arch/x86/include/asm/kvm_emulate.h

   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         u8 async_page_fault;
  27 };
  28
  29 /*
  30  * This struct is used to carry enough information from the instruction
  31  * decoder to main KVM so that a decision can be made whether the
  32  * instruction needs to be intercepted or not.
  33  */
  34 struct x86_instruction_info {
  35         u8  intercept;          /* which intercept                      */
  36         u8  rep_prefix;         /* rep prefix?                          */
  37         u8  modrm_mod;          /* mod part of modrm                    */
  38         u8  modrm_reg;          /* index of register used               */
  39         u8  modrm_rm;           /* rm part of modrm                     */
  40         u64 src_val;            /* value of source operand              */
  41         u64 dst_val;            /* value of destination operand         */
  42         u8  src_bytes;          /* size of source operand               */
  43         u8  dst_bytes;          /* size of destination operand          */
  44         u8  ad_bytes;           /* size of src/dst address              */
  45         u64 next_rip;           /* rip following the instruction        */
  46 };
  47
  48 /*
  49  * x86_emulate_ops:
  50  *
  51  * These operations represent the instruction emulator's interface to memory.
  52  * There are two categories of operation: those that act on ordinary memory
  53  * regions (*_std), and those that act on memory regions known to require
  54  * special treatment or emulation (*_emulated).
  55  *
  56  * The emulator assumes that an instruction accesses only one 'emulated memory'
  57  * location, that this location is the given linear faulting address (cr2), and
  58  * that this is one of the instruction's data operands. Instruction fetches and
  59  * stack operations are assumed never to access emulated memory. The emulator
  60  * automatically deduces which operand of a string-move operation is accessing
  61  * emulated memory, and assumes that the other operand accesses normal memory.
  62  *
  63  * NOTES:
  64  *  1. The emulator isn't very smart about emulated vs. standard memory.
  65  *     'Emulated memory' access addresses should be checked for sanity.
  66  *     'Normal memory' accesses may fault, and the caller must arrange to
  67  *     detect and handle reentrancy into the emulator via recursive faults.
  68  *     Accesses may be unaligned and may cross page boundaries.
  69  *  2. If the access fails (cannot emulate, or a standard access faults) then
  70  *     it is up to the memop to propagate the fault to the guest VM via
  71  *     some out-of-band mechanism, unknown to the emulator. The memop signals
  72  *     failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
  73  *     then immediately bail.
  74  *  3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
  75  *     cmpxchg8b_emulated need support 8-byte accesses.
  76  *  4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
  77  */
  78 /* Access completed successfully: continue emulation as normal. */
  79 #define X86EMUL_CONTINUE        0
  80 /* Access is unhandleable: bail from emulation and return error to caller. */
  81 #define X86EMUL_UNHANDLEABLE    1
  82 /* Terminate emulation but return success to the caller. */
  83 #define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
  84 #define X86EMUL_RETRY_INSTR     3 /* retry the instruction for some reason */
  85 #define X86EMUL_CMPXCHG_FAILED  4 /* cmpxchg did not see expected value */
  86 #define X86EMUL_IO_NEEDED       5 /* IO is needed to complete emulation */
  87 #define X86EMUL_INTERCEPTED     6 /* Intercepted by nested VMCB/VMCS */
  88
  89 struct x86_emulate_ops {
  90         /*
  91          * read_gpr: read a general purpose register (rax - r15)
  92          *
  93          * @reg: gpr number.
  94          */
  95         ulong (*read_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg);
  96         /*
  97          * write_gpr: write a general purpose register (rax - r15)
  98          *
  99          * @reg: gpr number.
 100          * @val: value to write.
 101          */
 102         void (*write_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val);
 103         /*
 104          * read_std: Read bytes of standard (non-emulated/special) memory.
 105          *           Used for descriptor reading.
 106          *  @addr:  [IN ] Linear address from which to read.
 107          *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
 108          *  @bytes: [IN ] Number of bytes to read from memory.
 109          */
 110         int (*read_std)(struct x86_emulate_ctxt *ctxt,
 111                         unsigned long addr, void *val,
 112                         unsigned int bytes,
 113                         struct x86_exception *fault);
 114
 115         /*
 116          * read_phys: Read bytes of standard (non-emulated/special) memory.
 117          *            Used for descriptor reading.
 118          *  @addr:  [IN ] Physical address from which to read.
 119          *  @val:   [OUT] Value read from memory.
 120          *  @bytes: [IN ] Number of bytes to read from memory.
 121          */
 122         int (*read_phys)(struct x86_emulate_ctxt *ctxt, unsigned long addr,
 123                         void *val, unsigned int bytes);
 124
 125         /*
 126          * write_std: Write bytes of standard (non-emulated/special) memory.
 127          *            Used for descriptor writing.
 128          *  @addr:  [IN ] Linear address to which to write.
 129          *  @val:   [OUT] Value write to memory, zero-extended to 'u_long'.
 130          *  @bytes: [IN ] Number of bytes to write to memory.
 131          */
 132         int (*write_std)(struct x86_emulate_ctxt *ctxt,
 133                          unsigned long addr, void *val, unsigned int bytes,
 134                          struct x86_exception *fault);
 135         /*
 136          * fetch: Read bytes of standard (non-emulated/special) memory.
 137          *        Used for instruction fetch.
 138          *  @addr:  [IN ] Linear address from which to read.
 139          *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
 140          *  @bytes: [IN ] Number of bytes to read from memory.
 141          */
 142         int (*fetch)(struct x86_emulate_ctxt *ctxt,
 143                      unsigned long addr, void *val, unsigned int bytes,
 144                      struct x86_exception *fault);
 145
 146         /*
 147          * read_emulated: Read bytes from emulated/special memory area.
 148          *  @addr:  [IN ] Linear address from which to read.
 149          *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
 150          *  @bytes: [IN ] Number of bytes to read from memory.
 151          */
 152         int (*read_emulated)(struct x86_emulate_ctxt *ctxt,
 153                              unsigned long addr, void *val, unsigned int bytes,
 154                              struct x86_exception *fault);
 155
 156         /*
 157          * write_emulated: Write bytes to emulated/special memory area.
 158          *  @addr:  [IN ] Linear address to which to write.
 159          *  @val:   [IN ] Value to write to memory (low-order bytes used as
 160          *                required).
 161          *  @bytes: [IN ] Number of bytes to write to memory.
 162          */
 163         int (*write_emulated)(struct x86_emulate_ctxt *ctxt,
 164                               unsigned long addr, const void *val,
 165                               unsigned int bytes,
 166                               struct x86_exception *fault);
 167
 168         /*
 169          * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
 170          *                   emulated/special memory area.
 171          *  @addr:  [IN ] Linear address to access.
 172          *  @old:   [IN ] Value expected to be current at @addr.
 173          *  @new:   [IN ] Value to write to @addr.
 174          *  @bytes: [IN ] Number of bytes to access using CMPXCHG.
 175          */
 176         int (*cmpxchg_emulated)(struct x86_emulate_ctxt *ctxt,
 177                                 unsigned long addr,
 178                                 const void *old,
 179                                 const void *new,
 180                                 unsigned int bytes,
 181                                 struct x86_exception *fault);
 182         void (*invlpg)(struct x86_emulate_ctxt *ctxt, ulong addr);
 183
 184         int (*pio_in_emulated)(struct x86_emulate_ctxt *ctxt,
 185                                int size, unsigned short port, void *val,
 186                                unsigned int count);
 187
 188         int (*pio_out_emulated)(struct x86_emulate_ctxt *ctxt,
 189                                 int size, unsigned short port, const void *val,
 190                                 unsigned int count);
 191
 192         bool (*get_segment)(struct x86_emulate_ctxt *ctxt, u16 *selector,
 193                             struct desc_struct *desc, u32 *base3, int seg);
 194         void (*set_segment)(struct x86_emulate_ctxt *ctxt, u16 selector,
 195                             struct desc_struct *desc, u32 base3, int seg);
 196         unsigned long (*get_cached_segment_base)(struct x86_emulate_ctxt *ctxt,
 197                                                  int seg);
 198         void (*get_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 199         void (*get_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 200         void (*set_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 201         void (*set_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 202         ulong (*get_cr)(struct x86_emulate_ctxt *ctxt, int cr);
 203         int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val);
 204         int (*cpl)(struct x86_emulate_ctxt *ctxt);
 205         int (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong *dest);
 206         int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
 207         u64 (*get_smbase)(struct x86_emulate_ctxt *ctxt);
 208         void (*set_smbase)(struct x86_emulate_ctxt *ctxt, u64 smbase);
 209         int (*set_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data);
 210         int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
 211         int (*check_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc);
 212         int (*read_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc, u64 *pdata);
 213         void (*halt)(struct x86_emulate_ctxt *ctxt);
 214         void (*wbinvd)(struct x86_emulate_ctxt *ctxt);
 215         int (*fix_hypercall)(struct x86_emulate_ctxt *ctxt);
 216         void (*get_fpu)(struct x86_emulate_ctxt *ctxt); /* disables preempt */
 217         void (*put_fpu)(struct x86_emulate_ctxt *ctxt); /* reenables preempt */
 218         int (*intercept)(struct x86_emulate_ctxt *ctxt,
 219                          struct x86_instruction_info *info,
 220                          enum x86_intercept_stage stage);
 221
 222         void (*get_cpuid)(struct x86_emulate_ctxt *ctxt,
 223                           u32 *eax, u32 *ebx, u32 *ecx, u32 *edx);
 224         void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked);
 225
 226         unsigned (*get_hflags)(struct x86_emulate_ctxt *ctxt);
 227         void (*set_hflags)(struct x86_emulate_ctxt *ctxt, unsigned hflags);
 228 };
 229
 230 typedef u32 __attribute__((vector_size(16))) sse128_t;
 231
 232 /* Type, address-of, and value of an instruction's operand. */
 233 struct operand {
 234         enum { OP_REG, OP_MEM, OP_MEM_STR, OP_IMM, OP_XMM, OP_MM, OP_NONE } type;
 235         unsigned int bytes;
 236         unsigned int count;
 237         union {
 238                 unsigned long orig_val;
 239                 u64 orig_val64;
 240         };
 241         union {
 242                 unsigned long *reg;
 243                 struct segmented_address {
 244                         ulong ea;
 245                         unsigned seg;
 246                 } mem;
 247                 unsigned xmm;
 248                 unsigned mm;
 249         } addr;
 250         union {
 251                 unsigned long val;
 252                 u64 val64;
 253                 char valptr[sizeof(sse128_t)];
 254                 sse128_t vec_val;
 255                 u64 mm_val;
 256                 void *data;
 257         };
 258 };
 259
 260 struct fetch_cache {
 261         u8 data[15];
 262         u8 *ptr;
 263         u8 *end;
 264 };
 265
 266 struct read_cache {
 267         u8 data[1024];
 268         unsigned long pos;
 269         unsigned long end;
 270 };
 271
 272 /* Execution mode, passed to the emulator. */
 273 enum x86emul_mode {
 274         X86EMUL_MODE_REAL,      /* Real mode.             */
 275         X86EMUL_MODE_VM86,      /* Virtual 8086 mode.     */
 276         X86EMUL_MODE_PROT16,    /* 16-bit protected mode. */
 277         X86EMUL_MODE_PROT32,    /* 32-bit protected mode. */
 278         X86EMUL_MODE_PROT64,    /* 64-bit (long) mode.    */
 279 };
 280
 281 /* These match some of the HF_* flags defined in kvm_host.h  */
 282 #define X86EMUL_GUEST_MASK           (1 << 5) /* VCPU is in guest-mode */
 283 #define X86EMUL_SMM_MASK             (1 << 6)
 284 #define X86EMUL_SMM_INSIDE_NMI_MASK  (1 << 7)
 285
 286 struct x86_emulate_ctxt {
 287         const struct x86_emulate_ops *ops;
 288
 289         /* Register state before/after emulation. */
 290         unsigned long eflags;
 291         unsigned long eip; /* eip before instruction emulation */
 292         /* Emulated execution mode, represented by an X86EMUL_MODE value. */
 293         enum x86emul_mode mode;
 294
 295         /* interruptibility state, as a result of execution of STI or MOV SS */
 296         int interruptibility;
 297
 298         bool perm_ok; /* do not check permissions if true */
 299         bool ud;        /* inject an #UD if host doesn't support insn */
 300         bool tf;        /* TF value before instruction (after for syscall/sysret) */
 301
 302         bool have_exception;
 303         struct x86_exception exception;
 304
 305         /*
 306          * decode cache
 307          */
 308
 309         /* current opcode length in bytes */
 310         u8 opcode_len;
 311         u8 b;
 312         u8 intercept;
 313         u8 op_bytes;
 314         u8 ad_bytes;
 315         struct operand src;
 316         struct operand src2;
 317         struct operand dst;
 318         int (*execute)(struct x86_emulate_ctxt *ctxt);
 319         int (*check_perm)(struct x86_emulate_ctxt *ctxt);
 320         /*
 321          * The following six fields are cleared together,
 322          * the rest are initialized unconditionally in x86_decode_insn
 323          * or elsewhere
 324          */
 325         bool rip_relative;
 326         u8 rex_prefix;
 327         u8 lock_prefix;
 328         u8 rep_prefix;
 329         /* bitmaps of registers in _regs[] that can be read */
 330         u32 regs_valid;
 331         /* bitmaps of registers in _regs[] that have been written */
 332         u32 regs_dirty;
 333         /* modrm */
 334         u8 modrm;
 335         u8 modrm_mod;
 336         u8 modrm_reg;
 337         u8 modrm_rm;
 338         u8 modrm_seg;
 339         u8 seg_override;
 340         u64 d;
 341         unsigned long _eip;
 342         struct operand memop;
 343         /* Fields above regs are cleared together. */
 344         unsigned long _regs[NR_VCPU_REGS];
 345         struct operand *memopp;
 346         struct fetch_cache fetch;
 347         struct read_cache io_read;
 348         struct read_cache mem_read;
 349 };
 350
 351 /* Repeat String Operation Prefix */
 352 #define REPE_PREFIX     0xf3
 353 #define REPNE_PREFIX    0xf2
 354
 355 /* CPUID vendors */
 356 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx 0x68747541
 357 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx 0x444d4163
 358 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_edx 0x69746e65
 359
 360 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx 0x69444d41
 361 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx 0x21726574
 362 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_edx 0x74656273
 363
 364 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ebx 0x756e6547
 365 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e
 366 #define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69
 367
 368 enum x86_intercept_stage {
 369         X86_ICTP_NONE = 0,   /* Allow zero-init to not match anything */
 370         X86_ICPT_PRE_EXCEPT,
 371         X86_ICPT_POST_EXCEPT,
 372         X86_ICPT_POST_MEMACCESS,
 373 };
 374
 375 enum x86_intercept {
 376         x86_intercept_none,
 377         x86_intercept_cr_read,
 378         x86_intercept_cr_write,
 379         x86_intercept_clts,
 380         x86_intercept_lmsw,
 381         x86_intercept_smsw,
 382         x86_intercept_dr_read,
 383         x86_intercept_dr_write,
 384         x86_intercept_lidt,
 385         x86_intercept_sidt,
 386         x86_intercept_lgdt,
 387         x86_intercept_sgdt,
 388         x86_intercept_lldt,
 389         x86_intercept_sldt,
 390         x86_intercept_ltr,
 391         x86_intercept_str,
 392         x86_intercept_rdtsc,
 393         x86_intercept_rdpmc,
 394         x86_intercept_pushf,
 395         x86_intercept_popf,
 396         x86_intercept_cpuid,
 397         x86_intercept_rsm,
 398         x86_intercept_iret,
 399         x86_intercept_intn,
 400         x86_intercept_invd,
 401         x86_intercept_pause,
 402         x86_intercept_hlt,
 403         x86_intercept_invlpg,
 404         x86_intercept_invlpga,
 405         x86_intercept_vmrun,
 406         x86_intercept_vmload,
 407         x86_intercept_vmsave,
 408         x86_intercept_vmmcall,
 409         x86_intercept_stgi,
 410         x86_intercept_clgi,
 411         x86_intercept_skinit,
 412         x86_intercept_rdtscp,
 413         x86_intercept_icebp,
 414         x86_intercept_wbinvd,
 415         x86_intercept_monitor,
 416         x86_intercept_mwait,
 417         x86_intercept_rdmsr,
 418         x86_intercept_wrmsr,
 419         x86_intercept_in,
 420         x86_intercept_ins,
 421         x86_intercept_out,
 422         x86_intercept_outs,
 423
 424         nr_x86_intercepts
 425 };
 426
 427 /* Host execution mode. */
 428 #if defined(CONFIG_X86_32)
 429 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
 430 #elif defined(CONFIG_X86_64)
 431 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
 432 #endif
 433
 434 int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len);
 435 bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt);
 436 #define EMULATION_FAILED -1
 437 #define EMULATION_OK 0
 438 #define EMULATION_RESTART 1
 439 #define EMULATION_INTERCEPTED 2
 440 void init_decode_cache(struct x86_emulate_ctxt *ctxt);
 441 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt);
 442 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
 443                          u16 tss_selector, int idt_index, int reason,
 444                          bool has_error_code, u32 error_code);
 445 int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq);
 446 void emulator_invalidate_register_cache(struct x86_emulate_ctxt *ctxt);
 447 void emulator_writeback_register_cache(struct x86_emulate_ctxt *ctxt);
 448 bool emulator_can_use_gpa(struct x86_emulate_ctxt *ctxt);
 449
 450 #endif /* _ASM_X86_KVM_X86_EMULATE_H */