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 void (*set_rflags)(struct x86_emulate_ctxt *ctxt, ulong val); 180 int (*cpl)(struct x86_emulate_ctxt *ctxt); 181 int (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong *dest); 182 int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value); 183 int (*set_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data); 184 int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata); 185 int (*read_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc, u64 *pdata); 186 void (*halt)(struct x86_emulate_ctxt *ctxt); 187 void (*wbinvd)(struct x86_emulate_ctxt *ctxt); 188 int (*fix_hypercall)(struct x86_emulate_ctxt *ctxt); 189 void (*get_fpu)(struct x86_emulate_ctxt *ctxt); /* disables preempt */ 190 void (*put_fpu)(struct x86_emulate_ctxt *ctxt); /* reenables preempt */ 191 int (*intercept)(struct x86_emulate_ctxt *ctxt, 192 struct x86_instruction_info *info, 193 enum x86_intercept_stage stage); 194 195 bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt, 196 u32 *eax, u32 *ebx, u32 *ecx, u32 *edx); 197 }; 198 199 typedef u32 __attribute__((vector_size(16))) sse128_t; 200 201 /* Type, address-of, and value of an instruction's operand. */ 202 struct operand { 203 enum { OP_REG, OP_MEM, OP_IMM, OP_XMM, OP_NONE } type; 204 unsigned int bytes; 205 union { 206 unsigned long orig_val; 207 u64 orig_val64; 208 }; 209 union { 210 unsigned long *reg; 211 struct segmented_address { 212 ulong ea; 213 unsigned seg; 214 } mem; 215 unsigned xmm; 216 } addr; 217 union { 218 unsigned long val; 219 u64 val64; 220 char valptr[sizeof(unsigned long) + 2]; 221 sse128_t vec_val; 222 }; 223 }; 224 225 struct fetch_cache { 226 u8 data[15]; 227 unsigned long start; 228 unsigned long end; 229 }; 230 231 struct read_cache { 232 u8 data[1024]; 233 unsigned long pos; 234 unsigned long end; 235 }; 236 237 struct x86_emulate_ctxt { 238 struct x86_emulate_ops *ops; 239 240 /* Register state before/after emulation. */ 241 unsigned long eflags; 242 unsigned long eip; /* eip before instruction emulation */ 243 /* Emulated execution mode, represented by an X86EMUL_MODE value. */ 244 int mode; 245 246 /* interruptibility state, as a result of execution of STI or MOV SS */ 247 int interruptibility; 248 249 bool guest_mode; /* guest running a nested guest */ 250 bool perm_ok; /* do not check permissions if true */ 251 bool only_vendor_specific_insn; 252 253 bool have_exception; 254 struct x86_exception exception; 255 256 /* decode cache */ 257 u8 twobyte; 258 u8 b; 259 u8 intercept; 260 u8 lock_prefix; 261 u8 rep_prefix; 262 u8 op_bytes; 263 u8 ad_bytes; 264 u8 rex_prefix; 265 struct operand src; 266 struct operand src2; 267 struct operand dst; 268 bool has_seg_override; 269 u8 seg_override; 270 u64 d; 271 int (*execute)(struct x86_emulate_ctxt *ctxt); 272 int (*check_perm)(struct x86_emulate_ctxt *ctxt); 273 /* modrm */ 274 u8 modrm; 275 u8 modrm_mod; 276 u8 modrm_reg; 277 u8 modrm_rm; 278 u8 modrm_seg; 279 bool rip_relative; 280 unsigned long _eip; 281 /* Fields above regs are cleared together. */ 282 unsigned long regs[NR_VCPU_REGS]; 283 struct operand memop; 284 struct operand *memopp; 285 struct fetch_cache fetch; 286 struct read_cache io_read; 287 struct read_cache mem_read; 288 }; 289 290 /* Repeat String Operation Prefix */ 291 #define REPE_PREFIX 0xf3 292 #define REPNE_PREFIX 0xf2 293 294 /* Execution mode, passed to the emulator. */ 295 #define X86EMUL_MODE_REAL 0 /* Real mode. */ 296 #define X86EMUL_MODE_VM86 1 /* Virtual 8086 mode. */ 297 #define X86EMUL_MODE_PROT16 2 /* 16-bit protected mode. */ 298 #define X86EMUL_MODE_PROT32 4 /* 32-bit protected mode. */ 299 #define X86EMUL_MODE_PROT64 8 /* 64-bit (long) mode. */ 300 301 /* any protected mode */ 302 #define X86EMUL_MODE_PROT (X86EMUL_MODE_PROT16|X86EMUL_MODE_PROT32| \ 303 X86EMUL_MODE_PROT64) 304 305 /* CPUID vendors */ 306 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx 0x68747541 307 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx 0x444d4163 308 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_edx 0x69746e65 309 310 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx 0x69444d41 311 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx 0x21726574 312 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_edx 0x74656273 313 314 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ebx 0x756e6547 315 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e 316 #define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69 317 318 enum x86_intercept_stage { 319 X86_ICTP_NONE = 0, /* Allow zero-init to not match anything */ 320 X86_ICPT_PRE_EXCEPT, 321 X86_ICPT_POST_EXCEPT, 322 X86_ICPT_POST_MEMACCESS, 323 }; 324 325 enum x86_intercept { 326 x86_intercept_none, 327 x86_intercept_cr_read, 328 x86_intercept_cr_write, 329 x86_intercept_clts, 330 x86_intercept_lmsw, 331 x86_intercept_smsw, 332 x86_intercept_dr_read, 333 x86_intercept_dr_write, 334 x86_intercept_lidt, 335 x86_intercept_sidt, 336 x86_intercept_lgdt, 337 x86_intercept_sgdt, 338 x86_intercept_lldt, 339 x86_intercept_sldt, 340 x86_intercept_ltr, 341 x86_intercept_str, 342 x86_intercept_rdtsc, 343 x86_intercept_rdpmc, 344 x86_intercept_pushf, 345 x86_intercept_popf, 346 x86_intercept_cpuid, 347 x86_intercept_rsm, 348 x86_intercept_iret, 349 x86_intercept_intn, 350 x86_intercept_invd, 351 x86_intercept_pause, 352 x86_intercept_hlt, 353 x86_intercept_invlpg, 354 x86_intercept_invlpga, 355 x86_intercept_vmrun, 356 x86_intercept_vmload, 357 x86_intercept_vmsave, 358 x86_intercept_vmmcall, 359 x86_intercept_stgi, 360 x86_intercept_clgi, 361 x86_intercept_skinit, 362 x86_intercept_rdtscp, 363 x86_intercept_icebp, 364 x86_intercept_wbinvd, 365 x86_intercept_monitor, 366 x86_intercept_mwait, 367 x86_intercept_rdmsr, 368 x86_intercept_wrmsr, 369 x86_intercept_in, 370 x86_intercept_ins, 371 x86_intercept_out, 372 x86_intercept_outs, 373 374 nr_x86_intercepts 375 }; 376 377 /* Host execution mode. */ 378 #if defined(CONFIG_X86_32) 379 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32 380 #elif defined(CONFIG_X86_64) 381 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64 382 #endif 383 384 int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len); 385 bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt); 386 #define EMULATION_FAILED -1 387 #define EMULATION_OK 0 388 #define EMULATION_RESTART 1 389 #define EMULATION_INTERCEPTED 2 390 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt); 391 int emulator_task_switch(struct x86_emulate_ctxt *ctxt, 392 u16 tss_selector, int idt_index, int reason, 393 bool has_error_code, u32 error_code); 394 int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq); 395 #endif /* _ASM_X86_KVM_X86_EMULATE_H */ 396