arch/x86/include/asm/kvm_emulate.h

   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
  17 struct x86_emulate_ctxt;
  18 enum x86_intercept;
  19 enum x86_intercept_stage;
  20
  21 struct x86_exception {
  22         u8 vector;
  23         bool error_code_valid;
  24         u16 error_code;
  25         bool nested_page_fault;
  26         u64 address; /* cr2 or nested page fault gpa */
  27         u8 async_page_fault;
  28 };
  29
  30 /*
  31  * This struct is used to carry enough information from the instruction
  32  * decoder to main KVM so that a decision can be made whether the
  33  * instruction needs to be intercepted or not.
  34  */
  35 struct x86_instruction_info {
  36         u8  intercept;          /* which intercept                      */
  37         u8  rep_prefix;         /* rep prefix?                          */
  38         u8  modrm_mod;          /* mod part of modrm                    */
  39         u8  modrm_reg;          /* index of register used               */
  40         u8  modrm_rm;           /* rm part of modrm                     */
  41         u64 src_val;            /* value of source operand              */
  42         u64 dst_val;            /* value of destination operand         */
  43         u8  src_bytes;          /* size of source operand               */
  44         u8  dst_bytes;          /* size of destination operand          */
  45         u8  ad_bytes;           /* size of src/dst address              */
  46         u64 next_rip;           /* rip following the instruction        */
  47 };
  48
  49 /*
  50  * x86_emulate_ops:
  51  *
  52  * These operations represent the instruction emulator's interface to memory.
  53  * There are two categories of operation: those that act on ordinary memory
  54  * regions (*_std), and those that act on memory regions known to require
  55  * special treatment or emulation (*_emulated).
  56  *
  57  * The emulator assumes that an instruction accesses only one 'emulated memory'
  58  * location, that this location is the given linear faulting address (cr2), and
  59  * that this is one of the instruction's data operands. Instruction fetches and
  60  * stack operations are assumed never to access emulated memory. The emulator
  61  * automatically deduces which operand of a string-move operation is accessing
  62  * emulated memory, and assumes that the other operand accesses normal memory.
  63  *
  64  * NOTES:
  65  *  1. The emulator isn't very smart about emulated vs. standard memory.
  66  *     'Emulated memory' access addresses should be checked for sanity.
  67  *     'Normal memory' accesses may fault, and the caller must arrange to
  68  *     detect and handle reentrancy into the emulator via recursive faults.
  69  *     Accesses may be unaligned and may cross page boundaries.
  70  *  2. If the access fails (cannot emulate, or a standard access faults) then
  71  *     it is up to the memop to propagate the fault to the guest VM via
  72  *     some out-of-band mechanism, unknown to the emulator. The memop signals
  73  *     failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
  74  *     then immediately bail.
  75  *  3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
  76  *     cmpxchg8b_emulated need support 8-byte accesses.
  77  *  4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
  78  */
  79 /* Access completed successfully: continue emulation as normal. */
  80 #define X86EMUL_CONTINUE        0
  81 /* Access is unhandleable: bail from emulation and return error to caller. */
  82 #define X86EMUL_UNHANDLEABLE    1
  83 /* Terminate emulation but return success to the caller. */
  84 #define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
  85 #define X86EMUL_RETRY_INSTR     3 /* retry the instruction for some reason */
  86 #define X86EMUL_CMPXCHG_FAILED  4 /* cmpxchg did not see expected value */
  87 #define X86EMUL_IO_NEEDED       5 /* IO is needed to complete emulation */
  88 #define X86EMUL_INTERCEPTED     6 /* Intercepted by nested VMCB/VMCS */
  89
  90 struct x86_emulate_ops {
  91         /*
  92          * read_gpr: read a general purpose register (rax - r15)
  93          *
  94          * @reg: gpr number.
  95          */
  96         ulong (*read_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg);
  97         /*
  98          * write_gpr: write a general purpose register (rax - r15)
  99          *
 100          * @reg: gpr number.
 101          * @val: value to write.
 102          */
 103         void (*write_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val);
 104         /*
 105          * read_std: Read bytes of standard (non-emulated/special) memory.
 106          *           Used for descriptor reading.
 107          *  @addr:  [IN ] Linear address from which to read.
 108          *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
 109          *  @bytes: [IN ] Number of bytes to read from memory.
 110          *  @system:[IN ] Whether the access is forced to be at CPL0.
 111          */
 112         int (*read_std)(struct x86_emulate_ctxt *ctxt,
 113                         unsigned long addr, void *val,
 114                         unsigned int bytes,
 115                         struct x86_exception *fault, bool system);
 116
 117         /*
 118          * read_phys: Read bytes of standard (non-emulated/special) memory.
 119          *            Used for descriptor reading.
 120          *  @addr:  [IN ] Physical address from which to read.
 121          *  @val:   [OUT] Value read from memory.
 122          *  @bytes: [IN ] Number of bytes to read from memory.
 123          */
 124         int (*read_phys)(struct x86_emulate_ctxt *ctxt, unsigned long addr,
 125                         void *val, unsigned int bytes);
 126
 127         /*
 128          * write_std: Write bytes of standard (non-emulated/special) memory.
 129          *            Used for descriptor writing.
 130          *  @addr:  [IN ] Linear address to which to write.
 131          *  @val:   [OUT] Value write to memory, zero-extended to 'u_long'.
 132          *  @bytes: [IN ] Number of bytes to write to memory.
 133          *  @system:[IN ] Whether the access is forced to be at CPL0.
 134          */
 135         int (*write_std)(struct x86_emulate_ctxt *ctxt,
 136                          unsigned long addr, void *val, unsigned int bytes,
 137                          struct x86_exception *fault, bool system);
 138         /*
 139          * fetch: Read bytes of standard (non-emulated/special) memory.
 140          *        Used for instruction fetch.
 141          *  @addr:  [IN ] Linear address from which to read.
 142          *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
 143          *  @bytes: [IN ] Number of bytes to read from memory.
 144          */
 145         int (*fetch)(struct x86_emulate_ctxt *ctxt,
 146                      unsigned long addr, void *val, unsigned int bytes,
 147                      struct x86_exception *fault);
 148
 149         /*
 150          * read_emulated: Read bytes from emulated/special memory area.
 151          *  @addr:  [IN ] Linear address from which to read.
 152          *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
 153          *  @bytes: [IN ] Number of bytes to read from memory.
 154          */
 155         int (*read_emulated)(struct x86_emulate_ctxt *ctxt,
 156                              unsigned long addr, void *val, unsigned int bytes,
 157                              struct x86_exception *fault);
 158
 159         /*
 160          * write_emulated: Write bytes to emulated/special memory area.
 161          *  @addr:  [IN ] Linear address to which to write.
 162          *  @val:   [IN ] Value to write to memory (low-order bytes used as
 163          *                required).
 164          *  @bytes: [IN ] Number of bytes to write to memory.
 165          */
 166         int (*write_emulated)(struct x86_emulate_ctxt *ctxt,
 167                               unsigned long addr, const void *val,
 168                               unsigned int bytes,
 169                               struct x86_exception *fault);
 170
 171         /*
 172          * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
 173          *                   emulated/special memory area.
 174          *  @addr:  [IN ] Linear address to access.
 175          *  @old:   [IN ] Value expected to be current at @addr.
 176          *  @new:   [IN ] Value to write to @addr.
 177          *  @bytes: [IN ] Number of bytes to access using CMPXCHG.
 178          */
 179         int (*cmpxchg_emulated)(struct x86_emulate_ctxt *ctxt,
 180                                 unsigned long addr,
 181                                 const void *old,
 182                                 const void *new,
 183                                 unsigned int bytes,
 184                                 struct x86_exception *fault);
 185         void (*invlpg)(struct x86_emulate_ctxt *ctxt, ulong addr);
 186
 187         int (*pio_in_emulated)(struct x86_emulate_ctxt *ctxt,
 188                                int size, unsigned short port, void *val,
 189                                unsigned int count);
 190
 191         int (*pio_out_emulated)(struct x86_emulate_ctxt *ctxt,
 192                                 int size, unsigned short port, const void *val,
 193                                 unsigned int count);
 194
 195         bool (*get_segment)(struct x86_emulate_ctxt *ctxt, u16 *selector,
 196                             struct desc_struct *desc, u32 *base3, int seg);
 197         void (*set_segment)(struct x86_emulate_ctxt *ctxt, u16 selector,
 198                             struct desc_struct *desc, u32 base3, int seg);
 199         unsigned long (*get_cached_segment_base)(struct x86_emulate_ctxt *ctxt,
 200                                                  int seg);
 201         void (*get_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 202         void (*get_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 203         void (*set_gdt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 204         void (*set_idt)(struct x86_emulate_ctxt *ctxt, struct desc_ptr *dt);
 205         ulong (*get_cr)(struct x86_emulate_ctxt *ctxt, int cr);
 206         int (*set_cr)(struct x86_emulate_ctxt *ctxt, int cr, ulong val);
 207         int (*cpl)(struct x86_emulate_ctxt *ctxt);
 208         int (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong *dest);
 209         int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
 210         u64 (*get_smbase)(struct x86_emulate_ctxt *ctxt);
 211         void (*set_smbase)(struct x86_emulate_ctxt *ctxt, u64 smbase);
 212         int (*set_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data);
 213         int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
 214         int (*check_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc);
 215         int (*read_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc, u64 *pdata);
 216         void (*halt)(struct x86_emulate_ctxt *ctxt);
 217         void (*wbinvd)(struct x86_emulate_ctxt *ctxt);
 218         int (*fix_hypercall)(struct x86_emulate_ctxt *ctxt);
 219         int (*intercept)(struct x86_emulate_ctxt *ctxt,
 220                          struct x86_instruction_info *info,
 221                          enum x86_intercept_stage stage);
 222
 223         bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt, u32 *eax, u32 *ebx,
 224                           u32 *ecx, u32 *edx, bool check_limit);
 225         void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked);
 226
 227         unsigned (*get_hflags)(struct x86_emulate_ctxt *ctxt);
 228         void (*set_hflags)(struct x86_emulate_ctxt *ctxt, unsigned hflags);
 229         int (*pre_leave_smm)(struct x86_emulate_ctxt *ctxt, u64 smbase);
 230
 231 };
 232
 233 typedef u32 __attribute__((vector_size(16))) sse128_t;
 234
 235 /* Type, address-of, and value of an instruction's operand. */
 236 struct operand {
 237         enum { OP_REG, OP_MEM, OP_MEM_STR, OP_IMM, OP_XMM, OP_MM, OP_NONE } type;
 238         unsigned int bytes;
 239         unsigned int count;
 240         union {
 241                 unsigned long orig_val;
 242                 u64 orig_val64;
 243         };
 244         union {
 245                 unsigned long *reg;
 246                 struct segmented_address {
 247                         ulong ea;
 248                         unsigned seg;
 249                 } mem;
 250                 unsigned xmm;
 251                 unsigned mm;
 252         } addr;
 253         union {
 254                 unsigned long val;
 255                 u64 val64;
 256                 char valptr[sizeof(sse128_t)];
 257                 sse128_t vec_val;
 258                 u64 mm_val;
 259                 void *data;
 260         };
 261 };
 262
 263 struct fetch_cache {
 264         u8 data[15];
 265         u8 *ptr;
 266         u8 *end;
 267 };
 268
 269 struct read_cache {
 270         u8 data[1024];
 271         unsigned long pos;
 272         unsigned long end;
 273 };
 274
 275 /* Execution mode, passed to the emulator. */
 276 enum x86emul_mode {
 277         X86EMUL_MODE_REAL,      /* Real mode.             */
 278         X86EMUL_MODE_VM86,      /* Virtual 8086 mode.     */
 279         X86EMUL_MODE_PROT16,    /* 16-bit protected mode. */
 280         X86EMUL_MODE_PROT32,    /* 32-bit protected mode. */
 281         X86EMUL_MODE_PROT64,    /* 64-bit (long) mode.    */
 282 };
 283
 284 /* These match some of the HF_* flags defined in kvm_host.h  */
 285 #define X86EMUL_GUEST_MASK           (1 << 5) /* VCPU is in guest-mode */
 286 #define X86EMUL_SMM_MASK             (1 << 6)
 287 #define X86EMUL_SMM_INSIDE_NMI_MASK  (1 << 7)
 288
 289 struct x86_emulate_ctxt {
 290         const struct x86_emulate_ops *ops;
 291
 292         /* Register state before/after emulation. */
 293         unsigned long eflags;
 294         unsigned long eip; /* eip before instruction emulation */
 295         /* Emulated execution mode, represented by an X86EMUL_MODE value. */
 296         enum x86emul_mode mode;
 297
 298         /* interruptibility state, as a result of execution of STI or MOV SS */
 299         int interruptibility;
 300
 301         bool perm_ok; /* do not check permissions if true */
 302         bool ud;        /* inject an #UD if host doesn't support insn */
 303         bool tf;        /* TF value before instruction (after for syscall/sysret) */
 304
 305         bool have_exception;
 306         struct x86_exception exception;
 307
 308         /*
 309          * decode cache
 310          */
 311
 312         /* current opcode length in bytes */
 313         u8 opcode_len;
 314         u8 b;
 315         u8 intercept;
 316         u8 op_bytes;
 317         u8 ad_bytes;
 318         struct operand src;
 319         struct operand src2;
 320         struct operand dst;
 321         int (*execute)(struct x86_emulate_ctxt *ctxt);
 322         int (*check_perm)(struct x86_emulate_ctxt *ctxt);
 323         /*
 324          * The following six fields are cleared together,
 325          * the rest are initialized unconditionally in x86_decode_insn
 326          * or elsewhere
 327          */
 328         bool rip_relative;
 329         u8 rex_prefix;
 330         u8 lock_prefix;
 331         u8 rep_prefix;
 332         /* bitmaps of registers in _regs[] that can be read */
 333         u32 regs_valid;
 334         /* bitmaps of registers in _regs[] that have been written */
 335         u32 regs_dirty;
 336         /* modrm */
 337         u8 modrm;
 338         u8 modrm_mod;
 339         u8 modrm_reg;
 340         u8 modrm_rm;
 341         u8 modrm_seg;
 342         u8 seg_override;
 343         u64 d;
 344         unsigned long _eip;
 345         struct operand memop;
 346         /* Fields above regs are cleared together. */
 347         unsigned long _regs[NR_VCPU_REGS];
 348         struct operand *memopp;
 349         struct fetch_cache fetch;
 350         struct read_cache io_read;
 351         struct read_cache mem_read;
 352 };
 353
 354 /* Repeat String Operation Prefix */
 355 #define REPE_PREFIX     0xf3
 356 #define REPNE_PREFIX    0xf2
 357
 358 /* CPUID vendors */
 359 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx 0x68747541
 360 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx 0x444d4163
 361 #define X86EMUL_CPUID_VENDOR_AuthenticAMD_edx 0x69746e65
 362
 363 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx 0x69444d41
 364 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx 0x21726574
 365 #define X86EMUL_CPUID_VENDOR_AMDisbetterI_edx 0x74656273
 366
 367 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ebx 0x756e6547
 368 #define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e
 369 #define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69
 370
 371 enum x86_intercept_stage {
 372         X86_ICTP_NONE = 0,   /* Allow zero-init to not match anything */
 373         X86_ICPT_PRE_EXCEPT,
 374         X86_ICPT_POST_EXCEPT,
 375         X86_ICPT_POST_MEMACCESS,
 376 };
 377
 378 enum x86_intercept {
 379         x86_intercept_none,
 380         x86_intercept_cr_read,
 381         x86_intercept_cr_write,
 382         x86_intercept_clts,
 383         x86_intercept_lmsw,
 384         x86_intercept_smsw,
 385         x86_intercept_dr_read,
 386         x86_intercept_dr_write,
 387         x86_intercept_lidt,
 388         x86_intercept_sidt,
 389         x86_intercept_lgdt,
 390         x86_intercept_sgdt,
 391         x86_intercept_lldt,
 392         x86_intercept_sldt,
 393         x86_intercept_ltr,
 394         x86_intercept_str,
 395         x86_intercept_rdtsc,
 396         x86_intercept_rdpmc,
 397         x86_intercept_pushf,
 398         x86_intercept_popf,
 399         x86_intercept_cpuid,
 400         x86_intercept_rsm,
 401         x86_intercept_iret,
 402         x86_intercept_intn,
 403         x86_intercept_invd,
 404         x86_intercept_pause,
 405         x86_intercept_hlt,
 406         x86_intercept_invlpg,
 407         x86_intercept_invlpga,
 408         x86_intercept_vmrun,
 409         x86_intercept_vmload,
 410         x86_intercept_vmsave,
 411         x86_intercept_vmmcall,
 412         x86_intercept_stgi,
 413         x86_intercept_clgi,
 414         x86_intercept_skinit,
 415         x86_intercept_rdtscp,
 416         x86_intercept_icebp,
 417         x86_intercept_wbinvd,
 418         x86_intercept_monitor,
 419         x86_intercept_mwait,
 420         x86_intercept_rdmsr,
 421         x86_intercept_wrmsr,
 422         x86_intercept_in,
 423         x86_intercept_ins,
 424         x86_intercept_out,
 425         x86_intercept_outs,
 426
 427         nr_x86_intercepts
 428 };
 429
 430 /* Host execution mode. */
 431 #if defined(CONFIG_X86_32)
 432 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
 433 #elif defined(CONFIG_X86_64)
 434 #define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
 435 #endif
 436
 437 int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len);
 438 bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt);
 439 #define EMULATION_FAILED -1
 440 #define EMULATION_OK 0
 441 #define EMULATION_RESTART 1
 442 #define EMULATION_INTERCEPTED 2
 443 void init_decode_cache(struct x86_emulate_ctxt *ctxt);
 444 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt);
 445 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
 446                          u16 tss_selector, int idt_index, int reason,
 447                          bool has_error_code, u32 error_code);
 448 int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq);
 449 void emulator_invalidate_register_cache(struct x86_emulate_ctxt *ctxt);
 450 void emulator_writeback_register_cache(struct x86_emulate_ctxt *ctxt);
 451 bool emulator_can_use_gpa(struct x86_emulate_ctxt *ctxt);
 452
 453 #endif /* _ASM_X86_KVM_X86_EMULATE_H */