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1/* SPDX-License-Identifier: GPL-2.0 */
2/******************************************************************************
3 * x86_emulate.h
4 *
5 * Generic x86 (32-bit and 64-bit) instruction decoder and emulator.
6 *
7 * Copyright (c) 2005 Keir Fraser
8 *
9 * From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4
10 */
11
12#ifndef _ASM_X86_KVM_X86_EMULATE_H
13#define _ASM_X86_KVM_X86_EMULATE_H
14
15#include <asm/desc_defs.h>
16#include "fpu.h"
17
18struct x86_emulate_ctxt;
19enum x86_intercept;
20enum x86_intercept_stage;
21
22struct x86_exception {
23 u8 vector;
24 bool error_code_valid;
25 u16 error_code;
26 bool nested_page_fault;
27 u64 address; /* cr2 or nested page fault gpa */
28 u8 async_page_fault;
29 unsigned long exit_qualification;
30};
31
32/*
33 * This struct is used to carry enough information from the instruction
34 * decoder to main KVM so that a decision can be made whether the
35 * instruction needs to be intercepted or not.
36 */
37struct x86_instruction_info {
38 u8 intercept; /* which intercept */
39 u8 rep_prefix; /* rep prefix? */
40 u8 modrm_mod; /* mod part of modrm */
41 u8 modrm_reg; /* index of register used */
42 u8 modrm_rm; /* rm part of modrm */
43 u64 src_val; /* value of source operand */
44 u64 dst_val; /* value of destination operand */
45 u8 src_bytes; /* size of source operand */
46 u8 dst_bytes; /* size of destination operand */
47 u8 ad_bytes; /* size of src/dst address */
48 u64 next_rip; /* rip following the instruction */
49};
50
51/*
52 * x86_emulate_ops:
53 *
54 * These operations represent the instruction emulator's interface to memory.
55 * There are two categories of operation: those that act on ordinary memory
56 * regions (*_std), and those that act on memory regions known to require
57 * special treatment or emulation (*_emulated).
58 *
59 * The emulator assumes that an instruction accesses only one 'emulated memory'
60 * location, that this location is the given linear faulting address (cr2), and
61 * that this is one of the instruction's data operands. Instruction fetches and
62 * stack operations are assumed never to access emulated memory. The emulator
63 * automatically deduces which operand of a string-move operation is accessing
64 * emulated memory, and assumes that the other operand accesses normal memory.
65 *
66 * NOTES:
67 * 1. The emulator isn't very smart about emulated vs. standard memory.
68 * 'Emulated memory' access addresses should be checked for sanity.
69 * 'Normal memory' accesses may fault, and the caller must arrange to
70 * detect and handle reentrancy into the emulator via recursive faults.
71 * Accesses may be unaligned and may cross page boundaries.
72 * 2. If the access fails (cannot emulate, or a standard access faults) then
73 * it is up to the memop to propagate the fault to the guest VM via
74 * some out-of-band mechanism, unknown to the emulator. The memop signals
75 * failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
76 * then immediately bail.
77 * 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
78 * cmpxchg8b_emulated need support 8-byte accesses.
79 * 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
80 */
81/* Access completed successfully: continue emulation as normal. */
82#define X86EMUL_CONTINUE 0
83/* Access is unhandleable: bail from emulation and return error to caller. */
84#define X86EMUL_UNHANDLEABLE 1
85/* Terminate emulation but return success to the caller. */
86#define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
87#define X86EMUL_RETRY_INSTR 3 /* retry the instruction for some reason */
88#define X86EMUL_CMPXCHG_FAILED 4 /* cmpxchg did not see expected value */
89#define X86EMUL_IO_NEEDED 5 /* IO is needed to complete emulation */
90#define X86EMUL_INTERCEPTED 6 /* Intercepted by nested VMCB/VMCS */
91
92/* x86-specific emulation flags */
93#define X86EMUL_F_WRITE BIT(0)
94#define X86EMUL_F_FETCH BIT(1)
95#define X86EMUL_F_IMPLICIT BIT(2)
96#define X86EMUL_F_INVLPG BIT(3)
97#define X86EMUL_F_MSR BIT(4)
98#define X86EMUL_F_DT_LOAD BIT(5)
99
100struct x86_emulate_ops {
101 void (*vm_bugged)(struct x86_emulate_ctxt *ctxt);
102 /*
103 * read_gpr: read a general purpose register (rax - r15)
104 *
105 * @reg: gpr number.
106 */
107 ulong (*read_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg);
108 /*
109 * write_gpr: write a general purpose register (rax - r15)
110 *
111 * @reg: gpr number.
112 * @val: value to write.
113 */
114 void (*write_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val);
115 /*
116 * read_std: Read bytes of standard (non-emulated/special) memory.
117 * Used for descriptor reading.
118 * @addr: [IN ] Linear address from which to read.
119 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
120 * @bytes: [IN ] Number of bytes to read from memory.
121 * @system:[IN ] Whether the access is forced to be at CPL0.
122 */
123 int (*read_std)(struct x86_emulate_ctxt *ctxt,
124 unsigned long addr, void *val,
125 unsigned int bytes,
126 struct x86_exception *fault, bool system);
127
128 /*
129 * write_std: Write bytes of standard (non-emulated/special) memory.
130 * Used for descriptor writing.
131 * @addr: [IN ] Linear address to which to write.
132 * @val: [OUT] Value write to memory, zero-extended to 'u_long'.
133 * @bytes: [IN ] Number of bytes to write to memory.
134 * @system:[IN ] Whether the access is forced to be at CPL0.
135 */
136 int (*write_std)(struct x86_emulate_ctxt *ctxt,
137 unsigned long addr, void *val, unsigned int bytes,
138 struct x86_exception *fault, bool system);
139 /*
140 * fetch: Read bytes of standard (non-emulated/special) memory.
141 * Used for instruction fetch.
142 * @addr: [IN ] Linear address from which to read.
143 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
144 * @bytes: [IN ] Number of bytes to read from memory.
145 */
146 int (*fetch)(struct x86_emulate_ctxt *ctxt,
147 unsigned long addr, void *val, unsigned int bytes,
148 struct x86_exception *fault);
149
150 /*
151 * read_emulated: Read bytes from emulated/special memory area.
152 * @addr: [IN ] Linear address from which to read.
153 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
154 * @bytes: [IN ] Number of bytes to read from memory.
155 */
156 int (*read_emulated)(struct x86_emulate_ctxt *ctxt,
157 unsigned long addr, void *val, unsigned int bytes,
158 struct x86_exception *fault);
159
160 /*
161 * write_emulated: Write bytes to emulated/special memory area.
162 * @addr: [IN ] Linear address to which to write.
163 * @val: [IN ] Value to write to memory (low-order bytes used as
164 * required).
165 * @bytes: [IN ] Number of bytes to write to memory.
166 */
167 int (*write_emulated)(struct x86_emulate_ctxt *ctxt,
168 unsigned long addr, const void *val,
169 unsigned int bytes,
170 struct x86_exception *fault);
171
172 /*
173 * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
174 * emulated/special memory area.
175 * @addr: [IN ] Linear address to access.
176 * @old: [IN ] Value expected to be current at @addr.
177 * @new: [IN ] Value to write to @addr.
178 * @bytes: [IN ] Number of bytes to access using CMPXCHG.
179 */
180 int (*cmpxchg_emulated)(struct x86_emulate_ctxt *ctxt,
181 unsigned long addr,
182 const void *old,
183 const void *new,
184 unsigned int bytes,
185 struct x86_exception *fault);
186 void (*invlpg)(struct x86_emulate_ctxt *ctxt, ulong addr);
187
188 int (*pio_in_emulated)(struct x86_emulate_ctxt *ctxt,
189 int size, unsigned short port, void *val,
190 unsigned int count);
191
192 int (*pio_out_emulated)(struct x86_emulate_ctxt *ctxt,
193 int size, unsigned short port, const void *val,
194 unsigned int count);
195
196 bool (*get_segment)(struct x86_emulate_ctxt *ctxt, u16 *selector,
197 struct desc_struct *desc, u32 *base3, int seg);
198 void (*set_segment)(struct x86_emulate_ctxt *ctxt, u16 selector,
199 struct desc_struct *desc, u32 base3, int seg);
200 unsigned long (*get_cached_segment_base)(struct x86_emulate_ctxt *ctxt,
201 int seg);
202 void (*get_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
203 void (*get_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
204 void (*set_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
205 void (*set_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
206 ulong (*get_cr)(struct x86_emulate_ctxt *ctxt, int cr);
207 int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val);
208 int (*cpl)(struct x86_emulate_ctxt *ctxt);
209 ulong (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr);
210 int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
211 int (*set_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data);
212 int (*get_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
213 int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
214 int (*check_rdpmc_early)(struct x86_emulate_ctxt *ctxt, u32 pmc);
215 int (*read_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc, u64 *pdata);
216 void (*halt)(struct x86_emulate_ctxt *ctxt);
217 void (*wbinvd)(struct x86_emulate_ctxt *ctxt);
218 int (*fix_hypercall)(struct x86_emulate_ctxt *ctxt);
219 int (*intercept)(struct x86_emulate_ctxt *ctxt,
220 struct x86_instruction_info *info,
221 enum x86_intercept_stage stage);
222
223 bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt, u32 *eax, u32 *ebx,
224 u32 *ecx, u32 *edx, bool exact_only);
225 bool (*guest_has_movbe)(struct x86_emulate_ctxt *ctxt);
226 bool (*guest_has_fxsr)(struct x86_emulate_ctxt *ctxt);
227 bool (*guest_has_rdpid)(struct x86_emulate_ctxt *ctxt);
228 bool (*guest_cpuid_is_intel_compatible)(struct x86_emulate_ctxt *ctxt);
229
230 void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked);
231
232 bool (*is_smm)(struct x86_emulate_ctxt *ctxt);
233 bool (*is_guest_mode)(struct x86_emulate_ctxt *ctxt);
234 int (*leave_smm)(struct x86_emulate_ctxt *ctxt);
235 void (*triple_fault)(struct x86_emulate_ctxt *ctxt);
236 int (*set_xcr)(struct x86_emulate_ctxt *ctxt, u32 index, u64 xcr);
237
238 gva_t (*get_untagged_addr)(struct x86_emulate_ctxt *ctxt, gva_t addr,
239 unsigned int flags);
240
241 bool (*is_canonical_addr)(struct x86_emulate_ctxt *ctxt, gva_t addr,
242 unsigned int flags);
243};
244
245/* Type, address-of, and value of an instruction's operand. */
246struct operand {
247 enum { OP_REG, OP_MEM, OP_MEM_STR, OP_IMM, OP_XMM, OP_MM, OP_NONE } type;
248 unsigned int bytes;
249 unsigned int count;
250 union {
251 unsigned long orig_val;
252 u64 orig_val64;
253 };
254 union {
255 unsigned long *reg;
256 struct segmented_address {
257 ulong ea;
258 unsigned seg;
259 } mem;
260 unsigned xmm;
261 unsigned mm;
262 } addr;
263 union {
264 unsigned long val;
265 u64 val64;
266 char valptr[sizeof(sse128_t)];
267 sse128_t vec_val;
268 u64 mm_val;
269 void *data;
270 };
271};
272
273struct fetch_cache {
274 u8 data[15];
275 u8 *ptr;
276 u8 *end;
277};
278
279struct read_cache {
280 u8 data[1024];
281 unsigned long pos;
282 unsigned long end;
283};
284
285/* Execution mode, passed to the emulator. */
286enum x86emul_mode {
287 X86EMUL_MODE_REAL, /* Real mode. */
288 X86EMUL_MODE_VM86, /* Virtual 8086 mode. */
289 X86EMUL_MODE_PROT16, /* 16-bit protected mode. */
290 X86EMUL_MODE_PROT32, /* 32-bit protected mode. */
291 X86EMUL_MODE_PROT64, /* 64-bit (long) mode. */
292};
293
294/*
295 * fastop functions are declared as taking a never-defined fastop parameter,
296 * so they can't be called from C directly.
297 */
298struct fastop;
299
300typedef void (*fastop_t)(struct fastop *);
301
302/*
303 * The emulator's _regs array tracks only the GPRs, i.e. excludes RIP. RIP is
304 * tracked/accessed via _eip, and except for RIP relative addressing, which
305 * also uses _eip, RIP cannot be a register operand nor can it be an operand in
306 * a ModRM or SIB byte.
307 */
308#ifdef CONFIG_X86_64
309#define NR_EMULATOR_GPRS 16
310#else
311#define NR_EMULATOR_GPRS 8
312#endif
313
314struct x86_emulate_ctxt {
315 void *vcpu;
316 const struct x86_emulate_ops *ops;
317
318 /* Register state before/after emulation. */
319 unsigned long eflags;
320 unsigned long eip; /* eip before instruction emulation */
321 /* Emulated execution mode, represented by an X86EMUL_MODE value. */
322 enum x86emul_mode mode;
323
324 /* interruptibility state, as a result of execution of STI or MOV SS */
325 int interruptibility;
326
327 bool perm_ok; /* do not check permissions if true */
328 bool tf; /* TF value before instruction (after for syscall/sysret) */
329
330 bool have_exception;
331 struct x86_exception exception;
332
333 /* GPA available */
334 bool gpa_available;
335 gpa_t gpa_val;
336
337 /*
338 * decode cache
339 */
340
341 /* current opcode length in bytes */
342 u8 opcode_len;
343 u8 b;
344 u8 intercept;
345 u8 op_bytes;
346 u8 ad_bytes;
347 union {
348 int (*execute)(struct x86_emulate_ctxt *ctxt);
349 fastop_t fop;
350 };
351 int (*check_perm)(struct x86_emulate_ctxt *ctxt);
352
353 bool rip_relative;
354 u8 rex_prefix;
355 u8 lock_prefix;
356 u8 rep_prefix;
357 /* bitmaps of registers in _regs[] that can be read */
358 u16 regs_valid;
359 /* bitmaps of registers in _regs[] that have been written */
360 u16 regs_dirty;
361 /* modrm */
362 u8 modrm;
363 u8 modrm_mod;
364 u8 modrm_reg;
365 u8 modrm_rm;
366 u8 modrm_seg;
367 u8 seg_override;
368 u64 d;
369 unsigned long _eip;
370
371 /* Here begins the usercopy section. */
372 struct operand src;
373 struct operand src2;
374 struct operand dst;
375 struct operand memop;
376 unsigned long _regs[NR_EMULATOR_GPRS];
377 struct operand *memopp;
378 struct fetch_cache fetch;
379 struct read_cache io_read;
380 struct read_cache mem_read;
381 bool is_branch;
382};
383
384#define KVM_EMULATOR_BUG_ON(cond, ctxt) \
385({ \
386 int __ret = (cond); \
387 \
388 if (WARN_ON_ONCE(__ret)) \
389 ctxt->ops->vm_bugged(ctxt); \
390 unlikely(__ret); \
391})
392
393/* Repeat String Operation Prefix */
394#define REPE_PREFIX 0xf3
395#define REPNE_PREFIX 0xf2
396
397/* CPUID vendors */
398#define X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx 0x68747541
399#define X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx 0x444d4163
400#define X86EMUL_CPUID_VENDOR_AuthenticAMD_edx 0x69746e65
401
402#define X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx 0x69444d41
403#define X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx 0x21726574
404#define X86EMUL_CPUID_VENDOR_AMDisbetterI_edx 0x74656273
405
406#define X86EMUL_CPUID_VENDOR_HygonGenuine_ebx 0x6f677948
407#define X86EMUL_CPUID_VENDOR_HygonGenuine_ecx 0x656e6975
408#define X86EMUL_CPUID_VENDOR_HygonGenuine_edx 0x6e65476e
409
410#define X86EMUL_CPUID_VENDOR_GenuineIntel_ebx 0x756e6547
411#define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e
412#define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69
413
414#define X86EMUL_CPUID_VENDOR_CentaurHauls_ebx 0x746e6543
415#define X86EMUL_CPUID_VENDOR_CentaurHauls_ecx 0x736c7561
416#define X86EMUL_CPUID_VENDOR_CentaurHauls_edx 0x48727561
417
418static inline bool is_guest_vendor_intel(u32 ebx, u32 ecx, u32 edx)
419{
420 return ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx &&
421 ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx &&
422 edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx;
423}
424
425static inline bool is_guest_vendor_amd(u32 ebx, u32 ecx, u32 edx)
426{
427 return (ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx &&
428 ecx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx &&
429 edx == X86EMUL_CPUID_VENDOR_AuthenticAMD_edx) ||
430 (ebx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx &&
431 ecx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx &&
432 edx == X86EMUL_CPUID_VENDOR_AMDisbetterI_edx);
433}
434
435static inline bool is_guest_vendor_hygon(u32 ebx, u32 ecx, u32 edx)
436{
437 return ebx == X86EMUL_CPUID_VENDOR_HygonGenuine_ebx &&
438 ecx == X86EMUL_CPUID_VENDOR_HygonGenuine_ecx &&
439 edx == X86EMUL_CPUID_VENDOR_HygonGenuine_edx;
440}
441
442enum x86_intercept_stage {
443 X86_ICTP_NONE = 0, /* Allow zero-init to not match anything */
444 X86_ICPT_PRE_EXCEPT,
445 X86_ICPT_POST_EXCEPT,
446 X86_ICPT_POST_MEMACCESS,
447};
448
449enum x86_intercept {
450 x86_intercept_none,
451 x86_intercept_cr_read,
452 x86_intercept_cr_write,
453 x86_intercept_clts,
454 x86_intercept_lmsw,
455 x86_intercept_smsw,
456 x86_intercept_dr_read,
457 x86_intercept_dr_write,
458 x86_intercept_lidt,
459 x86_intercept_sidt,
460 x86_intercept_lgdt,
461 x86_intercept_sgdt,
462 x86_intercept_lldt,
463 x86_intercept_sldt,
464 x86_intercept_ltr,
465 x86_intercept_str,
466 x86_intercept_rdtsc,
467 x86_intercept_rdpmc,
468 x86_intercept_pushf,
469 x86_intercept_popf,
470 x86_intercept_cpuid,
471 x86_intercept_rsm,
472 x86_intercept_iret,
473 x86_intercept_intn,
474 x86_intercept_invd,
475 x86_intercept_pause,
476 x86_intercept_hlt,
477 x86_intercept_invlpg,
478 x86_intercept_invlpga,
479 x86_intercept_vmrun,
480 x86_intercept_vmload,
481 x86_intercept_vmsave,
482 x86_intercept_vmmcall,
483 x86_intercept_stgi,
484 x86_intercept_clgi,
485 x86_intercept_skinit,
486 x86_intercept_rdtscp,
487 x86_intercept_rdpid,
488 x86_intercept_icebp,
489 x86_intercept_wbinvd,
490 x86_intercept_monitor,
491 x86_intercept_mwait,
492 x86_intercept_rdmsr,
493 x86_intercept_wrmsr,
494 x86_intercept_in,
495 x86_intercept_ins,
496 x86_intercept_out,
497 x86_intercept_outs,
498 x86_intercept_xsetbv,
499
500 nr_x86_intercepts
501};
502
503/* Host execution mode. */
504#if defined(CONFIG_X86_32)
505#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
506#elif defined(CONFIG_X86_64)
507#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
508#endif
509
510int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len, int emulation_type);
511bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt);
512#define EMULATION_FAILED -1
513#define EMULATION_OK 0
514#define EMULATION_RESTART 1
515#define EMULATION_INTERCEPTED 2
516void init_decode_cache(struct x86_emulate_ctxt *ctxt);
517int x86_emulate_insn(struct x86_emulate_ctxt *ctxt);
518int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
519 u16 tss_selector, int idt_index, int reason,
520 bool has_error_code, u32 error_code);
521int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq);
522void emulator_invalidate_register_cache(struct x86_emulate_ctxt *ctxt);
523void emulator_writeback_register_cache(struct x86_emulate_ctxt *ctxt);
524bool emulator_can_use_gpa(struct x86_emulate_ctxt *ctxt);
525
526static inline ulong reg_read(struct x86_emulate_ctxt *ctxt, unsigned nr)
527{
528 if (KVM_EMULATOR_BUG_ON(nr >= NR_EMULATOR_GPRS, ctxt))
529 nr &= NR_EMULATOR_GPRS - 1;
530
531 if (!(ctxt->regs_valid & (1 << nr))) {
532 ctxt->regs_valid |= 1 << nr;
533 ctxt->_regs[nr] = ctxt->ops->read_gpr(ctxt, nr);
534 }
535 return ctxt->_regs[nr];
536}
537
538static inline ulong *reg_write(struct x86_emulate_ctxt *ctxt, unsigned nr)
539{
540 if (KVM_EMULATOR_BUG_ON(nr >= NR_EMULATOR_GPRS, ctxt))
541 nr &= NR_EMULATOR_GPRS - 1;
542
543 BUILD_BUG_ON(sizeof(ctxt->regs_dirty) * BITS_PER_BYTE < NR_EMULATOR_GPRS);
544 BUILD_BUG_ON(sizeof(ctxt->regs_valid) * BITS_PER_BYTE < NR_EMULATOR_GPRS);
545
546 ctxt->regs_valid |= 1 << nr;
547 ctxt->regs_dirty |= 1 << nr;
548 return &ctxt->_regs[nr];
549}
550
551static inline ulong *reg_rmw(struct x86_emulate_ctxt *ctxt, unsigned nr)
552{
553 reg_read(ctxt, nr);
554 return reg_write(ctxt, nr);
555}
556
557#endif /* _ASM_X86_KVM_X86_EMULATE_H */