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1/******************************************************************************
2 * x86_emulate.c
3 *
4 * Generic x86 (32-bit and 64-bit) instruction decoder and emulator.
5 *
6 * Copyright (c) 2005 Keir Fraser
7 *
8 * Linux coding style, mod r/m decoder, segment base fixes, real-mode
9 * privileged instructions:
10 *
11 * Copyright (C) 2006 Qumranet
12 *
13 * Avi Kivity <avi@qumranet.com>
14 * Yaniv Kamay <yaniv@qumranet.com>
15 *
16 * This work is licensed under the terms of the GNU GPL, version 2. See
17 * the COPYING file in the top-level directory.
18 *
19 * From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4
20 */
21
22#ifndef __KERNEL__
23#include <stdio.h>
24#include <stdint.h>
25#include <public/xen.h>
26#define DPRINTF(_f, _a ...) printf(_f , ## _a)
27#else
28#include "kvm.h"
29#include "x86.h"
30#define DPRINTF(x...) do {} while (0)
31#endif
32#include "x86_emulate.h"
33#include <linux/module.h>
34
35/*
36 * Opcode effective-address decode tables.
37 * Note that we only emulate instructions that have at least one memory
38 * operand (excluding implicit stack references). We assume that stack
39 * references and instruction fetches will never occur in special memory
40 * areas that require emulation. So, for example, 'mov <imm>,<reg>' need
41 * not be handled.
42 */
43
44/* Operand sizes: 8-bit operands or specified/overridden size. */
45#define ByteOp (1<<0) /* 8-bit operands. */
46/* Destination operand type. */
47#define ImplicitOps (1<<1) /* Implicit in opcode. No generic decode. */
48#define DstReg (2<<1) /* Register operand. */
49#define DstMem (3<<1) /* Memory operand. */
50#define DstMask (3<<1)
51/* Source operand type. */
52#define SrcNone (0<<3) /* No source operand. */
53#define SrcImplicit (0<<3) /* Source operand is implicit in the opcode. */
54#define SrcReg (1<<3) /* Register operand. */
55#define SrcMem (2<<3) /* Memory operand. */
56#define SrcMem16 (3<<3) /* Memory operand (16-bit). */
57#define SrcMem32 (4<<3) /* Memory operand (32-bit). */
58#define SrcImm (5<<3) /* Immediate operand. */
59#define SrcImmByte (6<<3) /* 8-bit sign-extended immediate operand. */
60#define SrcMask (7<<3)
61/* Generic ModRM decode. */
62#define ModRM (1<<6)
63/* Destination is only written; never read. */
64#define Mov (1<<7)
65#define BitOp (1<<8)
66#define MemAbs (1<<9) /* Memory operand is absolute displacement */
67
68static u16 opcode_table[256] = {
69 /* 0x00 - 0x07 */
70 ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
71 ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
72 0, 0, 0, 0,
73 /* 0x08 - 0x0F */
74 ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
75 ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
76 0, 0, 0, 0,
77 /* 0x10 - 0x17 */
78 ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
79 ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
80 0, 0, 0, 0,
81 /* 0x18 - 0x1F */
82 ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
83 ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
84 0, 0, 0, 0,
85 /* 0x20 - 0x27 */
86 ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
87 ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
88 SrcImmByte, SrcImm, 0, 0,
89 /* 0x28 - 0x2F */
90 ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
91 ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
92 0, 0, 0, 0,
93 /* 0x30 - 0x37 */
94 ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
95 ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
96 0, 0, 0, 0,
97 /* 0x38 - 0x3F */
98 ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
99 ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
100 0, 0, 0, 0,
101 /* 0x40 - 0x47 */
102 DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg,
103 /* 0x48 - 0x4F */
104 DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg,
105 /* 0x50 - 0x57 */
106 SrcReg, SrcReg, SrcReg, SrcReg, SrcReg, SrcReg, SrcReg, SrcReg,
107 /* 0x58 - 0x5F */
108 DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg,
109 /* 0x60 - 0x67 */
110 0, 0, 0, DstReg | SrcMem32 | ModRM | Mov /* movsxd (x86/64) */ ,
111 0, 0, 0, 0,
112 /* 0x68 - 0x6F */
113 0, 0, ImplicitOps|Mov, 0,
114 SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps, /* insb, insw/insd */
115 SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps, /* outsb, outsw/outsd */
116 /* 0x70 - 0x77 */
117 ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
118 ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
119 /* 0x78 - 0x7F */
120 ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
121 ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
122 /* 0x80 - 0x87 */
123 ByteOp | DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,
124 ByteOp | DstMem | SrcImm | ModRM, DstMem | SrcImmByte | ModRM,
125 ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
126 ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
127 /* 0x88 - 0x8F */
128 ByteOp | DstMem | SrcReg | ModRM | Mov, DstMem | SrcReg | ModRM | Mov,
129 ByteOp | DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
130 0, ModRM | DstReg, 0, DstMem | SrcNone | ModRM | Mov,
131 /* 0x90 - 0x9F */
132 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ImplicitOps, ImplicitOps, 0, 0,
133 /* 0xA0 - 0xA7 */
134 ByteOp | DstReg | SrcMem | Mov | MemAbs, DstReg | SrcMem | Mov | MemAbs,
135 ByteOp | DstMem | SrcReg | Mov | MemAbs, DstMem | SrcReg | Mov | MemAbs,
136 ByteOp | ImplicitOps | Mov, ImplicitOps | Mov,
137 ByteOp | ImplicitOps, ImplicitOps,
138 /* 0xA8 - 0xAF */
139 0, 0, ByteOp | ImplicitOps | Mov, ImplicitOps | Mov,
140 ByteOp | ImplicitOps | Mov, ImplicitOps | Mov,
141 ByteOp | ImplicitOps, ImplicitOps,
142 /* 0xB0 - 0xBF */
143 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
144 /* 0xC0 - 0xC7 */
145 ByteOp | DstMem | SrcImm | ModRM, DstMem | SrcImmByte | ModRM,
146 0, ImplicitOps, 0, 0,
147 ByteOp | DstMem | SrcImm | ModRM | Mov, DstMem | SrcImm | ModRM | Mov,
148 /* 0xC8 - 0xCF */
149 0, 0, 0, 0, 0, 0, 0, 0,
150 /* 0xD0 - 0xD7 */
151 ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM,
152 ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM,
153 0, 0, 0, 0,
154 /* 0xD8 - 0xDF */
155 0, 0, 0, 0, 0, 0, 0, 0,
156 /* 0xE0 - 0xE7 */
157 0, 0, 0, 0, 0, 0, 0, 0,
158 /* 0xE8 - 0xEF */
159 ImplicitOps, SrcImm|ImplicitOps, 0, SrcImmByte|ImplicitOps, 0, 0, 0, 0,
160 /* 0xF0 - 0xF7 */
161 0, 0, 0, 0,
162 ImplicitOps, ImplicitOps,
163 ByteOp | DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM,
164 /* 0xF8 - 0xFF */
165 ImplicitOps, 0, ImplicitOps, ImplicitOps,
166 0, 0, ByteOp | DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM
167};
168
169static u16 twobyte_table[256] = {
170 /* 0x00 - 0x0F */
171 0, SrcMem | ModRM | DstReg, 0, 0, 0, 0, ImplicitOps, 0,
172 ImplicitOps, ImplicitOps, 0, 0, 0, ImplicitOps | ModRM, 0, 0,
173 /* 0x10 - 0x1F */
174 0, 0, 0, 0, 0, 0, 0, 0, ImplicitOps | ModRM, 0, 0, 0, 0, 0, 0, 0,
175 /* 0x20 - 0x2F */
176 ModRM | ImplicitOps, ModRM, ModRM | ImplicitOps, ModRM, 0, 0, 0, 0,
177 0, 0, 0, 0, 0, 0, 0, 0,
178 /* 0x30 - 0x3F */
179 ImplicitOps, 0, ImplicitOps, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
180 /* 0x40 - 0x47 */
181 DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
182 DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
183 DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
184 DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
185 /* 0x48 - 0x4F */
186 DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
187 DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
188 DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
189 DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
190 /* 0x50 - 0x5F */
191 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
192 /* 0x60 - 0x6F */
193 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
194 /* 0x70 - 0x7F */
195 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
196 /* 0x80 - 0x8F */
197 ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
198 ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
199 ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
200 ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
201 /* 0x90 - 0x9F */
202 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
203 /* 0xA0 - 0xA7 */
204 0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0,
205 /* 0xA8 - 0xAF */
206 0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0,
207 /* 0xB0 - 0xB7 */
208 ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, 0,
209 DstMem | SrcReg | ModRM | BitOp,
210 0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov,
211 DstReg | SrcMem16 | ModRM | Mov,
212 /* 0xB8 - 0xBF */
213 0, 0, DstMem | SrcImmByte | ModRM, DstMem | SrcReg | ModRM | BitOp,
214 0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov,
215 DstReg | SrcMem16 | ModRM | Mov,
216 /* 0xC0 - 0xCF */
217 0, 0, 0, DstMem | SrcReg | ModRM | Mov, 0, 0, 0, ImplicitOps | ModRM,
218 0, 0, 0, 0, 0, 0, 0, 0,
219 /* 0xD0 - 0xDF */
220 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
221 /* 0xE0 - 0xEF */
222 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
223 /* 0xF0 - 0xFF */
224 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
225};
226
227/* EFLAGS bit definitions. */
228#define EFLG_OF (1<<11)
229#define EFLG_DF (1<<10)
230#define EFLG_SF (1<<7)
231#define EFLG_ZF (1<<6)
232#define EFLG_AF (1<<4)
233#define EFLG_PF (1<<2)
234#define EFLG_CF (1<<0)
235
236/*
237 * Instruction emulation:
238 * Most instructions are emulated directly via a fragment of inline assembly
239 * code. This allows us to save/restore EFLAGS and thus very easily pick up
240 * any modified flags.
241 */
242
243#if defined(CONFIG_X86_64)
244#define _LO32 "k" /* force 32-bit operand */
245#define _STK "%%rsp" /* stack pointer */
246#elif defined(__i386__)
247#define _LO32 "" /* force 32-bit operand */
248#define _STK "%%esp" /* stack pointer */
249#endif
250
251/*
252 * These EFLAGS bits are restored from saved value during emulation, and
253 * any changes are written back to the saved value after emulation.
254 */
255#define EFLAGS_MASK (EFLG_OF|EFLG_SF|EFLG_ZF|EFLG_AF|EFLG_PF|EFLG_CF)
256
257/* Before executing instruction: restore necessary bits in EFLAGS. */
258#define _PRE_EFLAGS(_sav, _msk, _tmp) \
259 /* EFLAGS = (_sav & _msk) | (EFLAGS & ~_msk); */ \
260 "push %"_sav"; " \
261 "movl %"_msk",%"_LO32 _tmp"; " \
262 "andl %"_LO32 _tmp",("_STK"); " \
263 "pushf; " \
264 "notl %"_LO32 _tmp"; " \
265 "andl %"_LO32 _tmp",("_STK"); " \
266 "pop %"_tmp"; " \
267 "orl %"_LO32 _tmp",("_STK"); " \
268 "popf; " \
269 /* _sav &= ~msk; */ \
270 "movl %"_msk",%"_LO32 _tmp"; " \
271 "notl %"_LO32 _tmp"; " \
272 "andl %"_LO32 _tmp",%"_sav"; "
273
274/* After executing instruction: write-back necessary bits in EFLAGS. */
275#define _POST_EFLAGS(_sav, _msk, _tmp) \
276 /* _sav |= EFLAGS & _msk; */ \
277 "pushf; " \
278 "pop %"_tmp"; " \
279 "andl %"_msk",%"_LO32 _tmp"; " \
280 "orl %"_LO32 _tmp",%"_sav"; "
281
282/* Raw emulation: instruction has two explicit operands. */
283#define __emulate_2op_nobyte(_op,_src,_dst,_eflags,_wx,_wy,_lx,_ly,_qx,_qy) \
284 do { \
285 unsigned long _tmp; \
286 \
287 switch ((_dst).bytes) { \
288 case 2: \
289 __asm__ __volatile__ ( \
290 _PRE_EFLAGS("0", "4", "2") \
291 _op"w %"_wx"3,%1; " \
292 _POST_EFLAGS("0", "4", "2") \
293 : "=m" (_eflags), "=m" ((_dst).val), \
294 "=&r" (_tmp) \
295 : _wy ((_src).val), "i" (EFLAGS_MASK)); \
296 break; \
297 case 4: \
298 __asm__ __volatile__ ( \
299 _PRE_EFLAGS("0", "4", "2") \
300 _op"l %"_lx"3,%1; " \
301 _POST_EFLAGS("0", "4", "2") \
302 : "=m" (_eflags), "=m" ((_dst).val), \
303 "=&r" (_tmp) \
304 : _ly ((_src).val), "i" (EFLAGS_MASK)); \
305 break; \
306 case 8: \
307 __emulate_2op_8byte(_op, _src, _dst, \
308 _eflags, _qx, _qy); \
309 break; \
310 } \
311 } while (0)
312
313#define __emulate_2op(_op,_src,_dst,_eflags,_bx,_by,_wx,_wy,_lx,_ly,_qx,_qy) \
314 do { \
315 unsigned long _tmp; \
316 switch ((_dst).bytes) { \
317 case 1: \
318 __asm__ __volatile__ ( \
319 _PRE_EFLAGS("0", "4", "2") \
320 _op"b %"_bx"3,%1; " \
321 _POST_EFLAGS("0", "4", "2") \
322 : "=m" (_eflags), "=m" ((_dst).val), \
323 "=&r" (_tmp) \
324 : _by ((_src).val), "i" (EFLAGS_MASK)); \
325 break; \
326 default: \
327 __emulate_2op_nobyte(_op, _src, _dst, _eflags, \
328 _wx, _wy, _lx, _ly, _qx, _qy); \
329 break; \
330 } \
331 } while (0)
332
333/* Source operand is byte-sized and may be restricted to just %cl. */
334#define emulate_2op_SrcB(_op, _src, _dst, _eflags) \
335 __emulate_2op(_op, _src, _dst, _eflags, \
336 "b", "c", "b", "c", "b", "c", "b", "c")
337
338/* Source operand is byte, word, long or quad sized. */
339#define emulate_2op_SrcV(_op, _src, _dst, _eflags) \
340 __emulate_2op(_op, _src, _dst, _eflags, \
341 "b", "q", "w", "r", _LO32, "r", "", "r")
342
343/* Source operand is word, long or quad sized. */
344#define emulate_2op_SrcV_nobyte(_op, _src, _dst, _eflags) \
345 __emulate_2op_nobyte(_op, _src, _dst, _eflags, \
346 "w", "r", _LO32, "r", "", "r")
347
348/* Instruction has only one explicit operand (no source operand). */
349#define emulate_1op(_op, _dst, _eflags) \
350 do { \
351 unsigned long _tmp; \
352 \
353 switch ((_dst).bytes) { \
354 case 1: \
355 __asm__ __volatile__ ( \
356 _PRE_EFLAGS("0", "3", "2") \
357 _op"b %1; " \
358 _POST_EFLAGS("0", "3", "2") \
359 : "=m" (_eflags), "=m" ((_dst).val), \
360 "=&r" (_tmp) \
361 : "i" (EFLAGS_MASK)); \
362 break; \
363 case 2: \
364 __asm__ __volatile__ ( \
365 _PRE_EFLAGS("0", "3", "2") \
366 _op"w %1; " \
367 _POST_EFLAGS("0", "3", "2") \
368 : "=m" (_eflags), "=m" ((_dst).val), \
369 "=&r" (_tmp) \
370 : "i" (EFLAGS_MASK)); \
371 break; \
372 case 4: \
373 __asm__ __volatile__ ( \
374 _PRE_EFLAGS("0", "3", "2") \
375 _op"l %1; " \
376 _POST_EFLAGS("0", "3", "2") \
377 : "=m" (_eflags), "=m" ((_dst).val), \
378 "=&r" (_tmp) \
379 : "i" (EFLAGS_MASK)); \
380 break; \
381 case 8: \
382 __emulate_1op_8byte(_op, _dst, _eflags); \
383 break; \
384 } \
385 } while (0)
386
387/* Emulate an instruction with quadword operands (x86/64 only). */
388#if defined(CONFIG_X86_64)
389#define __emulate_2op_8byte(_op, _src, _dst, _eflags, _qx, _qy) \
390 do { \
391 __asm__ __volatile__ ( \
392 _PRE_EFLAGS("0", "4", "2") \
393 _op"q %"_qx"3,%1; " \
394 _POST_EFLAGS("0", "4", "2") \
395 : "=m" (_eflags), "=m" ((_dst).val), "=&r" (_tmp) \
396 : _qy ((_src).val), "i" (EFLAGS_MASK)); \
397 } while (0)
398
399#define __emulate_1op_8byte(_op, _dst, _eflags) \
400 do { \
401 __asm__ __volatile__ ( \
402 _PRE_EFLAGS("0", "3", "2") \
403 _op"q %1; " \
404 _POST_EFLAGS("0", "3", "2") \
405 : "=m" (_eflags), "=m" ((_dst).val), "=&r" (_tmp) \
406 : "i" (EFLAGS_MASK)); \
407 } while (0)
408
409#elif defined(__i386__)
410#define __emulate_2op_8byte(_op, _src, _dst, _eflags, _qx, _qy)
411#define __emulate_1op_8byte(_op, _dst, _eflags)
412#endif /* __i386__ */
413
414/* Fetch next part of the instruction being emulated. */
415#define insn_fetch(_type, _size, _eip) \
416({ unsigned long _x; \
417 rc = do_insn_fetch(ctxt, ops, (_eip), &_x, (_size)); \
418 if (rc != 0) \
419 goto done; \
420 (_eip) += (_size); \
421 (_type)_x; \
422})
423
424/* Access/update address held in a register, based on addressing mode. */
425#define address_mask(reg) \
426 ((c->ad_bytes == sizeof(unsigned long)) ? \
427 (reg) : ((reg) & ((1UL << (c->ad_bytes << 3)) - 1)))
428#define register_address(base, reg) \
429 ((base) + address_mask(reg))
430#define register_address_increment(reg, inc) \
431 do { \
432 /* signed type ensures sign extension to long */ \
433 int _inc = (inc); \
434 if (c->ad_bytes == sizeof(unsigned long)) \
435 (reg) += _inc; \
436 else \
437 (reg) = ((reg) & \
438 ~((1UL << (c->ad_bytes << 3)) - 1)) | \
439 (((reg) + _inc) & \
440 ((1UL << (c->ad_bytes << 3)) - 1)); \
441 } while (0)
442
443#define JMP_REL(rel) \
444 do { \
445 register_address_increment(c->eip, rel); \
446 } while (0)
447
448static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
449 struct x86_emulate_ops *ops,
450 unsigned long linear, u8 *dest)
451{
452 struct fetch_cache *fc = &ctxt->decode.fetch;
453 int rc;
454 int size;
455
456 if (linear < fc->start || linear >= fc->end) {
457 size = min(15UL, PAGE_SIZE - offset_in_page(linear));
458 rc = ops->read_std(linear, fc->data, size, ctxt->vcpu);
459 if (rc)
460 return rc;
461 fc->start = linear;
462 fc->end = linear + size;
463 }
464 *dest = fc->data[linear - fc->start];
465 return 0;
466}
467
468static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
469 struct x86_emulate_ops *ops,
470 unsigned long eip, void *dest, unsigned size)
471{
472 int rc = 0;
473
474 eip += ctxt->cs_base;
475 while (size--) {
476 rc = do_fetch_insn_byte(ctxt, ops, eip++, dest++);
477 if (rc)
478 return rc;
479 }
480 return 0;
481}
482
483/*
484 * Given the 'reg' portion of a ModRM byte, and a register block, return a
485 * pointer into the block that addresses the relevant register.
486 * @highbyte_regs specifies whether to decode AH,CH,DH,BH.
487 */
488static void *decode_register(u8 modrm_reg, unsigned long *regs,
489 int highbyte_regs)
490{
491 void *p;
492
493 p = &regs[modrm_reg];
494 if (highbyte_regs && modrm_reg >= 4 && modrm_reg < 8)
495 p = (unsigned char *)&regs[modrm_reg & 3] + 1;
496 return p;
497}
498
499static int read_descriptor(struct x86_emulate_ctxt *ctxt,
500 struct x86_emulate_ops *ops,
501 void *ptr,
502 u16 *size, unsigned long *address, int op_bytes)
503{
504 int rc;
505
506 if (op_bytes == 2)
507 op_bytes = 3;
508 *address = 0;
509 rc = ops->read_std((unsigned long)ptr, (unsigned long *)size, 2,
510 ctxt->vcpu);
511 if (rc)
512 return rc;
513 rc = ops->read_std((unsigned long)ptr + 2, address, op_bytes,
514 ctxt->vcpu);
515 return rc;
516}
517
518static int test_cc(unsigned int condition, unsigned int flags)
519{
520 int rc = 0;
521
522 switch ((condition & 15) >> 1) {
523 case 0: /* o */
524 rc |= (flags & EFLG_OF);
525 break;
526 case 1: /* b/c/nae */
527 rc |= (flags & EFLG_CF);
528 break;
529 case 2: /* z/e */
530 rc |= (flags & EFLG_ZF);
531 break;
532 case 3: /* be/na */
533 rc |= (flags & (EFLG_CF|EFLG_ZF));
534 break;
535 case 4: /* s */
536 rc |= (flags & EFLG_SF);
537 break;
538 case 5: /* p/pe */
539 rc |= (flags & EFLG_PF);
540 break;
541 case 7: /* le/ng */
542 rc |= (flags & EFLG_ZF);
543 /* fall through */
544 case 6: /* l/nge */
545 rc |= (!(flags & EFLG_SF) != !(flags & EFLG_OF));
546 break;
547 }
548
549 /* Odd condition identifiers (lsb == 1) have inverted sense. */
550 return (!!rc ^ (condition & 1));
551}
552
553static void decode_register_operand(struct operand *op,
554 struct decode_cache *c,
555 int inhibit_bytereg)
556{
557 unsigned reg = c->modrm_reg;
558 int highbyte_regs = c->rex_prefix == 0;
559
560 if (!(c->d & ModRM))
561 reg = (c->b & 7) | ((c->rex_prefix & 1) << 3);
562 op->type = OP_REG;
563 if ((c->d & ByteOp) && !inhibit_bytereg) {
564 op->ptr = decode_register(reg, c->regs, highbyte_regs);
565 op->val = *(u8 *)op->ptr;
566 op->bytes = 1;
567 } else {
568 op->ptr = decode_register(reg, c->regs, 0);
569 op->bytes = c->op_bytes;
570 switch (op->bytes) {
571 case 2:
572 op->val = *(u16 *)op->ptr;
573 break;
574 case 4:
575 op->val = *(u32 *)op->ptr;
576 break;
577 case 8:
578 op->val = *(u64 *) op->ptr;
579 break;
580 }
581 }
582 op->orig_val = op->val;
583}
584
585static int decode_modrm(struct x86_emulate_ctxt *ctxt,
586 struct x86_emulate_ops *ops)
587{
588 struct decode_cache *c = &ctxt->decode;
589 u8 sib;
590 int index_reg = 0, base_reg = 0, scale, rip_relative = 0;
591 int rc = 0;
592
593 if (c->rex_prefix) {
594 c->modrm_reg = (c->rex_prefix & 4) << 1; /* REX.R */
595 index_reg = (c->rex_prefix & 2) << 2; /* REX.X */
596 c->modrm_rm = base_reg = (c->rex_prefix & 1) << 3; /* REG.B */
597 }
598
599 c->modrm = insn_fetch(u8, 1, c->eip);
600 c->modrm_mod |= (c->modrm & 0xc0) >> 6;
601 c->modrm_reg |= (c->modrm & 0x38) >> 3;
602 c->modrm_rm |= (c->modrm & 0x07);
603 c->modrm_ea = 0;
604 c->use_modrm_ea = 1;
605
606 if (c->modrm_mod == 3) {
607 c->modrm_val = *(unsigned long *)
608 decode_register(c->modrm_rm, c->regs, c->d & ByteOp);
609 return rc;
610 }
611
612 if (c->ad_bytes == 2) {
613 unsigned bx = c->regs[VCPU_REGS_RBX];
614 unsigned bp = c->regs[VCPU_REGS_RBP];
615 unsigned si = c->regs[VCPU_REGS_RSI];
616 unsigned di = c->regs[VCPU_REGS_RDI];
617
618 /* 16-bit ModR/M decode. */
619 switch (c->modrm_mod) {
620 case 0:
621 if (c->modrm_rm == 6)
622 c->modrm_ea += insn_fetch(u16, 2, c->eip);
623 break;
624 case 1:
625 c->modrm_ea += insn_fetch(s8, 1, c->eip);
626 break;
627 case 2:
628 c->modrm_ea += insn_fetch(u16, 2, c->eip);
629 break;
630 }
631 switch (c->modrm_rm) {
632 case 0:
633 c->modrm_ea += bx + si;
634 break;
635 case 1:
636 c->modrm_ea += bx + di;
637 break;
638 case 2:
639 c->modrm_ea += bp + si;
640 break;
641 case 3:
642 c->modrm_ea += bp + di;
643 break;
644 case 4:
645 c->modrm_ea += si;
646 break;
647 case 5:
648 c->modrm_ea += di;
649 break;
650 case 6:
651 if (c->modrm_mod != 0)
652 c->modrm_ea += bp;
653 break;
654 case 7:
655 c->modrm_ea += bx;
656 break;
657 }
658 if (c->modrm_rm == 2 || c->modrm_rm == 3 ||
659 (c->modrm_rm == 6 && c->modrm_mod != 0))
660 if (!c->override_base)
661 c->override_base = &ctxt->ss_base;
662 c->modrm_ea = (u16)c->modrm_ea;
663 } else {
664 /* 32/64-bit ModR/M decode. */
665 switch (c->modrm_rm) {
666 case 4:
667 case 12:
668 sib = insn_fetch(u8, 1, c->eip);
669 index_reg |= (sib >> 3) & 7;
670 base_reg |= sib & 7;
671 scale = sib >> 6;
672
673 switch (base_reg) {
674 case 5:
675 if (c->modrm_mod != 0)
676 c->modrm_ea += c->regs[base_reg];
677 else
678 c->modrm_ea +=
679 insn_fetch(s32, 4, c->eip);
680 break;
681 default:
682 c->modrm_ea += c->regs[base_reg];
683 }
684 switch (index_reg) {
685 case 4:
686 break;
687 default:
688 c->modrm_ea += c->regs[index_reg] << scale;
689 }
690 break;
691 case 5:
692 if (c->modrm_mod != 0)
693 c->modrm_ea += c->regs[c->modrm_rm];
694 else if (ctxt->mode == X86EMUL_MODE_PROT64)
695 rip_relative = 1;
696 break;
697 default:
698 c->modrm_ea += c->regs[c->modrm_rm];
699 break;
700 }
701 switch (c->modrm_mod) {
702 case 0:
703 if (c->modrm_rm == 5)
704 c->modrm_ea += insn_fetch(s32, 4, c->eip);
705 break;
706 case 1:
707 c->modrm_ea += insn_fetch(s8, 1, c->eip);
708 break;
709 case 2:
710 c->modrm_ea += insn_fetch(s32, 4, c->eip);
711 break;
712 }
713 }
714 if (rip_relative) {
715 c->modrm_ea += c->eip;
716 switch (c->d & SrcMask) {
717 case SrcImmByte:
718 c->modrm_ea += 1;
719 break;
720 case SrcImm:
721 if (c->d & ByteOp)
722 c->modrm_ea += 1;
723 else
724 if (c->op_bytes == 8)
725 c->modrm_ea += 4;
726 else
727 c->modrm_ea += c->op_bytes;
728 }
729 }
730done:
731 return rc;
732}
733
734static int decode_abs(struct x86_emulate_ctxt *ctxt,
735 struct x86_emulate_ops *ops)
736{
737 struct decode_cache *c = &ctxt->decode;
738 int rc = 0;
739
740 switch (c->ad_bytes) {
741 case 2:
742 c->modrm_ea = insn_fetch(u16, 2, c->eip);
743 break;
744 case 4:
745 c->modrm_ea = insn_fetch(u32, 4, c->eip);
746 break;
747 case 8:
748 c->modrm_ea = insn_fetch(u64, 8, c->eip);
749 break;
750 }
751done:
752 return rc;
753}
754
755int
756x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
757{
758 struct decode_cache *c = &ctxt->decode;
759 int rc = 0;
760 int mode = ctxt->mode;
761
762 /* Shadow copy of register state. Committed on successful emulation. */
763
764 memset(c, 0, sizeof(struct decode_cache));
765 c->eip = ctxt->vcpu->rip;
766 memcpy(c->regs, ctxt->vcpu->regs, sizeof c->regs);
767
768 switch (mode) {
769 case X86EMUL_MODE_REAL:
770 case X86EMUL_MODE_PROT16:
771 c->op_bytes = c->ad_bytes = 2;
772 break;
773 case X86EMUL_MODE_PROT32:
774 c->op_bytes = c->ad_bytes = 4;
775 break;
776#ifdef CONFIG_X86_64
777 case X86EMUL_MODE_PROT64:
778 c->op_bytes = 4;
779 c->ad_bytes = 8;
780 break;
781#endif
782 default:
783 return -1;
784 }
785
786 /* Legacy prefixes. */
787 for (;;) {
788 switch (c->b = insn_fetch(u8, 1, c->eip)) {
789 case 0x66: /* operand-size override */
790 c->op_bytes ^= 6; /* switch between 2/4 bytes */
791 break;
792 case 0x67: /* address-size override */
793 if (mode == X86EMUL_MODE_PROT64)
794 /* switch between 4/8 bytes */
795 c->ad_bytes ^= 12;
796 else
797 /* switch between 2/4 bytes */
798 c->ad_bytes ^= 6;
799 break;
800 case 0x2e: /* CS override */
801 c->override_base = &ctxt->cs_base;
802 break;
803 case 0x3e: /* DS override */
804 c->override_base = &ctxt->ds_base;
805 break;
806 case 0x26: /* ES override */
807 c->override_base = &ctxt->es_base;
808 break;
809 case 0x64: /* FS override */
810 c->override_base = &ctxt->fs_base;
811 break;
812 case 0x65: /* GS override */
813 c->override_base = &ctxt->gs_base;
814 break;
815 case 0x36: /* SS override */
816 c->override_base = &ctxt->ss_base;
817 break;
818 case 0x40 ... 0x4f: /* REX */
819 if (mode != X86EMUL_MODE_PROT64)
820 goto done_prefixes;
821 c->rex_prefix = c->b;
822 continue;
823 case 0xf0: /* LOCK */
824 c->lock_prefix = 1;
825 break;
826 case 0xf2: /* REPNE/REPNZ */
827 case 0xf3: /* REP/REPE/REPZ */
828 c->rep_prefix = 1;
829 break;
830 default:
831 goto done_prefixes;
832 }
833
834 /* Any legacy prefix after a REX prefix nullifies its effect. */
835
836 c->rex_prefix = 0;
837 }
838
839done_prefixes:
840
841 /* REX prefix. */
842 if (c->rex_prefix)
843 if (c->rex_prefix & 8)
844 c->op_bytes = 8; /* REX.W */
845
846 /* Opcode byte(s). */
847 c->d = opcode_table[c->b];
848 if (c->d == 0) {
849 /* Two-byte opcode? */
850 if (c->b == 0x0f) {
851 c->twobyte = 1;
852 c->b = insn_fetch(u8, 1, c->eip);
853 c->d = twobyte_table[c->b];
854 }
855
856 /* Unrecognised? */
857 if (c->d == 0) {
858 DPRINTF("Cannot emulate %02x\n", c->b);
859 return -1;
860 }
861 }
862
863 /* ModRM and SIB bytes. */
864 if (c->d & ModRM)
865 rc = decode_modrm(ctxt, ops);
866 else if (c->d & MemAbs)
867 rc = decode_abs(ctxt, ops);
868 if (rc)
869 goto done;
870
871 if (!c->override_base)
872 c->override_base = &ctxt->ds_base;
873 if (mode == X86EMUL_MODE_PROT64 &&
874 c->override_base != &ctxt->fs_base &&
875 c->override_base != &ctxt->gs_base)
876 c->override_base = NULL;
877
878 if (c->override_base)
879 c->modrm_ea += *c->override_base;
880
881 if (c->ad_bytes != 8)
882 c->modrm_ea = (u32)c->modrm_ea;
883 /*
884 * Decode and fetch the source operand: register, memory
885 * or immediate.
886 */
887 switch (c->d & SrcMask) {
888 case SrcNone:
889 break;
890 case SrcReg:
891 decode_register_operand(&c->src, c, 0);
892 break;
893 case SrcMem16:
894 c->src.bytes = 2;
895 goto srcmem_common;
896 case SrcMem32:
897 c->src.bytes = 4;
898 goto srcmem_common;
899 case SrcMem:
900 c->src.bytes = (c->d & ByteOp) ? 1 :
901 c->op_bytes;
902 /* Don't fetch the address for invlpg: it could be unmapped. */
903 if (c->twobyte && c->b == 0x01 && c->modrm_reg == 7)
904 break;
905 srcmem_common:
906 /*
907 * For instructions with a ModR/M byte, switch to register
908 * access if Mod = 3.
909 */
910 if ((c->d & ModRM) && c->modrm_mod == 3) {
911 c->src.type = OP_REG;
912 break;
913 }
914 c->src.type = OP_MEM;
915 break;
916 case SrcImm:
917 c->src.type = OP_IMM;
918 c->src.ptr = (unsigned long *)c->eip;
919 c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
920 if (c->src.bytes == 8)
921 c->src.bytes = 4;
922 /* NB. Immediates are sign-extended as necessary. */
923 switch (c->src.bytes) {
924 case 1:
925 c->src.val = insn_fetch(s8, 1, c->eip);
926 break;
927 case 2:
928 c->src.val = insn_fetch(s16, 2, c->eip);
929 break;
930 case 4:
931 c->src.val = insn_fetch(s32, 4, c->eip);
932 break;
933 }
934 break;
935 case SrcImmByte:
936 c->src.type = OP_IMM;
937 c->src.ptr = (unsigned long *)c->eip;
938 c->src.bytes = 1;
939 c->src.val = insn_fetch(s8, 1, c->eip);
940 break;
941 }
942
943 /* Decode and fetch the destination operand: register or memory. */
944 switch (c->d & DstMask) {
945 case ImplicitOps:
946 /* Special instructions do their own operand decoding. */
947 return 0;
948 case DstReg:
949 decode_register_operand(&c->dst, c,
950 c->twobyte && (c->b == 0xb6 || c->b == 0xb7));
951 break;
952 case DstMem:
953 if ((c->d & ModRM) && c->modrm_mod == 3) {
954 c->dst.type = OP_REG;
955 break;
956 }
957 c->dst.type = OP_MEM;
958 break;
959 }
960
961done:
962 return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
963}
964
965static inline void emulate_push(struct x86_emulate_ctxt *ctxt)
966{
967 struct decode_cache *c = &ctxt->decode;
968
969 c->dst.type = OP_MEM;
970 c->dst.bytes = c->op_bytes;
971 c->dst.val = c->src.val;
972 register_address_increment(c->regs[VCPU_REGS_RSP], -c->op_bytes);
973 c->dst.ptr = (void *) register_address(ctxt->ss_base,
974 c->regs[VCPU_REGS_RSP]);
975}
976
977static inline int emulate_grp1a(struct x86_emulate_ctxt *ctxt,
978 struct x86_emulate_ops *ops)
979{
980 struct decode_cache *c = &ctxt->decode;
981 int rc;
982
983 /* 64-bit mode: POP always pops a 64-bit operand. */
984
985 if (ctxt->mode == X86EMUL_MODE_PROT64)
986 c->dst.bytes = 8;
987
988 rc = ops->read_std(register_address(ctxt->ss_base,
989 c->regs[VCPU_REGS_RSP]),
990 &c->dst.val, c->dst.bytes, ctxt->vcpu);
991 if (rc != 0)
992 return rc;
993
994 register_address_increment(c->regs[VCPU_REGS_RSP], c->dst.bytes);
995
996 return 0;
997}
998
999static inline void emulate_grp2(struct x86_emulate_ctxt *ctxt)
1000{
1001 struct decode_cache *c = &ctxt->decode;
1002 switch (c->modrm_reg) {
1003 case 0: /* rol */
1004 emulate_2op_SrcB("rol", c->src, c->dst, ctxt->eflags);
1005 break;
1006 case 1: /* ror */
1007 emulate_2op_SrcB("ror", c->src, c->dst, ctxt->eflags);
1008 break;
1009 case 2: /* rcl */
1010 emulate_2op_SrcB("rcl", c->src, c->dst, ctxt->eflags);
1011 break;
1012 case 3: /* rcr */
1013 emulate_2op_SrcB("rcr", c->src, c->dst, ctxt->eflags);
1014 break;
1015 case 4: /* sal/shl */
1016 case 6: /* sal/shl */
1017 emulate_2op_SrcB("sal", c->src, c->dst, ctxt->eflags);
1018 break;
1019 case 5: /* shr */
1020 emulate_2op_SrcB("shr", c->src, c->dst, ctxt->eflags);
1021 break;
1022 case 7: /* sar */
1023 emulate_2op_SrcB("sar", c->src, c->dst, ctxt->eflags);
1024 break;
1025 }
1026}
1027
1028static inline int emulate_grp3(struct x86_emulate_ctxt *ctxt,
1029 struct x86_emulate_ops *ops)
1030{
1031 struct decode_cache *c = &ctxt->decode;
1032 int rc = 0;
1033
1034 switch (c->modrm_reg) {
1035 case 0 ... 1: /* test */
1036 /*
1037 * Special case in Grp3: test has an immediate
1038 * source operand.
1039 */
1040 c->src.type = OP_IMM;
1041 c->src.ptr = (unsigned long *)c->eip;
1042 c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
1043 if (c->src.bytes == 8)
1044 c->src.bytes = 4;
1045 switch (c->src.bytes) {
1046 case 1:
1047 c->src.val = insn_fetch(s8, 1, c->eip);
1048 break;
1049 case 2:
1050 c->src.val = insn_fetch(s16, 2, c->eip);
1051 break;
1052 case 4:
1053 c->src.val = insn_fetch(s32, 4, c->eip);
1054 break;
1055 }
1056 emulate_2op_SrcV("test", c->src, c->dst, ctxt->eflags);
1057 break;
1058 case 2: /* not */
1059 c->dst.val = ~c->dst.val;
1060 break;
1061 case 3: /* neg */
1062 emulate_1op("neg", c->dst, ctxt->eflags);
1063 break;
1064 default:
1065 DPRINTF("Cannot emulate %02x\n", c->b);
1066 rc = X86EMUL_UNHANDLEABLE;
1067 break;
1068 }
1069done:
1070 return rc;
1071}
1072
1073static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt,
1074 struct x86_emulate_ops *ops)
1075{
1076 struct decode_cache *c = &ctxt->decode;
1077 int rc;
1078
1079 switch (c->modrm_reg) {
1080 case 0: /* inc */
1081 emulate_1op("inc", c->dst, ctxt->eflags);
1082 break;
1083 case 1: /* dec */
1084 emulate_1op("dec", c->dst, ctxt->eflags);
1085 break;
1086 case 4: /* jmp abs */
1087 if (c->b == 0xff)
1088 c->eip = c->dst.val;
1089 else {
1090 DPRINTF("Cannot emulate %02x\n", c->b);
1091 return X86EMUL_UNHANDLEABLE;
1092 }
1093 break;
1094 case 6: /* push */
1095
1096 /* 64-bit mode: PUSH always pushes a 64-bit operand. */
1097
1098 if (ctxt->mode == X86EMUL_MODE_PROT64) {
1099 c->dst.bytes = 8;
1100 rc = ops->read_std((unsigned long)c->dst.ptr,
1101 &c->dst.val, 8, ctxt->vcpu);
1102 if (rc != 0)
1103 return rc;
1104 }
1105 register_address_increment(c->regs[VCPU_REGS_RSP],
1106 -c->dst.bytes);
1107 rc = ops->write_emulated(register_address(ctxt->ss_base,
1108 c->regs[VCPU_REGS_RSP]), &c->dst.val,
1109 c->dst.bytes, ctxt->vcpu);
1110 if (rc != 0)
1111 return rc;
1112 c->dst.type = OP_NONE;
1113 break;
1114 default:
1115 DPRINTF("Cannot emulate %02x\n", c->b);
1116 return X86EMUL_UNHANDLEABLE;
1117 }
1118 return 0;
1119}
1120
1121static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt,
1122 struct x86_emulate_ops *ops,
1123 unsigned long cr2)
1124{
1125 struct decode_cache *c = &ctxt->decode;
1126 u64 old, new;
1127 int rc;
1128
1129 rc = ops->read_emulated(cr2, &old, 8, ctxt->vcpu);
1130 if (rc != 0)
1131 return rc;
1132
1133 if (((u32) (old >> 0) != (u32) c->regs[VCPU_REGS_RAX]) ||
1134 ((u32) (old >> 32) != (u32) c->regs[VCPU_REGS_RDX])) {
1135
1136 c->regs[VCPU_REGS_RAX] = (u32) (old >> 0);
1137 c->regs[VCPU_REGS_RDX] = (u32) (old >> 32);
1138 ctxt->eflags &= ~EFLG_ZF;
1139
1140 } else {
1141 new = ((u64)c->regs[VCPU_REGS_RCX] << 32) |
1142 (u32) c->regs[VCPU_REGS_RBX];
1143
1144 rc = ops->cmpxchg_emulated(cr2, &old, &new, 8, ctxt->vcpu);
1145 if (rc != 0)
1146 return rc;
1147 ctxt->eflags |= EFLG_ZF;
1148 }
1149 return 0;
1150}
1151
1152static inline int writeback(struct x86_emulate_ctxt *ctxt,
1153 struct x86_emulate_ops *ops)
1154{
1155 int rc;
1156 struct decode_cache *c = &ctxt->decode;
1157
1158 switch (c->dst.type) {
1159 case OP_REG:
1160 /* The 4-byte case *is* correct:
1161 * in 64-bit mode we zero-extend.
1162 */
1163 switch (c->dst.bytes) {
1164 case 1:
1165 *(u8 *)c->dst.ptr = (u8)c->dst.val;
1166 break;
1167 case 2:
1168 *(u16 *)c->dst.ptr = (u16)c->dst.val;
1169 break;
1170 case 4:
1171 *c->dst.ptr = (u32)c->dst.val;
1172 break; /* 64b: zero-ext */
1173 case 8:
1174 *c->dst.ptr = c->dst.val;
1175 break;
1176 }
1177 break;
1178 case OP_MEM:
1179 if (c->lock_prefix)
1180 rc = ops->cmpxchg_emulated(
1181 (unsigned long)c->dst.ptr,
1182 &c->dst.orig_val,
1183 &c->dst.val,
1184 c->dst.bytes,
1185 ctxt->vcpu);
1186 else
1187 rc = ops->write_emulated(
1188 (unsigned long)c->dst.ptr,
1189 &c->dst.val,
1190 c->dst.bytes,
1191 ctxt->vcpu);
1192 if (rc != 0)
1193 return rc;
1194 break;
1195 case OP_NONE:
1196 /* no writeback */
1197 break;
1198 default:
1199 break;
1200 }
1201 return 0;
1202}
1203
1204int
1205x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
1206{
1207 unsigned long cr2 = ctxt->cr2;
1208 u64 msr_data;
1209 unsigned long saved_eip = 0;
1210 struct decode_cache *c = &ctxt->decode;
1211 int rc = 0;
1212
1213 /* Shadow copy of register state. Committed on successful emulation.
1214 * NOTE: we can copy them from vcpu as x86_decode_insn() doesn't
1215 * modify them.
1216 */
1217
1218 memcpy(c->regs, ctxt->vcpu->regs, sizeof c->regs);
1219 saved_eip = c->eip;
1220
1221 if (((c->d & ModRM) && (c->modrm_mod != 3)) || (c->d & MemAbs))
1222 cr2 = c->modrm_ea;
1223
1224 if (c->src.type == OP_MEM) {
1225 c->src.ptr = (unsigned long *)cr2;
1226 c->src.val = 0;
1227 rc = ops->read_emulated((unsigned long)c->src.ptr,
1228 &c->src.val,
1229 c->src.bytes,
1230 ctxt->vcpu);
1231 if (rc != 0)
1232 goto done;
1233 c->src.orig_val = c->src.val;
1234 }
1235
1236 if ((c->d & DstMask) == ImplicitOps)
1237 goto special_insn;
1238
1239
1240 if (c->dst.type == OP_MEM) {
1241 c->dst.ptr = (unsigned long *)cr2;
1242 c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
1243 c->dst.val = 0;
1244 if (c->d & BitOp) {
1245 unsigned long mask = ~(c->dst.bytes * 8 - 1);
1246
1247 c->dst.ptr = (void *)c->dst.ptr +
1248 (c->src.val & mask) / 8;
1249 }
1250 if (!(c->d & Mov) &&
1251 /* optimisation - avoid slow emulated read */
1252 ((rc = ops->read_emulated((unsigned long)c->dst.ptr,
1253 &c->dst.val,
1254 c->dst.bytes, ctxt->vcpu)) != 0))
1255 goto done;
1256 }
1257 c->dst.orig_val = c->dst.val;
1258
1259 if (c->twobyte)
1260 goto twobyte_insn;
1261
1262 switch (c->b) {
1263 case 0x00 ... 0x05:
1264 add: /* add */
1265 emulate_2op_SrcV("add", c->src, c->dst, ctxt->eflags);
1266 break;
1267 case 0x08 ... 0x0d:
1268 or: /* or */
1269 emulate_2op_SrcV("or", c->src, c->dst, ctxt->eflags);
1270 break;
1271 case 0x10 ... 0x15:
1272 adc: /* adc */
1273 emulate_2op_SrcV("adc", c->src, c->dst, ctxt->eflags);
1274 break;
1275 case 0x18 ... 0x1d:
1276 sbb: /* sbb */
1277 emulate_2op_SrcV("sbb", c->src, c->dst, ctxt->eflags);
1278 break;
1279 case 0x20 ... 0x23:
1280 and: /* and */
1281 emulate_2op_SrcV("and", c->src, c->dst, ctxt->eflags);
1282 break;
1283 case 0x24: /* and al imm8 */
1284 c->dst.type = OP_REG;
1285 c->dst.ptr = &c->regs[VCPU_REGS_RAX];
1286 c->dst.val = *(u8 *)c->dst.ptr;
1287 c->dst.bytes = 1;
1288 c->dst.orig_val = c->dst.val;
1289 goto and;
1290 case 0x25: /* and ax imm16, or eax imm32 */
1291 c->dst.type = OP_REG;
1292 c->dst.bytes = c->op_bytes;
1293 c->dst.ptr = &c->regs[VCPU_REGS_RAX];
1294 if (c->op_bytes == 2)
1295 c->dst.val = *(u16 *)c->dst.ptr;
1296 else
1297 c->dst.val = *(u32 *)c->dst.ptr;
1298 c->dst.orig_val = c->dst.val;
1299 goto and;
1300 case 0x28 ... 0x2d:
1301 sub: /* sub */
1302 emulate_2op_SrcV("sub", c->src, c->dst, ctxt->eflags);
1303 break;
1304 case 0x30 ... 0x35:
1305 xor: /* xor */
1306 emulate_2op_SrcV("xor", c->src, c->dst, ctxt->eflags);
1307 break;
1308 case 0x38 ... 0x3d:
1309 cmp: /* cmp */
1310 emulate_2op_SrcV("cmp", c->src, c->dst, ctxt->eflags);
1311 break;
1312 case 0x40 ... 0x47: /* inc r16/r32 */
1313 emulate_1op("inc", c->dst, ctxt->eflags);
1314 break;
1315 case 0x48 ... 0x4f: /* dec r16/r32 */
1316 emulate_1op("dec", c->dst, ctxt->eflags);
1317 break;
1318 case 0x50 ... 0x57: /* push reg */
1319 c->dst.type = OP_MEM;
1320 c->dst.bytes = c->op_bytes;
1321 c->dst.val = c->src.val;
1322 register_address_increment(c->regs[VCPU_REGS_RSP],
1323 -c->op_bytes);
1324 c->dst.ptr = (void *) register_address(
1325 ctxt->ss_base, c->regs[VCPU_REGS_RSP]);
1326 break;
1327 case 0x58 ... 0x5f: /* pop reg */
1328 pop_instruction:
1329 if ((rc = ops->read_std(register_address(ctxt->ss_base,
1330 c->regs[VCPU_REGS_RSP]), c->dst.ptr,
1331 c->op_bytes, ctxt->vcpu)) != 0)
1332 goto done;
1333
1334 register_address_increment(c->regs[VCPU_REGS_RSP],
1335 c->op_bytes);
1336 c->dst.type = OP_NONE; /* Disable writeback. */
1337 break;
1338 case 0x63: /* movsxd */
1339 if (ctxt->mode != X86EMUL_MODE_PROT64)
1340 goto cannot_emulate;
1341 c->dst.val = (s32) c->src.val;
1342 break;
1343 case 0x80 ... 0x83: /* Grp1 */
1344 switch (c->modrm_reg) {
1345 case 0:
1346 goto add;
1347 case 1:
1348 goto or;
1349 case 2:
1350 goto adc;
1351 case 3:
1352 goto sbb;
1353 case 4:
1354 goto and;
1355 case 5:
1356 goto sub;
1357 case 6:
1358 goto xor;
1359 case 7:
1360 goto cmp;
1361 }
1362 break;
1363 case 0x84 ... 0x85:
1364 emulate_2op_SrcV("test", c->src, c->dst, ctxt->eflags);
1365 break;
1366 case 0x86 ... 0x87: /* xchg */
1367 /* Write back the register source. */
1368 switch (c->dst.bytes) {
1369 case 1:
1370 *(u8 *) c->src.ptr = (u8) c->dst.val;
1371 break;
1372 case 2:
1373 *(u16 *) c->src.ptr = (u16) c->dst.val;
1374 break;
1375 case 4:
1376 *c->src.ptr = (u32) c->dst.val;
1377 break; /* 64b reg: zero-extend */
1378 case 8:
1379 *c->src.ptr = c->dst.val;
1380 break;
1381 }
1382 /*
1383 * Write back the memory destination with implicit LOCK
1384 * prefix.
1385 */
1386 c->dst.val = c->src.val;
1387 c->lock_prefix = 1;
1388 break;
1389 case 0x88 ... 0x8b: /* mov */
1390 goto mov;
1391 case 0x8d: /* lea r16/r32, m */
1392 c->dst.val = c->modrm_val;
1393 break;
1394 case 0x8f: /* pop (sole member of Grp1a) */
1395 rc = emulate_grp1a(ctxt, ops);
1396 if (rc != 0)
1397 goto done;
1398 break;
1399 case 0xa0 ... 0xa1: /* mov */
1400 c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
1401 c->dst.val = c->src.val;
1402 break;
1403 case 0xa2 ... 0xa3: /* mov */
1404 c->dst.val = (unsigned long)c->regs[VCPU_REGS_RAX];
1405 break;
1406 case 0xc0 ... 0xc1:
1407 emulate_grp2(ctxt);
1408 break;
1409 case 0xc6 ... 0xc7: /* mov (sole member of Grp11) */
1410 mov:
1411 c->dst.val = c->src.val;
1412 break;
1413 case 0xd0 ... 0xd1: /* Grp2 */
1414 c->src.val = 1;
1415 emulate_grp2(ctxt);
1416 break;
1417 case 0xd2 ... 0xd3: /* Grp2 */
1418 c->src.val = c->regs[VCPU_REGS_RCX];
1419 emulate_grp2(ctxt);
1420 break;
1421 case 0xf6 ... 0xf7: /* Grp3 */
1422 rc = emulate_grp3(ctxt, ops);
1423 if (rc != 0)
1424 goto done;
1425 break;
1426 case 0xfe ... 0xff: /* Grp4/Grp5 */
1427 rc = emulate_grp45(ctxt, ops);
1428 if (rc != 0)
1429 goto done;
1430 break;
1431 }
1432
1433writeback:
1434 rc = writeback(ctxt, ops);
1435 if (rc != 0)
1436 goto done;
1437
1438 /* Commit shadow register state. */
1439 memcpy(ctxt->vcpu->regs, c->regs, sizeof c->regs);
1440 ctxt->vcpu->rip = c->eip;
1441
1442done:
1443 if (rc == X86EMUL_UNHANDLEABLE) {
1444 c->eip = saved_eip;
1445 return -1;
1446 }
1447 return 0;
1448
1449special_insn:
1450 if (c->twobyte)
1451 goto twobyte_special_insn;
1452 switch (c->b) {
1453 case 0x6a: /* push imm8 */
1454 c->src.val = 0L;
1455 c->src.val = insn_fetch(s8, 1, c->eip);
1456 emulate_push(ctxt);
1457 break;
1458 case 0x6c: /* insb */
1459 case 0x6d: /* insw/insd */
1460 if (kvm_emulate_pio_string(ctxt->vcpu, NULL,
1461 1,
1462 (c->d & ByteOp) ? 1 : c->op_bytes,
1463 c->rep_prefix ?
1464 address_mask(c->regs[VCPU_REGS_RCX]) : 1,
1465 (ctxt->eflags & EFLG_DF),
1466 register_address(ctxt->es_base,
1467 c->regs[VCPU_REGS_RDI]),
1468 c->rep_prefix,
1469 c->regs[VCPU_REGS_RDX]) == 0) {
1470 c->eip = saved_eip;
1471 return -1;
1472 }
1473 return 0;
1474 case 0x6e: /* outsb */
1475 case 0x6f: /* outsw/outsd */
1476 if (kvm_emulate_pio_string(ctxt->vcpu, NULL,
1477 0,
1478 (c->d & ByteOp) ? 1 : c->op_bytes,
1479 c->rep_prefix ?
1480 address_mask(c->regs[VCPU_REGS_RCX]) : 1,
1481 (ctxt->eflags & EFLG_DF),
1482 register_address(c->override_base ?
1483 *c->override_base :
1484 ctxt->ds_base,
1485 c->regs[VCPU_REGS_RSI]),
1486 c->rep_prefix,
1487 c->regs[VCPU_REGS_RDX]) == 0) {
1488 c->eip = saved_eip;
1489 return -1;
1490 }
1491 return 0;
1492 case 0x70 ... 0x7f: /* jcc (short) */ {
1493 int rel = insn_fetch(s8, 1, c->eip);
1494
1495 if (test_cc(c->b, ctxt->eflags))
1496 JMP_REL(rel);
1497 break;
1498 }
1499 case 0x9c: /* pushf */
1500 c->src.val = (unsigned long) ctxt->eflags;
1501 emulate_push(ctxt);
1502 break;
1503 case 0x9d: /* popf */
1504 c->dst.ptr = (unsigned long *) &ctxt->eflags;
1505 goto pop_instruction;
1506 case 0xc3: /* ret */
1507 c->dst.ptr = &c->eip;
1508 goto pop_instruction;
1509 case 0xf4: /* hlt */
1510 ctxt->vcpu->halt_request = 1;
1511 goto done;
1512 case 0xf5: /* cmc */
1513 /* complement carry flag from eflags reg */
1514 ctxt->eflags ^= EFLG_CF;
1515 c->dst.type = OP_NONE; /* Disable writeback. */
1516 break;
1517 case 0xf8: /* clc */
1518 ctxt->eflags &= ~EFLG_CF;
1519 c->dst.type = OP_NONE; /* Disable writeback. */
1520 break;
1521 case 0xfa: /* cli */
1522 ctxt->eflags &= ~X86_EFLAGS_IF;
1523 c->dst.type = OP_NONE; /* Disable writeback. */
1524 break;
1525 case 0xfb: /* sti */
1526 ctxt->eflags |= X86_EFLAGS_IF;
1527 c->dst.type = OP_NONE; /* Disable writeback. */
1528 break;
1529 }
1530 if (c->rep_prefix) {
1531 if (c->regs[VCPU_REGS_RCX] == 0) {
1532 ctxt->vcpu->rip = c->eip;
1533 goto done;
1534 }
1535 c->regs[VCPU_REGS_RCX]--;
1536 c->eip = ctxt->vcpu->rip;
1537 }
1538 switch (c->b) {
1539 case 0xa4 ... 0xa5: /* movs */
1540 c->dst.type = OP_MEM;
1541 c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
1542 c->dst.ptr = (unsigned long *)register_address(
1543 ctxt->es_base,
1544 c->regs[VCPU_REGS_RDI]);
1545 if ((rc = ops->read_emulated(register_address(
1546 c->override_base ? *c->override_base :
1547 ctxt->ds_base,
1548 c->regs[VCPU_REGS_RSI]),
1549 &c->dst.val,
1550 c->dst.bytes, ctxt->vcpu)) != 0)
1551 goto done;
1552 register_address_increment(c->regs[VCPU_REGS_RSI],
1553 (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
1554 : c->dst.bytes);
1555 register_address_increment(c->regs[VCPU_REGS_RDI],
1556 (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
1557 : c->dst.bytes);
1558 break;
1559 case 0xa6 ... 0xa7: /* cmps */
1560 DPRINTF("Urk! I don't handle CMPS.\n");
1561 goto cannot_emulate;
1562 case 0xaa ... 0xab: /* stos */
1563 c->dst.type = OP_MEM;
1564 c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
1565 c->dst.ptr = (unsigned long *)register_address(
1566 ctxt->es_base,
1567 c->regs[VCPU_REGS_RDI]);
1568 c->dst.val = c->regs[VCPU_REGS_RAX];
1569 register_address_increment(c->regs[VCPU_REGS_RDI],
1570 (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
1571 : c->dst.bytes);
1572 break;
1573 case 0xac ... 0xad: /* lods */
1574 c->dst.type = OP_REG;
1575 c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
1576 c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
1577 if ((rc = ops->read_emulated(register_address(
1578 c->override_base ? *c->override_base :
1579 ctxt->ds_base,
1580 c->regs[VCPU_REGS_RSI]),
1581 &c->dst.val,
1582 c->dst.bytes,
1583 ctxt->vcpu)) != 0)
1584 goto done;
1585 register_address_increment(c->regs[VCPU_REGS_RSI],
1586 (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
1587 : c->dst.bytes);
1588 break;
1589 case 0xae ... 0xaf: /* scas */
1590 DPRINTF("Urk! I don't handle SCAS.\n");
1591 goto cannot_emulate;
1592 case 0xe8: /* call (near) */ {
1593 long int rel;
1594 switch (c->op_bytes) {
1595 case 2:
1596 rel = insn_fetch(s16, 2, c->eip);
1597 break;
1598 case 4:
1599 rel = insn_fetch(s32, 4, c->eip);
1600 break;
1601 default:
1602 DPRINTF("Call: Invalid op_bytes\n");
1603 goto cannot_emulate;
1604 }
1605 c->src.val = (unsigned long) c->eip;
1606 JMP_REL(rel);
1607 c->op_bytes = c->ad_bytes;
1608 emulate_push(ctxt);
1609 break;
1610 }
1611 case 0xe9: /* jmp rel */
1612 case 0xeb: /* jmp rel short */
1613 JMP_REL(c->src.val);
1614 c->dst.type = OP_NONE; /* Disable writeback. */
1615 break;
1616
1617
1618 }
1619 goto writeback;
1620
1621twobyte_insn:
1622 switch (c->b) {
1623 case 0x01: /* lgdt, lidt, lmsw */
1624 switch (c->modrm_reg) {
1625 u16 size;
1626 unsigned long address;
1627
1628 case 0: /* vmcall */
1629 if (c->modrm_mod != 3 || c->modrm_rm != 1)
1630 goto cannot_emulate;
1631
1632 rc = kvm_fix_hypercall(ctxt->vcpu);
1633 if (rc)
1634 goto done;
1635
1636 kvm_emulate_hypercall(ctxt->vcpu);
1637 break;
1638 case 2: /* lgdt */
1639 rc = read_descriptor(ctxt, ops, c->src.ptr,
1640 &size, &address, c->op_bytes);
1641 if (rc)
1642 goto done;
1643 realmode_lgdt(ctxt->vcpu, size, address);
1644 break;
1645 case 3: /* lidt/vmmcall */
1646 if (c->modrm_mod == 3 && c->modrm_rm == 1) {
1647 rc = kvm_fix_hypercall(ctxt->vcpu);
1648 if (rc)
1649 goto done;
1650 kvm_emulate_hypercall(ctxt->vcpu);
1651 } else {
1652 rc = read_descriptor(ctxt, ops, c->src.ptr,
1653 &size, &address,
1654 c->op_bytes);
1655 if (rc)
1656 goto done;
1657 realmode_lidt(ctxt->vcpu, size, address);
1658 }
1659 break;
1660 case 4: /* smsw */
1661 if (c->modrm_mod != 3)
1662 goto cannot_emulate;
1663 *(u16 *)&c->regs[c->modrm_rm]
1664 = realmode_get_cr(ctxt->vcpu, 0);
1665 break;
1666 case 6: /* lmsw */
1667 if (c->modrm_mod != 3)
1668 goto cannot_emulate;
1669 realmode_lmsw(ctxt->vcpu, (u16)c->modrm_val,
1670 &ctxt->eflags);
1671 break;
1672 case 7: /* invlpg*/
1673 emulate_invlpg(ctxt->vcpu, cr2);
1674 break;
1675 default:
1676 goto cannot_emulate;
1677 }
1678 /* Disable writeback. */
1679 c->dst.type = OP_NONE;
1680 break;
1681 case 0x21: /* mov from dr to reg */
1682 if (c->modrm_mod != 3)
1683 goto cannot_emulate;
1684 rc = emulator_get_dr(ctxt, c->modrm_reg, &c->regs[c->modrm_rm]);
1685 if (rc)
1686 goto cannot_emulate;
1687 c->dst.type = OP_NONE; /* no writeback */
1688 break;
1689 case 0x23: /* mov from reg to dr */
1690 if (c->modrm_mod != 3)
1691 goto cannot_emulate;
1692 rc = emulator_set_dr(ctxt, c->modrm_reg,
1693 c->regs[c->modrm_rm]);
1694 if (rc)
1695 goto cannot_emulate;
1696 c->dst.type = OP_NONE; /* no writeback */
1697 break;
1698 case 0x40 ... 0x4f: /* cmov */
1699 c->dst.val = c->dst.orig_val = c->src.val;
1700 if (!test_cc(c->b, ctxt->eflags))
1701 c->dst.type = OP_NONE; /* no writeback */
1702 break;
1703 case 0xa3:
1704 bt: /* bt */
1705 c->dst.type = OP_NONE;
1706 /* only subword offset */
1707 c->src.val &= (c->dst.bytes << 3) - 1;
1708 emulate_2op_SrcV_nobyte("bt", c->src, c->dst, ctxt->eflags);
1709 break;
1710 case 0xab:
1711 bts: /* bts */
1712 /* only subword offset */
1713 c->src.val &= (c->dst.bytes << 3) - 1;
1714 emulate_2op_SrcV_nobyte("bts", c->src, c->dst, ctxt->eflags);
1715 break;
1716 case 0xb0 ... 0xb1: /* cmpxchg */
1717 /*
1718 * Save real source value, then compare EAX against
1719 * destination.
1720 */
1721 c->src.orig_val = c->src.val;
1722 c->src.val = c->regs[VCPU_REGS_RAX];
1723 emulate_2op_SrcV("cmp", c->src, c->dst, ctxt->eflags);
1724 if (ctxt->eflags & EFLG_ZF) {
1725 /* Success: write back to memory. */
1726 c->dst.val = c->src.orig_val;
1727 } else {
1728 /* Failure: write the value we saw to EAX. */
1729 c->dst.type = OP_REG;
1730 c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
1731 }
1732 break;
1733 case 0xb3:
1734 btr: /* btr */
1735 /* only subword offset */
1736 c->src.val &= (c->dst.bytes << 3) - 1;
1737 emulate_2op_SrcV_nobyte("btr", c->src, c->dst, ctxt->eflags);
1738 break;
1739 case 0xb6 ... 0xb7: /* movzx */
1740 c->dst.bytes = c->op_bytes;
1741 c->dst.val = (c->d & ByteOp) ? (u8) c->src.val
1742 : (u16) c->src.val;
1743 break;
1744 case 0xba: /* Grp8 */
1745 switch (c->modrm_reg & 3) {
1746 case 0:
1747 goto bt;
1748 case 1:
1749 goto bts;
1750 case 2:
1751 goto btr;
1752 case 3:
1753 goto btc;
1754 }
1755 break;
1756 case 0xbb:
1757 btc: /* btc */
1758 /* only subword offset */
1759 c->src.val &= (c->dst.bytes << 3) - 1;
1760 emulate_2op_SrcV_nobyte("btc", c->src, c->dst, ctxt->eflags);
1761 break;
1762 case 0xbe ... 0xbf: /* movsx */
1763 c->dst.bytes = c->op_bytes;
1764 c->dst.val = (c->d & ByteOp) ? (s8) c->src.val :
1765 (s16) c->src.val;
1766 break;
1767 case 0xc3: /* movnti */
1768 c->dst.bytes = c->op_bytes;
1769 c->dst.val = (c->op_bytes == 4) ? (u32) c->src.val :
1770 (u64) c->src.val;
1771 break;
1772 }
1773 goto writeback;
1774
1775twobyte_special_insn:
1776 switch (c->b) {
1777 case 0x06:
1778 emulate_clts(ctxt->vcpu);
1779 break;
1780 case 0x08: /* invd */
1781 break;
1782 case 0x09: /* wbinvd */
1783 break;
1784 case 0x0d: /* GrpP (prefetch) */
1785 case 0x18: /* Grp16 (prefetch/nop) */
1786 break;
1787 case 0x20: /* mov cr, reg */
1788 if (c->modrm_mod != 3)
1789 goto cannot_emulate;
1790 c->regs[c->modrm_rm] =
1791 realmode_get_cr(ctxt->vcpu, c->modrm_reg);
1792 break;
1793 case 0x22: /* mov reg, cr */
1794 if (c->modrm_mod != 3)
1795 goto cannot_emulate;
1796 realmode_set_cr(ctxt->vcpu,
1797 c->modrm_reg, c->modrm_val, &ctxt->eflags);
1798 break;
1799 case 0x30:
1800 /* wrmsr */
1801 msr_data = (u32)c->regs[VCPU_REGS_RAX]
1802 | ((u64)c->regs[VCPU_REGS_RDX] << 32);
1803 rc = kvm_set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data);
1804 if (rc) {
1805 kvm_x86_ops->inject_gp(ctxt->vcpu, 0);
1806 c->eip = ctxt->vcpu->rip;
1807 }
1808 rc = X86EMUL_CONTINUE;
1809 break;
1810 case 0x32:
1811 /* rdmsr */
1812 rc = kvm_get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], &msr_data);
1813 if (rc) {
1814 kvm_x86_ops->inject_gp(ctxt->vcpu, 0);
1815 c->eip = ctxt->vcpu->rip;
1816 } else {
1817 c->regs[VCPU_REGS_RAX] = (u32)msr_data;
1818 c->regs[VCPU_REGS_RDX] = msr_data >> 32;
1819 }
1820 rc = X86EMUL_CONTINUE;
1821 break;
1822 case 0x80 ... 0x8f: /* jnz rel, etc*/ {
1823 long int rel;
1824
1825 switch (c->op_bytes) {
1826 case 2:
1827 rel = insn_fetch(s16, 2, c->eip);
1828 break;
1829 case 4:
1830 rel = insn_fetch(s32, 4, c->eip);
1831 break;
1832 case 8:
1833 rel = insn_fetch(s64, 8, c->eip);
1834 break;
1835 default:
1836 DPRINTF("jnz: Invalid op_bytes\n");
1837 goto cannot_emulate;
1838 }
1839 if (test_cc(c->b, ctxt->eflags))
1840 JMP_REL(rel);
1841 break;
1842 }
1843 case 0xc7: /* Grp9 (cmpxchg8b) */
1844 rc = emulate_grp9(ctxt, ops, cr2);
1845 if (rc != 0)
1846 goto done;
1847 break;
1848 }
1849 /* Disable writeback. */
1850 c->dst.type = OP_NONE;
1851 goto writeback;
1852
1853cannot_emulate:
1854 DPRINTF("Cannot emulate %02x\n", c->b);
1855 c->eip = saved_eip;
1856 return -1;
1857}