    pCtx->gdtr.cbGdt = u32Val;
                }

                /* Guest IDTR. */
                if (fWhat & CPUMCTX_EXTRN_IDTR)
                {
                    rc = VMXReadVmcsNw(VMX_VMCS_GUEST_IDTR_BASE,    &pCtx->idtr.pIdt);  AssertRC(rc);
                    rc = VMXReadVmcs32(VMX_VMCS32_GUEST_IDTR_LIMIT, &u32Val);           AssertRC(rc);
                    pCtx->idtr.cbIdt = u32Val;
                }

                /* Guest TR. */
                if (fWhat & CPUMCTX_EXTRN_TR)
                {
                    /* Real-mode emulation using virtual-8086 mode has the fake TSS (pRealModeTSS) in TR,
                       don't need to import that one. */
                    if (!pVmcsInfo->pShared->RealMode.fRealOnV86Active)
                        vmxHCImportGuestTr(pVCpu);
                }
            }

            if (fWhat & CPUMCTX_EXTRN_DR7)
            {
                if (!pVCpu->hmr0.s.fUsingHyperDR7)
                {
                    rc = VMXReadVmcsNw(VMX_VMCS_GUEST_DR7, &pCtx->dr[7]);
                    AssertRC(rc);
                }
            }

            if (fWhat & CPUMCTX_EXTRN_SYSENTER_MSRS)
            {
                rc = VMXReadVmcsNw(VMX_VMCS_GUEST_SYSENTER_EIP,  &pCtx->SysEnter.eip);  AssertRC(rc);
                rc = VMXReadVmcsNw(VMX_VMCS_GUEST_SYSENTER_ESP,  &pCtx->SysEnter.esp);  AssertRC(rc);
                rc = VMXReadVmcs32(VMX_VMCS32_GUEST_SYSENTER_CS, &u32Val);              AssertRC(rc);
                pCtx->SysEnter.cs = u32Val;
            }

            if (fWhat & CPUMCTX_EXTRN_KERNEL_GS_BASE)
            {
                if (   pVM->hmr0.s.fAllow64BitGuests
                    && (pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST))
                    pCtx->msrKERNELGSBASE = ASMRdMsr(MSR_K8_KERNEL_GS_BASE);
            }

            if (fWhat & CPUMCTX_EXTRN_SYSCALL_MSRS)
            {
                if (   pVM->hmr0.s.fAllow64BitGuests
                    && (pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST))
                {
                    pCtx->msrLSTAR  = ASMRdMsr(MSR_K8_LSTAR);
                    pCtx->msrSTAR   = ASMRdMsr(MSR_K6_STAR);
                    pCtx->msrSFMASK = ASMRdMsr(MSR_K8_SF_MASK);
                }
            }

            if (fWhat & (CPUMCTX_EXTRN_TSC_AUX | CPUMCTX_EXTRN_OTHER_MSRS))
            {
                PVMXVMCSINFOSHARED pVmcsInfoShared = pVmcsInfo->pShared;
                PCVMXAUTOMSR       pMsrs           = (PCVMXAUTOMSR)pVmcsInfo->pvGuestMsrStore;
                uint32_t const     cMsrs           = pVmcsInfo->cExitMsrStore;
                Assert(pMsrs);
                Assert(cMsrs <= VMX_MISC_MAX_MSRS(g_HmMsrs.u.vmx.u64Misc));
                Assert(sizeof(*pMsrs) * cMsrs <= X86_PAGE_4K_SIZE);
                for (uint32_t i = 0; i < cMsrs; i++)
                {
                    uint32_t const idMsr = pMsrs[i].u32Msr;
                    switch (idMsr)
                    {
                        case MSR_K8_TSC_AUX:        CPUMSetGuestTscAux(pVCpu, pMsrs[i].u64Value);     break;
                        case MSR_IA32_SPEC_CTRL:    CPUMSetGuestSpecCtrl(pVCpu, pMsrs[i].u64Value);   break;
                        case MSR_K6_EFER:           /* Can't be changed without causing a VM-exit */  break;
                        default:
                        {
                            uint32_t idxLbrMsr;
                            if (pVM->hmr0.s.vmx.fLbr)
                            {
                                if (hmR0VmxIsLbrBranchFromMsr(pVM, idMsr, &idxLbrMsr))
                                {
                                    Assert(idxLbrMsr < RT_ELEMENTS(pVmcsInfoShared->au64LbrFromIpMsr));
                                    pVmcsInfoShared->au64LbrFromIpMsr[idxLbrMsr] = pMsrs[i].u64Value;
                                    break;
                                }
                                if (hmR0VmxIsLbrBranchToMsr(pVM, idMsr, &idxLbrMsr))
                                {
                                    Assert(idxLbrMsr < RT_ELEMENTS(pVmcsInfoShared->au64LbrFromIpMsr));
                                    pVmcsInfoShared->au64LbrToIpMsr[idxLbrMsr] = pMsrs[i].u64Value;
                                    break;
                                }
                                if (idMsr == pVM->hmr0.s.vmx.idLbrTosMsr)
                                {
                                    pVmcsInfoShared->u64LbrTosMsr = pMsrs[i].u64Value;
                                    break;
                                }
                                /* Fallthru (no break) */
                            }
                            pCtx->fExtrn = 0;
                            pVCpu->hm.s.u32HMError = pMsrs->u32Msr;
                            ASMSetFlags(fEFlags);
                            AssertMsgFailed(("Unexpected MSR in auto-load/store area. idMsr=%#RX32 cMsrs=%u\n", idMsr, cMsrs));
                            return VERR_HM_UNEXPECTED_LD_ST_MSR;
                        }
                    }
                }
            }

            if (fWhat & CPUMCTX_EXTRN_CR_MASK)
            {
                if (fWhat & CPUMCTX_EXTRN_CR0)
                {
                    uint64_t u64Cr0;
                    uint64_t u64Shadow;
                    rc = VMXReadVmcsNw(VMX_VMCS_GUEST_CR0,            &u64Cr0);       AssertRC(rc);
                    rc = VMXReadVmcsNw(VMX_VMCS_CTRL_CR0_READ_SHADOW, &u64Shadow);    AssertRC(rc);
#ifndef VBOX_WITH_NESTED_HWVIRT_VMX
                    u64Cr0 = (u64Cr0    & ~pVmcsInfo->u64Cr0Mask)
                           | (u64Shadow &  pVmcsInfo->u64Cr0Mask);
#else
                    if (!CPUMIsGuestInVmxNonRootMode(pCtx))
                    {
                        u64Cr0 = (u64Cr0    & ~pVmcsInfo->u64Cr0Mask)
                               | (u64Shadow &  pVmcsInfo->u64Cr0Mask);
                    }
                    else
                    {
                        /*
                         * We've merged the guest and nested-guest's CR0 guest/host mask while executing
                         * the nested-guest using hardware-assisted VMX. Accordingly we need to
                         * re-construct CR0. See @bugref{9180#c95} for details.
                         */
                        PCVMXVMCSINFO const pVmcsInfoGst = &pVCpu->hmr0.s.vmx.VmcsInfo;
                        PVMXVVMCS const     pVmcsNstGst  = &pVCpu->cpum.GstCtx.hwvirt.vmx.Vmcs;
                        u64Cr0 = (u64Cr0                     & ~pVmcsInfo->u64Cr0Mask)
                               | (pVmcsNstGst->u64GuestCr0.u &  pVmcsNstGst->u64Cr0Mask.u)
                               | (u64Shadow                  & (pVmcsInfoGst->u64Cr0Mask & ~pVmcsNstGst->u64Cr0Mask.u));
                    }
#endif
                    VMMRZCallRing3Disable(pVCpu);   /* May call into PGM which has Log statements. */
                    CPUMSetGuestCR0(pVCpu, u64Cr0);
                    VMMRZCallRing3Enable(pVCpu);
                }

                if (fWhat & CPUMCTX_EXTRN_CR4)
                {
                    uint64_t u64Cr4;
                    uint64_t u64Shadow;
                    rc  = VMXReadVmcsNw(VMX_VMCS_GUEST_CR4,            &u64Cr4);      AssertRC(rc);
                    rc |= VMXReadVmcsNw(VMX_VMCS_CTRL_CR4_READ_SHADOW, &u64Shadow);   AssertRC(rc);
#ifndef VBOX_WITH_NESTED_HWVIRT_VMX
                    u64Cr4 = (u64Cr4    & ~pVmcsInfo->u64Cr4Mask)
                           | (u64Shadow &  pVmcsInfo->u64Cr4Mask);
#else
                    if (!CPUMIsGuestInVmxNonRootMode(pCtx))
                    {
                        u64Cr4 = (u64Cr4    & ~pVmcsInfo->u64Cr4Mask)
                               | (u64Shadow &  pVmcsInfo->u64Cr4Mask);
                    }
                    else
                    {
                        /*
                         * We've merged the guest and nested-guest's CR4 guest/host mask while executing
                         * the nested-guest using hardware-assisted VMX. Accordingly we need to
                         * re-construct CR4. See @bugref{9180#c95} for details.
                         */
                        PCVMXVMCSINFO const pVmcsInfoGst = &pVCpu->hmr0.s.vmx.VmcsInfo;
                        PVMXVVMCS const     pVmcsNstGst  = &pVCpu->cpum.GstCtx.hwvirt.vmx.Vmcs;
                        u64Cr4 = (u64Cr4                     & ~pVmcsInfo->u64Cr4Mask)
                               | (pVmcsNstGst->u64GuestCr4.u &  pVmcsNstGst->u64Cr4Mask.u)
                               | (u64Shadow                  & (pVmcsInfoGst->u64Cr4Mask & ~pVmcsNstGst->u64Cr4Mask.u));
                    }
#endif
                    pCtx->cr4 = u64Cr4;
                }

                if (fWhat & CPUMCTX_EXTRN_CR3)
                {
                    /* CR0.PG bit changes are always intercepted, so it's up to date. */
                    if (   pVM->hmr0.s.vmx.fUnrestrictedGuest
                        || (   pVM->hmr0.s.fNestedPaging
                            && CPUMIsGuestPagingEnabledEx(pCtx)))
                    {
                        uint64_t u64Cr3;
                        rc = VMXReadVmcsNw(VMX_VMCS_GUEST_CR3, &u64Cr3);  AssertRC(rc);
                        if (pCtx->cr3 != u64Cr3)
                        {
                            pCtx->cr3 = u64Cr3;
                            VMCPU_FF_SET(pVCpu, VMCPU_FF_HM_UPDATE_CR3);
                        }

                        /*
                         * If the guest is in PAE mode, sync back the PDPE's into the guest state.
                         * CR4.PAE, CR0.PG, EFER MSR changes are always intercepted, so they're up to date.
                         */
                        if (CPUMIsGuestInPAEModeEx(pCtx))
                        {
                            X86PDPE aPaePdpes[4];
                            rc = VMXReadVmcs64(VMX_VMCS64_GUEST_PDPTE0_FULL, &aPaePdpes[0].u);     AssertRC(rc);
                            rc = VMXReadVmcs64(VMX_VMCS64_GUEST_PDPTE1_FULL, &aPaePdpes[1].u);     AssertRC(rc);
                            rc = VMXReadVmcs64(VMX_VMCS64_GUEST_PDPTE2_FULL, &aPaePdpes[2].u);     AssertRC(rc);
                            rc = VMXReadVmcs64(VMX_VMCS64_GUEST_PDPTE3_FULL, &aPaePdpes[3].u);     AssertRC(rc);
                            if (memcmp(&aPaePdpes[0], &pCtx->aPaePdpes[0], sizeof(aPaePdpes)))
                            {
                                memcpy(&pCtx->aPaePdpes[0], &aPaePdpes[0], sizeof(aPaePdpes));
                                /* PGM now updates PAE PDPTEs while updating CR3. */
                                VMCPU_FF_SET(pVCpu, VMCPU_FF_HM_UPDATE_CR3);
                            }
                        }
                    }
                }
            }

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
            if (fWhat & CPUMCTX_EXTRN_HWVIRT)
            {
                if (   (pVmcsInfo->u32ProcCtls2 & VMX_PROC_CTLS2_VMCS_SHADOWING)
                    && !CPUMIsGuestInVmxNonRootMode(pCtx))
                {
                    Assert(CPUMIsGuestInVmxRootMode(pCtx));
                    rc = vmxHCCopyShadowToNstGstVmcs(pVCpu, pVmcsInfo);
                    if (RT_SUCCESS(rc))
                    { /* likely */ }
                    else
                        break;
                }
            }
#endif
        } while (0);

        if (RT_SUCCESS(rc))
        {
            /* Update fExtrn. */
            pCtx->fExtrn &= ~fWhat;

            /* If everything has been imported, clear the HM keeper bit. */
            if (!(pCtx->fExtrn & HMVMX_CPUMCTX_EXTRN_ALL))
            {
                pCtx->fExtrn &= ~CPUMCTX_EXTRN_KEEPER_HM;
                Assert(!pCtx->fExtrn);
            }
        }
    }
    else
        AssertMsg(!pCtx->fExtrn || (pCtx->fExtrn & HMVMX_CPUMCTX_EXTRN_ALL), ("%#RX64\n", pCtx->fExtrn));

    /*
     * Restore interrupts.
     */
    ASMSetFlags(fEFlags);

    STAM_PROFILE_ADV_STOP(& pVCpu->hm.s.StatImportGuestState, x);

    if (RT_SUCCESS(rc))
    { /* likely */ }
    else
        return rc;

    /*
     * Honor any pending CR3 updates.
     *
     * Consider this scenario: VM-exit -> VMMRZCallRing3Enable() -> do stuff that causes a longjmp -> VMXR0CallRing3Callback()
     * -> VMMRZCallRing3Disable() -> hmR0VmxImportGuestState() -> Sets VMCPU_FF_HM_UPDATE_CR3 pending -> return from the longjmp
     * -> continue with VM-exit handling -> hmR0VmxImportGuestState() and here we are.
     *
     * The reason for such complicated handling is because VM-exits that call into PGM expect CR3 to be up-to-date and thus
     * if any CR3-saves -before- the VM-exit (longjmp) postponed the CR3 update via the force-flag, any VM-exit handler that
     * calls into PGM when it re-saves CR3 will end up here and we call PGMUpdateCR3(). This is why the code below should
     * -NOT- check if CPUMCTX_EXTRN_CR3 is set!
     *
     * The longjmp exit path can't check these CR3 force-flags and call code that takes a lock again. We cover for it here.
     *
     * The force-flag is checked first as it's cheaper for potential superfluous calls to this function.
     */
    if (   VMCPU_FF_IS_SET(pVCpu, VMCPU_FF_HM_UPDATE_CR3)
        && VMMRZCallRing3IsEnabled(pVCpu))
    {
        Assert(!(ASMAtomicUoReadU64(&pCtx->fExtrn) & CPUMCTX_EXTRN_CR3));
        PGMUpdateCR3(pVCpu, CPUMGetGuestCR3(pVCpu));
        Assert(!VMCPU_FF_IS_SET(pVCpu, VMCPU_FF_HM_UPDATE_CR3));
    }

    return VINF_SUCCESS;
}


/**
 * Saves the guest state from the VMCS into the guest-CPU context.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 * @param   fWhat   What to import, CPUMCTX_EXTRN_XXX.
 */
VMMR0DECL(int) VMXR0ImportStateOnDemand(PVMCPUCC pVCpu, uint64_t fWhat)
{
    AssertPtr(pVCpu);
    PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
    return hmR0VmxImportGuestState(pVCpu, pVmcsInfo, fWhat);
}


/**
 * Gets VMX VM-exit auxiliary information.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxExitAux     Where to store the VM-exit auxiliary info.
 * @param   fWhat           What to fetch, HMVMX_READ_XXX.
 */
VMMR0DECL(int) VMXR0GetExitAuxInfo(PVMCPUCC pVCpu, PVMXEXITAUX pVmxExitAux, uint32_t fWhat)
{
    PVMXTRANSIENT pVmxTransient = pVCpu->hmr0.s.vmx.pVmxTransient;
    if (RT_LIKELY(pVmxTransient))
    {
        AssertCompile(sizeof(fWhat) == sizeof(pVmxTransient->fVmcsFieldsRead));
        fWhat &= ~pVmxTransient->fVmcsFieldsRead;

        /* The exit reason is always available. */
        pVmxExitAux->uReason = pVmxTransient->uExitReason;

        if (fWhat & HMVMX_READ_EXIT_QUALIFICATION)
        {
            vmxHCReadExitQualVmcs(pVCpu, pVmxTransient);
            fWhat &= ~HMVMX_READ_EXIT_QUALIFICATION;
            pVmxExitAux->u64Qual = pVmxTransient->uExitQual;
        }

        if (fWhat & HMVMX_READ_IDT_VECTORING_INFO)
        {
            vmxHCReadIdtVectoringInfoVmcs(pVCpu, pVmxTransient);
            fWhat &= ~HMVMX_READ_IDT_VECTORING_INFO;
            pVmxExitAux->uIdtVectoringInfo = pVmxTransient->uIdtVectoringInfo;
        }

        if (fWhat & HMVMX_READ_IDT_VECTORING_ERROR_CODE)
        {
            vmxHCReadIdtVectoringErrorCodeVmcs(pVCpu, pVmxTransient);
            fWhat &= ~HMVMX_READ_IDT_VECTORING_ERROR_CODE;
            pVmxExitAux->uIdtVectoringErrCode = pVmxTransient->uIdtVectoringErrorCode;
        }

        if (fWhat & HMVMX_READ_EXIT_INSTR_LEN)
        {
            vmxHCReadExitInstrLenVmcs(pVCpu, pVmxTransient);
            fWhat &= ~HMVMX_READ_EXIT_INSTR_LEN;
            pVmxExitAux->cbInstr = pVmxTransient->cbExitInstr;
        }

        if (fWhat & HMVMX_READ_EXIT_INTERRUPTION_INFO)
        {
            vmxHCReadExitIntInfoVmcs(pVCpu, pVmxTransient);
            fWhat &= ~HMVMX_READ_EXIT_INTERRUPTION_INFO;
            pVmxExitAux->uExitIntInfo = pVmxTransient->uExitIntInfo;
        }

        if (fWhat & HMVMX_READ_EXIT_INTERRUPTION_ERROR_CODE)
        {
            vmxHCReadExitIntErrorCodeVmcs(pVCpu, pVmxTransient);
            fWhat &= ~HMVMX_READ_EXIT_INTERRUPTION_ERROR_CODE;
            pVmxExitAux->uExitIntErrCode = pVmxTransient->uExitIntErrorCode;
        }

        if (fWhat & HMVMX_READ_EXIT_INSTR_INFO)
        {
            vmxHCReadExitInstrInfoVmcs(pVCpu, pVmxTransient);
            fWhat &= ~HMVMX_READ_EXIT_INSTR_INFO;
            pVmxExitAux->InstrInfo.u = pVmxTransient->ExitInstrInfo.u;
        }

        if (fWhat & HMVMX_READ_GUEST_LINEAR_ADDR)
        {
            vmxHCReadGuestLinearAddrVmcs(pVCpu, pVmxTransient);
            fWhat &= ~HMVMX_READ_GUEST_LINEAR_ADDR;
            pVmxExitAux->u64GuestLinearAddr = pVmxTransient->uGuestLinearAddr;
        }

        if (fWhat & HMVMX_READ_GUEST_PHYSICAL_ADDR)
        {
            vmxHCReadGuestPhysicalAddrVmcs(pVCpu, pVmxTransient);
            fWhat &= ~HMVMX_READ_GUEST_PHYSICAL_ADDR;
            pVmxExitAux->u64GuestPhysAddr = pVmxTransient->uGuestPhysicalAddr;
        }

        if (fWhat & HMVMX_READ_GUEST_PENDING_DBG_XCPTS)
        {
            vmxHCReadGuestPendingDbgXctps(pVCpu, pVmxTransient);
            fWhat &= ~HMVMX_READ_GUEST_PENDING_DBG_XCPTS;
            pVmxExitAux->u64GuestPendingDbgXcpts = pVmxTransient->uGuestPendingDbgXcpts;
        }

        AssertMsg(!fWhat, ("fWhat=%#RX32 fVmcsFieldsRead=%#RX32\n", fWhat, pVmxTransient->fVmcsFieldsRead));
        return VINF_SUCCESS;
    }
    return VERR_NOT_AVAILABLE;
}


/**
 * Does the necessary state syncing before returning to ring-3 for any reason
 * (longjmp, preemption, voluntary exits to ring-3) from VT-x.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   fImportState    Whether to import the guest state from the VMCS back
 *                          to the guest-CPU context.
 *
 * @remarks No-long-jmp zone!!!
 */
static int hmR0VmxLeave(PVMCPUCC pVCpu, bool fImportState)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

    RTCPUID const idCpu = RTMpCpuId();
    Log4Func(("HostCpuId=%u\n", idCpu));

    /*
     * !!! IMPORTANT !!!
     * If you modify code here, check whether VMXR0CallRing3Callback() needs to be updated too.
     */

    /* Save the guest state if necessary. */
    PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
    if (fImportState)
    {
        int rc = hmR0VmxImportGuestState(pVCpu, pVmcsInfo, HMVMX_CPUMCTX_EXTRN_ALL);
        AssertRCReturn(rc, rc);
    }

    /* Restore host FPU state if necessary. We will resync on next R0 reentry. */
    CPUMR0FpuStateMaybeSaveGuestAndRestoreHost(pVCpu);
    Assert(!CPUMIsGuestFPUStateActive(pVCpu));

    /* Restore host debug registers if necessary. We will resync on next R0 reentry. */
#ifdef VBOX_STRICT
    if (CPUMIsHyperDebugStateActive(pVCpu))
        Assert(pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_MOV_DR_EXIT);
#endif
    CPUMR0DebugStateMaybeSaveGuestAndRestoreHost(pVCpu, true /* save DR6 */);
    Assert(!CPUMIsGuestDebugStateActive(pVCpu));
    Assert(!CPUMIsHyperDebugStateActive(pVCpu));

    /* Restore host-state bits that VT-x only restores partially. */
    if (pVCpu->hmr0.s.vmx.fRestoreHostFlags > VMX_RESTORE_HOST_REQUIRED)
    {
        Log4Func(("Restoring Host State: fRestoreHostFlags=%#RX32 HostCpuId=%u\n", pVCpu->hmr0.s.vmx.fRestoreHostFlags, idCpu));
        VMXRestoreHostState(pVCpu->hmr0.s.vmx.fRestoreHostFlags, &pVCpu->hmr0.s.vmx.RestoreHost);
    }
    pVCpu->hmr0.s.vmx.fRestoreHostFlags = 0;

    /* Restore the lazy host MSRs as we're leaving VT-x context. */
    if (pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST)
    {
        /* We shouldn't restore the host MSRs without saving the guest MSRs first. */
        if (!fImportState)
        {
            int rc = hmR0VmxImportGuestState(pVCpu, pVmcsInfo, CPUMCTX_EXTRN_KERNEL_GS_BASE | CPUMCTX_EXTRN_SYSCALL_MSRS);
            AssertRCReturn(rc, rc);
        }
        hmR0VmxLazyRestoreHostMsrs(pVCpu);
        Assert(!pVCpu->hmr0.s.vmx.fLazyMsrs);
    }
    else
        pVCpu->hmr0.s.vmx.fLazyMsrs = 0;

    /* Update auto-load/store host MSRs values when we re-enter VT-x (as we could be on a different CPU). */
    pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs = false;

    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatEntry);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatImportGuestState);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExportGuestState);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatPreExit);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExitHandling);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExitIO);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExitMovCRx);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExitXcptNmi);
    STAM_PROFILE_ADV_SET_STOPPED(&pVCpu->hm.s.StatExitVmentry);
    STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchLongJmpToR3);

    VMCPU_CMPXCHG_STATE(pVCpu, VMCPUSTATE_STARTED_HM, VMCPUSTATE_STARTED_EXEC);

    /** @todo This partially defeats the purpose of having preemption hooks.
     *  The problem is, deregistering the hooks should be moved to a place that
     *  lasts until the EMT is about to be destroyed not everytime while leaving HM
     *  context.
     */
    int rc = hmR0VmxClearVmcs(pVmcsInfo);
    AssertRCReturn(rc, rc);

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /*
     * A valid shadow VMCS is made active as part of VM-entry. It is necessary to
     * clear a shadow VMCS before allowing that VMCS to become active on another
     * logical processor. We may or may not be importing guest state which clears
     * it, so cover for it here.
     *
     * See Intel spec. 24.11.1 "Software Use of Virtual-Machine Control Structures".
     */
    if (   pVmcsInfo->pvShadowVmcs
        && pVmcsInfo->fShadowVmcsState != VMX_V_VMCS_LAUNCH_STATE_CLEAR)
    {
        rc = vmxHCClearShadowVmcs(pVmcsInfo);
        AssertRCReturn(rc, rc);
    }

    /*
     * Flag that we need to re-export the host state if we switch to this VMCS before
     * executing guest or nested-guest code.
     */
    pVmcsInfo->idHostCpuState = NIL_RTCPUID;
#endif

    Log4Func(("Cleared Vmcs. HostCpuId=%u\n", idCpu));
    NOREF(idCpu);
    return VINF_SUCCESS;
}


/**
 * Leaves the VT-x session.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jmp zone!!!
 */
static int hmR0VmxLeaveSession(PVMCPUCC pVCpu)
{
    HM_DISABLE_PREEMPT(pVCpu);
    HMVMX_ASSERT_CPU_SAFE(pVCpu);
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /* When thread-context hooks are used, we can avoid doing the leave again if we had been preempted before
       and done this from the VMXR0ThreadCtxCallback(). */
    if (!pVCpu->hmr0.s.fLeaveDone)
    {
        int rc2 = hmR0VmxLeave(pVCpu, true /* fImportState */);
        AssertRCReturnStmt(rc2, HM_RESTORE_PREEMPT(), rc2);
        pVCpu->hmr0.s.fLeaveDone = true;
    }
    Assert(!pVCpu->cpum.GstCtx.fExtrn);

    /*
     * !!! IMPORTANT !!!
     * If you modify code here, make sure to check whether VMXR0CallRing3Callback() needs to be updated too.
     */

    /* Deregister hook now that we've left HM context before re-enabling preemption. */
    /** @todo Deregistering here means we need to VMCLEAR always
     *        (longjmp/exit-to-r3) in VT-x which is not efficient, eliminate need
     *        for calling VMMR0ThreadCtxHookDisable here! */
    VMMR0ThreadCtxHookDisable(pVCpu);

    /* Leave HM context. This takes care of local init (term) and deregistering the longjmp-to-ring-3 callback. */
    int rc = HMR0LeaveCpu(pVCpu);
    HM_RESTORE_PREEMPT();
    return rc;
}


/**
 * Take necessary actions before going back to ring-3.
 *
 * An action requires us to go back to ring-3. This function does the necessary
 * steps before we can safely return to ring-3. This is not the same as longjmps
 * to ring-3, this is voluntary and prepares the guest so it may continue
 * executing outside HM (recompiler/IEM).
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 * @param   rcExit  The reason for exiting to ring-3. Can be
 *                  VINF_VMM_UNKNOWN_RING3_CALL.
 */
static int hmR0VmxExitToRing3(PVMCPUCC pVCpu, VBOXSTRICTRC rcExit)
{
    HMVMX_ASSERT_PREEMPT_SAFE(pVCpu);

    PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
    if (RT_UNLIKELY(rcExit == VERR_VMX_INVALID_VMCS_PTR))
    {
        VMXGetCurrentVmcs(&pVCpu->hm.s.vmx.LastError.HCPhysCurrentVmcs);
        pVCpu->hm.s.vmx.LastError.u32VmcsRev   = *(uint32_t *)pVmcsInfo->pvVmcs;
        pVCpu->hm.s.vmx.LastError.idEnteredCpu = pVCpu->hmr0.s.idEnteredCpu;
        /* LastError.idCurrentCpu was updated in hmR0VmxPreRunGuestCommitted(). */
    }

    /* Please, no longjumps here (any logging shouldn't flush jump back to ring-3). NO LOGGING BEFORE THIS POINT! */
    VMMRZCallRing3Disable(pVCpu);
    Log4Func(("rcExit=%d\n", VBOXSTRICTRC_VAL(rcExit)));

    /*
     * Convert any pending HM events back to TRPM due to premature exits to ring-3.
     * We need to do this only on returns to ring-3 and not for longjmps to ring3.
     *
     * This is because execution may continue from ring-3 and we would need to inject
     * the event from there (hence place it back in TRPM).
     */
    if (pVCpu->hm.s.Event.fPending)
    {
        vmxHCPendingEventToTrpmTrap(pVCpu);
        Assert(!pVCpu->hm.s.Event.fPending);

        /* Clear the events from the VMCS. */
        int rc = VMXWriteVmcs32(VMX_VMCS32_CTRL_ENTRY_INTERRUPTION_INFO, 0);    AssertRC(rc);
        rc     = VMXWriteVmcs32(VMX_VMCS_GUEST_PENDING_DEBUG_XCPTS, 0);         AssertRC(rc);
    }
#ifdef VBOX_STRICT
    /*
     * We check for rcExit here since for errors like VERR_VMX_UNABLE_TO_START_VM (which are
     * fatal), we don't care about verifying duplicate injection of events. Errors like
     * VERR_EM_INTERPRET are converted to their VINF_* counterparts -prior- to  calling this
     * function so those should and will be checked below.
     */
    else if (RT_SUCCESS(rcExit))
    {
        /*
         * Ensure we don't accidentally clear a pending HM event without clearing the VMCS.
         * This can be pretty hard to debug otherwise, interrupts might get injected twice
         * occasionally, see @bugref{9180#c42}.
         *
         * However, if the VM-entry failed, any VM entry-interruption info. field would
         * be left unmodified as the event would not have been injected to the guest. In
         * such cases, don't assert, we're not going to continue guest execution anyway.
         */
        uint32_t uExitReason;
        uint32_t uEntryIntInfo;
        int rc = VMXReadVmcs32(VMX_VMCS32_RO_EXIT_REASON, &uExitReason);
        rc    |= VMXReadVmcs32(VMX_VMCS32_CTRL_ENTRY_INTERRUPTION_INFO, &uEntryIntInfo);
        AssertRC(rc);
        AssertMsg(VMX_EXIT_REASON_HAS_ENTRY_FAILED(uExitReason) || !VMX_ENTRY_INT_INFO_IS_VALID(uEntryIntInfo),
                  ("uExitReason=%#RX32 uEntryIntInfo=%#RX32 rcExit=%d\n", uExitReason, uEntryIntInfo, VBOXSTRICTRC_VAL(rcExit)));
    }
#endif

    /*
     * Clear the interrupt-window and NMI-window VMCS controls as we could have got
     * a VM-exit with higher priority than interrupt-window or NMI-window VM-exits
     * (e.g. TPR below threshold).
     */
    if (!CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx))
    {
        vmxHCClearIntWindowExitVmcs(pVCpu, pVmcsInfo);
        vmxHCClearNmiWindowExitVmcs(pVCpu, pVmcsInfo);
    }

    /* If we're emulating an instruction, we shouldn't have any TRPM traps pending
       and if we're injecting an event we should have a TRPM trap pending. */
    AssertMsg(rcExit != VINF_EM_RAW_INJECT_TRPM_EVENT || TRPMHasTrap(pVCpu), ("%Rrc\n", VBOXSTRICTRC_VAL(rcExit)));
#ifndef DEBUG_bird /* Triggered after firing an NMI against NT4SP1, possibly a triple fault in progress. */
    AssertMsg(rcExit != VINF_EM_RAW_EMULATE_INSTR || !TRPMHasTrap(pVCpu), ("%Rrc\n", VBOXSTRICTRC_VAL(rcExit)));
#endif

    /* Save guest state and restore host state bits. */
    int rc = hmR0VmxLeaveSession(pVCpu);
    AssertRCReturn(rc, rc);
    STAM_COUNTER_DEC(&pVCpu->hm.s.StatSwitchLongJmpToR3);

    /* Thread-context hooks are unregistered at this point!!! */
    /* Ring-3 callback notifications are unregistered at this point!!! */

    /* Sync recompiler state. */
    VMCPU_FF_CLEAR(pVCpu, VMCPU_FF_TO_R3);
    CPUMSetChangedFlags(pVCpu, CPUM_CHANGED_SYSENTER_MSR
                             | CPUM_CHANGED_LDTR
                             | CPUM_CHANGED_GDTR
                             | CPUM_CHANGED_IDTR
                             | CPUM_CHANGED_TR
                             | CPUM_CHANGED_HIDDEN_SEL_REGS);
    if (   pVCpu->CTX_SUFF(pVM)->hmr0.s.fNestedPaging
        && CPUMIsGuestPagingEnabledEx(&pVCpu->cpum.GstCtx))
        CPUMSetChangedFlags(pVCpu, CPUM_CHANGED_GLOBAL_TLB_FLUSH);

    Assert(!pVCpu->hmr0.s.fClearTrapFlag);

    /* Update the exit-to-ring 3 reason. */
    pVCpu->hm.s.rcLastExitToR3 = VBOXSTRICTRC_VAL(rcExit);

    /* On our way back from ring-3 reload the guest state if there is a possibility of it being changed. */
    if (   rcExit != VINF_EM_RAW_INTERRUPT
        || CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx))
    {
        Assert(!(pVCpu->cpum.GstCtx.fExtrn & HMVMX_CPUMCTX_EXTRN_ALL));
        ASMAtomicUoOrU64(&pVCpu->hm.s.fCtxChanged, HM_CHANGED_ALL_GUEST);
    }

    STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchExitToR3);
    VMMRZCallRing3Enable(pVCpu);
    return rc;
}


/**
 * VMMRZCallRing3() callback wrapper which saves the guest state before we
 * longjump due to a ring-0 assertion.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 */
VMMR0DECL(int) VMXR0AssertionCallback(PVMCPUCC pVCpu)
{
    /*
     * !!! IMPORTANT !!!
     * If you modify code here, check whether hmR0VmxLeave() and hmR0VmxLeaveSession() needs to be updated too.
     * This is a stripped down version which gets out ASAP, trying to not trigger any further assertions.
     */
    VMMR0AssertionRemoveNotification(pVCpu);
    VMMRZCallRing3Disable(pVCpu);
    HM_DISABLE_PREEMPT(pVCpu);

    PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
    vmxHCImportGuestState(pVCpu, pVmcsInfo, HMVMX_CPUMCTX_EXTRN_ALL);
    CPUMR0FpuStateMaybeSaveGuestAndRestoreHost(pVCpu);
    CPUMR0DebugStateMaybeSaveGuestAndRestoreHost(pVCpu, true /* save DR6 */);

    /* Restore host-state bits that VT-x only restores partially. */
    if (pVCpu->hmr0.s.vmx.fRestoreHostFlags > VMX_RESTORE_HOST_REQUIRED)
        VMXRestoreHostState(pVCpu->hmr0.s.vmx.fRestoreHostFlags, &pVCpu->hmr0.s.vmx.RestoreHost);
    pVCpu->hmr0.s.vmx.fRestoreHostFlags = 0;

    /* Restore the lazy host MSRs as we're leaving VT-x context. */
    if (pVCpu->hmr0.s.vmx.fLazyMsrs & VMX_LAZY_MSRS_LOADED_GUEST)
        hmR0VmxLazyRestoreHostMsrs(pVCpu);

    /* Update auto-load/store host MSRs values when we re-enter VT-x (as we could be on a different CPU). */
    pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs = false;
    VMCPU_CMPXCHG_STATE(pVCpu, VMCPUSTATE_STARTED_HM, VMCPUSTATE_STARTED_EXEC);

    /* Clear the current VMCS data back to memory (shadow VMCS if any would have been
       cleared as part of importing the guest state above. */
    hmR0VmxClearVmcs(pVmcsInfo);

    /** @todo eliminate the need for calling VMMR0ThreadCtxHookDisable here!  */
    VMMR0ThreadCtxHookDisable(pVCpu);

    /* Leave HM context. This takes care of local init (term). */
    HMR0LeaveCpu(pVCpu);
    HM_RESTORE_PREEMPT();
    return VINF_SUCCESS;
}


/**
 * Enters the VT-x session.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 */
VMMR0DECL(int) VMXR0Enter(PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);
    Assert(pVCpu->CTX_SUFF(pVM)->hm.s.vmx.fSupported);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    LogFlowFunc(("pVCpu=%p\n", pVCpu));
    Assert((pVCpu->hm.s.fCtxChanged &  (HM_CHANGED_HOST_CONTEXT | HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE))
                                    == (HM_CHANGED_HOST_CONTEXT | HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE));

#ifdef VBOX_STRICT
    /* At least verify VMX is enabled, since we can't check if we're in VMX root mode without #GP'ing. */
    RTCCUINTREG uHostCr4 = ASMGetCR4();
    if (!(uHostCr4 & X86_CR4_VMXE))
    {
        LogRelFunc(("X86_CR4_VMXE bit in CR4 is not set!\n"));
        return VERR_VMX_X86_CR4_VMXE_CLEARED;
    }
#endif

    /*
     * Do the EMT scheduled L1D and MDS flush here if needed.
     */
    if (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_L1D_SCHED)
        ASMWrMsr(MSR_IA32_FLUSH_CMD, MSR_IA32_FLUSH_CMD_F_L1D);
    else if (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_MDS_SCHED)
        hmR0MdsClear();

    /*
     * Load the appropriate VMCS as the current and active one.
     */
    PVMXVMCSINFO pVmcsInfo;
    bool const fInNestedGuestMode = CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx);
    if (!fInNestedGuestMode)
        pVmcsInfo = &pVCpu->hmr0.s.vmx.VmcsInfo;
    else
        pVmcsInfo = &pVCpu->hmr0.s.vmx.VmcsInfoNstGst;
    int rc = hmR0VmxLoadVmcs(pVmcsInfo);
    if (RT_SUCCESS(rc))
    {
        pVCpu->hmr0.s.vmx.fSwitchedToNstGstVmcs           = fInNestedGuestMode;
        pVCpu->hm.s.vmx.fSwitchedToNstGstVmcsCopyForRing3 = fInNestedGuestMode;
        pVCpu->hmr0.s.fLeaveDone = false;
        Log4Func(("Loaded Vmcs. HostCpuId=%u\n", RTMpCpuId()));
    }
    return rc;
}


/**
 * The thread-context callback.
 *
 * This is used together with RTThreadCtxHookCreate() on platforms which
 * supports it, and directly from VMMR0EmtPrepareForBlocking() and
 * VMMR0EmtResumeAfterBlocking() on platforms which don't.
 *
 * @param   enmEvent        The thread-context event.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   fGlobalInit     Whether global VT-x/AMD-V init. was used.
 * @thread  EMT(pVCpu)
 */
VMMR0DECL(void) VMXR0ThreadCtxCallback(RTTHREADCTXEVENT enmEvent, PVMCPUCC pVCpu, bool fGlobalInit)
{
    AssertPtr(pVCpu);
    RT_NOREF1(fGlobalInit);

    switch (enmEvent)
    {
        case RTTHREADCTXEVENT_OUT:
        {
            Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
            VMCPU_ASSERT_EMT(pVCpu);

            /* No longjmps (logger flushes, locks) in this fragile context. */
            VMMRZCallRing3Disable(pVCpu);
            Log4Func(("Preempting: HostCpuId=%u\n", RTMpCpuId()));

            /* Restore host-state (FPU, debug etc.) */
            if (!pVCpu->hmr0.s.fLeaveDone)
            {
                /*
                 * Do -not- import the guest-state here as we might already be in the middle of importing
                 * it, esp. bad if we're holding the PGM lock, see comment in hmR0VmxImportGuestState().
                 */
                hmR0VmxLeave(pVCpu, false /* fImportState */);
                pVCpu->hmr0.s.fLeaveDone = true;
            }

            /* Leave HM context, takes care of local init (term). */
            int rc = HMR0LeaveCpu(pVCpu);
            AssertRC(rc);

            /* Restore longjmp state. */
            VMMRZCallRing3Enable(pVCpu);
            STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatSwitchPreempt);
            break;
        }

        case RTTHREADCTXEVENT_IN:
        {
            Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
            VMCPU_ASSERT_EMT(pVCpu);

            /* Do the EMT scheduled L1D and MDS flush here if needed. */
            if (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_L1D_SCHED)
                ASMWrMsr(MSR_IA32_FLUSH_CMD, MSR_IA32_FLUSH_CMD_F_L1D);
            else if (pVCpu->hmr0.s.fWorldSwitcher & HM_WSF_MDS_SCHED)
                hmR0MdsClear();

            /* No longjmps here, as we don't want to trigger preemption (& its hook) while resuming. */
            VMMRZCallRing3Disable(pVCpu);
            Log4Func(("Resumed: HostCpuId=%u\n", RTMpCpuId()));

            /* Initialize the bare minimum state required for HM. This takes care of
               initializing VT-x if necessary (onlined CPUs, local init etc.) */
            int rc = hmR0EnterCpu(pVCpu);
            AssertRC(rc);
            Assert(   (pVCpu->hm.s.fCtxChanged & (HM_CHANGED_HOST_CONTEXT | HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE))
                                              == (HM_CHANGED_HOST_CONTEXT | HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE));

            /* Load the active VMCS as the current one. */
            PVMXVMCSINFO pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);
            rc = hmR0VmxLoadVmcs(pVmcsInfo);
            AssertRC(rc);
            Log4Func(("Resumed: Loaded Vmcs. HostCpuId=%u\n", RTMpCpuId()));
            pVCpu->hmr0.s.fLeaveDone = false;

            /* Restore longjmp state. */
            VMMRZCallRing3Enable(pVCpu);
            break;
        }

        default:
            break;
    }
}


/**
 * Exports the host state into the VMCS host-state area.
 * Sets up the VM-exit MSR-load area.
 *
 * The CPU state will be loaded from these fields on every successful VM-exit.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
static int hmR0VmxExportHostState(PVMCPUCC pVCpu)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    int rc = VINF_SUCCESS;
    if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_HOST_CONTEXT)
    {
        uint64_t uHostCr4 = hmR0VmxExportHostControlRegs();

        rc = hmR0VmxExportHostSegmentRegs(pVCpu, uHostCr4);
        AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

        hmR0VmxExportHostMsrs(pVCpu);

        pVCpu->hm.s.fCtxChanged &= ~HM_CHANGED_HOST_CONTEXT;
    }
    return rc;
}


/**
 * Saves the host state in the VMCS host-state.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 *
 * @remarks No-long-jump zone!!!
 */
VMMR0DECL(int) VMXR0ExportHostState(PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));

    /*
     * Export the host state here while entering HM context.
     * When thread-context hooks are used, we might get preempted and have to re-save the host
     * state but most of the time we won't be, so do it here before we disable interrupts.
     */
    return hmR0VmxExportHostState(pVCpu);
}


/**
 * Exports the guest state into the VMCS guest-state area.
 *
 * The will typically be done before VM-entry when the guest-CPU state and the
 * VMCS state may potentially be out of sync.
 *
 * Sets up the VM-entry MSR-load and VM-exit MSR-store areas. Sets up the
 * VM-entry controls.
 * Sets up the appropriate VMX non-root function to execute guest code based on
 * the guest CPU mode.
 *
 * @returns VBox strict status code.
 * @retval  VINF_EM_RESCHEDULE_REM if we try to emulate non-paged guest code
 *          without unrestricted guest execution and the VMMDev is not presently
 *          mapped (e.g. EFI32).
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static VBOXSTRICTRC hmR0VmxExportGuestState(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient)
{
    AssertPtr(pVCpu);
    HMVMX_ASSERT_PREEMPT_SAFE(pVCpu);
    LogFlowFunc(("pVCpu=%p\n", pVCpu));

    STAM_PROFILE_ADV_START(&pVCpu->hm.s.StatExportGuestState, x);

    /*
     * Determine real-on-v86 mode.
     * Used when the guest is in real-mode and unrestricted guest execution is not used.
     */
    PVMXVMCSINFOSHARED pVmcsInfoShared = pVmxTransient->pVmcsInfo->pShared;
    if (    pVCpu->CTX_SUFF(pVM)->hmr0.s.vmx.fUnrestrictedGuest
        || !CPUMIsGuestInRealModeEx(&pVCpu->cpum.GstCtx))
        pVmcsInfoShared->RealMode.fRealOnV86Active = false;
    else
    {
        Assert(!pVmxTransient->fIsNestedGuest);
        pVmcsInfoShared->RealMode.fRealOnV86Active = true;
    }

    /*
     * Any ordering dependency among the sub-functions below must be explicitly stated using comments.
     * Ideally, assert that the cross-dependent bits are up-to-date at the point of using it.
     */
    int rc = vmxHCExportGuestEntryExitCtls(pVCpu, pVmxTransient);
    AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

    rc = vmxHCExportGuestCR0(pVCpu, pVmxTransient);
    AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

    VBOXSTRICTRC rcStrict = vmxHCExportGuestCR3AndCR4(pVCpu, pVmxTransient);
    if (rcStrict == VINF_SUCCESS)
    { /* likely */ }
    else
    {
        Assert(rcStrict == VINF_EM_RESCHEDULE_REM || RT_FAILURE_NP(rcStrict));
        return rcStrict;
    }

    rc = vmxHCExportGuestSegRegsXdtr(pVCpu, pVmxTransient);
    AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

    rc = hmR0VmxExportGuestMsrs(pVCpu, pVmxTransient);
    AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

    vmxHCExportGuestApicTpr(pVCpu, pVmxTransient);
    vmxHCExportGuestXcptIntercepts(pVCpu, pVmxTransient);
    vmxHCExportGuestRip(pVCpu);
    hmR0VmxExportGuestRsp(pVCpu);
    vmxHCExportGuestRflags(pVCpu, pVmxTransient);

    rc = hmR0VmxExportGuestHwvirtState(pVCpu, pVmxTransient);
    AssertLogRelMsgRCReturn(rc, ("rc=%Rrc\n", rc), rc);

    /* Clear any bits that may be set but exported unconditionally or unused/reserved bits. */
    ASMAtomicUoAndU64(&pVCpu->hm.s.fCtxChanged, ~(  (HM_CHANGED_GUEST_GPRS_MASK & ~HM_CHANGED_GUEST_RSP)
                                                  |  HM_CHANGED_GUEST_CR2
                                                  | (HM_CHANGED_GUEST_DR_MASK & ~HM_CHANGED_GUEST_DR7)
                                                  |  HM_CHANGED_GUEST_X87
                                                  |  HM_CHANGED_GUEST_SSE_AVX
                                                  |  HM_CHANGED_GUEST_OTHER_XSAVE
                                                  |  HM_CHANGED_GUEST_XCRx
                                                  |  HM_CHANGED_GUEST_KERNEL_GS_BASE /* Part of lazy or auto load-store MSRs. */
                                                  |  HM_CHANGED_GUEST_SYSCALL_MSRS   /* Part of lazy or auto load-store MSRs. */
                                                  |  HM_CHANGED_GUEST_TSC_AUX
                                                  |  HM_CHANGED_GUEST_OTHER_MSRS
                                                  | (HM_CHANGED_KEEPER_STATE_MASK & ~HM_CHANGED_VMX_MASK)));

    STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatExportGuestState, x);
    return rc;
}


/**
 * Exports the state shared between the host and guest into the VMCS.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxExportSharedState(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient)
{
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

    if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_GUEST_DR_MASK)
    {
        int rc = hmR0VmxExportSharedDebugState(pVCpu, pVmxTransient);
        AssertRC(rc);
        pVCpu->hm.s.fCtxChanged &= ~HM_CHANGED_GUEST_DR_MASK;

        /* Loading shared debug bits might have changed eflags.TF bit for debugging purposes. */
        if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_GUEST_RFLAGS)
            vmxHCExportGuestRflags(pVCpu, pVmxTransient);
    }

    if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_VMX_GUEST_LAZY_MSRS)
    {
        hmR0VmxLazyLoadGuestMsrs(pVCpu);
        pVCpu->hm.s.fCtxChanged &= ~HM_CHANGED_VMX_GUEST_LAZY_MSRS;
    }

    AssertMsg(!(pVCpu->hm.s.fCtxChanged & HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE),
              ("fCtxChanged=%#RX64\n", pVCpu->hm.s.fCtxChanged));
}


/**
 * Worker for loading the guest-state bits in the inner VT-x execution loop.
 *
 * @returns Strict VBox status code (i.e. informational status codes too).
 * @retval  VINF_EM_RESCHEDULE_REM if we try to emulate non-paged guest code
 *          without unrestricted guest execution and the VMMDev is not presently
 *          mapped (e.g. EFI32).
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks No-long-jump zone!!!
 */
static VBOXSTRICTRC hmR0VmxExportGuestStateOptimal(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient)
{
    HMVMX_ASSERT_PREEMPT_SAFE(pVCpu);
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

#ifdef HMVMX_ALWAYS_SYNC_FULL_GUEST_STATE
    ASMAtomicUoOrU64(&pVCpu->hm.s.fCtxChanged, HM_CHANGED_ALL_GUEST);
#endif

    /*
     * For many VM-exits only RIP/RSP/RFLAGS (and HWVIRT state when executing a nested-guest)
     * changes. First try to export only these without going through all other changed-flag checks.
     */
    VBOXSTRICTRC   rcStrict;
    uint64_t const fCtxMask     = HM_CHANGED_ALL_GUEST & ~HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE;
    uint64_t const fMinimalMask = HM_CHANGED_GUEST_RIP | HM_CHANGED_GUEST_RSP | HM_CHANGED_GUEST_RFLAGS | HM_CHANGED_GUEST_HWVIRT;
    uint64_t const fCtxChanged  = ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged);

    /* If only RIP/RSP/RFLAGS/HWVIRT changed, export only those (quicker, happens more often).*/
    if (    (fCtxChanged & fMinimalMask)
        && !(fCtxChanged & (fCtxMask & ~fMinimalMask)))
    {
        vmxHCExportGuestRip(pVCpu);
        hmR0VmxExportGuestRsp(pVCpu);
        vmxHCExportGuestRflags(pVCpu, pVmxTransient);
        rcStrict = hmR0VmxExportGuestHwvirtState(pVCpu, pVmxTransient);
        STAM_COUNTER_INC(&pVCpu->hm.s.StatExportMinimal);
    }
    /* If anything else also changed, go through the full export routine and export as required. */
    else if (fCtxChanged & fCtxMask)
    {
        rcStrict = hmR0VmxExportGuestState(pVCpu, pVmxTransient);
        if (RT_LIKELY(rcStrict == VINF_SUCCESS))
        { /* likely */}
        else
        {
            AssertMsg(rcStrict == VINF_EM_RESCHEDULE_REM, ("Failed to export guest state! rc=%Rrc\n",
                                                           VBOXSTRICTRC_VAL(rcStrict)));
            Assert(!VMMRZCallRing3IsEnabled(pVCpu));
            return rcStrict;
        }
        STAM_COUNTER_INC(&pVCpu->hm.s.StatExportFull);
    }
    /* Nothing changed, nothing to load here. */
    else
        rcStrict = VINF_SUCCESS;

#ifdef VBOX_STRICT
    /* All the guest state bits should be loaded except maybe the host context and/or the shared host/guest bits. */
    uint64_t const fCtxChangedCur = ASMAtomicUoReadU64(&pVCpu->hm.s.fCtxChanged);
    AssertMsg(!(fCtxChangedCur & fCtxMask), ("fCtxChangedCur=%#RX64\n", fCtxChangedCur));
#endif
    return rcStrict;
}


/**
 * Map the APIC-access page for virtualizing APIC accesses.
 *
 * This can cause a longjumps to R3 due to the acquisition of the PGM lock. Hence,
 * this not done as part of exporting guest state, see @bugref{8721}.
 *
 * @returns VBox status code.
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   GCPhysApicBase  The guest-physical address of the APIC access page.
 */
static int hmR0VmxMapHCApicAccessPage(PVMCPUCC pVCpu, RTGCPHYS GCPhysApicBase)
{
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    Assert(GCPhysApicBase);

    LogFunc(("Mappping HC APIC-access page at %#RGp\n", GCPhysApicBase));

    /* Unalias the existing mapping. */
    int rc = PGMHandlerPhysicalReset(pVM, GCPhysApicBase);
    AssertRCReturn(rc, rc);

    /* Map the HC APIC-access page in place of the MMIO page, also updates the shadow page tables if necessary. */
    Assert(pVM->hmr0.s.vmx.HCPhysApicAccess != NIL_RTHCPHYS);
    rc = IOMR0MmioMapMmioHCPage(pVM, pVCpu, GCPhysApicBase, pVM->hmr0.s.vmx.HCPhysApicAccess, X86_PTE_RW | X86_PTE_P);
    AssertRCReturn(rc, rc);

    return VINF_SUCCESS;
}


/**
 * Worker function passed to RTMpOnSpecific() that is to be called on the target
 * CPU.
 *
 * @param   idCpu       The ID for the CPU the function is called on.
 * @param   pvUser1     Null, not used.
 * @param   pvUser2     Null, not used.
 */
static DECLCALLBACK(void) hmR0DispatchHostNmi(RTCPUID idCpu, void *pvUser1, void *pvUser2)
{
    RT_NOREF3(idCpu, pvUser1, pvUser2);
    VMXDispatchHostNmi();
}


/**
 * Dispatching an NMI on the host CPU that received it.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pVmcsInfo   The VMCS info. object corresponding to the VMCS that was
 *                      executing when receiving the host NMI in VMX non-root
 *                      operation.
 */
static int hmR0VmxExitHostNmi(PVMCPUCC pVCpu, PCVMXVMCSINFO pVmcsInfo)
{
    RTCPUID const idCpu = pVmcsInfo->idHostCpuExec;
    Assert(idCpu != NIL_RTCPUID);

    /*
     * We don't want to delay dispatching the NMI any more than we have to. However,
     * we have already chosen -not- to dispatch NMIs when interrupts were still disabled
     * after executing guest or nested-guest code for the following reasons:
     *
     *   - We would need to perform VMREADs with interrupts disabled and is orders of
     *     magnitude worse when we run as a nested hypervisor without VMCS shadowing
     *     supported by the host hypervisor.
     *
     *   - It affects the common VM-exit scenario and keeps interrupts disabled for a
     *     longer period of time just for handling an edge case like host NMIs which do
     *     not occur nearly as frequently as other VM-exits.
     *
     * Let's cover the most likely scenario first. Check if we are on the target CPU
     * and dispatch the NMI right away. This should be much faster than calling into
     * RTMpOnSpecific() machinery.
     */
    bool fDispatched = false;
    RTCCUINTREG const fEFlags = ASMIntDisableFlags();
    if (idCpu == RTMpCpuId())
    {
        VMXDispatchHostNmi();
        fDispatched = true;
    }
    ASMSetFlags(fEFlags);
    if (fDispatched)
    {
        STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatExitHostNmiInGC);
        return VINF_SUCCESS;
    }

    /*
     * RTMpOnSpecific() waits until the worker function has run on the target CPU. So
     * there should be no race or recursion even if we are unlucky enough to be preempted
     * (to the target CPU) without dispatching the host NMI above.
     */
    STAM_REL_COUNTER_INC(&pVCpu->hm.s.StatExitHostNmiInGCIpi);
    return RTMpOnSpecific(idCpu, &hmR0DispatchHostNmi, NULL /* pvUser1 */,  NULL /* pvUser2 */);
}


#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
/**
 * Merges the guest with the nested-guest MSR bitmap in preparation of executing the
 * nested-guest using hardware-assisted VMX.
 *
 * @param   pVCpu               The cross context virtual CPU structure.
 * @param   pVmcsInfoNstGst     The nested-guest VMCS info. object.
 * @param   pVmcsInfoGst        The guest VMCS info. object.
 */
static void hmR0VmxMergeMsrBitmapNested(PCVMCPUCC pVCpu, PVMXVMCSINFO pVmcsInfoNstGst, PCVMXVMCSINFO pVmcsInfoGst)
{
    uint32_t const cbMsrBitmap    = X86_PAGE_4K_SIZE;
    uint64_t       *pu64MsrBitmap = (uint64_t *)pVmcsInfoNstGst->pvMsrBitmap;
    Assert(pu64MsrBitmap);

    /*
     * We merge the guest MSR bitmap with the nested-guest MSR bitmap such that any
     * MSR that is intercepted by the guest is also intercepted while executing the
     * nested-guest using hardware-assisted VMX.
     *
     * Note! If the nested-guest is not using an MSR bitmap, every MSR must cause a
     *       nested-guest VM-exit even if the outer guest is not intercepting some
     *       MSRs. We cannot assume the caller has initialized the nested-guest
     *       MSR bitmap in this case.
     *
     *       The nested hypervisor may also switch whether it uses MSR bitmaps for
     *       each of its VM-entry, hence initializing it once per-VM while setting
     *       up the nested-guest VMCS is not sufficient.
     */
    PCVMXVVMCS const pVmcsNstGst  = &pVCpu->cpum.GstCtx.hwvirt.vmx.Vmcs;
    if (pVmcsNstGst->u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS)
    {
        uint64_t const *pu64MsrBitmapNstGst = (uint64_t const *)&pVCpu->cpum.GstCtx.hwvirt.vmx.abMsrBitmap[0];
        uint64_t const *pu64MsrBitmapGst    = (uint64_t const *)pVmcsInfoGst->pvMsrBitmap;
        Assert(pu64MsrBitmapNstGst);
        Assert(pu64MsrBitmapGst);

        /** @todo Detect and use EVEX.POR? */
        uint32_t const cFrags = cbMsrBitmap / sizeof(uint64_t);
        for (uint32_t i = 0; i < cFrags; i++)
            pu64MsrBitmap[i] = pu64MsrBitmapNstGst[i] | pu64MsrBitmapGst[i];
    }
    else
        ASMMemFill32(pu64MsrBitmap, cbMsrBitmap, UINT32_C(0xffffffff));
}


/**
 * Merges the guest VMCS in to the nested-guest VMCS controls in preparation of
 * hardware-assisted VMX execution of the nested-guest.
 *
 * For a guest, we don't modify these controls once we set up the VMCS and hence
 * this function is never called.
 *
 * For nested-guests since the nested hypervisor provides these controls on every
 * nested-guest VM-entry and could potentially change them everytime we need to
 * merge them before every nested-guest VM-entry.
 *
 * @returns VBox status code.
 * @param   pVCpu   The cross context virtual CPU structure.
 */
static int hmR0VmxMergeVmcsNested(PVMCPUCC pVCpu)
{
    PVMCC const         pVM          = pVCpu->CTX_SUFF(pVM);
    PCVMXVMCSINFO const pVmcsInfoGst = &pVCpu->hmr0.s.vmx.VmcsInfo;
    PCVMXVVMCS const    pVmcsNstGst  = &pVCpu->cpum.GstCtx.hwvirt.vmx.Vmcs;

    /*
     * Merge the controls with the requirements of the guest VMCS.
     *
     * We do not need to validate the nested-guest VMX features specified in the nested-guest
     * VMCS with the features supported by the physical CPU as it's already done by the
     * VMLAUNCH/VMRESUME instruction emulation.
     *
     * This is because the VMX features exposed by CPUM (through CPUID/MSRs) to the guest are
     * derived from the VMX features supported by the physical CPU.
     */

    /* Pin-based VM-execution controls. */
    uint32_t const u32PinCtls = pVmcsNstGst->u32PinCtls | pVmcsInfoGst->u32PinCtls;

    /* Processor-based VM-execution controls. */
    uint32_t       u32ProcCtls = (pVmcsNstGst->u32ProcCtls  & ~VMX_PROC_CTLS_USE_IO_BITMAPS)
                               | (pVmcsInfoGst->u32ProcCtls & ~(  VMX_PROC_CTLS_INT_WINDOW_EXIT
                                                                | VMX_PROC_CTLS_NMI_WINDOW_EXIT
                                                                | VMX_PROC_CTLS_MOV_DR_EXIT
                                                                | VMX_PROC_CTLS_USE_TPR_SHADOW
                                                                | VMX_PROC_CTLS_MONITOR_TRAP_FLAG));

    /* Secondary processor-based VM-execution controls. */
    uint32_t const u32ProcCtls2 = (pVmcsNstGst->u32ProcCtls2  & ~VMX_PROC_CTLS2_VPID)
                                | (pVmcsInfoGst->u32ProcCtls2 & ~(  VMX_PROC_CTLS2_VIRT_APIC_ACCESS
                                                                  | VMX_PROC_CTLS2_INVPCID
                                                                  | VMX_PROC_CTLS2_VMCS_SHADOWING
                                                                  | VMX_PROC_CTLS2_RDTSCP
                                                                  | VMX_PROC_CTLS2_XSAVES_XRSTORS
                                                                  | VMX_PROC_CTLS2_APIC_REG_VIRT
                                                                  | VMX_PROC_CTLS2_VIRT_INT_DELIVERY
                                                                  | VMX_PROC_CTLS2_VMFUNC));

    /*
     * VM-entry controls:
     * These controls contains state that depends on the nested-guest state (primarily
     * EFER MSR) and is thus not constant between VMLAUNCH/VMRESUME and the nested-guest
     * VM-exit. Although the nested hypervisor cannot change it, we need to in order to
     * properly continue executing the nested-guest if the EFER MSR changes but does not
     * cause a nested-guest VM-exits.
     *
     * VM-exit controls:
     * These controls specify the host state on return. We cannot use the controls from
     * the nested hypervisor state as is as it would contain the guest state rather than
     * the host state. Since the host state is subject to change (e.g. preemption, trips
     * to ring-3, longjmp and rescheduling to a different host CPU) they are not constant
     * through VMLAUNCH/VMRESUME and the nested-guest VM-exit.
     *
     * VM-entry MSR-load:
     * The guest MSRs from the VM-entry MSR-load area are already loaded into the guest-CPU
     * context by the VMLAUNCH/VMRESUME instruction emulation.
     *
     * VM-exit MSR-store:
     * The VM-exit emulation will take care of populating the MSRs from the guest-CPU context
     * back into the VM-exit MSR-store area.
     *
     * VM-exit MSR-load areas:
     * This must contain the real host MSRs with hardware-assisted VMX execution. Hence, we
     * can entirely ignore what the nested hypervisor wants to load here.
     */

    /*
     * Exception bitmap.
     *
     * We could remove #UD from the guest bitmap and merge it with the nested-guest bitmap
     * here (and avoid doing anything while exporting nested-guest state), but to keep the
     * code more flexible if intercepting exceptions become more dynamic in the future we do
     * it as part of exporting the nested-guest state.
     */
    uint32_t const u32XcptBitmap = pVmcsNstGst->u32XcptBitmap | pVmcsInfoGst->u32XcptBitmap;

    /*
     * CR0/CR4 guest/host mask.
     *
     * Modifications by the nested-guest to CR0/CR4 bits owned by the host and the guest must
     * cause VM-exits, so we need to merge them here.
     */
    uint64_t const u64Cr0Mask = pVmcsNstGst->u64Cr0Mask.u | pVmcsInfoGst->u64Cr0Mask;
    uint64_t const u64Cr4Mask = pVmcsNstGst->u64Cr4Mask.u | pVmcsInfoGst->u64Cr4Mask;

    /*
     * Page-fault error-code mask and match.
     *
     * Although we require unrestricted guest execution (and thereby nested-paging) for
     * hardware-assisted VMX execution of nested-guests and thus the outer guest doesn't
     * normally intercept #PFs, it might intercept them for debugging purposes.
     *
     * If the outer guest is not intercepting #PFs, we can use the nested-guest #PF filters.
     * If the outer guest is intercepting #PFs, we must intercept all #PFs.
     */
    uint32_t u32XcptPFMask;
    uint32_t u32XcptPFMatch;
    if (!(pVmcsInfoGst->u32XcptBitmap & RT_BIT(X86_XCPT_PF)))
    {
        u32XcptPFMask  = pVmcsNstGst->u32XcptPFMask;
        u32XcptPFMatch = pVmcsNstGst->u32XcptPFMatch;
    }
    else
    {
        u32XcptPFMask  = 0;
        u32XcptPFMatch = 0;
    }

    /*
     * Pause-Loop exiting.
     */
    /** @todo r=bird: given that both pVM->hm.s.vmx.cPleGapTicks and
     *        pVM->hm.s.vmx.cPleWindowTicks defaults to zero, I cannot see how
     *        this will work... */
    uint32_t const cPleGapTicks    = RT_MIN(pVM->hm.s.vmx.cPleGapTicks,    pVmcsNstGst->u32PleGap);
    uint32_t const cPleWindowTicks = RT_MIN(pVM->hm.s.vmx.cPleWindowTicks, pVmcsNstGst->u32PleWindow);

    /*
     * Pending debug exceptions.
     * Currently just copy whatever the nested-guest provides us.
     */
    uint64_t const uPendingDbgXcpts = pVmcsNstGst->u64GuestPendingDbgXcpts.u;

    /*
     * I/O Bitmap.
     *
     * We do not use the I/O bitmap that may be provided by the nested hypervisor as we always
     * intercept all I/O port accesses.
     */
    Assert(u32ProcCtls & VMX_PROC_CTLS_UNCOND_IO_EXIT);
    Assert(!(u32ProcCtls & VMX_PROC_CTLS_USE_IO_BITMAPS));

    /*
     * VMCS shadowing.
     *
     * We do not yet expose VMCS shadowing to the guest and thus VMCS shadowing should not be
     * enabled while executing the nested-guest.
     */
    Assert(!(u32ProcCtls2 & VMX_PROC_CTLS2_VMCS_SHADOWING));

    /*
     * APIC-access page.
     */
    RTHCPHYS HCPhysApicAccess;
    if (u32ProcCtls2 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS)
    {
        Assert(g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS);
        RTGCPHYS const GCPhysApicAccess = pVmcsNstGst->u64AddrApicAccess.u;

        /** @todo NSTVMX: This is not really correct but currently is required to make
         *        things work. We need to re-enable the page handler when we fallback to
         *        IEM execution of the nested-guest! */
        PGMHandlerPhysicalPageTempOff(pVM, GCPhysApicAccess, GCPhysApicAccess);

        void          *pvPage;
        PGMPAGEMAPLOCK PgLockApicAccess;
        int rc = PGMPhysGCPhys2CCPtr(pVM, GCPhysApicAccess, &pvPage, &PgLockApicAccess);
        if (RT_SUCCESS(rc))
        {
            rc = PGMPhysGCPhys2HCPhys(pVM, GCPhysApicAccess, &HCPhysApicAccess);
            AssertMsgRCReturn(rc, ("Failed to get host-physical address for APIC-access page at %#RGp\n", GCPhysApicAccess), rc);

            /** @todo Handle proper releasing of page-mapping lock later. */
            PGMPhysReleasePageMappingLock(pVCpu->CTX_SUFF(pVM), &PgLockApicAccess);
        }
        else
            return rc;
    }
    else
        HCPhysApicAccess = 0;

    /*
     * Virtual-APIC page and TPR threshold.
     */
    RTHCPHYS HCPhysVirtApic;
    uint32_t u32TprThreshold;
    if (u32ProcCtls & VMX_PROC_CTLS_USE_TPR_SHADOW)
    {
        Assert(g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_TPR_SHADOW);
        RTGCPHYS const GCPhysVirtApic = pVmcsNstGst->u64AddrVirtApic.u;

        void          *pvPage;
        PGMPAGEMAPLOCK PgLockVirtApic;
        int rc = PGMPhysGCPhys2CCPtr(pVM, GCPhysVirtApic, &pvPage, &PgLockVirtApic);
        if (RT_SUCCESS(rc))
        {
            rc = PGMPhysGCPhys2HCPhys(pVM, GCPhysVirtApic, &HCPhysVirtApic);
            AssertMsgRCReturn(rc, ("Failed to get host-physical address for virtual-APIC page at %#RGp\n", GCPhysVirtApic), rc);

            /** @todo Handle proper releasing of page-mapping lock later. */
            PGMPhysReleasePageMappingLock(pVCpu->CTX_SUFF(pVM), &PgLockVirtApic);
        }
        else
            return rc;

        u32TprThreshold = pVmcsNstGst->u32TprThreshold;
    }
    else
    {
        HCPhysVirtApic  = 0;
        u32TprThreshold = 0;

        /*
         * We must make sure CR8 reads/write must cause VM-exits when TPR shadowing is not
         * used by the nested hypervisor. Preventing MMIO accesses to the physical APIC will
         * be taken care of by EPT/shadow paging.
         */
        if (pVM->hmr0.s.fAllow64BitGuests)
            u32ProcCtls |= VMX_PROC_CTLS_CR8_STORE_EXIT
                        |  VMX_PROC_CTLS_CR8_LOAD_EXIT;
    }

    /*
     * Validate basic assumptions.
     */
    PVMXVMCSINFO pVmcsInfoNstGst = &pVCpu->hmr0.s.vmx.VmcsInfoNstGst;
    Assert(pVM->hmr0.s.vmx.fUnrestrictedGuest);
    Assert(g_HmMsrs.u.vmx.ProcCtls.n.allowed1 & VMX_PROC_CTLS_USE_SECONDARY_CTLS);
    Assert(hmGetVmxActiveVmcsInfo(pVCpu) == pVmcsInfoNstGst);

    /*
     * Commit it to the nested-guest VMCS.
     */
    int rc = VINF_SUCCESS;
    if (pVmcsInfoNstGst->u32PinCtls != u32PinCtls)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PIN_EXEC, u32PinCtls);
    if (pVmcsInfoNstGst->u32ProcCtls != u32ProcCtls)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC, u32ProcCtls);
    if (pVmcsInfoNstGst->u32ProcCtls2 != u32ProcCtls2)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PROC_EXEC2, u32ProcCtls2);
    if (pVmcsInfoNstGst->u32XcptBitmap != u32XcptBitmap)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_EXCEPTION_BITMAP, u32XcptBitmap);
    if (pVmcsInfoNstGst->u64Cr0Mask != u64Cr0Mask)
        rc |= VMXWriteVmcsNw(VMX_VMCS_CTRL_CR0_MASK, u64Cr0Mask);
    if (pVmcsInfoNstGst->u64Cr4Mask != u64Cr4Mask)
        rc |= VMXWriteVmcsNw(VMX_VMCS_CTRL_CR4_MASK, u64Cr4Mask);
    if (pVmcsInfoNstGst->u32XcptPFMask != u32XcptPFMask)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MASK, u32XcptPFMask);
    if (pVmcsInfoNstGst->u32XcptPFMatch != u32XcptPFMatch)
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PAGEFAULT_ERROR_MATCH, u32XcptPFMatch);
    if (   !(u32ProcCtls  & VMX_PROC_CTLS_PAUSE_EXIT)
        &&  (u32ProcCtls2 & VMX_PROC_CTLS2_PAUSE_LOOP_EXIT))
    {
        Assert(g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_PAUSE_LOOP_EXIT);
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PLE_GAP, cPleGapTicks);
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_PLE_WINDOW, cPleWindowTicks);
    }
    if (u32ProcCtls & VMX_PROC_CTLS_USE_TPR_SHADOW)
    {
        rc |= VMXWriteVmcs32(VMX_VMCS32_CTRL_TPR_THRESHOLD, u32TprThreshold);
        rc |= VMXWriteVmcs64(VMX_VMCS64_CTRL_VIRT_APIC_PAGEADDR_FULL, HCPhysVirtApic);
    }
    if (u32ProcCtls2 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS)
        rc |= VMXWriteVmcs64(VMX_VMCS64_CTRL_APIC_ACCESSADDR_FULL, HCPhysApicAccess);
    rc |= VMXWriteVmcsNw(VMX_VMCS_GUEST_PENDING_DEBUG_XCPTS, uPendingDbgXcpts);
    AssertRC(rc);

    /*
     * Update the nested-guest VMCS cache.
     */
    pVmcsInfoNstGst->u32PinCtls     = u32PinCtls;
    pVmcsInfoNstGst->u32ProcCtls    = u32ProcCtls;
    pVmcsInfoNstGst->u32ProcCtls2   = u32ProcCtls2;
    pVmcsInfoNstGst->u32XcptBitmap  = u32XcptBitmap;
    pVmcsInfoNstGst->u64Cr0Mask     = u64Cr0Mask;
    pVmcsInfoNstGst->u64Cr4Mask     = u64Cr4Mask;
    pVmcsInfoNstGst->u32XcptPFMask  = u32XcptPFMask;
    pVmcsInfoNstGst->u32XcptPFMatch = u32XcptPFMatch;
    pVmcsInfoNstGst->HCPhysVirtApic = HCPhysVirtApic;

    /*
     * We need to flush the TLB if we are switching the APIC-access page address.
     * See Intel spec. 28.3.3.4 "Guidelines for Use of the INVEPT Instruction".
     */
    if (u32ProcCtls2 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS)
        pVCpu->hm.s.vmx.fSwitchedNstGstFlushTlb = true;

    /*
     * MSR bitmap.
     *
     * The MSR bitmap address has already been initialized while setting up the nested-guest
     * VMCS, here we need to merge the MSR bitmaps.
     */
    if (u32ProcCtls & VMX_PROC_CTLS_USE_MSR_BITMAPS)
        hmR0VmxMergeMsrBitmapNested(pVCpu, pVmcsInfoNstGst, pVmcsInfoGst);

    return VINF_SUCCESS;
}
#endif /* VBOX_WITH_NESTED_HWVIRT_VMX */


/**
 * Does the preparations before executing guest code in VT-x.
 *
 * This may cause longjmps to ring-3 and may even result in rescheduling to the
 * recompiler/IEM. We must be cautious what we do here regarding committing
 * guest-state information into the VMCS assuming we assuredly execute the
 * guest in VT-x mode.
 *
 * If we fall back to the recompiler/IEM after updating the VMCS and clearing
 * the common-state (TRPM/forceflags), we must undo those changes so that the
 * recompiler/IEM can (and should) use them when it resumes guest execution.
 * Otherwise such operations must be done when we can no longer exit to ring-3.
 *
 * @returns Strict VBox status code (i.e. informational status codes too).
 * @retval  VINF_SUCCESS if we can proceed with running the guest, interrupts
 *          have been disabled.
 * @retval  VINF_VMX_VMEXIT if a nested-guest VM-exit occurs (e.g., while evaluating
 *          pending events).
 * @retval  VINF_EM_RESET if a triple-fault occurs while injecting a
 *          double-fault into the guest.
 * @retval  VINF_EM_DBG_STEPPED if @a fStepping is true and an event was
 *          dispatched directly.
 * @retval  VINF_* scheduling changes, we have to go back to ring-3.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   fStepping       Whether we are single-stepping the guest in the
 *                          hypervisor debugger. Makes us ignore some of the reasons
 *                          for returning to ring-3, and return VINF_EM_DBG_STEPPED
 *                          if event dispatching took place.
 */
static VBOXSTRICTRC hmR0VmxPreRunGuest(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient, bool fStepping)
{
    Assert(VMMRZCallRing3IsEnabled(pVCpu));

    Log4Func(("fIsNested=%RTbool fStepping=%RTbool\n", pVmxTransient->fIsNestedGuest, fStepping));

#ifdef VBOX_WITH_NESTED_HWVIRT_ONLY_IN_IEM
    if (pVmxTransient->fIsNestedGuest)
    {
        RT_NOREF2(pVCpu, fStepping);
        Log2Func(("Rescheduling to IEM due to nested-hwvirt or forced IEM exec -> VINF_EM_RESCHEDULE_REM\n"));
        return VINF_EM_RESCHEDULE_REM;
    }
#endif

    /*
     * Check and process force flag actions, some of which might require us to go back to ring-3.
     */
    VBOXSTRICTRC rcStrict = vmxHCCheckForceFlags(pVCpu, pVmxTransient->fIsNestedGuest, fStepping);
    if (rcStrict == VINF_SUCCESS)
    {
        /* FFs don't get set all the time. */
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        if (   pVmxTransient->fIsNestedGuest
            && !CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx))
        {
            STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchNstGstVmexit);
            return VINF_VMX_VMEXIT;
        }
#endif
    }
    else
        return rcStrict;

    /*
     * Virtualize memory-mapped accesses to the physical APIC (may take locks).
     */
    PVMCC pVM = pVCpu->CTX_SUFF(pVM);
    if (   !pVCpu->hm.s.vmx.u64GstMsrApicBase
        && (g_HmMsrs.u.vmx.ProcCtls2.n.allowed1 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS)
        && PDMHasApic(pVM))
    {
        /* Get the APIC base MSR from the virtual APIC device. */
        uint64_t const uApicBaseMsr = APICGetBaseMsrNoCheck(pVCpu);

        /* Map the APIC access page. */
        int rc = hmR0VmxMapHCApicAccessPage(pVCpu, uApicBaseMsr & ~(RTGCPHYS)GUEST_PAGE_OFFSET_MASK);
        AssertRCReturn(rc, rc);

        /* Update the per-VCPU cache of the APIC base MSR corresponding to the mapped APIC access page. */
        pVCpu->hm.s.vmx.u64GstMsrApicBase = uApicBaseMsr;
    }

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /*
     * Merge guest VMCS controls with the nested-guest VMCS controls.
     *
     * Even if we have not executed the guest prior to this (e.g. when resuming from a
     * saved state), we should be okay with merging controls as we initialize the
     * guest VMCS controls as part of VM setup phase.
     */
    if (   pVmxTransient->fIsNestedGuest
        && !pVCpu->hm.s.vmx.fMergedNstGstCtls)
    {
        int rc = hmR0VmxMergeVmcsNested(pVCpu);
        AssertRCReturn(rc, rc);
        pVCpu->hm.s.vmx.fMergedNstGstCtls = true;
    }
#endif

    /*
     * Evaluate events to be injected into the guest.
     *
     * Events in TRPM can be injected without inspecting the guest state.
     * If any new events (interrupts/NMI) are pending currently, we try to set up the
     * guest to cause a VM-exit the next time they are ready to receive the event.
     */
    if (TRPMHasTrap(pVCpu))
        vmxHCTrpmTrapToPendingEvent(pVCpu);

    uint32_t fIntrState;
    rcStrict = vmxHCEvaluatePendingEvent(pVCpu, pVmxTransient->pVmcsInfo, pVmxTransient->fIsNestedGuest,
                                         &fIntrState);

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /*
     * While evaluating pending events if something failed (unlikely) or if we were
     * preparing to run a nested-guest but performed a nested-guest VM-exit, we should bail.
     */
    if (rcStrict != VINF_SUCCESS)
        return rcStrict;
    if (   pVmxTransient->fIsNestedGuest
        && !CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx))
    {
        STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchNstGstVmexit);
        return VINF_VMX_VMEXIT;
    }
#else
    Assert(rcStrict == VINF_SUCCESS);
#endif

    /*
     * Event injection may take locks (currently the PGM lock for real-on-v86 case) and thus
     * needs to be done with longjmps or interrupts + preemption enabled. Event injection might
     * also result in triple-faulting the VM.
     *
     * With nested-guests, the above does not apply since unrestricted guest execution is a
     * requirement. Regardless, we do this here to avoid duplicating code elsewhere.
     */
    rcStrict = vmxHCInjectPendingEvent(pVCpu, pVmxTransient->pVmcsInfo, pVmxTransient->fIsNestedGuest,
                                       fIntrState, fStepping);
    if (RT_LIKELY(rcStrict == VINF_SUCCESS))
    { /* likely */ }
    else
    {
        AssertMsg(rcStrict == VINF_EM_RESET || (rcStrict == VINF_EM_DBG_STEPPED && fStepping),
                  ("%Rrc\n", VBOXSTRICTRC_VAL(rcStrict)));
        return rcStrict;
    }

    /*
     * A longjump might result in importing CR3 even for VM-exits that don't necessarily
     * import CR3 themselves. We will need to update them here, as even as late as the above
     * hmR0VmxInjectPendingEvent() call may lazily import guest-CPU state on demand causing
     * the below force flags to be set.
     */
    if (VMCPU_FF_IS_SET(pVCpu, VMCPU_FF_HM_UPDATE_CR3))
    {
        Assert(!(ASMAtomicUoReadU64(&pVCpu->cpum.GstCtx.fExtrn) & CPUMCTX_EXTRN_CR3));
        int rc2 = PGMUpdateCR3(pVCpu, CPUMGetGuestCR3(pVCpu));
        AssertMsgReturn(rc2 == VINF_SUCCESS || rc2 == VINF_PGM_SYNC_CR3,
                        ("%Rrc\n", rc2), RT_FAILURE_NP(rc2) ? rc2 : VERR_IPE_UNEXPECTED_INFO_STATUS);
        Assert(!VMCPU_FF_IS_SET(pVCpu, VMCPU_FF_HM_UPDATE_CR3));
    }

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /* Paranoia. */
    Assert(!pVmxTransient->fIsNestedGuest || CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx));
#endif

    /*
     * No longjmps to ring-3 from this point on!!!
     * Asserts() will still longjmp to ring-3 (but won't return), which is intentional, better than a kernel panic.
     * This also disables flushing of the R0-logger instance (if any).
     */
    VMMRZCallRing3Disable(pVCpu);

    /*
     * Export the guest state bits.
     *
     * We cannot perform longjmps while loading the guest state because we do not preserve the
     * host/guest state (although the VMCS will be preserved) across longjmps which can cause
     * CPU migration.
     *
     * If we are injecting events to a real-on-v86 mode guest, we would have updated RIP and some segment
     * registers. Hence, exporting of the guest state needs to be done -after- injection of events.
     */
    rcStrict = hmR0VmxExportGuestStateOptimal(pVCpu, pVmxTransient);
    if (RT_LIKELY(rcStrict == VINF_SUCCESS))
    { /* likely */ }
    else
    {
        VMMRZCallRing3Enable(pVCpu);
        return rcStrict;
    }

    /*
     * We disable interrupts so that we don't miss any interrupts that would flag preemption
     * (IPI/timers etc.) when thread-context hooks aren't used and we've been running with
     * preemption disabled for a while.  Since this is purely to aid the
     * RTThreadPreemptIsPending() code, it doesn't matter that it may temporarily reenable and
     * disable interrupt on NT.
     *
     * We need to check for force-flags that could've possible been altered since we last
     * checked them (e.g. by PDMGetInterrupt() leaving the PDM critical section,
     * see @bugref{6398}).
     *
     * We also check a couple of other force-flags as a last opportunity to get the EMT back
     * to ring-3 before executing guest code.
     */
    pVmxTransient->fEFlags = ASMIntDisableFlags();

    if (   (   !VM_FF_IS_ANY_SET(pVM, VM_FF_EMT_RENDEZVOUS | VM_FF_TM_VIRTUAL_SYNC)
            && !VMCPU_FF_IS_ANY_SET(pVCpu, VMCPU_FF_HM_TO_R3_MASK))
        || (   fStepping /* Optimized for the non-stepping case, so a bit of unnecessary work when stepping. */
            && !VMCPU_FF_IS_ANY_SET(pVCpu, VMCPU_FF_HM_TO_R3_MASK & ~(VMCPU_FF_TIMER | VMCPU_FF_PDM_CRITSECT))) )
    {
        if (!RTThreadPreemptIsPending(NIL_RTTHREAD))
        {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
            /*
             * If we are executing a nested-guest make sure that we should intercept subsequent
             * events. The one we are injecting might be part of VM-entry. This is mainly to keep
             * the VM-exit instruction emulation happy.
             */
            if (pVmxTransient->fIsNestedGuest)
                CPUMSetGuestVmxInterceptEvents(&pVCpu->cpum.GstCtx, true);
#endif

            /*
             * We've injected any pending events. This is really the point of no return (to ring-3).
             *
             * Note! The caller expects to continue with interrupts & longjmps disabled on successful
             *       returns from this function, so do -not- enable them here.
             */
            pVCpu->hm.s.Event.fPending = false;
            return VINF_SUCCESS;
        }

        STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchPendingHostIrq);
        rcStrict = VINF_EM_RAW_INTERRUPT;
    }
    else
    {
        STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchHmToR3FF);
        rcStrict = VINF_EM_RAW_TO_R3;
    }

    ASMSetFlags(pVmxTransient->fEFlags);
    VMMRZCallRing3Enable(pVCpu);

    return rcStrict;
}


/**
 * Final preparations before executing guest code using hardware-assisted VMX.
 *
 * We can no longer get preempted to a different host CPU and there are no returns
 * to ring-3. We ignore any errors that may happen from this point (e.g. VMWRITE
 * failures), this function is not intended to fail sans unrecoverable hardware
 * errors.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 *
 * @remarks Called with preemption disabled.
 * @remarks No-long-jump zone!!!
 */
static void hmR0VmxPreRunGuestCommitted(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient)
{
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));
    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
    Assert(!pVCpu->hm.s.Event.fPending);

    /*
     * Indicate start of guest execution and where poking EMT out of guest-context is recognized.
     */
    VMCPU_ASSERT_STATE(pVCpu, VMCPUSTATE_STARTED_HM);
    VMCPU_SET_STATE(pVCpu, VMCPUSTATE_STARTED_EXEC);

    PVMCC         pVM          = pVCpu->CTX_SUFF(pVM);
    PVMXVMCSINFO  pVmcsInfo    = pVmxTransient->pVmcsInfo;
    PHMPHYSCPU    pHostCpu     = hmR0GetCurrentCpu();
    RTCPUID const idCurrentCpu = pHostCpu->idCpu;

    if (!CPUMIsGuestFPUStateActive(pVCpu))
    {
        STAM_PROFILE_ADV_START(&pVCpu->hm.s.StatLoadGuestFpuState, x);
        if (CPUMR0LoadGuestFPU(pVM, pVCpu) == VINF_CPUM_HOST_CR0_MODIFIED)
            pVCpu->hm.s.fCtxChanged |= HM_CHANGED_HOST_CONTEXT;
        STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatLoadGuestFpuState, x);
        STAM_COUNTER_INC(&pVCpu->hm.s.StatLoadGuestFpu);
    }

    /*
     * Re-export the host state bits as we may've been preempted (only happens when
     * thread-context hooks are used or when the VM start function changes) or if
     * the host CR0 is modified while loading the guest FPU state above.
     *
     * The 64-on-32 switcher saves the (64-bit) host state into the VMCS and if we
     * changed the switcher back to 32-bit, we *must* save the 32-bit host state here,
     * see @bugref{8432}.
     *
     * This may also happen when switching to/from a nested-guest VMCS without leaving
     * ring-0.
     */
    if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_HOST_CONTEXT)
    {
        hmR0VmxExportHostState(pVCpu);
        STAM_COUNTER_INC(&pVCpu->hm.s.StatExportHostState);
    }
    Assert(!(pVCpu->hm.s.fCtxChanged & HM_CHANGED_HOST_CONTEXT));

    /*
     * Export the state shared between host and guest (FPU, debug, lazy MSRs).
     */
    if (pVCpu->hm.s.fCtxChanged & HM_CHANGED_VMX_HOST_GUEST_SHARED_STATE)
        hmR0VmxExportSharedState(pVCpu, pVmxTransient);
    AssertMsg(!pVCpu->hm.s.fCtxChanged, ("fCtxChanged=%#RX64\n", pVCpu->hm.s.fCtxChanged));

    /*
     * Store status of the shared guest/host debug state at the time of VM-entry.
     */
    pVmxTransient->fWasGuestDebugStateActive = CPUMIsGuestDebugStateActive(pVCpu);
    pVmxTransient->fWasHyperDebugStateActive = CPUMIsHyperDebugStateActive(pVCpu);

    /*
     * Always cache the TPR-shadow if the virtual-APIC page exists, thereby skipping
     * more than one conditional check. The post-run side of our code shall determine
     * if it needs to sync. the virtual APIC TPR with the TPR-shadow.
     */
    if (pVmcsInfo->pbVirtApic)
        pVmxTransient->u8GuestTpr = pVmcsInfo->pbVirtApic[XAPIC_OFF_TPR];

    /*
     * Update the host MSRs values in the VM-exit MSR-load area.
     */
    if (!pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs)
    {
        if (pVmcsInfo->cExitMsrLoad > 0)
            hmR0VmxUpdateAutoLoadHostMsrs(pVCpu, pVmcsInfo);
        pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs = true;
    }

    /*
     * Evaluate if we need to intercept guest RDTSC/P accesses. Set up the
     * VMX-preemption timer based on the next virtual sync clock deadline.
     */
    if (   !pVmxTransient->fUpdatedTscOffsettingAndPreemptTimer
        || idCurrentCpu != pVCpu->hmr0.s.idLastCpu)
    {
        hmR0VmxUpdateTscOffsettingAndPreemptTimer(pVCpu, pVmxTransient, idCurrentCpu);
        pVmxTransient->fUpdatedTscOffsettingAndPreemptTimer = true;
    }

    /* Record statistics of how often we use TSC offsetting as opposed to intercepting RDTSC/P. */
    bool const fIsRdtscIntercepted = RT_BOOL(pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_RDTSC_EXIT);
    if (!fIsRdtscIntercepted)
        STAM_COUNTER_INC(&pVCpu->hm.s.StatTscOffset);
    else
        STAM_COUNTER_INC(&pVCpu->hm.s.StatTscIntercept);

    ASMAtomicUoWriteBool(&pVCpu->hm.s.fCheckedTLBFlush, true);  /* Used for TLB flushing, set this across the world switch. */
    hmR0VmxFlushTaggedTlb(pHostCpu, pVCpu, pVmcsInfo);          /* Invalidate the appropriate guest entries from the TLB. */
    Assert(idCurrentCpu == pVCpu->hmr0.s.idLastCpu);
    pVCpu->hm.s.vmx.LastError.idCurrentCpu = idCurrentCpu;      /* Record the error reporting info. with the current host CPU. */
    pVmcsInfo->idHostCpuState = idCurrentCpu;                   /* Record the CPU for which the host-state has been exported. */
    pVmcsInfo->idHostCpuExec  = idCurrentCpu;                   /* Record the CPU on which we shall execute. */

    STAM_PROFILE_ADV_STOP_START(&pVCpu->hm.s.StatEntry, &pVCpu->hm.s.StatInGC, x);

    TMNotifyStartOfExecution(pVM, pVCpu);                       /* Notify TM to resume its clocks when TSC is tied to execution,
                                                                   as we're about to start executing the guest. */

    /*
     * Load the guest TSC_AUX MSR when we are not intercepting RDTSCP.
     *
     * This is done this late as updating the TSC offsetting/preemption timer above
     * figures out if we can skip intercepting RDTSCP by calculating the number of
     * host CPU ticks till the next virtual sync deadline (for the dynamic case).
     */
    if (   (pVmcsInfo->u32ProcCtls2 & VMX_PROC_CTLS2_RDTSCP)
        && !fIsRdtscIntercepted)
    {
        vmxHCImportGuestState(pVCpu, pVmcsInfo, CPUMCTX_EXTRN_TSC_AUX);

        /* NB: Because we call hmR0VmxAddAutoLoadStoreMsr with fUpdateHostMsr=true,
           it's safe even after hmR0VmxUpdateAutoLoadHostMsrs has already been done. */
        int rc = hmR0VmxAddAutoLoadStoreMsr(pVCpu, pVmxTransient, MSR_K8_TSC_AUX, CPUMGetGuestTscAux(pVCpu),
                                            true /* fSetReadWrite */, true /* fUpdateHostMsr */);
        AssertRC(rc);
        Assert(!pVmxTransient->fRemoveTscAuxMsr);
        pVmxTransient->fRemoveTscAuxMsr = true;
    }

#ifdef VBOX_STRICT
    Assert(pVCpu->hmr0.s.vmx.fUpdatedHostAutoMsrs);
    hmR0VmxCheckAutoLoadStoreMsrs(pVCpu, pVmcsInfo, pVmxTransient->fIsNestedGuest);
    hmR0VmxCheckHostEferMsr(pVmcsInfo);
    AssertRC(vmxHCCheckCachedVmcsCtls(pVCpu, pVmcsInfo, pVmxTransient->fIsNestedGuest));
#endif

#ifdef HMVMX_ALWAYS_CHECK_GUEST_STATE
    /** @todo r=ramshankar: We can now probably use iemVmxVmentryCheckGuestState here.
     *        Add a PVMXMSRS parameter to it, so that IEM can look at the host MSRs,
     *        see @bugref{9180#c54}. */
    uint32_t const uInvalidReason = hmR0VmxCheckGuestState(pVCpu, pVmcsInfo);
    if (uInvalidReason != VMX_IGS_REASON_NOT_FOUND)
        Log4(("hmR0VmxCheckGuestState returned %#x\n", uInvalidReason));
#endif
}


/**
 * First C routine invoked after running guest code using hardware-assisted VMX.
 *
 * @param   pVCpu           The cross context virtual CPU structure.
 * @param   pVmxTransient   The VMX-transient structure.
 * @param   rcVMRun         Return code of VMLAUNCH/VMRESUME.
 *
 * @remarks Called with interrupts disabled, and returns with interrupts enabled!
 *
 * @remarks No-long-jump zone!!! This function will however re-enable longjmps
 *          unconditionally when it is safe to do so.
 */
static void hmR0VmxPostRunGuest(PVMCPUCC pVCpu, PVMXTRANSIENT pVmxTransient, int rcVMRun)
{
    ASMAtomicUoWriteBool(&pVCpu->hm.s.fCheckedTLBFlush, false); /* See HMInvalidatePageOnAllVCpus(): used for TLB flushing. */
    ASMAtomicIncU32(&pVCpu->hmr0.s.cWorldSwitchExits);          /* Initialized in vmR3CreateUVM(): used for EMT poking. */
    pVCpu->hm.s.fCtxChanged            = 0;                     /* Exits/longjmps to ring-3 requires saving the guest state. */
    pVmxTransient->fVmcsFieldsRead     = 0;                     /* Transient fields need to be read from the VMCS. */
    pVmxTransient->fVectoringPF        = false;                 /* Vectoring page-fault needs to be determined later. */
    pVmxTransient->fVectoringDoublePF  = false;                 /* Vectoring double page-fault needs to be determined later. */

    PVMXVMCSINFO pVmcsInfo = pVmxTransient->pVmcsInfo;
    if (!(pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_RDTSC_EXIT))
    {
        uint64_t uGstTsc;
        if (!pVmxTransient->fIsNestedGuest)
            uGstTsc = pVCpu->hmr0.s.uTscExit + pVmcsInfo->u64TscOffset;
        else
        {
            uint64_t const uNstGstTsc = pVCpu->hmr0.s.uTscExit + pVmcsInfo->u64TscOffset;
            uGstTsc = CPUMRemoveNestedGuestTscOffset(pVCpu, uNstGstTsc);
        }
        TMCpuTickSetLastSeen(pVCpu, uGstTsc);                           /* Update TM with the guest TSC. */
    }

    STAM_PROFILE_ADV_STOP_START(&pVCpu->hm.s.StatInGC, &pVCpu->hm.s.StatPreExit, x);
    TMNotifyEndOfExecution(pVCpu->CTX_SUFF(pVM), pVCpu, pVCpu->hmr0.s.uTscExit); /* Notify TM that the guest is no longer running. */
    VMCPU_SET_STATE(pVCpu, VMCPUSTATE_STARTED_HM);

    pVCpu->hmr0.s.vmx.fRestoreHostFlags |= VMX_RESTORE_HOST_REQUIRED;   /* Some host state messed up by VMX needs restoring. */
    pVmcsInfo->fVmcsState |= VMX_V_VMCS_LAUNCH_STATE_LAUNCHED;          /* Use VMRESUME instead of VMLAUNCH in the next run. */
#ifdef VBOX_STRICT
    hmR0VmxCheckHostEferMsr(pVmcsInfo);                                 /* Verify that the host EFER MSR wasn't modified. */
#endif
    Assert(!ASMIntAreEnabled());
    ASMSetFlags(pVmxTransient->fEFlags);                                /* Enable interrupts. */
    Assert(!VMMRZCallRing3IsEnabled(pVCpu));

#ifdef HMVMX_ALWAYS_CLEAN_TRANSIENT
    /*
     * Clean all the VMCS fields in the transient structure before reading
     * anything from the VMCS.
     */
    pVmxTransient->uExitReason            = 0;
    pVmxTransient->uExitIntErrorCode      = 0;
    pVmxTransient->uExitQual              = 0;
    pVmxTransient->uGuestLinearAddr       = 0;
    pVmxTransient->uExitIntInfo           = 0;
    pVmxTransient->cbExitInstr            = 0;
    pVmxTransient->ExitInstrInfo.u        = 0;
    pVmxTransient->uEntryIntInfo          = 0;
    pVmxTransient->uEntryXcptErrorCode    = 0;
    pVmxTransient->cbEntryInstr           = 0;
    pVmxTransient->uIdtVectoringInfo      = 0;
    pVmxTransient->uIdtVectoringErrorCode = 0;
#endif

    /*
     * Save the basic VM-exit reason and check if the VM-entry failed.
     * See Intel spec. 24.9.1 "Basic VM-exit Information".
     */
    uint32_t uExitReason;
    int rc = VMXReadVmcs32(VMX_VMCS32_RO_EXIT_REASON, &uExitReason);
    AssertRC(rc);
    pVmxTransient->uExitReason    = VMX_EXIT_REASON_BASIC(uExitReason);
    pVmxTransient->fVMEntryFailed = VMX_EXIT_REASON_HAS_ENTRY_FAILED(uExitReason);

    /*
     * Log the VM-exit before logging anything else as otherwise it might be a
     * tad confusing what happens before and after the world-switch.
     */
    HMVMX_LOG_EXIT(pVCpu, uExitReason);

    /*
     * Remove the TSC_AUX MSR from the auto-load/store MSR area and reset any MSR
     * bitmap permissions, if it was added before VM-entry.
     */
    if (pVmxTransient->fRemoveTscAuxMsr)
    {
        hmR0VmxRemoveAutoLoadStoreMsr(pVCpu, pVmxTransient, MSR_K8_TSC_AUX);
        pVmxTransient->fRemoveTscAuxMsr = false;
    }

    /*
     * Check if VMLAUNCH/VMRESUME succeeded.
     * If this failed, we cause a guru meditation and cease further execution.
     */
    if (RT_LIKELY(rcVMRun == VINF_SUCCESS))
    {
        /*
         * Update the VM-exit history array here even if the VM-entry failed due to:
         *   - Invalid guest state.
         *   - MSR loading.
         *   - Machine-check event.
         *
         * In any of the above cases we will still have a "valid" VM-exit reason
         * despite @a fVMEntryFailed being false.
         *
         * See Intel spec. 26.7 "VM-Entry failures during or after loading guest state".
         *
         * Note! We don't have CS or RIP at this point.  Will probably address that later
         *       by amending the history entry added here.
         */
        EMHistoryAddExit(pVCpu, EMEXIT_MAKE_FT(EMEXIT_F_KIND_VMX, pVmxTransient->uExitReason & EMEXIT_F_TYPE_MASK),
                         UINT64_MAX, pVCpu->hmr0.s.uTscExit);

        if (RT_LIKELY(!pVmxTransient->fVMEntryFailed))
        {
            VMMRZCallRing3Enable(pVCpu);
            Assert(!VMCPU_FF_IS_SET(pVCpu, VMCPU_FF_HM_UPDATE_CR3));

#ifdef HMVMX_ALWAYS_SAVE_RO_GUEST_STATE
            hmR0VmxReadAllRoFieldsVmcs(pVmxTransient);
#endif

            /*
             * Always import the guest-interruptibility state as we need it while evaluating
             * injecting events on re-entry.
             *
             * We don't import CR0 (when unrestricted guest execution is unavailable) despite
             * checking for real-mode while exporting the state because all bits that cause
             * mode changes wrt CR0 are intercepted.
             */
            uint64_t const fImportMask = CPUMCTX_EXTRN_INHIBIT_INT
                                       | CPUMCTX_EXTRN_INHIBIT_NMI
#if defined(HMVMX_ALWAYS_SYNC_FULL_GUEST_STATE) || defined(HMVMX_ALWAYS_SAVE_FULL_GUEST_STATE)
                                       | HMVMX_CPUMCTX_EXTRN_ALL
#elif defined(HMVMX_ALWAYS_SAVE_GUEST_RFLAGS)
                                       | CPUMCTX_EXTRN_RFLAGS
#endif
                                       ;
            rc = vmxHCImportGuestState(pVCpu, pVmcsInfo, fImportMask);
            AssertRC(rc);

            /*
             * Sync the TPR shadow with our APIC state.
             */
            if (   !pVmxTransient->fIsNestedGuest
                && (pVmcsInfo->u32ProcCtls & VMX_PROC_CTLS_USE_TPR_SHADOW))
            {
                Assert(pVmcsInfo->pbVirtApic);
                if (pVmxTransient->u8GuestTpr != pVmcsInfo->pbVirtApic[XAPIC_OFF_TPR])
                {
                    rc = APICSetTpr(pVCpu, pVmcsInfo->pbVirtApic[XAPIC_OFF_TPR]);
                    AssertRC(rc);
                    ASMAtomicUoOrU64(&pVCpu->hm.s.fCtxChanged, HM_CHANGED_GUEST_APIC_TPR);
                }
            }

            Assert(VMMRZCallRing3IsEnabled(pVCpu));
            Assert(   pVmxTransient->fWasGuestDebugStateActive == false
                   || pVmxTransient->fWasHyperDebugStateActive == false);
            return;
        }
    }
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    else if (pVmxTransient->fIsNestedGuest)
        AssertMsgFailed(("VMLAUNCH/VMRESUME failed but shouldn't happen when VMLAUNCH/VMRESUME was emulated in IEM!\n"));
#endif
    else
        Log4Func(("VM-entry failure: rcVMRun=%Rrc fVMEntryFailed=%RTbool\n", rcVMRun, pVmxTransient->fVMEntryFailed));

    VMMRZCallRing3Enable(pVCpu);
}


/**
 * Runs the guest code using hardware-assisted VMX the normal way.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pcLoops     Pointer to the number of executed loops.
 */
static VBOXSTRICTRC hmR0VmxRunGuestCodeNormal(PVMCPUCC pVCpu, uint32_t *pcLoops)
{
    uint32_t const cMaxResumeLoops = pVCpu->CTX_SUFF(pVM)->hmr0.s.cMaxResumeLoops;
    Assert(pcLoops);
    Assert(*pcLoops <= cMaxResumeLoops);
    Assert(!CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx));

#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
    /*
     * Switch to the guest VMCS as we may have transitioned from executing the nested-guest
     * without leaving ring-0. Otherwise, if we came from ring-3 we would have loaded the
     * guest VMCS while entering the VMX ring-0 session.
     */
    if (pVCpu->hmr0.s.vmx.fSwitchedToNstGstVmcs)
    {
        int rc = vmxHCSwitchToGstOrNstGstVmcs(pVCpu, false /* fSwitchToNstGstVmcs */);
        if (RT_SUCCESS(rc))
        { /* likely */ }
        else
        {
            LogRelFunc(("Failed to switch to the guest VMCS. rc=%Rrc\n", rc));
            return rc;
        }
    }
#endif

    VMXTRANSIENT VmxTransient;
    RT_ZERO(VmxTransient);
    VmxTransient.pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);

    /* Paranoia. */
    Assert(VmxTransient.pVmcsInfo == &pVCpu->hmr0.s.vmx.VmcsInfo);

    VBOXSTRICTRC rcStrict = VERR_INTERNAL_ERROR_5;
    for (;;)
    {
        Assert(!HMR0SuspendPending());
        HMVMX_ASSERT_CPU_SAFE(pVCpu);
        STAM_PROFILE_ADV_START(&pVCpu->hm.s.StatEntry, x);

        /*
         * Preparatory work for running nested-guest code, this may force us to
         * return to ring-3.
         *
         * Warning! This bugger disables interrupts on VINF_SUCCESS!
         */
        rcStrict = hmR0VmxPreRunGuest(pVCpu, &VmxTransient, false /* fStepping */);
        if (rcStrict != VINF_SUCCESS)
            break;

        /* Interrupts are disabled at this point! */
        hmR0VmxPreRunGuestCommitted(pVCpu, &VmxTransient);
        int rcRun = hmR0VmxRunGuest(pVCpu, &VmxTransient);
        hmR0VmxPostRunGuest(pVCpu, &VmxTransient, rcRun);
        /* Interrupts are re-enabled at this point! */

        /*
         * Check for errors with running the VM (VMLAUNCH/VMRESUME).
         */
        if (RT_SUCCESS(rcRun))
        { /* very likely */ }
        else
        {
            STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatPreExit, x);
            hmR0VmxReportWorldSwitchError(pVCpu, rcRun, &VmxTransient);
            return rcRun;
        }

        /*
         * Profile the VM-exit.
         */
        AssertMsg(VmxTransient.uExitReason <= VMX_EXIT_MAX, ("%#x\n", VmxTransient.uExitReason));
        STAM_COUNTER_INC(&pVCpu->hm.s.StatExitAll);
        STAM_COUNTER_INC(&pVCpu->hm.s.aStatExitReason[VmxTransient.uExitReason & MASK_EXITREASON_STAT]);
        STAM_PROFILE_ADV_STOP_START(&pVCpu->hm.s.StatPreExit, &pVCpu->hm.s.StatExitHandling, x);
        HMVMX_START_EXIT_DISPATCH_PROF();

        VBOXVMM_R0_HMVMX_VMEXIT_NOCTX(pVCpu, &pVCpu->cpum.GstCtx, VmxTransient.uExitReason);

        /*
         * Handle the VM-exit.
         */
#ifdef HMVMX_USE_FUNCTION_TABLE
        rcStrict = g_aVMExitHandlers[VmxTransient.uExitReason].pfn(pVCpu, &VmxTransient);
#else
        rcStrict = hmR0VmxHandleExit(pVCpu, &VmxTransient);
#endif
        STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatExitHandling, x);
        if (rcStrict == VINF_SUCCESS)
        {
            if (++(*pcLoops) <= cMaxResumeLoops)
                continue;
            STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchMaxResumeLoops);
            rcStrict = VINF_EM_RAW_INTERRUPT;
        }
        break;
    }

    STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatEntry, x);
    return rcStrict;
}


#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
/**
 * Runs the nested-guest code using hardware-assisted VMX.
 *
 * @returns VBox status code.
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pcLoops     Pointer to the number of executed loops.
 *
 * @sa      hmR0VmxRunGuestCodeNormal.
 */
static VBOXSTRICTRC hmR0VmxRunGuestCodeNested(PVMCPUCC pVCpu, uint32_t *pcLoops)
{
    uint32_t const cMaxResumeLoops = pVCpu->CTX_SUFF(pVM)->hmr0.s.cMaxResumeLoops;
    Assert(pcLoops);
    Assert(*pcLoops <= cMaxResumeLoops);
    Assert(CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx));

    /*
     * Switch to the nested-guest VMCS as we may have transitioned from executing the
     * guest without leaving ring-0. Otherwise, if we came from ring-3 we would have
     * loaded the nested-guest VMCS while entering the VMX ring-0 session.
     */
    if (!pVCpu->hmr0.s.vmx.fSwitchedToNstGstVmcs)
    {
        int rc = vmxHCSwitchToGstOrNstGstVmcs(pVCpu, true /* fSwitchToNstGstVmcs */);
        if (RT_SUCCESS(rc))
        { /* likely */ }
        else
        {
            LogRelFunc(("Failed to switch to the nested-guest VMCS. rc=%Rrc\n", rc));
            return rc;
        }
    }

    VMXTRANSIENT VmxTransient;
    RT_ZERO(VmxTransient);
    VmxTransient.pVmcsInfo      = hmGetVmxActiveVmcsInfo(pVCpu);
    VmxTransient.fIsNestedGuest = true;

    /* Paranoia. */
    Assert(VmxTransient.pVmcsInfo == &pVCpu->hmr0.s.vmx.VmcsInfoNstGst);

    /* Setup pointer so PGM/IEM can query VM-exit auxiliary info. on demand in ring-0. */
    pVCpu->hmr0.s.vmx.pVmxTransient = &VmxTransient;

    VBOXSTRICTRC rcStrict = VERR_INTERNAL_ERROR_5;
    for (;;)
    {
        Assert(!HMR0SuspendPending());
        HMVMX_ASSERT_CPU_SAFE(pVCpu);
        STAM_PROFILE_ADV_START(&pVCpu->hm.s.StatEntry, x);

        /*
         * Preparatory work for running guest code, this may force us to
         * return to ring-3.
         *
         * Warning! This bugger disables interrupts on VINF_SUCCESS!
         */
        rcStrict = hmR0VmxPreRunGuest(pVCpu, &VmxTransient, false /* fStepping */);
        if (rcStrict != VINF_SUCCESS)
            break;

        /* Interrupts are disabled at this point! */
        hmR0VmxPreRunGuestCommitted(pVCpu, &VmxTransient);
        int rcRun = hmR0VmxRunGuest(pVCpu, &VmxTransient);
        hmR0VmxPostRunGuest(pVCpu, &VmxTransient, rcRun);
        /* Interrupts are re-enabled at this point! */

        /*
         * Check for errors with running the VM (VMLAUNCH/VMRESUME).
         */
        if (RT_SUCCESS(rcRun))
        { /* very likely */ }
        else
        {
            STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatPreExit, x);
            hmR0VmxReportWorldSwitchError(pVCpu, rcRun, &VmxTransient);
            rcStrict = rcRun;
            break;
        }

        /*
         * Undo temporary disabling of the APIC-access page monitoring we did in hmR0VmxMergeVmcsNested.
         * This is needed for NestedTrap0eHandler (and IEM) to cause nested-guest APIC-access VM-exits.
         */
        if (VmxTransient.pVmcsInfo->u32ProcCtls2 & VMX_PROC_CTLS2_VIRT_APIC_ACCESS)
        {
            PVMXVVMCS const pVmcsNstGst      = &pVCpu->cpum.GstCtx.hwvirt.vmx.Vmcs;
            RTGCPHYS const  GCPhysApicAccess = pVmcsNstGst->u64AddrApicAccess.u;
            PGMHandlerPhysicalReset(pVCpu->CTX_SUFF(pVM), GCPhysApicAccess);
        }

        /*
         * Profile the VM-exit.
         */
        AssertMsg(VmxTransient.uExitReason <= VMX_EXIT_MAX, ("%#x\n", VmxTransient.uExitReason));
        STAM_COUNTER_INC(&pVCpu->hm.s.StatNestedExitAll);
        STAM_COUNTER_INC(&pVCpu->hm.s.aStatNestedExitReason[VmxTransient.uExitReason & MASK_EXITREASON_STAT]);
        STAM_PROFILE_ADV_STOP_START(&pVCpu->hm.s.StatPreExit, &pVCpu->hm.s.StatExitHandling, x);
        HMVMX_START_EXIT_DISPATCH_PROF();

        VBOXVMM_R0_HMVMX_VMEXIT_NOCTX(pVCpu, &pVCpu->cpum.GstCtx, VmxTransient.uExitReason);

        /*
         * Handle the VM-exit.
         */
        rcStrict = vmxHCHandleExitNested(pVCpu, &VmxTransient);
        STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatExitHandling, x);
        if (rcStrict == VINF_SUCCESS)
        {
            if (!CPUMIsGuestInVmxNonRootMode(&pVCpu->cpum.GstCtx))
            {
                STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchNstGstVmexit);
                rcStrict = VINF_VMX_VMEXIT;
            }
            else
            {
                if (++(*pcLoops) <= cMaxResumeLoops)
                    continue;
                STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchMaxResumeLoops);
                rcStrict = VINF_EM_RAW_INTERRUPT;
            }
        }
        else
            Assert(rcStrict != VINF_VMX_VMEXIT);
        break;
    }

    /* Ensure VM-exit auxiliary info. is no longer available. */
    pVCpu->hmr0.s.vmx.pVmxTransient = NULL;

    STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatEntry, x);
    return rcStrict;
}
#endif /* VBOX_WITH_NESTED_HWVIRT_VMX */


/** @name Execution loop for single stepping, DBGF events and expensive Dtrace
 *  probes.
 *
 * The following few functions and associated structure contains the bloat
 * necessary for providing detailed debug events and dtrace probes as well as
 * reliable host side single stepping.  This works on the principle of
 * "subclassing" the normal execution loop and workers.  We replace the loop
 * method completely and override selected helpers to add necessary adjustments
 * to their core operation.
 *
 * The goal is to keep the "parent" code lean and mean, so as not to sacrifice
 * any performance for debug and analysis features.
 *
 * @{
 */

/**
 * Single steps guest code using hardware-assisted VMX.
 *
 * This is -not- the same as the guest single-stepping itself (say using EFLAGS.TF)
 * but single-stepping through the hypervisor debugger.
 *
 * @returns Strict VBox status code (i.e. informational status codes too).
 * @param   pVCpu       The cross context virtual CPU structure.
 * @param   pcLoops     Pointer to the number of executed loops.
 *
 * @note    Mostly the same as hmR0VmxRunGuestCodeNormal().
 */
static VBOXSTRICTRC hmR0VmxRunGuestCodeDebug(PVMCPUCC pVCpu, uint32_t *pcLoops)
{
    uint32_t const cMaxResumeLoops = pVCpu->CTX_SUFF(pVM)->hmr0.s.cMaxResumeLoops;
    Assert(pcLoops);
    Assert(*pcLoops <= cMaxResumeLoops);

    VMXTRANSIENT VmxTransient;
    RT_ZERO(VmxTransient);
    VmxTransient.pVmcsInfo = hmGetVmxActiveVmcsInfo(pVCpu);

    /* Set HMCPU indicators.  */
    bool const fSavedSingleInstruction = pVCpu->hm.s.fSingleInstruction;
    pVCpu->hm.s.fSingleInstruction     = pVCpu->hm.s.fSingleInstruction || DBGFIsStepping(pVCpu);
    pVCpu->hmr0.s.fDebugWantRdTscExit    = false;
    pVCpu->hmr0.s.fUsingDebugLoop        = true;

    /* State we keep to help modify and later restore the VMCS fields we alter, and for detecting steps.  */
    VMXRUNDBGSTATE DbgState;
    vmxHCRunDebugStateInit(pVCpu, &VmxTransient, &DbgState);
    vmxHCPreRunGuestDebugStateUpdate(pVCpu, &VmxTransient, &DbgState);

    /*
     * The loop.
     */
    VBOXSTRICTRC rcStrict  = VERR_INTERNAL_ERROR_5;
    for (;;)
    {
        Assert(!HMR0SuspendPending());
        HMVMX_ASSERT_CPU_SAFE(pVCpu);
        STAM_PROFILE_ADV_START(&pVCpu->hm.s.StatEntry, x);
        bool fStepping = pVCpu->hm.s.fSingleInstruction;

        /* Set up VM-execution controls the next two can respond to. */
        vmxHCPreRunGuestDebugStateApply(pVCpu, &VmxTransient, &DbgState);

        /*
         * Preparatory work for running guest code, this may force us to
         * return to ring-3.
         *
         * Warning! This bugger disables interrupts on VINF_SUCCESS!
         */
        rcStrict = hmR0VmxPreRunGuest(pVCpu, &VmxTransient, fStepping);
        if (rcStrict != VINF_SUCCESS)
            break;

        /* Interrupts are disabled at this point! */
        hmR0VmxPreRunGuestCommitted(pVCpu, &VmxTransient);

        /* Override any obnoxious code in the above two calls. */
        vmxHCPreRunGuestDebugStateApply(pVCpu, &VmxTransient, &DbgState);

        /*
         * Finally execute the guest.
         */
        int rcRun = hmR0VmxRunGuest(pVCpu, &VmxTransient);

        hmR0VmxPostRunGuest(pVCpu, &VmxTransient, rcRun);
        /* Interrupts are re-enabled at this point! */

        /* Check for errors with running the VM (VMLAUNCH/VMRESUME). */
        if (RT_SUCCESS(rcRun))
        { /* very likely */ }
        else
        {
            STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatPreExit, x);
            hmR0VmxReportWorldSwitchError(pVCpu, rcRun, &VmxTransient);
            return rcRun;
        }

        /* Profile the VM-exit. */
        AssertMsg(VmxTransient.uExitReason <= VMX_EXIT_MAX, ("%#x\n", VmxTransient.uExitReason));
        STAM_COUNTER_INC(&pVCpu->hm.s.StatDebugExitAll);
        STAM_COUNTER_INC(&pVCpu->hm.s.aStatExitReason[VmxTransient.uExitReason & MASK_EXITREASON_STAT]);
        STAM_PROFILE_ADV_STOP_START(&pVCpu->hm.s.StatPreExit, &pVCpu->hm.s.StatExitHandling, x);
        HMVMX_START_EXIT_DISPATCH_PROF();

        VBOXVMM_R0_HMVMX_VMEXIT_NOCTX(pVCpu, &pVCpu->cpum.GstCtx, VmxTransient.uExitReason);

        /*
         * Handle the VM-exit - we quit earlier on certain VM-exits, see hmR0VmxHandleExitDebug().
         */
        rcStrict = vmxHCRunDebugHandleExit(pVCpu, &VmxTransient, &DbgState);
        STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatExitHandling, x);
        if (rcStrict != VINF_SUCCESS)
            break;
        if (++(*pcLoops) > cMaxResumeLoops)
        {
            STAM_COUNTER_INC(&pVCpu->hm.s.StatSwitchMaxResumeLoops);
            rcStrict = VINF_EM_RAW_INTERRUPT;
            break;
        }

        /*
         * Stepping: Did the RIP change, if so, consider it a single step.
         * Otherwise, make sure one of the TFs gets set.
         */
        if (fStepping)
        {
            int rc = hmR0VmxImportGuestState(pVCpu, VmxTransient.pVmcsInfo, CPUMCTX_EXTRN_CS | CPUMCTX_EXTRN_RIP);
            AssertRC(rc);
            if (   pVCpu->cpum.GstCtx.rip    != DbgState.uRipStart
                || pVCpu->cpum.GstCtx.cs.Sel != DbgState.uCsStart)
            {
                rcStrict = VINF_EM_DBG_STEPPED;
                break;
            }
            ASMAtomicUoOrU64(&pVCpu->hm.s.fCtxChanged, HM_CHANGED_GUEST_DR7);
        }

        /*
         * Update when dtrace settings changes (DBGF kicks us, so no need to check).
         */
        if (VBOXVMM_GET_SETTINGS_SEQ_NO() != DbgState.uDtraceSettingsSeqNo)
            vmxHCPreRunGuestDebugStateUpdate(pVCpu, &VmxTransient, &DbgState);

        /* Restore all controls applied by hmR0VmxPreRunGuestDebugStateApply above. */
        rcStrict = vmxHCRunDebugStateRevert(pVCpu, &VmxTransient, &DbgState, rcStrict);
        Assert(rcStrict == VINF_SUCCESS);
    }

    /*
     * Clear the X86_EFL_TF if necessary.
     */
    if (pVCpu->hmr0.s.fClearTrapFlag)
    {
        int rc = hmR0VmxImportGuestState(pVCpu, VmxTransient.pVmcsInfo, CPUMCTX_EXTRN_RFLAGS);
        AssertRC(rc);
        pVCpu->hmr0.s.fClearTrapFlag = false;
        pVCpu->cpum.GstCtx.eflags.Bits.u1TF = 0;
    }
    /** @todo there seems to be issues with the resume flag when the monitor trap
     *        flag is pending without being used. Seen early in bios init when
     *        accessing APIC page in protected mode. */

/** @todo we need to do hmR0VmxRunDebugStateRevert here too, in case we broke
 *        out of the above loop. */

    /* Restore HMCPU indicators. */
    pVCpu->hmr0.s.fUsingDebugLoop     = false;
    pVCpu->hmr0.s.fDebugWantRdTscExit = false;
    pVCpu->hm.s.fSingleInstruction  = fSavedSingleInstruction;

    STAM_PROFILE_ADV_STOP(&pVCpu->hm.s.StatEntry, x);
    return rcStrict;
}

/** @} */


/**
 * Checks if any expensive dtrace probes are enabled and we should go to the
 * debug loop.
 *
 * @returns true if we should use debug loop, false if not.
 */
static bool hmR0VmxAnyExpensiveProbesEnabled(void)
{
    /* It's probably faster to OR the raw 32-bit counter variables together.
       Since the variables are in an array and the probes are next to one
       another (more or less), we have good locality.  So, better read
       eight-nine cache lines ever time and only have one conditional, than
       128+ conditionals, right? */
    return (  VBOXVMM_R0_HMVMX_VMEXIT_ENABLED_RAW() /* expensive too due to context */
            | VBOXVMM_XCPT_DE_ENABLED_RAW()
            | VBOXVMM_XCPT_DB_ENABLED_RAW()
            | VBOXVMM_XCPT_BP_ENABLED_RAW()
            | VBOXVMM_XCPT_OF_ENABLED_RAW()
            | VBOXVMM_XCPT_BR_ENABLED_RAW()
            | VBOXVMM_XCPT_UD_ENABLED_RAW()
            | VBOXVMM_XCPT_NM_ENABLED_RAW()
            | VBOXVMM_XCPT_DF_ENABLED_RAW()
            | VBOXVMM_XCPT_TS_ENABLED_RAW()
            | VBOXVMM_XCPT_NP_ENABLED_RAW()
            | VBOXVMM_XCPT_SS_ENABLED_RAW()
            | VBOXVMM_XCPT_GP_ENABLED_RAW()
            | VBOXVMM_XCPT_PF_ENABLED_RAW()
            | VBOXVMM_XCPT_MF_ENABLED_RAW()
            | VBOXVMM_XCPT_AC_ENABLED_RAW()
            | VBOXVMM_XCPT_XF_ENABLED_RAW()
            | VBOXVMM_XCPT_VE_ENABLED_RAW()
            | VBOXVMM_XCPT_SX_ENABLED_RAW()
            | VBOXVMM_INT_SOFTWARE_ENABLED_RAW()
            | VBOXVMM_INT_HARDWARE_ENABLED_RAW()
           ) != 0
        || (  VBOXVMM_INSTR_HALT_ENABLED_RAW()
            | VBOXVMM_INSTR_MWAIT_ENABLED_RAW()
            | VBOXVMM_INSTR_MONITOR_ENABLED_RAW()
            | VBOXVMM_INSTR_CPUID_ENABLED_RAW()
            | VBOXVMM_INSTR_INVD_ENABLED_RAW()
            | VBOXVMM_INSTR_WBINVD_ENABLED_RAW()
            | VBOXVMM_INSTR_INVLPG_ENABLED_RAW()
            | VBOXVMM_INSTR_RDTSC_ENABLED_RAW()
            | VBOXVMM_INSTR_RDTSCP_ENABLED_RAW()
            | VBOXVMM_INSTR_RDPMC_ENABLED_RAW()
            | VBOXVMM_INSTR_RDMSR_ENABLED_RAW()
            | VBOXVMM_INSTR_WRMSR_ENABLED_RAW()
            | VBOXVMM_INSTR_CRX_READ_ENABLED_RAW()
            | VBOXVMM_INSTR_CRX_WRITE_ENABLED_RAW()
            | VBOXVMM_INSTR_DRX_READ_ENABLED_RAW()
            | VBOXVMM_INSTR_DRX_WRITE_ENABLED_RAW()
            | VBOXVMM_INSTR_PAUSE_ENABLED_RAW()
            | VBOXVMM_INSTR_XSETBV_ENABLED_RAW()
            | VBOXVMM_INSTR_SIDT_ENABLED_RAW()
            | VBOXVMM_INSTR_LIDT_ENABLED_RAW()
            | VBOXVMM_INSTR_SGDT_ENABLED_RAW()
            | VBOXVMM_INSTR_LGDT_ENABLED_RAW()
            | VBOXVMM_INSTR_SLDT_ENABLED_RAW()
            | VBOXVMM_INSTR_LLDT_ENABLED_RAW()
            | VBOXVMM_INSTR_STR_ENABLED_RAW()
            | VBOXVMM_INSTR_LTR_ENABLED_RAW()
            | VBOXVMM_INSTR_GETSEC_ENABLED_RAW()
            | VBOXVMM_INSTR_RSM_ENABLED_RAW()
            | VBOXVMM_INSTR_RDRAND_ENABLED_RAW()
            | VBOXVMM_INSTR_RDSEED_ENABLED_RAW()
            | VBOXVMM_INSTR_XSAVES_ENABLED_RAW()
            | VBOXVMM_INSTR_XRSTORS_ENABLED_RAW()
            | VBOXVMM_INSTR_VMM_CALL_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMCLEAR_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMLAUNCH_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMPTRLD_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMPTRST_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMREAD_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMRESUME_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMWRITE_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMXOFF_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMXON_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_VMFUNC_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_INVEPT_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_INVVPID_ENABLED_RAW()
            | VBOXVMM_INSTR_VMX_INVPCID_ENABLED_RAW()
           ) != 0
        || (  VBOXVMM_EXIT_TASK_SWITCH_ENABLED_RAW()
            | VBOXVMM_EXIT_HALT_ENABLED_RAW()
            | VBOXVMM_EXIT_MWAIT_ENABLED_RAW()
            | VBOXVMM_EXIT_MONITOR_ENABLED_RAW()
            | VBOXVMM_EXIT_CPUID_ENABLED_RAW()
            | VBOXVMM_EXIT_INVD_ENABLED_RAW()
            | VBOXVMM_EXIT_WBINVD_ENABLED_RAW()
            | VBOXVMM_EXIT_INVLPG_ENABLED_RAW()
            | VBOXVMM_EXIT_RDTSC_ENABLED_RAW()
            | VBOXVMM_EXIT_RDTSCP_ENABLED_RAW()
            | VBOXVMM_EXIT_RDPMC_ENABLED_RAW()
            | VBOXVMM_EXIT_RDMSR_ENABLED_RAW()
            | VBOXVMM_EXIT_WRMSR_ENABLED_RAW()
            | VBOXVMM_EXIT_CRX_READ_ENABLED_RAW()
            | VBOXVMM_EXIT_CRX_WRITE_ENABLED_RAW()
            | VBOXVMM_EXIT_DRX_READ_ENABLED_RAW()
            | VBOXVMM_EXIT_DRX_WRITE_ENABLED_RAW()
            | VBOXVMM_EXIT_PAUSE_ENABLED_RAW()
            | VBOXVMM_EXIT_XSETBV_ENABLED_RAW()
            | VBOXVMM_EXIT_SIDT_ENABLED_RAW()
            | VBOXVMM_EXIT_LIDT_ENABLED_RAW()
            | VBOXVMM_EXIT_SGDT_ENABLED_RAW()
            | VBOXVMM_EXIT_LGDT_ENABLED_RAW()
            | VBOXVMM_EXIT_SLDT_ENABLED_RAW()
            | VBOXVMM_EXIT_LLDT_ENABLED_RAW()
            | VBOXVMM_EXIT_STR_ENABLED_RAW()
            | VBOXVMM_EXIT_LTR_ENABLED_RAW()
            | VBOXVMM_EXIT_GETSEC_ENABLED_RAW()
            | VBOXVMM_EXIT_RSM_ENABLED_RAW()
            | VBOXVMM_EXIT_RDRAND_ENABLED_RAW()
            | VBOXVMM_EXIT_RDSEED_ENABLED_RAW()
            | VBOXVMM_EXIT_XSAVES_ENABLED_RAW()
            | VBOXVMM_EXIT_XRSTORS_ENABLED_RAW()
            | VBOXVMM_EXIT_VMM_CALL_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMCLEAR_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMLAUNCH_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMPTRLD_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMPTRST_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMREAD_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMRESUME_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMWRITE_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMXOFF_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMXON_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VMFUNC_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_INVEPT_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_INVVPID_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_INVPCID_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_EPT_VIOLATION_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_EPT_MISCONFIG_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VAPIC_ACCESS_ENABLED_RAW()
            | VBOXVMM_EXIT_VMX_VAPIC_WRITE_ENABLED_RAW()
           ) != 0;
}


/**
 * Runs the guest using hardware-assisted VMX.
 *
 * @returns Strict VBox status code (i.e. informational status codes too).
 * @param   pVCpu   The cross context virtual CPU structure.
 */
VMMR0DECL(VBOXSTRICTRC) VMXR0RunGuestCode(PVMCPUCC pVCpu)
{
    AssertPtr(pVCpu);
    PCPUMCTX pCtx = &pVCpu->cpum.GstCtx;
    Assert(VMMRZCallRing3IsEnabled(pVCpu));
    Assert(!ASMAtomicUoReadU64(&pCtx->fExtrn));
    HMVMX_ASSERT_PREEMPT_SAFE(pVCpu);

    VBOXSTRICTRC rcStrict;
    uint32_t     cLoops = 0;
    for (;;)
    {
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        bool const fInNestedGuestMode = CPUMIsGuestInVmxNonRootMode(pCtx);
#else
        NOREF(pCtx);
        bool const fInNestedGuestMode = false;
#endif
        if (!fInNestedGuestMode)
        {
            if (   !pVCpu->hm.s.fUseDebugLoop
                && (!VBOXVMM_ANY_PROBES_ENABLED() || !hmR0VmxAnyExpensiveProbesEnabled())
                && !DBGFIsStepping(pVCpu)
                && !pVCpu->CTX_SUFF(pVM)->dbgf.ro.cEnabledInt3Breakpoints)
                rcStrict = hmR0VmxRunGuestCodeNormal(pVCpu, &cLoops);
            else
                rcStrict = hmR0VmxRunGuestCodeDebug(pVCpu, &cLoops);
        }
#ifdef VBOX_WITH_NESTED_HWVIRT_VMX
        else
            rcStrict = hmR0VmxRunGuestCodeNested(pVCpu, &cLoops);

        if (rcStrict == VINF_VMX_VMLAUNCH_VMRESUME)
        {
            Assert(CPUMIsGuestInVmxNonRootMode(pCtx));
            continue;
        }
        if (rcStrict == VINF_VMX_VMEXIT)
        {
            Assert(!CPUMIsGuestInVmxNonRootMode(pCtx));
            continue;
        }
#endif
        break;
    }

    int const rcLoop = VBOXSTRICTRC_VAL(rcStrict);
    switch (rcLoop)
    {
        case VERR_EM_INTERPRETER:   rcStrict = VINF_EM_RAW_EMULATE_INSTR;   break;
        case VINF_EM_RESET:         rcStrict = VINF_EM_TRIPLE_FAULT;        break;
    }

    int rc2 = hmR0VmxExitToRing3(pVCpu, rcStrict);
    if (RT_FAILURE(rc2))
    {
        pVCpu->hm.s.u32HMError = (uint32_t)VBOXSTRICTRC_VAL(rcStrict);
        rcStrict = rc2;
    }
    Assert(!ASMAtomicUoReadU64(&pCtx->fExtrn));
    Assert(!VMMR0AssertionIsNotificationSet(pVCpu));
    return rcStrict;
}