Changeset 91308 in vbox

Timestamp:

Sep 17, 2021 9:35:52 PM (3 years ago)

Author:

vboxsync

Message:

VMM/CPUM: Comments/todos for some big CPUMCTX members. bugref:10093

Location:

trunk

Files:

• include/VBox/vmm/cpumctx.h (modified) (4 diffs)
• src/VBox/VMM/VMMR0/HMSVMR0.cpp (modified) (3 diffs)

trunk/include/VBox/vmm/cpumctx.h

@@ -506 +506 @@
                  * This need not be physically contiguous pages because we use the one from
                  * HMPHYSCPU while executing the nested-guest using hardware-assisted SVM.
-                 * This one is just used for caching the bitmap from guest physical memory. */
+                 * This one is just used for caching the bitmap from guest physical memory.
+                 *
+                 * @todo r=bird: This is not used directly by AMD-V hardware, so it doesn't
+                 *       really need to even be page aligned.
+                 *
+                 *       Also, couldn't we just access the guest page directly when we need to,
+                 *       or do we have to use a cached copy of it? */
                 uint8_t                 abMsrBitmap[SVM_MSRPM_PAGES * X86_PAGE_SIZE];
                 /** 0x7000 - The IOPM (IO Permission bitmap).
@@ -515 +521 @@
                  *
                  * This one is just used for caching the IOPM from guest physical memory in
-                 * case the guest hypervisor allows direct access to some IO ports. */
+                 * case the guest hypervisor allows direct access to some IO ports.
+                 *
+                 * @todo r=bird: This is not used directly by AMD-V hardware, so it doesn't
+                 *       really need to even be page aligned.
+                 *
+                 *       Also, couldn't we just access the guest page directly when we need to,
+                 *       or do we have to use a cached copy of it? */
                 uint8_t                 abIoBitmap[SVM_IOPM_PAGES * X86_PAGE_SIZE];
 
@@ -543 +555 @@
                 /** 0X5000 - The shadow VMCS. */
                 VMXVVMCS                ShadowVmcs;
-                /** 0x6000 - The VMREAD bitmap. */
+                /** 0x6000 - The VMREAD bitmap.
+                 * @todo r=bird: Do we really need to keep copies for these?  Couldn't we just
+                 *       access the guest memory directly as needed?   */
                 uint8_t                 abVmreadBitmap[VMX_V_VMREAD_VMWRITE_BITMAP_SIZE];
-                /** 0x7000 - The VMWRITE bitmap. */
+                /** 0x7000 - The VMWRITE bitmap.
+                 * @todo r=bird: Do we really need to keep copies for these?  Couldn't we just
+                 *       access the guest memory directly as needed?  */
                 uint8_t                 abVmwriteBitmap[VMX_V_VMREAD_VMWRITE_BITMAP_SIZE];
                 /** 0x8000 - The VM-entry MSR-load area. */
@@ -553 +569 @@
                 /** 0xc000 - The VM-exit MSR-load area. */
                 VMXAUTOMSR              aExitMsrLoadArea[VMX_V_AUTOMSR_AREA_SIZE / sizeof(VMXAUTOMSR)];
-                /** 0xe000 - The MSR permission bitmap. */
+                /** 0xe000 - The MSR permission bitmap.
+                 * @todo r=bird: Do we really need to keep copies for these?  Couldn't we just
+                 *       access the guest memory directly as needed?  */
                 uint8_t                 abMsrBitmap[VMX_V_MSR_BITMAP_SIZE];
-                /** 0xf000 - The I/O permission bitmap. */
+                /** 0xf000 - The I/O permission bitmap.
+                 * @todo r=bird: Do we really need to keep copies for these?  Couldn't we just
+                 *       access the guest memory directly as needed? */
                 uint8_t                 abIoBitmap[VMX_V_IO_BITMAP_A_SIZE + VMX_V_IO_BITMAP_B_SIZE];
                 /** 0x11000 - The virtual-APIC page.

trunk/src/VBox/VMM/VMMR0/HMSVMR0.cpp

@@ -2490 +2490 @@
 }
 
-
 #ifdef VBOX_WITH_NESTED_HWVIRT_SVM
+
 /**
  * Merges the guest and nested-guest MSR permission bitmap.
@@ -2605 +2605 @@
         pVCpu->hmr0.s.svm.fSyncVTpr = false;
 
-#ifdef DEBUG_ramshankar
+# ifdef DEBUG_ramshankar
         /* For debugging purposes - copy the LBR info. from outer guest VMCB. */
         pVmcbNstGstCtrl->LbrVirt.n.u1LbrVirt = pVmcb->ctrl.LbrVirt.n.u1LbrVirt;
-#endif
+# endif
 
         /*
@@ -2640 +2640 @@
     }
 }
+
 #endif /* VBOX_WITH_NESTED_HWVIRT_SVM */
-
 
 /**