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 u8 src_bytes
; /* size of source operand */
41 u8 dst_bytes
; /* size of destination operand */
42 u8 ad_bytes
; /* size of src/dst address */
43 u64 next_rip
; /* rip following the instruction */
49 * These operations represent the instruction emulator's interface to memory.
50 * There are two categories of operation: those that act on ordinary memory
51 * regions (*_std), and those that act on memory regions known to require
52 * special treatment or emulation (*_emulated).
54 * The emulator assumes that an instruction accesses only one 'emulated memory'
55 * location, that this location is the given linear faulting address (cr2), and
56 * that this is one of the instruction's data operands. Instruction fetches and
57 * stack operations are assumed never to access emulated memory. The emulator
58 * automatically deduces which operand of a string-move operation is accessing
59 * emulated memory, and assumes that the other operand accesses normal memory.
62 * 1. The emulator isn't very smart about emulated vs. standard memory.
63 * 'Emulated memory' access addresses should be checked for sanity.
64 * 'Normal memory' accesses may fault, and the caller must arrange to
65 * detect and handle reentrancy into the emulator via recursive faults.
66 * Accesses may be unaligned and may cross page boundaries.
67 * 2. If the access fails (cannot emulate, or a standard access faults) then
68 * it is up to the memop to propagate the fault to the guest VM via
69 * some out-of-band mechanism, unknown to the emulator. The memop signals
70 * failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
71 * then immediately bail.
72 * 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
73 * cmpxchg8b_emulated need support 8-byte accesses.
74 * 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
76 /* Access completed successfully: continue emulation as normal. */
77 #define X86EMUL_CONTINUE 0
78 /* Access is unhandleable: bail from emulation and return error to caller. */
79 #define X86EMUL_UNHANDLEABLE 1
80 /* Terminate emulation but return success to the caller. */
81 #define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
82 #define X86EMUL_RETRY_INSTR 3 /* retry the instruction for some reason */
83 #define X86EMUL_CMPXCHG_FAILED 4 /* cmpxchg did not see expected value */
84 #define X86EMUL_IO_NEEDED 5 /* IO is needed to complete emulation */
85 #define X86EMUL_INTERCEPTED 6 /* Intercepted by nested VMCB/VMCS */
87 struct x86_emulate_ops
{
89 * read_std: Read bytes of standard (non-emulated/special) memory.
90 * Used for descriptor reading.
91 * @addr: [IN ] Linear address from which to read.
92 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
93 * @bytes: [IN ] Number of bytes to read from memory.
95 int (*read_std
)(struct x86_emulate_ctxt
*ctxt
,
96 unsigned long addr
, void *val
,
98 struct x86_exception
*fault
);
101 * write_std: Write bytes of standard (non-emulated/special) memory.
102 * Used for descriptor writing.
103 * @addr: [IN ] Linear address to which to write.
104 * @val: [OUT] Value write to memory, zero-extended to 'u_long'.
105 * @bytes: [IN ] Number of bytes to write to memory.
107 int (*write_std
)(struct x86_emulate_ctxt
*ctxt
,
108 unsigned long addr
, void *val
, unsigned int bytes
,
109 struct x86_exception
*fault
);
111 * fetch: Read bytes of standard (non-emulated/special) memory.
112 * Used for instruction fetch.
113 * @addr: [IN ] Linear address from which to read.
114 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
115 * @bytes: [IN ] Number of bytes to read from memory.
117 int (*fetch
)(struct x86_emulate_ctxt
*ctxt
,
118 unsigned long addr
, void *val
, unsigned int bytes
,
119 struct x86_exception
*fault
);
122 * read_emulated: Read bytes from emulated/special memory area.
123 * @addr: [IN ] Linear address from which to read.
124 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
125 * @bytes: [IN ] Number of bytes to read from memory.
127 int (*read_emulated
)(struct x86_emulate_ctxt
*ctxt
,
128 unsigned long addr
, void *val
, unsigned int bytes
,
129 struct x86_exception
*fault
);
132 * write_emulated: Write bytes to emulated/special memory area.
133 * @addr: [IN ] Linear address to which to write.
134 * @val: [IN ] Value to write to memory (low-order bytes used as
136 * @bytes: [IN ] Number of bytes to write to memory.
138 int (*write_emulated
)(struct x86_emulate_ctxt
*ctxt
,
139 unsigned long addr
, const void *val
,
141 struct x86_exception
*fault
);
144 * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
145 * emulated/special memory area.
146 * @addr: [IN ] Linear address to access.
147 * @old: [IN ] Value expected to be current at @addr.
148 * @new: [IN ] Value to write to @addr.
149 * @bytes: [IN ] Number of bytes to access using CMPXCHG.
151 int (*cmpxchg_emulated
)(struct x86_emulate_ctxt
*ctxt
,
156 struct x86_exception
*fault
);
158 int (*pio_in_emulated
)(struct x86_emulate_ctxt
*ctxt
,
159 int size
, unsigned short port
, void *val
,
162 int (*pio_out_emulated
)(struct x86_emulate_ctxt
*ctxt
,
163 int size
, unsigned short port
, const void *val
,
166 bool (*get_cached_descriptor
)(struct x86_emulate_ctxt
*ctxt
,
167 struct desc_struct
*desc
, u32
*base3
,
169 void (*set_cached_descriptor
)(struct x86_emulate_ctxt
*ctxt
,
170 struct desc_struct
*desc
, u32 base3
,
172 u16 (*get_segment_selector
)(struct x86_emulate_ctxt
*ctxt
, int seg
);
173 void (*set_segment_selector
)(struct x86_emulate_ctxt
*ctxt
,
175 unsigned long (*get_cached_segment_base
)(struct x86_emulate_ctxt
*ctxt
,
177 void (*get_gdt
)(struct x86_emulate_ctxt
*ctxt
, struct desc_ptr
*dt
);
178 void (*get_idt
)(struct x86_emulate_ctxt
*ctxt
, struct desc_ptr
*dt
);
179 void (*set_gdt
)(struct x86_emulate_ctxt
*ctxt
, struct desc_ptr
*dt
);
180 void (*set_idt
)(struct x86_emulate_ctxt
*ctxt
, struct desc_ptr
*dt
);
181 ulong (*get_cr
)(struct x86_emulate_ctxt
*ctxt
, int cr
);
182 int (*set_cr
)(struct x86_emulate_ctxt
*ctxt
, int cr
, ulong val
);
183 int (*cpl
)(struct x86_emulate_ctxt
*ctxt
);
184 int (*get_dr
)(struct x86_emulate_ctxt
*ctxt
, int dr
, ulong
*dest
);
185 int (*set_dr
)(struct x86_emulate_ctxt
*ctxt
, int dr
, ulong value
);
186 int (*set_msr
)(struct x86_emulate_ctxt
*ctxt
, u32 msr_index
, u64 data
);
187 int (*get_msr
)(struct x86_emulate_ctxt
*ctxt
, u32 msr_index
, u64
*pdata
);
188 void (*get_fpu
)(struct x86_emulate_ctxt
*ctxt
); /* disables preempt */
189 void (*put_fpu
)(struct x86_emulate_ctxt
*ctxt
); /* reenables preempt */
190 int (*intercept
)(struct x86_emulate_ctxt
*ctxt
,
191 struct x86_instruction_info
*info
,
192 enum x86_intercept_stage stage
);
195 typedef u32
__attribute__((vector_size(16))) sse128_t
;
197 /* Type, address-of, and value of an instruction's operand. */
199 enum { OP_REG
, OP_MEM
, OP_IMM
, OP_XMM
, OP_NONE
} type
;
202 unsigned long orig_val
;
207 struct segmented_address
{
216 char valptr
[sizeof(unsigned long) + 2];
233 struct decode_cache
{
245 bool has_seg_override
;
248 int (*execute
)(struct x86_emulate_ctxt
*ctxt
);
249 int (*check_perm
)(struct x86_emulate_ctxt
*ctxt
);
250 unsigned long regs
[NR_VCPU_REGS
];
259 struct fetch_cache fetch
;
260 struct read_cache io_read
;
261 struct read_cache mem_read
;
264 struct x86_emulate_ctxt
{
265 struct x86_emulate_ops
*ops
;
267 /* Register state before/after emulation. */
268 struct kvm_vcpu
*vcpu
;
270 unsigned long eflags
;
271 unsigned long eip
; /* eip before instruction emulation */
272 /* Emulated execution mode, represented by an X86EMUL_MODE value. */
275 /* interruptibility state, as a result of execution of STI or MOV SS */
276 int interruptibility
;
278 bool guest_mode
; /* guest running a nested guest */
279 bool perm_ok
; /* do not check permissions if true */
280 bool only_vendor_specific_insn
;
283 struct x86_exception exception
;
286 struct decode_cache decode
;
289 /* Repeat String Operation Prefix */
290 #define REPE_PREFIX 0xf3
291 #define REPNE_PREFIX 0xf2
293 /* Execution mode, passed to the emulator. */
294 #define X86EMUL_MODE_REAL 0 /* Real mode. */
295 #define X86EMUL_MODE_VM86 1 /* Virtual 8086 mode. */
296 #define X86EMUL_MODE_PROT16 2 /* 16-bit protected mode. */
297 #define X86EMUL_MODE_PROT32 4 /* 32-bit protected mode. */
298 #define X86EMUL_MODE_PROT64 8 /* 64-bit (long) mode. */
300 /* any protected mode */
301 #define X86EMUL_MODE_PROT (X86EMUL_MODE_PROT16|X86EMUL_MODE_PROT32| \
304 enum x86_intercept_stage
{
306 X86_ICPT_POST_EXCEPT
,
307 X86_ICPT_POST_MEMACCESS
,
312 x86_intercept_cr_read
,
313 x86_intercept_cr_write
,
317 x86_intercept_dr_read
,
318 x86_intercept_dr_write
,
338 x86_intercept_invlpg
,
339 x86_intercept_invlpga
,
341 x86_intercept_vmload
,
342 x86_intercept_vmsave
,
343 x86_intercept_vmmcall
,
346 x86_intercept_skinit
,
347 x86_intercept_rdtscp
,
349 x86_intercept_wbinvd
,
350 x86_intercept_monitor
,
362 /* Host execution mode. */
363 #if defined(CONFIG_X86_32)
364 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
365 #elif defined(CONFIG_X86_64)
366 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
369 int x86_decode_insn(struct x86_emulate_ctxt
*ctxt
, void *insn
, int insn_len
);
370 #define EMULATION_FAILED -1
371 #define EMULATION_OK 0
372 #define EMULATION_RESTART 1
373 #define EMULATION_INTERCEPTED 2
374 int x86_emulate_insn(struct x86_emulate_ctxt
*ctxt
);
375 int emulator_task_switch(struct x86_emulate_ctxt
*ctxt
,
376 u16 tss_selector
, int reason
,
377 bool has_error_code
, u32 error_code
);
378 int emulate_int_real(struct x86_emulate_ctxt
*ctxt
,
379 struct x86_emulate_ops
*ops
, int irq
);
380 #endif /* _ASM_X86_KVM_X86_EMULATE_H */