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 };
  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_gpr: read a general purpose register (rax - r15)
  90          *
  91          * @reg: gpr number.
  92          */
  93         ulong (*read_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg);
  94         /*
  95          * write_gpr: write a general purpose register (rax - r15)
  96          *
  97          * @reg: gpr number.
  98          * @val: value to write.
  99          */
 100         void (*write_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val);
 101         /*
 102          * read_std: Read bytes of standard (non-emulated/special) memory.
 103          *           Used for descriptor reading.
 104          *  @addr:  [IN ] Linear address from which to read.
 105          *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
 106          *  @bytes: [IN ] Number of bytes to read from memory.
 107          */
 108         int (*read_std)(struct x86_emulate_ctxt *ctxt,
 109                         unsigned long addr, void *val,
 110                         unsigned int bytes,
 111                         struct x86_exception *fault);
 112
 113         /*
 114          * write_std: Write bytes of standard (non-emulated/special) memory.
 115          *            Used for descriptor writing.
 116          *  @addr:  [IN ] Linear address to which to write.
 117          *  @val:   [OUT] Value write to memory, zero-extended to 'u_long'.
 118          *  @bytes: [IN ] Number of bytes to write to memory.
 119          */
 120         int (*write_std)(struct x86_emulate_ctxt *ctxt,
 121                          unsigned long addr, void *val, unsigned int bytes,
 122                          struct x86_exception *fault);
 123         /*
 124          * fetch: Read bytes of standard (non-emulated/special) memory.
 125          *        Used for instruction fetch.
 126          *  @addr:  [IN ] Linear address from which to read.
 127          *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
 128          *  @bytes: [IN ] Number of bytes to read from memory.
 129          */
 130         int (*fetch)(struct x86_emulate_ctxt *ctxt,
 131                      unsigned long addr, void *val, unsigned int bytes,
 132                      struct x86_exception *fault);
 133
 134         /*
 135          * read_emulated: Read bytes from emulated/special memory area.
 136          *  @addr:  [IN ] Linear address from which to read.
 137          *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
 138          *  @bytes: [IN ] Number of bytes to read from memory.
 139          */
 140         int (*read_emulated)(struct x86_emulate_ctxt *ctxt,
 141                              unsigned long addr, void *val, unsigned int bytes,
 142                              struct x86_exception *fault);
 143
 144         /*
 145          * write_emulated: Write bytes to emulated/special memory area.
 146          *  @addr:  [IN ] Linear address to which to write.
 147          *  @val:   [IN ] Value to write to memory (low-order bytes used as
 148          *                required).
 149          *  @bytes: [IN ] Number of bytes to write to memory.
 150          */
 151         int (*write_emulated)(struct x86_emulate_ctxt *ctxt,
 152                               unsigned long addr, const void *val,
 153                               unsigned int bytes,
 154                               struct x86_exception *fault);
 155
 156         /*
 157          * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
 158          *                   emulated/special memory area.
 159          *  @addr:  [IN ] Linear address to access.
 160          *  @old:   [IN ] Value expected to be current at @addr.
 161          *  @new:   [IN ] Value to write to @addr.
 162          *  @bytes: [IN ] Number of bytes to access using CMPXCHG.
 163          */
 164         int (*cmpxchg_emulated)(struct x86_emulate_ctxt *ctxt,
 165                                 unsigned long addr,
 166                                 const void *old,
 167                                 const void *new,
 168                                 unsigned int bytes,
 169                                 struct x86_exception *fault);
 170         void (*invlpg)(struct x86_emulate_ctxt *ctxt, ulong addr);
 171
 172         int (*pio_in_emulated)(struct x86_emulate_ctxt *ctxt,
 173                                int size, unsigned short port, void *val,
 174                                unsigned int count);
 175
 176         int (*pio_out_emulated)(struct x86_emulate_ctxt *ctxt,
 177                                 int size, unsigned short port, const void *val,
 178                                 unsigned int count);
 179
 180         bool (*get_segment)(struct x86_emulate_ctxt *ctxt, u16 *selector,
 181                             struct desc_struct *desc, u32 *base3, int seg);
 182         void (*set_segment)(struct x86_emulate_ctxt *ctxt, u16 selector,
 183                             struct desc_struct *desc, u32 base3, int seg);
 184         unsigned long (*get_cached_segment_base)(struct x86_emulate_ctxt *ctxt,
 185                                                  int seg);
 186         void (*get_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 187         void (*get_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 188         void (*set_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 189         void (*set_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 190         ulong (*get_cr)(struct x86_emulate_ctxt *ctxt, int cr);
 191         int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val);
 192         void (*set_rflags)(struct x86_emulate_ctxt *ctxt, ulong val);
 193         int (*cpl)(struct x86_emulate_ctxt *ctxt);
 194         int (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong *dest);
 195         int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
 196         int (*set_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data);
 197         int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
 198         int (*read_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc, u64 *pdata);
 199         void (*halt)(struct x86_emulate_ctxt *ctxt);
 200         void (*wbinvd)(struct x86_emulate_ctxt *ctxt);
 201         int (*fix_hypercall)(struct x86_emulate_ctxt *ctxt);
 202         void (*get_fpu)(struct x86_emulate_ctxt *ctxt); /* disables preempt */
 203         void (*put_fpu)(struct x86_emulate_ctxt *ctxt); /* reenables preempt */
 204         int (*intercept)(struct x86_emulate_ctxt *ctxt,
 205                          struct x86_instruction_info *info,
 206                          enum x86_intercept_stage stage);
 207
 208         void (*get_cpuid)(struct x86_emulate_ctxt *ctxt,
 209                           u32 *eax, u32 *ebx, u32 *ecx, u32 *edx);
 210 };
 211
 212 typedef u32 __attribute__((vector_size(16))) sse128_t;
 213
 214 /* Type, address-of, and value of an instruction's operand. */
 215 struct operand {
 216         enum { OP_REG, OP_MEM, OP_MEM_STR, OP_IMM, OP_XMM, OP_MM, OP_NONE } type;
 217         unsigned int bytes;
 218         unsigned int count;
 219         union {
 220                 unsigned long orig_val;
 221                 u64 orig_val64;
 222         };
 223         union {
 224                 unsigned long *reg;
 225                 struct segmented_address {
 226                         ulong ea;
 227                         unsigned seg;
 228                 } mem;
 229                 unsigned xmm;
 230                 unsigned mm;
 231         } addr;
 232         union {
 233                 unsigned long val;
 234                 u64 val64;
 235                 char valptr[sizeof(unsigned long) + 2];
 236                 sse128_t vec_val;
 237                 u64 mm_val;
 238                 void *data;
 239         };
 240 };
 241
 242 struct fetch_cache {
 243         u8 data[15];
 244         unsigned long start;
 245         unsigned long end;
 246 };
 247
 248 struct read_cache {
 249         u8 data[1024];
 250         unsigned long pos;
 251         unsigned long end;
 252 };
 253
 254 /* Execution mode, passed to the emulator. */
 255 enum x86emul_mode {
 256         X86EMUL_MODE_REAL,      /* Real mode.             */
 257         X86EMUL_MODE_VM86,      /* Virtual 8086 mode.     */
 258         X86EMUL_MODE_PROT16,    /* 16-bit protected mode. */
 259         X86EMUL_MODE_PROT32,    /* 32-bit protected mode. */
 260         X86EMUL_MODE_PROT64,    /* 64-bit (long) mode.    */
 261 };
 262
 263 struct x86_emulate_ctxt {
 264         const struct x86_emulate_ops *ops;
 265
 266         /* Register state before/after emulation. */
 267         unsigned long eflags;
 268         unsigned long eip; /* eip before instruction emulation */
 269         /* Emulated execution mode, represented by an X86EMUL_MODE value. */
 270         enum x86emul_mode mode;
 271
 272         /* interruptibility state, as a result of execution of STI or MOV SS */
 273         int interruptibility;
 274
 275         bool guest_mode; /* guest running a nested guest */
 276         bool perm_ok; /* do not check permissions if true */
 277         bool only_vendor_specific_insn;
 278
 279         bool have_exception;
 280         struct x86_exception exception;
 281
 282         /* decode cache */
 283         u8 twobyte;
 284         u8 b;
 285         u8 intercept;
 286         u8 lock_prefix;
 287         u8 rep_prefix;
 288         u8 op_bytes;
 289         u8 ad_bytes;
 290         u8 rex_prefix;
 291         struct operand src;
 292         struct operand src2;
 293         struct operand dst;
 294         bool has_seg_override;
 295         u8 seg_override;
 296         u64 d;
 297         int (*execute)(struct x86_emulate_ctxt *ctxt);
 298         int (*check_perm)(struct x86_emulate_ctxt *ctxt);
 299         /* modrm */
 300         u8 modrm;
 301         u8 modrm_mod;
 302         u8 modrm_reg;
 303         u8 modrm_rm;
 304         u8 modrm_seg;
 305         bool rip_relative;
 306         unsigned long _eip;
 307         struct operand memop;
 308         u32 regs_valid;  /* bitmaps of registers in _regs[] that can be read */
 309         u32 regs_dirty;  /* bitmaps of registers in _regs[] that have been written */
 310         /* Fields above regs are cleared together. */
 311         unsigned long _regs[NR_VCPU_REGS];
 312         struct operand *memopp;
 313         struct fetch_cache fetch;
 314         struct read_cache io_read;
 315         struct read_cache mem_read;
 316 };
 317
 318 /* Repeat String Operation Prefix */
 319 #define REPE_PREFIX     0xf3
 320 #define REPNE_PREFIX    0xf2
 321
 322 /* CPUID vendors */
 323 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx 0x68747541
 324 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx 0x444d4163
 325 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_edx 0x69746e65
 326
 327 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx 0x69444d41
 328 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx 0x21726574
 329 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_edx 0x74656273
 330
 331 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ebx 0x756e6547
 332 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e
 333 #define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69
 334
 335 enum x86_intercept_stage {
 336         X86_ICTP_NONE = 0,   /* Allow zero-init to not match anything */
 337         X86_ICPT_PRE_EXCEPT,
 338         X86_ICPT_POST_EXCEPT,
 339         X86_ICPT_POST_MEMACCESS,
 340 };
 341
 342 enum x86_intercept {
 343         x86_intercept_none,
 344         x86_intercept_cr_read,
 345         x86_intercept_cr_write,
 346         x86_intercept_clts,
 347         x86_intercept_lmsw,
 348         x86_intercept_smsw,
 349         x86_intercept_dr_read,
 350         x86_intercept_dr_write,
 351         x86_intercept_lidt,
 352         x86_intercept_sidt,
 353         x86_intercept_lgdt,
 354         x86_intercept_sgdt,
 355         x86_intercept_lldt,
 356         x86_intercept_sldt,
 357         x86_intercept_ltr,
 358         x86_intercept_str,
 359         x86_intercept_rdtsc,
 360         x86_intercept_rdpmc,
 361         x86_intercept_pushf,
 362         x86_intercept_popf,
 363         x86_intercept_cpuid,
 364         x86_intercept_rsm,
 365         x86_intercept_iret,
 366         x86_intercept_intn,
 367         x86_intercept_invd,
 368         x86_intercept_pause,
 369         x86_intercept_hlt,
 370         x86_intercept_invlpg,
 371         x86_intercept_invlpga,
 372         x86_intercept_vmrun,
 373         x86_intercept_vmload,
 374         x86_intercept_vmsave,
 375         x86_intercept_vmmcall,
 376         x86_intercept_stgi,
 377         x86_intercept_clgi,
 378         x86_intercept_skinit,
 379         x86_intercept_rdtscp,
 380         x86_intercept_icebp,
 381         x86_intercept_wbinvd,
 382         x86_intercept_monitor,
 383         x86_intercept_mwait,
 384         x86_intercept_rdmsr,
 385         x86_intercept_wrmsr,
 386         x86_intercept_in,
 387         x86_intercept_ins,
 388         x86_intercept_out,
 389         x86_intercept_outs,
 390
 391         nr_x86_intercepts
 392 };
 393
 394 /* Host execution mode. */
 395 #if defined(CONFIG_X86_32)
 396 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
 397 #elif defined(CONFIG_X86_64)
 398 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
 399 #endif
 400
 401 int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len);
 402 bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt);
 403 #define EMULATION_FAILED -1
 404 #define EMULATION_OK 0
 405 #define EMULATION_RESTART 1
 406 #define EMULATION_INTERCEPTED 2
 407 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt);
 408 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
 409                          u16 tss_selector, int idt_index, int reason,
 410                          bool has_error_code, u32 error_code);
 411 int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq);
 412 void emulator_invalidate_register_cache(struct x86_emulate_ctxt *ctxt);
 413 void emulator_writeback_register_cache(struct x86_emulate_ctxt *ctxt);
 414
 415 #endif /* _ASM_X86_KVM_X86_EMULATE_H */