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