1/****************************************************************************** 2 * x86_emulate.h 3 * 4 * Generic x86 (32-bit and 64-bit) instruction decoder and emulator. 5 * 6 * Copyright (c) 2005 Keir Fraser 7 * 8 * From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4 9 */ 10 11#ifndef _ASM_X86_KVM_X86_EMULATE_H 12#define _ASM_X86_KVM_X86_EMULATE_H 13 14struct x86_emulate_ctxt; 15 16/* 17 * x86_emulate_ops: 18 * 19 * These operations represent the instruction emulator's interface to memory. 20 * There are two categories of operation: those that act on ordinary memory 21 * regions (*_std), and those that act on memory regions known to require 22 * special treatment or emulation (*_emulated). 23 * 24 * The emulator assumes that an instruction accesses only one 'emulated memory' 25 * location, that this location is the given linear faulting address (cr2), and 26 * that this is one of the instruction's data operands. Instruction fetches and 27 * stack operations are assumed never to access emulated memory. The emulator 28 * automatically deduces which operand of a string-move operation is accessing 29 * emulated memory, and assumes that the other operand accesses normal memory. 30 * 31 * NOTES: 32 * 1. The emulator isn't very smart about emulated vs. standard memory. 33 * 'Emulated memory' access addresses should be checked for sanity. 34 * 'Normal memory' accesses may fault, and the caller must arrange to 35 * detect and handle reentrancy into the emulator via recursive faults. 36 * Accesses may be unaligned and may cross page boundaries. 37 * 2. If the access fails (cannot emulate, or a standard access faults) then 38 * it is up to the memop to propagate the fault to the guest VM via 39 * some out-of-band mechanism, unknown to the emulator. The memop signals 40 * failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will 41 * then immediately bail. 42 * 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only 43 * cmpxchg8b_emulated need support 8-byte accesses. 44 * 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system. 45 */ 46/* Access completed successfully: continue emulation as normal. */ 47#define X86EMUL_CONTINUE 0 48/* Access is unhandleable: bail from emulation and return error to caller. */ 49#define X86EMUL_UNHANDLEABLE 1 50/* Terminate emulation but return success to the caller. */ 51#define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */ 52#define X86EMUL_RETRY_INSTR 2 /* retry the instruction for some reason */ 53#define X86EMUL_CMPXCHG_FAILED 2 /* cmpxchg did not see expected value */ 54struct x86_emulate_ops { 55 /* 56 * read_std: Read bytes of standard (non-emulated/special) memory. 57 * Used for instruction fetch, stack operations, and others. 58 * @addr: [IN ] Linear address from which to read. 59 * @val: [OUT] Value read from memory, zero-extended to 'u_long'. 60 * @bytes: [IN ] Number of bytes to read from memory. 61 */ 62 int (*read_std)(unsigned long addr, void *val, 63 unsigned int bytes, struct kvm_vcpu *vcpu); 64 65 /* 66 * read_emulated: Read bytes from emulated/special memory area. 67 * @addr: [IN ] Linear address from which to read. 68 * @val: [OUT] Value read from memory, zero-extended to 'u_long'. 69 * @bytes: [IN ] Number of bytes to read from memory. 70 */ 71 int (*read_emulated)(unsigned long addr, 72 void *val, 73 unsigned int bytes, 74 struct kvm_vcpu *vcpu); 75 76 /* 77 * write_emulated: Read bytes from emulated/special memory area. 78 * @addr: [IN ] Linear address to which to write. 79 * @val: [IN ] Value to write to memory (low-order bytes used as 80 * required). 81 * @bytes: [IN ] Number of bytes to write to memory. 82 */ 83 int (*write_emulated)(unsigned long addr, 84 const void *val, 85 unsigned int bytes, 86 struct kvm_vcpu *vcpu); 87 88 /* 89 * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an 90 * emulated/special memory area. 91 * @addr: [IN ] Linear address to access. 92 * @old: [IN ] Value expected to be current at @addr. 93 * @new: [IN ] Value to write to @addr. 94 * @bytes: [IN ] Number of bytes to access using CMPXCHG. 95 */ 96 int (*cmpxchg_emulated)(unsigned long addr, 97 const void *old, 98 const void *new, 99 unsigned int bytes, 100 struct kvm_vcpu *vcpu); 101 102}; 103 104/* Type, address-of, and value of an instruction's operand. */ 105struct operand { 106 enum { OP_REG, OP_MEM, OP_IMM, OP_NONE } type; 107 unsigned int bytes; 108 unsigned long val, orig_val, *ptr; 109}; 110 111struct fetch_cache { 112 u8 data[15]; 113 unsigned long start; 114 unsigned long end; 115}; 116 117struct decode_cache { 118 u8 twobyte; 119 u8 b; 120 u8 lock_prefix; 121 u8 rep_prefix; 122 u8 op_bytes; 123 u8 ad_bytes; 124 u8 rex_prefix; 125 struct operand src; 126 struct operand src2; 127 struct operand dst; 128 bool has_seg_override; 129 u8 seg_override; 130 unsigned int d; 131 unsigned long regs[NR_VCPU_REGS]; 132 unsigned long eip; 133 /* modrm */ 134 u8 modrm; 135 u8 modrm_mod; 136 u8 modrm_reg; 137 u8 modrm_rm; 138 u8 use_modrm_ea; 139 bool rip_relative; 140 unsigned long modrm_ea; 141 void *modrm_ptr; 142 unsigned long modrm_val; 143 struct fetch_cache fetch; 144}; 145 146#define X86_SHADOW_INT_MOV_SS 1 147#define X86_SHADOW_INT_STI 2 148 149struct x86_emulate_ctxt { 150 /* Register state before/after emulation. */ 151 struct kvm_vcpu *vcpu; 152 153 unsigned long eflags; 154 /* Emulated execution mode, represented by an X86EMUL_MODE value. */ 155 int mode; 156 u32 cs_base; 157 158 /* interruptibility state, as a result of execution of STI or MOV SS */ 159 int interruptibility; 160 161 /* decode cache */ 162 struct decode_cache decode; 163}; 164 165/* Repeat String Operation Prefix */ 166#define REPE_PREFIX 1 167#define REPNE_PREFIX 2 168 169/* Execution mode, passed to the emulator. */ 170#define X86EMUL_MODE_REAL 0 /* Real mode. */ 171#define X86EMUL_MODE_PROT16 2 /* 16-bit protected mode. */ 172#define X86EMUL_MODE_PROT32 4 /* 32-bit protected mode. */ 173#define X86EMUL_MODE_PROT64 8 /* 64-bit (long) mode. */ 174 175/* Host execution mode. */ 176#if defined(CONFIG_X86_32) 177#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32 178#elif defined(CONFIG_X86_64) 179#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64 180#endif 181 182int x86_decode_insn(struct x86_emulate_ctxt *ctxt, 183 struct x86_emulate_ops *ops); 184int x86_emulate_insn(struct x86_emulate_ctxt *ctxt, 185 struct x86_emulate_ops *ops); 186 187#endif /* _ASM_X86_KVM_X86_EMULATE_H */ 188