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 enum x86_intercept; 18 enum x86_intercept_stage; 19 20 struct x86_exception { 21 u8 vector; 22 bool error_code_valid; 23 u16 error_code; 24 bool nested_page_fault; 25 u64 address; /* cr2 or nested page fault gpa */ 26 }; 27 28 /* 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. 32 */ 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 */ 44 }; 45 46 /* 47 * x86_emulate_ops: 48 * 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). 53 * 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. 60 * 61 * NOTES: 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. 75 */ 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 */ 86 87 struct x86_emulate_ops { 88 /* 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. 94 */ 95 int (*read_std)(struct x86_emulate_ctxt *ctxt, 96 unsigned long addr, void *val, 97 unsigned int bytes, 98 struct x86_exception *fault); 99 100 /* 101 * write_std: Write bytes of standard (non-emulated/special) memory. 102 * Used for descriptor writing. 103 * @addr: [IN ] Linear address to which to write. 104 * @val: [OUT] Value write to memory, zero-extended to 'u_long'. 105 * @bytes: [IN ] Number of bytes to write to memory. 106 */ 107 int (*write_std)(struct x86_emulate_ctxt *ctxt, 108 unsigned long addr, void *val, unsigned int bytes, 109 struct x86_exception *fault); 110 /* 111 * fetch: Read bytes of standard (non-emulated/special) memory. 112 * Used for instruction fetch. 113 * @addr: [IN ] Linear address from which to read. 114 * @val: [OUT] Value read from memory, zero-extended to 'u_long'. 115 * @bytes: [IN ] Number of bytes to read from memory. 116 */ 117 int (*fetch)(struct x86_emulate_ctxt *ctxt, 118 unsigned long addr, void *val, unsigned int bytes, 119 struct x86_exception *fault); 120 121 /* 122 * read_emulated: Read bytes from emulated/special memory area. 123 * @addr: [IN ] Linear address from which to read. 124 * @val: [OUT] Value read from memory, zero-extended to 'u_long'. 125 * @bytes: [IN ] Number of bytes to read from memory. 126 */ 127 int (*read_emulated)(struct x86_emulate_ctxt *ctxt, 128 unsigned long addr, void *val, unsigned int bytes, 129 struct x86_exception *fault); 130 131 /* 132 * write_emulated: Write bytes to emulated/special memory area. 133 * @addr: [IN ] Linear address to which to write. 134 * @val: [IN ] Value to write to memory (low-order bytes used as 135 * required). 136 * @bytes: [IN ] Number of bytes to write to memory. 137 */ 138 int (*write_emulated)(struct x86_emulate_ctxt *ctxt, 139 unsigned long addr, const void *val, 140 unsigned int bytes, 141 struct x86_exception *fault); 142 143 /* 144 * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an 145 * emulated/special memory area. 146 * @addr: [IN ] Linear address to access. 147 * @old: [IN ] Value expected to be current at @addr. 148 * @new: [IN ] Value to write to @addr. 149 * @bytes: [IN ] Number of bytes to access using CMPXCHG. 150 */ 151 int (*cmpxchg_emulated)(struct x86_emulate_ctxt *ctxt, 152 unsigned long addr, 153 const void *old, 154 const void *new, 155 unsigned int bytes, 156 struct x86_exception *fault); 157 void (*invlpg)(struct x86_emulate_ctxt *ctxt, ulong addr); 158 159 int (*pio_in_emulated)(struct x86_emulate_ctxt *ctxt, 160 int size, unsigned short port, void *val, 161 unsigned int count); 162 163 int (*pio_out_emulated)(struct x86_emulate_ctxt *ctxt, 164 int size, unsigned short port, const void *val, 165 unsigned int count); 166 167 bool (*get_segment)(struct x86_emulate_ctxt *ctxt, u16 *selector, 168 struct desc_struct *desc, u32 *base3, int seg); 169 void (*set_segment)(struct x86_emulate_ctxt *ctxt, u16 selector, 170 struct desc_struct *desc, u32 base3, int seg); 171 unsigned long (*get_cached_segment_base)(struct x86_emulate_ctxt *ctxt, 172 int seg); 173 void (*get_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt); 174 void (*get_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt); 175 void (*set_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt); 176 void (*set_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt); 177 ulong (*get_cr)(struct x86_emulate_ctxt *ctxt, int cr); 178 int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val); 179 int (*cpl)(struct x86_emulate_ctxt *ctxt); 180 int (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong *dest); 181 int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value); 182 int (*set_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data); 183 int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata); 184 int (*read_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc, u64 *pdata); 185 void (*halt)(struct x86_emulate_ctxt *ctxt); 186 void (*wbinvd)(struct x86_emulate_ctxt *ctxt); 187 int (*fix_hypercall)(struct x86_emulate_ctxt *ctxt); 188 void (*get_fpu)(struct x86_emulate_ctxt *ctxt); /* disables preempt */ 189 void (*put_fpu)(struct x86_emulate_ctxt *ctxt); /* reenables preempt */ 190 int (*intercept)(struct x86_emulate_ctxt *ctxt, 191 struct x86_instruction_info *info, 192 enum x86_intercept_stage stage); 193 194 bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt, 195 u32 *eax, u32 *ebx, u32 *ecx, u32 *edx); 196 }; 197 198 typedef u32 __attribute__((vector_size(16))) sse128_t; 199 200 /* Type, address-of, and value of an instruction's operand. */ 201 struct operand { 202 enum { OP_REG, OP_MEM, OP_IMM, OP_XMM, OP_NONE } type; 203 unsigned int bytes; 204 union { 205 unsigned long orig_val; 206 u64 orig_val64; 207 }; 208 union { 209 unsigned long *reg; 210 struct segmented_address { 211 ulong ea; 212 unsigned seg; 213 } mem; 214 unsigned xmm; 215 } addr; 216 union { 217 unsigned long val; 218 u64 val64; 219 char valptr[sizeof(unsigned long) + 2]; 220 sse128_t vec_val; 221 }; 222 }; 223 224 struct fetch_cache { 225 u8 data[15]; 226 unsigned long start; 227 unsigned long end; 228 }; 229 230 struct read_cache { 231 u8 data[1024]; 232 unsigned long pos; 233 unsigned long end; 234 }; 235 236 struct x86_emulate_ctxt { 237 struct x86_emulate_ops *ops; 238 239 /* Register state before/after emulation. */ 240 unsigned long eflags; 241 unsigned long eip; /* eip before instruction emulation */ 242 /* Emulated execution mode, represented by an X86EMUL_MODE value. */ 243 int mode; 244 245 /* interruptibility state, as a result of execution of STI or MOV SS */ 246 int interruptibility; 247 248 bool guest_mode; /* guest running a nested guest */ 249 bool perm_ok; /* do not check permissions if true */ 250 bool only_vendor_specific_insn; 251 252 bool have_exception; 253 struct x86_exception exception; 254 255 /* decode cache */ 256 u8 twobyte; 257 u8 b; 258 u8 intercept; 259 u8 lock_prefix; 260 u8 rep_prefix; 261 u8 op_bytes; 262 u8 ad_bytes; 263 u8 rex_prefix; 264 struct operand src; 265 struct operand src2; 266 struct operand dst; 267 bool has_seg_override; 268 u8 seg_override; 269 u64 d; 270 int (*execute)(struct x86_emulate_ctxt *ctxt); 271 int (*check_perm)(struct x86_emulate_ctxt *ctxt); 272 /* modrm */ 273 u8 modrm; 274 u8 modrm_mod; 275 u8 modrm_reg; 276 u8 modrm_rm; 277 u8 modrm_seg; 278 bool rip_relative; 279 unsigned long _eip; 280 /* Fields above regs are cleared together. */ 281 unsigned long regs[NR_VCPU_REGS]; 282 struct operand memop; 283 struct operand *memopp; 284 struct fetch_cache fetch; 285 struct read_cache io_read; 286 struct read_cache mem_read; 287 }; 288 289 /* Repeat String Operation Prefix */ 290 #define REPE_PREFIX 0xf3 291 #define REPNE_PREFIX 0xf2 292 293 /* Execution mode, passed to the emulator. */ 294 #define X86EMUL_MODE_REAL 0 /* Real mode. */ 295 #define X86EMUL_MODE_VM86 1 /* Virtual 8086 mode. */ 296 #define X86EMUL_MODE_PROT16 2 /* 16-bit protected mode. */ 297 #define X86EMUL_MODE_PROT32 4 /* 32-bit protected mode. */ 298 #define X86EMUL_MODE_PROT64 8 /* 64-bit (long) mode. */ 299 300 /* any protected mode */ 301 #define X86EMUL_MODE_PROT (X86EMUL_MODE_PROT16|X86EMUL_MODE_PROT32| \ 302 X86EMUL_MODE_PROT64) 303 304 /* CPUID vendors */ 305 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx 0x68747541 306 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx 0x444d4163 307 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_edx 0x69746e65 308 309 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx 0x69444d41 310 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx 0x21726574 311 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_edx 0x74656273 312 313 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ebx 0x756e6547 314 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e 315 #define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69 316 317 enum x86_intercept_stage { 318 X86_ICTP_NONE = 0, /* Allow zero-init to not match anything */ 319 X86_ICPT_PRE_EXCEPT, 320 X86_ICPT_POST_EXCEPT, 321 X86_ICPT_POST_MEMACCESS, 322 }; 323 324 enum x86_intercept { 325 x86_intercept_none, 326 x86_intercept_cr_read, 327 x86_intercept_cr_write, 328 x86_intercept_clts, 329 x86_intercept_lmsw, 330 x86_intercept_smsw, 331 x86_intercept_dr_read, 332 x86_intercept_dr_write, 333 x86_intercept_lidt, 334 x86_intercept_sidt, 335 x86_intercept_lgdt, 336 x86_intercept_sgdt, 337 x86_intercept_lldt, 338 x86_intercept_sldt, 339 x86_intercept_ltr, 340 x86_intercept_str, 341 x86_intercept_rdtsc, 342 x86_intercept_rdpmc, 343 x86_intercept_pushf, 344 x86_intercept_popf, 345 x86_intercept_cpuid, 346 x86_intercept_rsm, 347 x86_intercept_iret, 348 x86_intercept_intn, 349 x86_intercept_invd, 350 x86_intercept_pause, 351 x86_intercept_hlt, 352 x86_intercept_invlpg, 353 x86_intercept_invlpga, 354 x86_intercept_vmrun, 355 x86_intercept_vmload, 356 x86_intercept_vmsave, 357 x86_intercept_vmmcall, 358 x86_intercept_stgi, 359 x86_intercept_clgi, 360 x86_intercept_skinit, 361 x86_intercept_rdtscp, 362 x86_intercept_icebp, 363 x86_intercept_wbinvd, 364 x86_intercept_monitor, 365 x86_intercept_mwait, 366 x86_intercept_rdmsr, 367 x86_intercept_wrmsr, 368 x86_intercept_in, 369 x86_intercept_ins, 370 x86_intercept_out, 371 x86_intercept_outs, 372 373 nr_x86_intercepts 374 }; 375 376 /* Host execution mode. */ 377 #if defined(CONFIG_X86_32) 378 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32 379 #elif defined(CONFIG_X86_64) 380 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64 381 #endif 382 383 int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len); 384 bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt); 385 #define EMULATION_FAILED -1 386 #define EMULATION_OK 0 387 #define EMULATION_RESTART 1 388 #define EMULATION_INTERCEPTED 2 389 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt); 390 int emulator_task_switch(struct x86_emulate_ctxt *ctxt, 391 u16 tss_selector, int reason, 392 bool has_error_code, u32 error_code); 393 int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq); 394 #endif /* _ASM_X86_KVM_X86_EMULATE_H */ 395