1 /******************************************************************************
4 * Generic x86 (32-bit and 64-bit) instruction decoder and emulator.
6 * Copyright (c) 2005 Keir Fraser
8 * From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4
11 #ifndef _ASM_X86_KVM_X86_EMULATE_H
12 #define _ASM_X86_KVM_X86_EMULATE_H
14 #include <asm/desc_defs.h>
16 struct x86_emulate_ctxt;
18 enum x86_intercept_stage;
20 struct x86_exception {
22 bool error_code_valid;
24 bool nested_page_fault;
25 u64 address; /* cr2 or nested page fault gpa */
29 * This struct is used to carry enough information from the instruction
30 * decoder to main KVM so that a decision can be made whether the
31 * instruction needs to be intercepted or not.
33 struct x86_instruction_info {
34 u8 intercept; /* which intercept */
35 u8 rep_prefix; /* rep prefix? */
36 u8 modrm_mod; /* mod part of modrm */
37 u8 modrm_reg; /* index of register used */
38 u8 modrm_rm; /* rm part of modrm */
39 u64 src_val; /* value of source operand */
40 u64 dst_val; /* value of destination operand */
41 u8 src_bytes; /* size of source operand */
42 u8 dst_bytes; /* size of destination operand */
43 u8 ad_bytes; /* size of src/dst address */
44 u64 next_rip; /* rip following the instruction */
50 * These operations represent the instruction emulator's interface to memory.
51 * There are two categories of operation: those that act on ordinary memory
52 * regions (*_std), and those that act on memory regions known to require
53 * special treatment or emulation (*_emulated).
55 * The emulator assumes that an instruction accesses only one 'emulated memory'
56 * location, that this location is the given linear faulting address (cr2), and
57 * that this is one of the instruction's data operands. Instruction fetches and
58 * stack operations are assumed never to access emulated memory. The emulator
59 * automatically deduces which operand of a string-move operation is accessing
60 * emulated memory, and assumes that the other operand accesses normal memory.
63 * 1. The emulator isn't very smart about emulated vs. standard memory.
64 * 'Emulated memory' access addresses should be checked for sanity.
65 * 'Normal memory' accesses may fault, and the caller must arrange to
66 * detect and handle reentrancy into the emulator via recursive faults.
67 * Accesses may be unaligned and may cross page boundaries.
68 * 2. If the access fails (cannot emulate, or a standard access faults) then
69 * it is up to the memop to propagate the fault to the guest VM via
70 * some out-of-band mechanism, unknown to the emulator. The memop signals
71 * failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
72 * then immediately bail.
73 * 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
74 * cmpxchg8b_emulated need support 8-byte accesses.
75 * 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
77 /* Access completed successfully: continue emulation as normal. */
78 #define X86EMUL_CONTINUE 0
79 /* Access is unhandleable: bail from emulation and return error to caller. */
80 #define X86EMUL_UNHANDLEABLE 1
81 /* Terminate emulation but return success to the caller. */
82 #define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
83 #define X86EMUL_RETRY_INSTR 3 /* retry the instruction for some reason */
84 #define X86EMUL_CMPXCHG_FAILED 4 /* cmpxchg did not see expected value */
85 #define X86EMUL_IO_NEEDED 5 /* IO is needed to complete emulation */
86 #define X86EMUL_INTERCEPTED 6 /* Intercepted by nested VMCB/VMCS */
88 struct x86_emulate_ops {
90 * read_gpr: read a general purpose register (rax - r15)
94 ulong (*read_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg);
96 * write_gpr: write a general purpose register (rax - r15)
99 * @val: value to write.
101 void (*write_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val);
103 * read_std: Read bytes of standard (non-emulated/special) memory.
104 * Used for descriptor reading.
105 * @addr: [IN ] Linear address from which to read.
106 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
107 * @bytes: [IN ] Number of bytes to read from memory.
109 int (*read_std)(struct x86_emulate_ctxt *ctxt,
110 unsigned long addr, void *val,
112 struct x86_exception *fault);
115 * write_std: Write bytes of standard (non-emulated/special) memory.
116 * Used for descriptor writing.
117 * @addr: [IN ] Linear address to which to write.
118 * @val: [OUT] Value write to memory, zero-extended to 'u_long'.
119 * @bytes: [IN ] Number of bytes to write to memory.
121 int (*write_std)(struct x86_emulate_ctxt *ctxt,
122 unsigned long addr, void *val, unsigned int bytes,
123 struct x86_exception *fault);
125 * fetch: Read bytes of standard (non-emulated/special) memory.
126 * Used for instruction fetch.
127 * @addr: [IN ] Linear address from which to read.
128 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
129 * @bytes: [IN ] Number of bytes to read from memory.
131 int (*fetch)(struct x86_emulate_ctxt *ctxt,
132 unsigned long addr, void *val, unsigned int bytes,
133 struct x86_exception *fault);
136 * read_emulated: Read bytes from emulated/special memory area.
137 * @addr: [IN ] Linear address from which to read.
138 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
139 * @bytes: [IN ] Number of bytes to read from memory.
141 int (*read_emulated)(struct x86_emulate_ctxt *ctxt,
142 unsigned long addr, void *val, unsigned int bytes,
143 struct x86_exception *fault);
146 * write_emulated: Write bytes to emulated/special memory area.
147 * @addr: [IN ] Linear address to which to write.
148 * @val: [IN ] Value to write to memory (low-order bytes used as
150 * @bytes: [IN ] Number of bytes to write to memory.
152 int (*write_emulated)(struct x86_emulate_ctxt *ctxt,
153 unsigned long addr, const void *val,
155 struct x86_exception *fault);
158 * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
159 * emulated/special memory area.
160 * @addr: [IN ] Linear address to access.
161 * @old: [IN ] Value expected to be current at @addr.
162 * @new: [IN ] Value to write to @addr.
163 * @bytes: [IN ] Number of bytes to access using CMPXCHG.
165 int (*cmpxchg_emulated)(struct x86_emulate_ctxt *ctxt,
170 struct x86_exception *fault);
171 void (*invlpg)(struct x86_emulate_ctxt *ctxt, ulong addr);
173 int (*pio_in_emulated)(struct x86_emulate_ctxt *ctxt,
174 int size, unsigned short port, void *val,
177 int (*pio_out_emulated)(struct x86_emulate_ctxt *ctxt,
178 int size, unsigned short port, const void *val,
181 bool (*get_segment)(struct x86_emulate_ctxt *ctxt, u16 *selector,
182 struct desc_struct *desc, u32 *base3, int seg);
183 void (*set_segment)(struct x86_emulate_ctxt *ctxt, u16 selector,
184 struct desc_struct *desc, u32 base3, int seg);
185 unsigned long (*get_cached_segment_base)(struct x86_emulate_ctxt *ctxt,
187 void (*get_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
188 void (*get_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
189 void (*set_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
190 void (*set_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
191 ulong (*get_cr)(struct x86_emulate_ctxt *ctxt, int cr);
192 int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val);
193 int (*cpl)(struct x86_emulate_ctxt *ctxt);
194 int (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong *dest);
195 int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
196 u64 (*get_smbase)(struct x86_emulate_ctxt *ctxt);
197 void (*set_smbase)(struct x86_emulate_ctxt *ctxt, u64 smbase);
198 int (*set_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data);
199 int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
200 int (*check_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc);
201 int (*read_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc, u64 *pdata);
202 void (*halt)(struct x86_emulate_ctxt *ctxt);
203 void (*wbinvd)(struct x86_emulate_ctxt *ctxt);
204 int (*fix_hypercall)(struct x86_emulate_ctxt *ctxt);
205 void (*get_fpu)(struct x86_emulate_ctxt *ctxt); /* disables preempt */
206 void (*put_fpu)(struct x86_emulate_ctxt *ctxt); /* reenables preempt */
207 int (*intercept)(struct x86_emulate_ctxt *ctxt,
208 struct x86_instruction_info *info,
209 enum x86_intercept_stage stage);
211 void (*get_cpuid)(struct x86_emulate_ctxt *ctxt,
212 u32 *eax, u32 *ebx, u32 *ecx, u32 *edx);
213 void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked);
216 typedef u32 __attribute__((vector_size(16))) sse128_t;
218 /* Type, address-of, and value of an instruction's operand. */
220 enum { OP_REG, OP_MEM, OP_MEM_STR, OP_IMM, OP_XMM, OP_MM, OP_NONE } type;
224 unsigned long orig_val;
229 struct segmented_address {
239 char valptr[sizeof(sse128_t)];
258 /* Execution mode, passed to the emulator. */
260 X86EMUL_MODE_REAL, /* Real mode. */
261 X86EMUL_MODE_VM86, /* Virtual 8086 mode. */
262 X86EMUL_MODE_PROT16, /* 16-bit protected mode. */
263 X86EMUL_MODE_PROT32, /* 32-bit protected mode. */
264 X86EMUL_MODE_PROT64, /* 64-bit (long) mode. */
267 /* These match some of the HF_* flags defined in kvm_host.h */
268 #define X86EMUL_GUEST_MASK (1 << 5) /* VCPU is in guest-mode */
269 #define X86EMUL_SMM_MASK (1 << 6)
270 #define X86EMUL_SMM_INSIDE_NMI_MASK (1 << 7)
272 struct x86_emulate_ctxt {
273 const struct x86_emulate_ops *ops;
275 /* Register state before/after emulation. */
276 unsigned long eflags;
277 unsigned long eip; /* eip before instruction emulation */
278 /* Emulated execution mode, represented by an X86EMUL_MODE value. */
279 enum x86emul_mode mode;
281 /* interruptibility state, as a result of execution of STI or MOV SS */
282 int interruptibility;
285 bool perm_ok; /* do not check permissions if true */
286 bool ud; /* inject an #UD if host doesn't support insn */
289 struct x86_exception exception;
295 /* current opcode length in bytes */
304 int (*execute)(struct x86_emulate_ctxt *ctxt);
305 int (*check_perm)(struct x86_emulate_ctxt *ctxt);
307 * The following six fields are cleared together,
308 * the rest are initialized unconditionally in x86_decode_insn
315 /* bitmaps of registers in _regs[] that can be read */
317 /* bitmaps of registers in _regs[] that have been written */
328 struct operand memop;
329 /* Fields above regs are cleared together. */
330 unsigned long _regs[NR_VCPU_REGS];
331 struct operand *memopp;
332 struct fetch_cache fetch;
333 struct read_cache io_read;
334 struct read_cache mem_read;
337 /* Repeat String Operation Prefix */
338 #define REPE_PREFIX 0xf3
339 #define REPNE_PREFIX 0xf2
342 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx 0x68747541
343 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx 0x444d4163
344 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_edx 0x69746e65
346 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx 0x69444d41
347 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx 0x21726574
348 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_edx 0x74656273
350 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ebx 0x756e6547
351 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e
352 #define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69
354 enum x86_intercept_stage {
355 X86_ICTP_NONE = 0, /* Allow zero-init to not match anything */
357 X86_ICPT_POST_EXCEPT,
358 X86_ICPT_POST_MEMACCESS,
363 x86_intercept_cr_read,
364 x86_intercept_cr_write,
368 x86_intercept_dr_read,
369 x86_intercept_dr_write,
389 x86_intercept_invlpg,
390 x86_intercept_invlpga,
392 x86_intercept_vmload,
393 x86_intercept_vmsave,
394 x86_intercept_vmmcall,
397 x86_intercept_skinit,
398 x86_intercept_rdtscp,
400 x86_intercept_wbinvd,
401 x86_intercept_monitor,
413 /* Host execution mode. */
414 #if defined(CONFIG_X86_32)
415 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
416 #elif defined(CONFIG_X86_64)
417 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
420 int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len);
421 bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt);
422 #define EMULATION_FAILED -1
423 #define EMULATION_OK 0
424 #define EMULATION_RESTART 1
425 #define EMULATION_INTERCEPTED 2
426 void init_decode_cache(struct x86_emulate_ctxt *ctxt);
427 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt);
428 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
429 u16 tss_selector, int idt_index, int reason,
430 bool has_error_code, u32 error_code);
431 int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq);
432 void emulator_invalidate_register_cache(struct x86_emulate_ctxt *ctxt);
433 void emulator_writeback_register_cache(struct x86_emulate_ctxt *ctxt);
435 #endif /* _ASM_X86_KVM_X86_EMULATE_H */