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 14 #include <asm/desc_defs.h> 15 16 struct x86_emulate_ctxt; 17 18 struct x86_exception { 19 u8 vector; 20 bool error_code_valid; 21 u16 error_code; 22 bool nested_page_fault; 23 u64 address; /* cr2 or nested page fault gpa */ 24 }; 25 26 /* 27 * x86_emulate_ops: 28 * 29 * These operations represent the instruction emulator's interface to memory. 30 * There are two categories of operation: those that act on ordinary memory 31 * regions (*_std), and those that act on memory regions known to require 32 * special treatment or emulation (*_emulated). 33 * 34 * The emulator assumes that an instruction accesses only one 'emulated memory' 35 * location, that this location is the given linear faulting address (cr2), and 36 * that this is one of the instruction's data operands. Instruction fetches and 37 * stack operations are assumed never to access emulated memory. The emulator 38 * automatically deduces which operand of a string-move operation is accessing 39 * emulated memory, and assumes that the other operand accesses normal memory. 40 * 41 * NOTES: 42 * 1. The emulator isn't very smart about emulated vs. standard memory. 43 * 'Emulated memory' access addresses should be checked for sanity. 44 * 'Normal memory' accesses may fault, and the caller must arrange to 45 * detect and handle reentrancy into the emulator via recursive faults. 46 * Accesses may be unaligned and may cross page boundaries. 47 * 2. If the access fails (cannot emulate, or a standard access faults) then 48 * it is up to the memop to propagate the fault to the guest VM via 49 * some out-of-band mechanism, unknown to the emulator. The memop signals 50 * failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will 51 * then immediately bail. 52 * 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only 53 * cmpxchg8b_emulated need support 8-byte accesses. 54 * 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system. 55 */ 56 /* Access completed successfully: continue emulation as normal. */ 57 #define X86EMUL_CONTINUE 0 58 /* Access is unhandleable: bail from emulation and return error to caller. */ 59 #define X86EMUL_UNHANDLEABLE 1 60 /* Terminate emulation but return success to the caller. */ 61 #define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */ 62 #define X86EMUL_RETRY_INSTR 3 /* retry the instruction for some reason */ 63 #define X86EMUL_CMPXCHG_FAILED 4 /* cmpxchg did not see expected value */ 64 #define X86EMUL_IO_NEEDED 5 /* IO is needed to complete emulation */ 65 66 struct x86_emulate_ops { 67 /* 68 * read_std: Read bytes of standard (non-emulated/special) memory. 69 * Used for descriptor reading. 70 * @addr: [IN ] Linear address from which to read. 71 * @val: [OUT] Value read from memory, zero-extended to 'u_long'. 72 * @bytes: [IN ] Number of bytes to read from memory. 73 */ 74 int (*read_std)(unsigned long addr, void *val, 75 unsigned int bytes, struct kvm_vcpu *vcpu, 76 struct x86_exception *fault); 77 78 /* 79 * write_std: Write bytes of standard (non-emulated/special) memory. 80 * Used for descriptor writing. 81 * @addr: [IN ] Linear address to which to write. 82 * @val: [OUT] Value write to memory, zero-extended to 'u_long'. 83 * @bytes: [IN ] Number of bytes to write to memory. 84 */ 85 int (*write_std)(unsigned long addr, void *val, 86 unsigned int bytes, struct kvm_vcpu *vcpu, 87 struct x86_exception *fault); 88 /* 89 * fetch: Read bytes of standard (non-emulated/special) memory. 90 * Used for instruction fetch. 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. 94 */ 95 int (*fetch)(unsigned long addr, void *val, 96 unsigned int bytes, struct kvm_vcpu *vcpu, 97 struct x86_exception *fault); 98 99 /* 100 * read_emulated: Read bytes from emulated/special memory area. 101 * @addr: [IN ] Linear address from which to read. 102 * @val: [OUT] Value read from memory, zero-extended to 'u_long'. 103 * @bytes: [IN ] Number of bytes to read from memory. 104 */ 105 int (*read_emulated)(unsigned long addr, 106 void *val, 107 unsigned int bytes, 108 struct x86_exception *fault, 109 struct kvm_vcpu *vcpu); 110 111 /* 112 * write_emulated: Write bytes to emulated/special memory area. 113 * @addr: [IN ] Linear address to which to write. 114 * @val: [IN ] Value to write to memory (low-order bytes used as 115 * required). 116 * @bytes: [IN ] Number of bytes to write to memory. 117 */ 118 int (*write_emulated)(unsigned long addr, 119 const void *val, 120 unsigned int bytes, 121 struct x86_exception *fault, 122 struct kvm_vcpu *vcpu); 123 124 /* 125 * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an 126 * emulated/special memory area. 127 * @addr: [IN ] Linear address to access. 128 * @old: [IN ] Value expected to be current at @addr. 129 * @new: [IN ] Value to write to @addr. 130 * @bytes: [IN ] Number of bytes to access using CMPXCHG. 131 */ 132 int (*cmpxchg_emulated)(unsigned long addr, 133 const void *old, 134 const void *new, 135 unsigned int bytes, 136 struct x86_exception *fault, 137 struct kvm_vcpu *vcpu); 138 139 int (*pio_in_emulated)(int size, unsigned short port, void *val, 140 unsigned int count, struct kvm_vcpu *vcpu); 141 142 int (*pio_out_emulated)(int size, unsigned short port, const void *val, 143 unsigned int count, struct kvm_vcpu *vcpu); 144 145 bool (*get_cached_descriptor)(struct desc_struct *desc, u32 *base3, 146 int seg, struct kvm_vcpu *vcpu); 147 void (*set_cached_descriptor)(struct desc_struct *desc, u32 base3, 148 int seg, struct kvm_vcpu *vcpu); 149 u16 (*get_segment_selector)(int seg, struct kvm_vcpu *vcpu); 150 void (*set_segment_selector)(u16 sel, int seg, struct kvm_vcpu *vcpu); 151 unsigned long (*get_cached_segment_base)(int seg, struct kvm_vcpu *vcpu); 152 void (*get_gdt)(struct desc_ptr *dt, struct kvm_vcpu *vcpu); 153 void (*get_idt)(struct desc_ptr *dt, struct kvm_vcpu *vcpu); 154 ulong (*get_cr)(int cr, struct kvm_vcpu *vcpu); 155 int (*set_cr)(int cr, ulong val, struct kvm_vcpu *vcpu); 156 int (*cpl)(struct kvm_vcpu *vcpu); 157 int (*get_dr)(int dr, unsigned long *dest, struct kvm_vcpu *vcpu); 158 int (*set_dr)(int dr, unsigned long value, struct kvm_vcpu *vcpu); 159 int (*set_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 data); 160 int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata); 161 }; 162 163 /* Type, address-of, and value of an instruction's operand. */ 164 struct operand { 165 enum { OP_REG, OP_MEM, OP_IMM, OP_NONE } type; 166 unsigned int bytes; 167 union { 168 unsigned long orig_val; 169 u64 orig_val64; 170 }; 171 union { 172 unsigned long *reg; 173 struct segmented_address { 174 ulong ea; 175 unsigned seg; 176 } mem; 177 } addr; 178 union { 179 unsigned long val; 180 u64 val64; 181 char valptr[sizeof(unsigned long) + 2]; 182 }; 183 }; 184 185 struct fetch_cache { 186 u8 data[15]; 187 unsigned long start; 188 unsigned long end; 189 }; 190 191 struct read_cache { 192 u8 data[1024]; 193 unsigned long pos; 194 unsigned long end; 195 }; 196 197 struct decode_cache { 198 u8 twobyte; 199 u8 b; 200 u8 lock_prefix; 201 u8 rep_prefix; 202 u8 op_bytes; 203 u8 ad_bytes; 204 u8 rex_prefix; 205 struct operand src; 206 struct operand src2; 207 struct operand dst; 208 bool has_seg_override; 209 u8 seg_override; 210 unsigned int d; 211 int (*execute)(struct x86_emulate_ctxt *ctxt); 212 unsigned long regs[NR_VCPU_REGS]; 213 unsigned long eip; 214 /* modrm */ 215 u8 modrm; 216 u8 modrm_mod; 217 u8 modrm_reg; 218 u8 modrm_rm; 219 u8 modrm_seg; 220 bool rip_relative; 221 struct fetch_cache fetch; 222 struct read_cache io_read; 223 struct read_cache mem_read; 224 }; 225 226 struct x86_emulate_ctxt { 227 struct x86_emulate_ops *ops; 228 229 /* Register state before/after emulation. */ 230 struct kvm_vcpu *vcpu; 231 232 unsigned long eflags; 233 unsigned long eip; /* eip before instruction emulation */ 234 /* Emulated execution mode, represented by an X86EMUL_MODE value. */ 235 int mode; 236 u32 cs_base; 237 238 /* interruptibility state, as a result of execution of STI or MOV SS */ 239 int interruptibility; 240 241 bool perm_ok; /* do not check permissions if true */ 242 bool only_vendor_specific_insn; 243 244 bool have_exception; 245 struct x86_exception exception; 246 247 /* decode cache */ 248 struct decode_cache decode; 249 }; 250 251 /* Repeat String Operation Prefix */ 252 #define REPE_PREFIX 1 253 #define REPNE_PREFIX 2 254 255 /* Execution mode, passed to the emulator. */ 256 #define X86EMUL_MODE_REAL 0 /* Real mode. */ 257 #define X86EMUL_MODE_VM86 1 /* Virtual 8086 mode. */ 258 #define X86EMUL_MODE_PROT16 2 /* 16-bit protected mode. */ 259 #define X86EMUL_MODE_PROT32 4 /* 32-bit protected mode. */ 260 #define X86EMUL_MODE_PROT64 8 /* 64-bit (long) mode. */ 261 262 /* Host execution mode. */ 263 #if defined(CONFIG_X86_32) 264 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32 265 #elif defined(CONFIG_X86_64) 266 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64 267 #endif 268 269 int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len); 270 #define EMULATION_FAILED -1 271 #define EMULATION_OK 0 272 #define EMULATION_RESTART 1 273 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt); 274 int emulator_task_switch(struct x86_emulate_ctxt *ctxt, 275 u16 tss_selector, int reason, 276 bool has_error_code, u32 error_code); 277 int emulate_int_real(struct x86_emulate_ctxt *ctxt, 278 struct x86_emulate_ops *ops, int irq); 279 #endif /* _ASM_X86_KVM_X86_EMULATE_H */ 280