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)(unsigned long addr, void *val,
96 unsigned int bytes, struct kvm_vcpu *vcpu,
97 struct x86_exception *fault);
100 * write_std: Write bytes of standard (non-emulated/special) memory.
101 * Used for descriptor writing.
102 * @addr: [IN ] Linear address to which to write.
103 * @val: [OUT] Value write to memory, zero-extended to 'u_long'.
104 * @bytes: [IN ] Number of bytes to write to memory.
106 int (*write_std)(unsigned long addr, void *val,
107 unsigned int bytes, struct kvm_vcpu *vcpu,
108 struct x86_exception *fault);
110 * fetch: Read bytes of standard (non-emulated/special) memory.
111 * Used for instruction fetch.
112 * @addr: [IN ] Linear address from which to read.
113 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
114 * @bytes: [IN ] Number of bytes to read from memory.
116 int (*fetch)(unsigned long addr, void *val,
117 unsigned int bytes, struct kvm_vcpu *vcpu,
118 struct x86_exception *fault);
121 * read_emulated: Read bytes from emulated/special memory area.
122 * @addr: [IN ] Linear address from which to read.
123 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
124 * @bytes: [IN ] Number of bytes to read from memory.
126 int (*read_emulated)(unsigned long addr,
129 struct x86_exception *fault,
130 struct kvm_vcpu *vcpu);
133 * write_emulated: Write bytes to emulated/special memory area.
134 * @addr: [IN ] Linear address to which to write.
135 * @val: [IN ] Value to write to memory (low-order bytes used as
137 * @bytes: [IN ] Number of bytes to write to memory.
139 int (*write_emulated)(unsigned long addr,
142 struct x86_exception *fault,
143 struct kvm_vcpu *vcpu);
146 * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
147 * emulated/special memory area.
148 * @addr: [IN ] Linear address to access.
149 * @old: [IN ] Value expected to be current at @addr.
150 * @new: [IN ] Value to write to @addr.
151 * @bytes: [IN ] Number of bytes to access using CMPXCHG.
153 int (*cmpxchg_emulated)(unsigned long addr,
157 struct x86_exception *fault,
158 struct kvm_vcpu *vcpu);
160 int (*pio_in_emulated)(int size, unsigned short port, void *val,
161 unsigned int count, struct kvm_vcpu *vcpu);
163 int (*pio_out_emulated)(int size, unsigned short port, const void *val,
164 unsigned int count, struct kvm_vcpu *vcpu);
166 bool (*get_cached_descriptor)(struct desc_struct *desc, u32 *base3,
167 int seg, struct kvm_vcpu *vcpu);
168 void (*set_cached_descriptor)(struct desc_struct *desc, u32 base3,
169 int seg, struct kvm_vcpu *vcpu);
170 u16 (*get_segment_selector)(int seg, struct kvm_vcpu *vcpu);
171 void (*set_segment_selector)(u16 sel, int seg, struct kvm_vcpu *vcpu);
172 unsigned long (*get_cached_segment_base)(int seg, struct kvm_vcpu *vcpu);
173 void (*get_gdt)(struct desc_ptr *dt, struct kvm_vcpu *vcpu);
174 void (*get_idt)(struct desc_ptr *dt, struct kvm_vcpu *vcpu);
175 ulong (*get_cr)(int cr, struct kvm_vcpu *vcpu);
176 int (*set_cr)(int cr, ulong val, struct kvm_vcpu *vcpu);
177 int (*cpl)(struct kvm_vcpu *vcpu);
178 int (*get_dr)(int dr, unsigned long *dest, struct kvm_vcpu *vcpu);
179 int (*set_dr)(int dr, unsigned long value, struct kvm_vcpu *vcpu);
180 int (*set_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 data);
181 int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata);
182 void (*get_fpu)(struct x86_emulate_ctxt *ctxt); /* disables preempt */
183 void (*put_fpu)(struct x86_emulate_ctxt *ctxt); /* reenables preempt */
184 int (*intercept)(struct kvm_vcpu *vcpu,
185 struct x86_instruction_info *info,
186 enum x86_intercept_stage stage);
189 typedef u32 __attribute__((vector_size(16))) sse128_t;
191 /* Type, address-of, and value of an instruction's operand. */
193 enum { OP_REG, OP_MEM, OP_IMM, OP_XMM, OP_NONE } type;
196 unsigned long orig_val;
201 struct segmented_address {
210 char valptr[sizeof(unsigned long) + 2];
227 struct decode_cache {
239 bool has_seg_override;
242 int (*execute)(struct x86_emulate_ctxt *ctxt);
243 int (*check_perm)(struct x86_emulate_ctxt *ctxt);
244 unsigned long regs[NR_VCPU_REGS];
253 struct fetch_cache fetch;
254 struct read_cache io_read;
255 struct read_cache mem_read;
258 struct x86_emulate_ctxt {
259 struct x86_emulate_ops *ops;
261 /* Register state before/after emulation. */
262 struct kvm_vcpu *vcpu;
264 unsigned long eflags;
265 unsigned long eip; /* eip before instruction emulation */
266 /* Emulated execution mode, represented by an X86EMUL_MODE value. */
270 /* interruptibility state, as a result of execution of STI or MOV SS */
271 int interruptibility;
273 bool guest_mode; /* guest running a nested guest */
274 bool perm_ok; /* do not check permissions if true */
275 bool only_vendor_specific_insn;
278 struct x86_exception exception;
281 struct decode_cache decode;
284 /* Repeat String Operation Prefix */
285 #define REPE_PREFIX 0xf3
286 #define REPNE_PREFIX 0xf2
288 /* Execution mode, passed to the emulator. */
289 #define X86EMUL_MODE_REAL 0 /* Real mode. */
290 #define X86EMUL_MODE_VM86 1 /* Virtual 8086 mode. */
291 #define X86EMUL_MODE_PROT16 2 /* 16-bit protected mode. */
292 #define X86EMUL_MODE_PROT32 4 /* 32-bit protected mode. */
293 #define X86EMUL_MODE_PROT64 8 /* 64-bit (long) mode. */
295 /* any protected mode */
296 #define X86EMUL_MODE_PROT (X86EMUL_MODE_PROT16|X86EMUL_MODE_PROT32| \
299 enum x86_intercept_stage {
301 X86_ICPT_POST_EXCEPT,
302 X86_ICPT_POST_MEMACCESS,
307 x86_intercept_cr_read,
308 x86_intercept_cr_write,
331 x86_intercept_invlpg,
332 x86_intercept_invlpga,
334 x86_intercept_vmload,
335 x86_intercept_vmsave,
336 x86_intercept_vmmcall,
339 x86_intercept_skinit,
340 x86_intercept_rdtscp,
342 x86_intercept_wbinvd,
343 x86_intercept_monitor,
349 /* Host execution mode. */
350 #if defined(CONFIG_X86_32)
351 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
352 #elif defined(CONFIG_X86_64)
353 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
356 int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len);
357 #define EMULATION_FAILED -1
358 #define EMULATION_OK 0
359 #define EMULATION_RESTART 1
360 #define EMULATION_INTERCEPTED 2
361 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt);
362 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
363 u16 tss_selector, int reason,
364 bool has_error_code, u32 error_code);
365 int emulate_int_real(struct x86_emulate_ctxt *ctxt,
366 struct x86_emulate_ops *ops, int irq);
367 #endif /* _ASM_X86_KVM_X86_EMULATE_H */