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 */
31 * These operations represent the instruction emulator's interface to memory.
32 * There are two categories of operation: those that act on ordinary memory
33 * regions (*_std), and those that act on memory regions known to require
34 * special treatment or emulation (*_emulated).
36 * The emulator assumes that an instruction accesses only one 'emulated memory'
37 * location, that this location is the given linear faulting address (cr2), and
38 * that this is one of the instruction's data operands. Instruction fetches and
39 * stack operations are assumed never to access emulated memory. The emulator
40 * automatically deduces which operand of a string-move operation is accessing
41 * emulated memory, and assumes that the other operand accesses normal memory.
44 * 1. The emulator isn't very smart about emulated vs. standard memory.
45 * 'Emulated memory' access addresses should be checked for sanity.
46 * 'Normal memory' accesses may fault, and the caller must arrange to
47 * detect and handle reentrancy into the emulator via recursive faults.
48 * Accesses may be unaligned and may cross page boundaries.
49 * 2. If the access fails (cannot emulate, or a standard access faults) then
50 * it is up to the memop to propagate the fault to the guest VM via
51 * some out-of-band mechanism, unknown to the emulator. The memop signals
52 * failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
53 * then immediately bail.
54 * 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
55 * cmpxchg8b_emulated need support 8-byte accesses.
56 * 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
58 /* Access completed successfully: continue emulation as normal. */
59 #define X86EMUL_CONTINUE 0
60 /* Access is unhandleable: bail from emulation and return error to caller. */
61 #define X86EMUL_UNHANDLEABLE 1
62 /* Terminate emulation but return success to the caller. */
63 #define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
64 #define X86EMUL_RETRY_INSTR 3 /* retry the instruction for some reason */
65 #define X86EMUL_CMPXCHG_FAILED 4 /* cmpxchg did not see expected value */
66 #define X86EMUL_IO_NEEDED 5 /* IO is needed to complete emulation */
67 #define X86EMUL_INTERCEPTED 6 /* Intercepted by nested VMCB/VMCS */
69 struct x86_emulate_ops {
71 * read_std: Read bytes of standard (non-emulated/special) memory.
72 * Used for descriptor reading.
73 * @addr: [IN ] Linear address from which to read.
74 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
75 * @bytes: [IN ] Number of bytes to read from memory.
77 int (*read_std)(unsigned long addr, void *val,
78 unsigned int bytes, struct kvm_vcpu *vcpu,
79 struct x86_exception *fault);
82 * write_std: Write bytes of standard (non-emulated/special) memory.
83 * Used for descriptor writing.
84 * @addr: [IN ] Linear address to which to write.
85 * @val: [OUT] Value write to memory, zero-extended to 'u_long'.
86 * @bytes: [IN ] Number of bytes to write to memory.
88 int (*write_std)(unsigned long addr, void *val,
89 unsigned int bytes, struct kvm_vcpu *vcpu,
90 struct x86_exception *fault);
92 * fetch: Read bytes of standard (non-emulated/special) memory.
93 * Used for instruction fetch.
94 * @addr: [IN ] Linear address from which to read.
95 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
96 * @bytes: [IN ] Number of bytes to read from memory.
98 int (*fetch)(unsigned long addr, void *val,
99 unsigned int bytes, struct kvm_vcpu *vcpu,
100 struct x86_exception *fault);
103 * read_emulated: Read bytes from emulated/special memory area.
104 * @addr: [IN ] Linear address from which to read.
105 * @val: [OUT] Value read from memory, zero-extended to 'u_long'.
106 * @bytes: [IN ] Number of bytes to read from memory.
108 int (*read_emulated)(unsigned long addr,
111 struct x86_exception *fault,
112 struct kvm_vcpu *vcpu);
115 * write_emulated: Write bytes to emulated/special memory area.
116 * @addr: [IN ] Linear address to which to write.
117 * @val: [IN ] Value to write to memory (low-order bytes used as
119 * @bytes: [IN ] Number of bytes to write to memory.
121 int (*write_emulated)(unsigned long addr,
124 struct x86_exception *fault,
125 struct kvm_vcpu *vcpu);
128 * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
129 * emulated/special memory area.
130 * @addr: [IN ] Linear address to access.
131 * @old: [IN ] Value expected to be current at @addr.
132 * @new: [IN ] Value to write to @addr.
133 * @bytes: [IN ] Number of bytes to access using CMPXCHG.
135 int (*cmpxchg_emulated)(unsigned long addr,
139 struct x86_exception *fault,
140 struct kvm_vcpu *vcpu);
142 int (*pio_in_emulated)(int size, unsigned short port, void *val,
143 unsigned int count, struct kvm_vcpu *vcpu);
145 int (*pio_out_emulated)(int size, unsigned short port, const void *val,
146 unsigned int count, struct kvm_vcpu *vcpu);
148 bool (*get_cached_descriptor)(struct desc_struct *desc, u32 *base3,
149 int seg, struct kvm_vcpu *vcpu);
150 void (*set_cached_descriptor)(struct desc_struct *desc, u32 base3,
151 int seg, struct kvm_vcpu *vcpu);
152 u16 (*get_segment_selector)(int seg, struct kvm_vcpu *vcpu);
153 void (*set_segment_selector)(u16 sel, int seg, struct kvm_vcpu *vcpu);
154 unsigned long (*get_cached_segment_base)(int seg, struct kvm_vcpu *vcpu);
155 void (*get_gdt)(struct desc_ptr *dt, struct kvm_vcpu *vcpu);
156 void (*get_idt)(struct desc_ptr *dt, struct kvm_vcpu *vcpu);
157 ulong (*get_cr)(int cr, struct kvm_vcpu *vcpu);
158 int (*set_cr)(int cr, ulong val, struct kvm_vcpu *vcpu);
159 int (*cpl)(struct kvm_vcpu *vcpu);
160 int (*get_dr)(int dr, unsigned long *dest, struct kvm_vcpu *vcpu);
161 int (*set_dr)(int dr, unsigned long value, struct kvm_vcpu *vcpu);
162 int (*set_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 data);
163 int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata);
164 void (*get_fpu)(struct x86_emulate_ctxt *ctxt); /* disables preempt */
165 void (*put_fpu)(struct x86_emulate_ctxt *ctxt); /* reenables preempt */
166 int (*intercept)(struct x86_emulate_ctxt *ctxt,
167 enum x86_intercept intercept,
168 enum x86_intercept_stage stage);
171 typedef u32 __attribute__((vector_size(16))) sse128_t;
173 /* Type, address-of, and value of an instruction's operand. */
175 enum { OP_REG, OP_MEM, OP_IMM, OP_XMM, OP_NONE } type;
178 unsigned long orig_val;
183 struct segmented_address {
192 char valptr[sizeof(unsigned long) + 2];
209 struct decode_cache {
221 bool has_seg_override;
224 int (*execute)(struct x86_emulate_ctxt *ctxt);
225 unsigned long regs[NR_VCPU_REGS];
234 struct fetch_cache fetch;
235 struct read_cache io_read;
236 struct read_cache mem_read;
239 struct x86_emulate_ctxt {
240 struct x86_emulate_ops *ops;
242 /* Register state before/after emulation. */
243 struct kvm_vcpu *vcpu;
245 unsigned long eflags;
246 unsigned long eip; /* eip before instruction emulation */
247 /* Emulated execution mode, represented by an X86EMUL_MODE value. */
251 /* interruptibility state, as a result of execution of STI or MOV SS */
252 int interruptibility;
254 bool guest_mode; /* guest running a nested guest */
255 bool perm_ok; /* do not check permissions if true */
256 bool only_vendor_specific_insn;
259 struct x86_exception exception;
262 struct decode_cache decode;
265 /* Repeat String Operation Prefix */
266 #define REPE_PREFIX 0xf3
267 #define REPNE_PREFIX 0xf2
269 /* Execution mode, passed to the emulator. */
270 #define X86EMUL_MODE_REAL 0 /* Real mode. */
271 #define X86EMUL_MODE_VM86 1 /* Virtual 8086 mode. */
272 #define X86EMUL_MODE_PROT16 2 /* 16-bit protected mode. */
273 #define X86EMUL_MODE_PROT32 4 /* 32-bit protected mode. */
274 #define X86EMUL_MODE_PROT64 8 /* 64-bit (long) mode. */
276 enum x86_intercept_stage {
278 X86_ICPT_POST_EXCEPT,
279 X86_ICPT_POST_MEMACCESS,
288 /* Host execution mode. */
289 #if defined(CONFIG_X86_32)
290 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
291 #elif defined(CONFIG_X86_64)
292 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
295 int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len);
296 #define EMULATION_FAILED -1
297 #define EMULATION_OK 0
298 #define EMULATION_RESTART 1
299 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt);
300 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
301 u16 tss_selector, int reason,
302 bool has_error_code, u32 error_code);
303 int emulate_int_real(struct x86_emulate_ctxt *ctxt,
304 struct x86_emulate_ops *ops, int irq);
305 #endif /* _ASM_X86_KVM_X86_EMULATE_H */