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* x86_emulate.h
* Generic x86 (32-bit and 64-bit) instruction decoder and emulator.
* Copyright (c) 2005 Keir Fraser
* From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4
#ifndef __X86_EMULATE_H__
#define __X86_EMULATE_H__
struct x86_emulate_ctxt;
* x86_emulate_ops:
* These operations represent the instruction emulator's interface to memory.
* There are two categories of operation: those that act on ordinary memory
* regions (*_std), and those that act on memory regions known to require
* special treatment or emulation (*_emulated).
* The emulator assumes that an instruction accesses only one 'emulated memory'
* location, that this location is the given linear faulting address (cr2), and
* that this is one of the instruction's data operands. Instruction fetches and
* stack operations are assumed never to access emulated memory. The emulator
* automatically deduces which operand of a string-move operation is accessing
* emulated memory, and assumes that the other operand accesses normal memory.
* 1. The emulator isn't very smart about emulated vs. standard memory.
* 'Emulated memory' access addresses should be checked for sanity.
* 'Normal memory' accesses may fault, and the caller must arrange to
* detect and handle reentrancy into the emulator via recursive faults.
* Accesses may be unaligned and may cross page boundaries.
* 2. If the access fails (cannot emulate, or a standard access faults) then
* it is up to the memop to propagate the fault to the guest VM via
* some out-of-band mechanism, unknown to the emulator. The memop signals
* failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
* then immediately bail.
* 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
* cmpxchg8b_emulated need support 8-byte accesses.
* 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
/* Access completed successfully: continue emulation as normal. */
#define X86EMUL_CONTINUE 0
/* Access is unhandleable: bail from emulation and return error to caller. */
/* Terminate emulation but return success to the caller. */
#define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
#define X86EMUL_RETRY_INSTR 2 /* retry the instruction for some reason */
#define X86EMUL_CMPXCHG_FAILED 2 /* cmpxchg did not see expected value */
struct x86_emulate_ops {
* read_std: Read bytes of standard (non-emulated/special) memory.
* Used for instruction fetch, stack operations, and others.
* @addr: [IN ] Linear address from which to read.
* @val: [OUT] Value read from memory, zero-extended to 'u_long'.
* @bytes: [IN ] Number of bytes to read from memory.
int (*read_std)(unsigned long addr, void *val,
unsigned int bytes, struct kvm_vcpu *vcpu);
* read_emulated: Read bytes from emulated/special memory area.
* @addr: [IN ] Linear address from which to read.
* @val: [OUT] Value read from memory, zero-extended to 'u_long'.
* @bytes: [IN ] Number of bytes to read from memory.
int (*read_emulated) (unsigned long addr,
void *val,
unsigned int bytes,
struct kvm_vcpu *vcpu);
* write_emulated: Read bytes from emulated/special memory area.
* @addr: [IN ] Linear address to which to write.
* @val: [IN ] Value to write to memory (low-order bytes used as
* required).
* @bytes: [IN ] Number of bytes to write to memory.
int (*write_emulated) (unsigned long addr,
const void *val,
unsigned int bytes,
struct kvm_vcpu *vcpu);
* cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
* emulated/special memory area.
* @addr: [IN ] Linear address to access.
* @old: [IN ] Value expected to be current at @addr.
* @new: [IN ] Value to write to @addr.
* @bytes: [IN ] Number of bytes to access using CMPXCHG.
int (*cmpxchg_emulated) (unsigned long addr,
const void *old,
const void *new,
unsigned int bytes,
struct kvm_vcpu *vcpu);
/* Type, address-of, and value of an instruction's operand. */
struct operand {
enum { OP_REG, OP_MEM, OP_IMM, OP_NONE } type;
unsigned int bytes;
unsigned long val, orig_val, *ptr;
struct fetch_cache {
u8 data[15];
unsigned long start;
unsigned long end;
struct decode_cache {
u8 twobyte;
u8 b;
u8 lock_prefix;
u8 rep_prefix;
u8 op_bytes;
u8 ad_bytes;
u8 rex_prefix;
struct operand src;
struct operand dst;
unsigned long *override_base;
unsigned int d;
unsigned long regs[NR_VCPU_REGS];
unsigned long eip;
/* modrm */
u8 modrm;
u8 modrm_mod;
u8 modrm_reg;
u8 modrm_rm;
u8 use_modrm_ea;
unsigned long modrm_ea;
unsigned long modrm_val;
struct fetch_cache fetch;
struct x86_emulate_ctxt {
/* Register state before/after emulation. */
struct kvm_vcpu *vcpu;
/* Linear faulting address (if emulating a page-faulting instruction). */
unsigned long eflags;
/* Emulated execution mode, represented by an X86EMUL_MODE value. */
int mode;
unsigned long cs_base;
unsigned long ds_base;
unsigned long es_base;
unsigned long ss_base;
unsigned long gs_base;
unsigned long fs_base;
/* decode cache */
struct decode_cache decode;
/* Repeat String Operation Prefix */
#define REPE_PREFIX 1
#define REPNE_PREFIX 2
/* Execution mode, passed to the emulator. */
#define X86EMUL_MODE_REAL 0 /* Real mode. */
#define X86EMUL_MODE_PROT16 2 /* 16-bit protected mode. */
#define X86EMUL_MODE_PROT32 4 /* 32-bit protected mode. */
#define X86EMUL_MODE_PROT64 8 /* 64-bit (long) mode. */
/* Host execution mode. */
#if defined(__i386__)
#elif defined(CONFIG_X86_64)
int x86_decode_insn(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops);
int x86_emulate_insn(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops);
#endif /* __X86_EMULATE_H__ */