1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /****************************************************************************** 3 * x86_emulate.h 4 * 5 * Generic x86 (32-bit and 64-bit) instruction decoder and emulator. 6 * 7 * Copyright (c) 2005 Keir Fraser 8 * 9 * From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4 10 */ 11 12 #ifndef _ASM_X86_KVM_X86_EMULATE_H 13 #define _ASM_X86_KVM_X86_EMULATE_H 14 15 #include <asm/desc_defs.h> 16 #include "fpu.h" 17 18 struct x86_emulate_ctxt; 19 enum x86_intercept; 20 enum x86_intercept_stage; 21 22 struct x86_exception { 23 u8 vector; 24 bool error_code_valid; 25 u16 error_code; 26 bool nested_page_fault; 27 u64 address; /* cr2 or nested page fault gpa */ 28 u8 async_page_fault; 29 }; 30 31 /* 32 * This struct is used to carry enough information from the instruction 33 * decoder to main KVM so that a decision can be made whether the 34 * instruction needs to be intercepted or not. 35 */ 36 struct x86_instruction_info { 37 u8 intercept; /* which intercept */ 38 u8 rep_prefix; /* rep prefix? */ 39 u8 modrm_mod; /* mod part of modrm */ 40 u8 modrm_reg; /* index of register used */ 41 u8 modrm_rm; /* rm part of modrm */ 42 u64 src_val; /* value of source operand */ 43 u64 dst_val; /* value of destination operand */ 44 u8 src_bytes; /* size of source operand */ 45 u8 dst_bytes; /* size of destination operand */ 46 u8 ad_bytes; /* size of src/dst address */ 47 u64 next_rip; /* rip following the instruction */ 48 }; 49 50 /* 51 * x86_emulate_ops: 52 * 53 * These operations represent the instruction emulator's interface to memory. 54 * There are two categories of operation: those that act on ordinary memory 55 * regions (*_std), and those that act on memory regions known to require 56 * special treatment or emulation (*_emulated). 57 * 58 * The emulator assumes that an instruction accesses only one 'emulated memory' 59 * location, that this location is the given linear faulting address (cr2), and 60 * that this is one of the instruction's data operands. Instruction fetches and 61 * stack operations are assumed never to access emulated memory. The emulator 62 * automatically deduces which operand of a string-move operation is accessing 63 * emulated memory, and assumes that the other operand accesses normal memory. 64 * 65 * NOTES: 66 * 1. The emulator isn't very smart about emulated vs. standard memory. 67 * 'Emulated memory' access addresses should be checked for sanity. 68 * 'Normal memory' accesses may fault, and the caller must arrange to 69 * detect and handle reentrancy into the emulator via recursive faults. 70 * Accesses may be unaligned and may cross page boundaries. 71 * 2. If the access fails (cannot emulate, or a standard access faults) then 72 * it is up to the memop to propagate the fault to the guest VM via 73 * some out-of-band mechanism, unknown to the emulator. The memop signals 74 * failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will 75 * then immediately bail. 76 * 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only 77 * cmpxchg8b_emulated need support 8-byte accesses. 78 * 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system. 79 */ 80 /* Access completed successfully: continue emulation as normal. */ 81 #define X86EMUL_CONTINUE 0 82 /* Access is unhandleable: bail from emulation and return error to caller. */ 83 #define X86EMUL_UNHANDLEABLE 1 84 /* Terminate emulation but return success to the caller. */ 85 #define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */ 86 #define X86EMUL_RETRY_INSTR 3 /* retry the instruction for some reason */ 87 #define X86EMUL_CMPXCHG_FAILED 4 /* cmpxchg did not see expected value */ 88 #define X86EMUL_IO_NEEDED 5 /* IO is needed to complete emulation */ 89 #define X86EMUL_INTERCEPTED 6 /* Intercepted by nested VMCB/VMCS */ 90 91 struct x86_emulate_ops { 92 void (*vm_bugged)(struct x86_emulate_ctxt *ctxt); 93 /* 94 * read_gpr: read a general purpose register (rax - r15) 95 * 96 * @reg: gpr number. 97 */ 98 ulong (*read_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg); 99 /* 100 * write_gpr: write a general purpose register (rax - r15) 101 * 102 * @reg: gpr number. 103 * @val: value to write. 104 */ 105 void (*write_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val); 106 /* 107 * read_std: Read bytes of standard (non-emulated/special) memory. 108 * Used for descriptor reading. 109 * @addr: [IN ] Linear address from which to read. 110 * @val: [OUT] Value read from memory, zero-extended to 'u_long'. 111 * @bytes: [IN ] Number of bytes to read from memory. 112 * @system:[IN ] Whether the access is forced to be at CPL0. 113 */ 114 int (*read_std)(struct x86_emulate_ctxt *ctxt, 115 unsigned long addr, void *val, 116 unsigned int bytes, 117 struct x86_exception *fault, bool system); 118 119 /* 120 * write_std: Write bytes of standard (non-emulated/special) memory. 121 * Used for descriptor writing. 122 * @addr: [IN ] Linear address to which to write. 123 * @val: [OUT] Value write to memory, zero-extended to 'u_long'. 124 * @bytes: [IN ] Number of bytes to write to memory. 125 * @system:[IN ] Whether the access is forced to be at CPL0. 126 */ 127 int (*write_std)(struct x86_emulate_ctxt *ctxt, 128 unsigned long addr, void *val, unsigned int bytes, 129 struct x86_exception *fault, bool system); 130 /* 131 * fetch: Read bytes of standard (non-emulated/special) memory. 132 * Used for instruction fetch. 133 * @addr: [IN ] Linear address from which to read. 134 * @val: [OUT] Value read from memory, zero-extended to 'u_long'. 135 * @bytes: [IN ] Number of bytes to read from memory. 136 */ 137 int (*fetch)(struct x86_emulate_ctxt *ctxt, 138 unsigned long addr, void *val, unsigned int bytes, 139 struct x86_exception *fault); 140 141 /* 142 * read_emulated: Read bytes from emulated/special memory area. 143 * @addr: [IN ] Linear address from which to read. 144 * @val: [OUT] Value read from memory, zero-extended to 'u_long'. 145 * @bytes: [IN ] Number of bytes to read from memory. 146 */ 147 int (*read_emulated)(struct x86_emulate_ctxt *ctxt, 148 unsigned long addr, void *val, unsigned int bytes, 149 struct x86_exception *fault); 150 151 /* 152 * write_emulated: Write bytes to emulated/special memory area. 153 * @addr: [IN ] Linear address to which to write. 154 * @val: [IN ] Value to write to memory (low-order bytes used as 155 * required). 156 * @bytes: [IN ] Number of bytes to write to memory. 157 */ 158 int (*write_emulated)(struct x86_emulate_ctxt *ctxt, 159 unsigned long addr, const void *val, 160 unsigned int bytes, 161 struct x86_exception *fault); 162 163 /* 164 * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an 165 * emulated/special memory area. 166 * @addr: [IN ] Linear address to access. 167 * @old: [IN ] Value expected to be current at @addr. 168 * @new: [IN ] Value to write to @addr. 169 * @bytes: [IN ] Number of bytes to access using CMPXCHG. 170 */ 171 int (*cmpxchg_emulated)(struct x86_emulate_ctxt *ctxt, 172 unsigned long addr, 173 const void *old, 174 const void *new, 175 unsigned int bytes, 176 struct x86_exception *fault); 177 void (*invlpg)(struct x86_emulate_ctxt *ctxt, ulong addr); 178 179 int (*pio_in_emulated)(struct x86_emulate_ctxt *ctxt, 180 int size, unsigned short port, void *val, 181 unsigned int count); 182 183 int (*pio_out_emulated)(struct x86_emulate_ctxt *ctxt, 184 int size, unsigned short port, const void *val, 185 unsigned int count); 186 187 bool (*get_segment)(struct x86_emulate_ctxt *ctxt, u16 *selector, 188 struct desc_struct *desc, u32 *base3, int seg); 189 void (*set_segment)(struct x86_emulate_ctxt *ctxt, u16 selector, 190 struct desc_struct *desc, u32 base3, int seg); 191 unsigned long (*get_cached_segment_base)(struct x86_emulate_ctxt *ctxt, 192 int seg); 193 void (*get_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt); 194 void (*get_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt); 195 void (*set_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt); 196 void (*set_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt); 197 ulong (*get_cr)(struct x86_emulate_ctxt *ctxt, int cr); 198 int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val); 199 int (*cpl)(struct x86_emulate_ctxt *ctxt); 200 void (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong *dest); 201 int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value); 202 int (*set_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data); 203 int (*get_msr_with_filter)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata); 204 int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata); 205 int (*check_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc); 206 int (*read_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc, u64 *pdata); 207 void (*halt)(struct x86_emulate_ctxt *ctxt); 208 void (*wbinvd)(struct x86_emulate_ctxt *ctxt); 209 int (*fix_hypercall)(struct x86_emulate_ctxt *ctxt); 210 int (*intercept)(struct x86_emulate_ctxt *ctxt, 211 struct x86_instruction_info *info, 212 enum x86_intercept_stage stage); 213 214 bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt, u32 *eax, u32 *ebx, 215 u32 *ecx, u32 *edx, bool exact_only); 216 bool (*guest_has_long_mode)(struct x86_emulate_ctxt *ctxt); 217 bool (*guest_has_movbe)(struct x86_emulate_ctxt *ctxt); 218 bool (*guest_has_fxsr)(struct x86_emulate_ctxt *ctxt); 219 bool (*guest_has_rdpid)(struct x86_emulate_ctxt *ctxt); 220 221 void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked); 222 223 bool (*is_smm)(struct x86_emulate_ctxt *ctxt); 224 bool (*is_guest_mode)(struct x86_emulate_ctxt *ctxt); 225 int (*leave_smm)(struct x86_emulate_ctxt *ctxt); 226 void (*triple_fault)(struct x86_emulate_ctxt *ctxt); 227 int (*set_xcr)(struct x86_emulate_ctxt *ctxt, u32 index, u64 xcr); 228 }; 229 230 /* Type, address-of, and value of an instruction's operand. */ 231 struct operand { 232 enum { OP_REG, OP_MEM, OP_MEM_STR, OP_IMM, OP_XMM, OP_MM, OP_NONE } type; 233 unsigned int bytes; 234 unsigned int count; 235 union { 236 unsigned long orig_val; 237 u64 orig_val64; 238 }; 239 union { 240 unsigned long *reg; 241 struct segmented_address { 242 ulong ea; 243 unsigned seg; 244 } mem; 245 unsigned xmm; 246 unsigned mm; 247 } addr; 248 union { 249 unsigned long val; 250 u64 val64; 251 char valptr[sizeof(sse128_t)]; 252 sse128_t vec_val; 253 u64 mm_val; 254 void *data; 255 }; 256 }; 257 258 struct fetch_cache { 259 u8 data[15]; 260 u8 *ptr; 261 u8 *end; 262 }; 263 264 struct read_cache { 265 u8 data[1024]; 266 unsigned long pos; 267 unsigned long end; 268 }; 269 270 /* Execution mode, passed to the emulator. */ 271 enum x86emul_mode { 272 X86EMUL_MODE_REAL, /* Real mode. */ 273 X86EMUL_MODE_VM86, /* Virtual 8086 mode. */ 274 X86EMUL_MODE_PROT16, /* 16-bit protected mode. */ 275 X86EMUL_MODE_PROT32, /* 32-bit protected mode. */ 276 X86EMUL_MODE_PROT64, /* 64-bit (long) mode. */ 277 }; 278 279 /* 280 * fastop functions are declared as taking a never-defined fastop parameter, 281 * so they can't be called from C directly. 282 */ 283 struct fastop; 284 285 typedef void (*fastop_t)(struct fastop *); 286 287 /* 288 * The emulator's _regs array tracks only the GPRs, i.e. excludes RIP. RIP is 289 * tracked/accessed via _eip, and except for RIP relative addressing, which 290 * also uses _eip, RIP cannot be a register operand nor can it be an operand in 291 * a ModRM or SIB byte. 292 */ 293 #ifdef CONFIG_X86_64 294 #define NR_EMULATOR_GPRS 16 295 #else 296 #define NR_EMULATOR_GPRS 8 297 #endif 298 299 struct x86_emulate_ctxt { 300 void *vcpu; 301 const struct x86_emulate_ops *ops; 302 303 /* Register state before/after emulation. */ 304 unsigned long eflags; 305 unsigned long eip; /* eip before instruction emulation */ 306 /* Emulated execution mode, represented by an X86EMUL_MODE value. */ 307 enum x86emul_mode mode; 308 309 /* interruptibility state, as a result of execution of STI or MOV SS */ 310 int interruptibility; 311 312 bool perm_ok; /* do not check permissions if true */ 313 bool tf; /* TF value before instruction (after for syscall/sysret) */ 314 315 bool have_exception; 316 struct x86_exception exception; 317 318 /* GPA available */ 319 bool gpa_available; 320 gpa_t gpa_val; 321 322 /* 323 * decode cache 324 */ 325 326 /* current opcode length in bytes */ 327 u8 opcode_len; 328 u8 b; 329 u8 intercept; 330 u8 op_bytes; 331 u8 ad_bytes; 332 union { 333 int (*execute)(struct x86_emulate_ctxt *ctxt); 334 fastop_t fop; 335 }; 336 int (*check_perm)(struct x86_emulate_ctxt *ctxt); 337 338 bool rip_relative; 339 u8 rex_prefix; 340 u8 lock_prefix; 341 u8 rep_prefix; 342 /* bitmaps of registers in _regs[] that can be read */ 343 u16 regs_valid; 344 /* bitmaps of registers in _regs[] that have been written */ 345 u16 regs_dirty; 346 /* modrm */ 347 u8 modrm; 348 u8 modrm_mod; 349 u8 modrm_reg; 350 u8 modrm_rm; 351 u8 modrm_seg; 352 u8 seg_override; 353 u64 d; 354 unsigned long _eip; 355 356 /* Here begins the usercopy section. */ 357 struct operand src; 358 struct operand src2; 359 struct operand dst; 360 struct operand memop; 361 unsigned long _regs[NR_EMULATOR_GPRS]; 362 struct operand *memopp; 363 struct fetch_cache fetch; 364 struct read_cache io_read; 365 struct read_cache mem_read; 366 bool is_branch; 367 }; 368 369 #define KVM_EMULATOR_BUG_ON(cond, ctxt) \ 370 ({ \ 371 int __ret = (cond); \ 372 \ 373 if (WARN_ON_ONCE(__ret)) \ 374 ctxt->ops->vm_bugged(ctxt); \ 375 unlikely(__ret); \ 376 }) 377 378 /* Repeat String Operation Prefix */ 379 #define REPE_PREFIX 0xf3 380 #define REPNE_PREFIX 0xf2 381 382 /* CPUID vendors */ 383 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx 0x68747541 384 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx 0x444d4163 385 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_edx 0x69746e65 386 387 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx 0x69444d41 388 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx 0x21726574 389 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_edx 0x74656273 390 391 #define X86EMUL_CPUID_VENDOR_HygonGenuine_ebx 0x6f677948 392 #define X86EMUL_CPUID_VENDOR_HygonGenuine_ecx 0x656e6975 393 #define X86EMUL_CPUID_VENDOR_HygonGenuine_edx 0x6e65476e 394 395 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ebx 0x756e6547 396 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e 397 #define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69 398 399 #define X86EMUL_CPUID_VENDOR_CentaurHauls_ebx 0x746e6543 400 #define X86EMUL_CPUID_VENDOR_CentaurHauls_ecx 0x736c7561 401 #define X86EMUL_CPUID_VENDOR_CentaurHauls_edx 0x48727561 402 403 static inline bool is_guest_vendor_intel(u32 ebx, u32 ecx, u32 edx) 404 { 405 return ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx && 406 ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx && 407 edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx; 408 } 409 410 static inline bool is_guest_vendor_amd(u32 ebx, u32 ecx, u32 edx) 411 { 412 return (ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx && 413 ecx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx && 414 edx == X86EMUL_CPUID_VENDOR_AuthenticAMD_edx) || 415 (ebx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx && 416 ecx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx && 417 edx == X86EMUL_CPUID_VENDOR_AMDisbetterI_edx); 418 } 419 420 static inline bool is_guest_vendor_hygon(u32 ebx, u32 ecx, u32 edx) 421 { 422 return ebx == X86EMUL_CPUID_VENDOR_HygonGenuine_ebx && 423 ecx == X86EMUL_CPUID_VENDOR_HygonGenuine_ecx && 424 edx == X86EMUL_CPUID_VENDOR_HygonGenuine_edx; 425 } 426 427 enum x86_intercept_stage { 428 X86_ICTP_NONE = 0, /* Allow zero-init to not match anything */ 429 X86_ICPT_PRE_EXCEPT, 430 X86_ICPT_POST_EXCEPT, 431 X86_ICPT_POST_MEMACCESS, 432 }; 433 434 enum x86_intercept { 435 x86_intercept_none, 436 x86_intercept_cr_read, 437 x86_intercept_cr_write, 438 x86_intercept_clts, 439 x86_intercept_lmsw, 440 x86_intercept_smsw, 441 x86_intercept_dr_read, 442 x86_intercept_dr_write, 443 x86_intercept_lidt, 444 x86_intercept_sidt, 445 x86_intercept_lgdt, 446 x86_intercept_sgdt, 447 x86_intercept_lldt, 448 x86_intercept_sldt, 449 x86_intercept_ltr, 450 x86_intercept_str, 451 x86_intercept_rdtsc, 452 x86_intercept_rdpmc, 453 x86_intercept_pushf, 454 x86_intercept_popf, 455 x86_intercept_cpuid, 456 x86_intercept_rsm, 457 x86_intercept_iret, 458 x86_intercept_intn, 459 x86_intercept_invd, 460 x86_intercept_pause, 461 x86_intercept_hlt, 462 x86_intercept_invlpg, 463 x86_intercept_invlpga, 464 x86_intercept_vmrun, 465 x86_intercept_vmload, 466 x86_intercept_vmsave, 467 x86_intercept_vmmcall, 468 x86_intercept_stgi, 469 x86_intercept_clgi, 470 x86_intercept_skinit, 471 x86_intercept_rdtscp, 472 x86_intercept_rdpid, 473 x86_intercept_icebp, 474 x86_intercept_wbinvd, 475 x86_intercept_monitor, 476 x86_intercept_mwait, 477 x86_intercept_rdmsr, 478 x86_intercept_wrmsr, 479 x86_intercept_in, 480 x86_intercept_ins, 481 x86_intercept_out, 482 x86_intercept_outs, 483 x86_intercept_xsetbv, 484 485 nr_x86_intercepts 486 }; 487 488 /* Host execution mode. */ 489 #if defined(CONFIG_X86_32) 490 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32 491 #elif defined(CONFIG_X86_64) 492 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64 493 #endif 494 495 int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len, int emulation_type); 496 bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt); 497 #define EMULATION_FAILED -1 498 #define EMULATION_OK 0 499 #define EMULATION_RESTART 1 500 #define EMULATION_INTERCEPTED 2 501 void init_decode_cache(struct x86_emulate_ctxt *ctxt); 502 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt); 503 int emulator_task_switch(struct x86_emulate_ctxt *ctxt, 504 u16 tss_selector, int idt_index, int reason, 505 bool has_error_code, u32 error_code); 506 int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq); 507 void emulator_invalidate_register_cache(struct x86_emulate_ctxt *ctxt); 508 void emulator_writeback_register_cache(struct x86_emulate_ctxt *ctxt); 509 bool emulator_can_use_gpa(struct x86_emulate_ctxt *ctxt); 510 511 static inline ulong reg_read(struct x86_emulate_ctxt *ctxt, unsigned nr) 512 { 513 if (KVM_EMULATOR_BUG_ON(nr >= NR_EMULATOR_GPRS, ctxt)) 514 nr &= NR_EMULATOR_GPRS - 1; 515 516 if (!(ctxt->regs_valid & (1 << nr))) { 517 ctxt->regs_valid |= 1 << nr; 518 ctxt->_regs[nr] = ctxt->ops->read_gpr(ctxt, nr); 519 } 520 return ctxt->_regs[nr]; 521 } 522 523 static inline ulong *reg_write(struct x86_emulate_ctxt *ctxt, unsigned nr) 524 { 525 if (KVM_EMULATOR_BUG_ON(nr >= NR_EMULATOR_GPRS, ctxt)) 526 nr &= NR_EMULATOR_GPRS - 1; 527 528 BUILD_BUG_ON(sizeof(ctxt->regs_dirty) * BITS_PER_BYTE < NR_EMULATOR_GPRS); 529 BUILD_BUG_ON(sizeof(ctxt->regs_valid) * BITS_PER_BYTE < NR_EMULATOR_GPRS); 530 531 ctxt->regs_valid |= 1 << nr; 532 ctxt->regs_dirty |= 1 << nr; 533 return &ctxt->_regs[nr]; 534 } 535 536 static inline ulong *reg_rmw(struct x86_emulate_ctxt *ctxt, unsigned nr) 537 { 538 reg_read(ctxt, nr); 539 return reg_write(ctxt, nr); 540 } 541 542 #endif /* _ASM_X86_KVM_X86_EMULATE_H */ 543