VirtualBox

source: vbox/trunk/src/VBox/VMM/VMMAll/GCMAll.cpp@ 96860

Last change on this file since 96860 was 96407, checked in by vboxsync, 21 months ago

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1/** @file
2 * GCM - Guest Compatibility Manager - All Contexts.
3 */
4
5/*
6 * Copyright (C) 2022 Oracle and/or its affiliates.
7 *
8 * This file is part of VirtualBox base platform packages, as
9 * available from https://www.virtualbox.org.
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation, in version 3 of the
14 * License.
15 *
16 * This program is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, see <https://www.gnu.org/licenses>.
23 *
24 * SPDX-License-Identifier: GPL-3.0-only
25 */
26
27
28/*********************************************************************************************************************************
29* Header Files *
30*********************************************************************************************************************************/
31#define LOG_GROUP LOG_GROUP_GIM
32#include <VBox/vmm/gcm.h>
33#include <VBox/vmm/em.h> /* For EMInterpretDisasCurrent */
34#include "GCMInternal.h"
35#include <VBox/vmm/vmcc.h>
36
37#include <VBox/dis.h> /* For DISCPUSTATE */
38#include <iprt/errcore.h>
39#include <iprt/string.h>
40
41
42/**
43 * Checks whether GCM is enabled for this VM.
44 *
45 * @retval true if GCM is on.
46 * @retval false if no GCM fixer is enabled.
47 *
48 * @param pVM The cross context VM structure.
49 */
50VMMDECL(bool) GCMIsEnabled(PVM pVM)
51{
52 return pVM->gcm.s.enmFixerIds != GCMFIXER_NONE;
53}
54
55
56/**
57 * Gets the GCM fixers configured for this VM.
58 *
59 * @returns The GCM provider Id.
60 * @param pVM The cross context VM structure.
61 */
62VMMDECL(int32_t) GCMGetFixers(PVM pVM)
63{
64 return pVM->gcm.s.enmFixerIds;
65}
66
67
68/**
69 * Whether \#DE exceptions in the guest should be intercepted by GCM and
70 * possibly fixed up.
71 *
72 * @returns true if needed, false otherwise.
73 * @param pVCpu The cross context virtual CPU structure.
74 */
75VMM_INT_DECL(bool) GCMShouldTrapXcptDE(PVMCPUCC pVCpu)
76{
77 LogFlowFunc(("entered\n"));
78 PVM pVM = pVCpu->CTX_SUFF(pVM);
79 if (!GCMIsEnabled(pVM))
80 return false;
81
82 LogFunc(("GCM checking if #DE needs trapping\n"));
83
84 /* See if the enabled fixers need to intercept #DE. */
85 if ( pVM->gcm.s.enmFixerIds
86 & (GCMFIXER_DBZ_DOS | GCMFIXER_DBZ_OS2 | GCMFIXER_DBZ_WIN9X))
87 {
88 LogRel(("GCM: #DE should be trapped\n"));
89 return true;
90 }
91
92 return false;
93}
94
95
96/**
97 * Exception handler for \#DE when registered by GCM.
98 *
99 * @returns Strict VBox status code.
100 * @retval VINF_SUCCESS retry division and continue.
101 * @retval VERR_NOT_FOUND deliver exception to guest.
102 *
103 * @param pVCpu The cross context virtual CPU structure.
104 * @param pCtx Pointer to the guest-CPU context.
105 * @param pDis Pointer to the disassembled instruction state at RIP.
106 * If NULL is passed, it implies the disassembly of the
107 * the instruction at RIP is the
108 * responsibility of GCM.
109 * @param pcbInstr Where to store the instruction length of
110 * the divide instruction. Optional, can be
111 * NULL.
112 *
113 * @thread EMT(pVCpu).
114 */
115VMM_INT_DECL(VBOXSTRICTRC) GCMXcptDE(PVMCPUCC pVCpu, PCPUMCTX pCtx, PDISCPUSTATE pDis, uint8_t *pcbInstr)
116{
117 PVMCC pVM = pVCpu->CTX_SUFF(pVM);
118 Assert(GCMIsEnabled(pVM));
119 Assert(pDis || pcbInstr);
120 RT_NOREF(pDis);
121 RT_NOREF(pcbInstr);
122
123 LogRel(("GCM: Intercepted #DE at CS:RIP=%04x:%RX64 (%RX64 linear) RDX:RAX=%RX64:%RX64 RCX=%RX64 RBX=%RX64\n",
124 pCtx->cs.Sel, pCtx->rip, pCtx->cs.u64Base + pCtx->rip, pCtx->rdx, pCtx->rax, pCtx->rcx, pCtx->rbx));
125
126 if (pVM->gcm.s.enmFixerIds & GCMFIXER_DBZ_OS2)
127 {
128 if (pCtx->rcx == 0 && pCtx->rdx == 1 && pCtx->rax == 0x86a0)
129 {
130 /* OS/2 1.x drivers loaded during boot: DX:AX = 100,000, CX < 2 causes overflow. */
131 /* Example: OS/2 1.0 KBD01.SYS, 16,945 bytes, dated 10/21/1987, div cx at offset 2:2ffeh */
132 /* Code later merged into BASEDD01.SYS, crash fixed in OS/2 1.30.1; this should
133 * fix all affected versions of OS/2 1.x.
134 */
135 pCtx->rcx = 2;
136 return VINF_SUCCESS;
137 }
138 if ((uint16_t)pCtx->rbx == 0 && (uint16_t)pCtx->rdx == 0 && (uint16_t)pCtx->rax == 0x1000)
139 {
140 /* OS/2 2.1 and later boot loader: DX:AX = 0x1000, zero BX. May have junk in high words of all registers. */
141 /* Example: OS/2 MCP2 OS2LDR, 44,544 bytes, dated 03/08/2002, idiv bx at offset 847ah */
142 pCtx->rbx = (pCtx->rbx & ~0xffff) | 2;
143 return VINF_SUCCESS;
144 }
145 if (pCtx->rbx == 0 && pCtx->rdx == 0 && pCtx->rax == 0x100)
146 {
147 /* OS/2 2.0 boot loader: DX:AX = 0x100, zero BX. May have junk in high words of registers. */
148 /* Example: OS/2 2.0 OS2LDR, 32,256 bytes, dated 03/30/1992, idiv bx at offset 2298h */
149 pCtx->rbx = 2;
150 return VINF_SUCCESS;
151 }
152 }
153
154 if (pVM->gcm.s.enmFixerIds & GCMFIXER_DBZ_DOS)
155 {
156 /* NB: For 16-bit DOS software, we must generally only compare 16-bit registers.
157 * The contents of the high words may be unpredictable depending on the environment.
158 * For 32-bit Windows 3.x code that is not the case.
159 */
160 if (pCtx->rcx == 0 && pCtx->rdx == 0 && pCtx->rax == 0x100000)
161 {
162 /* NDIS.386 in WfW 3.11: CalibrateStall, EDX:EAX = 0x100000, zero ECX.
163 * Occurs when NDIS.386 loads.
164 */
165 pCtx->rcx = 0x20000; /* Want a large divisor to shorten stalls. */
166 return VINF_SUCCESS;
167 }
168 if (pCtx->rcx == 0 && pCtx->rdx == 0 && pCtx->rax > 0x100000)
169 {
170 /* NDIS.386 in WfW 3.11: NdisStallExecution, EDX:EAX = 0xYY00000, zero ECX.
171 * EDX:EAX is variable, but low 20 bits of EAX must be zero and EDX is likely
172 * to be zero as well.
173 * Only occurs if NdisStallExecution is called to do a longish stall.
174 */
175 pCtx->rcx = 22;
176 return VINF_SUCCESS;
177 }
178 if ((uint16_t)pCtx->rbx == 0 && (uint16_t)pCtx->rdx == 0 && (uint16_t)pCtx->rax == 0x64)
179 {
180 /* Norton Sysinfo or Diagnostics 8.0 DX:AX = 0x64 (100 decimal), zero BX. */
181 pCtx->rbx = (pCtx->rbx & 0xffff0000) | 1; /* BX = 1 */
182 return VINF_SUCCESS;
183 }
184 if ((uint16_t)pCtx->rbx == 0 && (uint16_t)pCtx->rdx == 0 && (uint16_t)pCtx->rax == 0xff)
185 {
186 /* IBM PC LAN Program 1.3: DX:AX=0xff (255 decimal), zero BX. */
187 /* NETWORK1.CMD, 64,324 bytes, dated 06/06/1988, div bx at offset 0xa400 in file. */
188 pCtx->rbx = (pCtx->rbx & 0xffff0000) | 1; /* BX = 1 */
189 return VINF_SUCCESS;
190 }
191 if ((uint16_t)pCtx->rdx == 0xffff && (uint16_t)pCtx->rax == 0xffff && (uint16_t)pCtx->rcx == 0xa8c0)
192 {
193 /* QNX 2.15C: DX:AX=0xffffffff (-1), constant CX = 0xa8c0 (43200). */
194 /* div cx at e.g. 2220:fa5 and 2220:10a0 in memory. */
195 pCtx->rdx = (pCtx->rdx & 0xffff0000) | 8; /* DX = 8 */
196 return VINF_SUCCESS;
197 }
198 if ((uint16_t)pCtx->rax > 0x1800 && ((uint16_t)pCtx->rax & 0x3f) == 0 && (uint16_t)pCtx->rbx == 0x19)
199 {
200 /* 3C501.COM ODI driver v1.21: AX > ~0x1900 (-1), BX = 0x19 (25). */
201 /* AX was shifted left by 6 bits so low bits must be zero. */
202 /* div bl at e.g. 06b3:2f80 and offset 0x2E80 in file. */
203 pCtx->rax = (pCtx->rax & 0xffff0000) | 0x8c0; /* AX = 0x8c0 */
204 return VINF_SUCCESS;
205 }
206 if ((uint16_t)pCtx->rcx == 0x37 && ((uint16_t)pCtx->rdx > 0x34))
207 {
208 /* Turbo Pascal, classic Runtime Error 200: CX = 55, DX > ~54, AX/BX variable. */
209 /* div cx at variable offset in file. */
210 pCtx->rdx = (pCtx->rdx & 0xffff0000) | 0x30; /* DX = 48 */
211 return VINF_SUCCESS;
212 }
213 }
214
215 if (pVM->gcm.s.enmFixerIds & GCMFIXER_DBZ_WIN9X)
216 {
217 if (pCtx->rcx == 0 && pCtx->rdx == 0 && pCtx->rax == 0x100000)
218 {
219 /* NDIS.VXD in Win9x: EDX:EAX = 0x100000, zero ECX. */
220 /* Example: Windows 95 NDIS.VXD, 99,084 bytes, dated 07/11/1994, div ecx at 28:Cxxxx80B */
221 /* Crash fixed in Windows 98 SE. */
222 pCtx->rcx = 0x20000; /* Want a large divisor to shorten stalls. */
223 return VINF_SUCCESS;
224 }
225 if (pCtx->rcx < 3 && pCtx->rdx == 2 && pCtx->rax == 0x540be400)
226 {
227 /* SCSI.PDR, ESDI506.PDR in Win95: EDX:EAX = 0x2540be400 (10,000,000,000 decimal), ECX < 3. */
228 /* Example: Windows 95 SCSIPORT.PDR, 23,133 bytes, dated 07/11/1995, div ecx at 28:Cxxxx876 */
229 /* Example: Win95 OSR2 ESDI506.PDR, 24,390 bytes, dated 04/24/1996, div ecx at 28:Cxxxx8E3 */
230 /* Crash fixed in Windows 98. */
231 pCtx->rcx = 1000;
232 return VINF_SUCCESS;
233 }
234 if (pCtx->rcx == 0 && pCtx->rdx == 0x3d && pCtx->rax == 0x9000000)
235 {
236 /* Unknown source, Win9x shutdown, div ecx. */
237 /* GCM: Intercepted #DE at CS:RIP=0028:c0050f8e RDX:RAX=3d:9000000 (250000*1024*1024) RCX=0 RBX=c19200e8 [RBX variable] */
238 pCtx->rcx = 4096;
239 return VINF_SUCCESS;
240 }
241 }
242
243 /* If we got this far, deliver exception to guest. */
244 return VERR_NOT_FOUND;
245}
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