diff options
| -rw-r--r-- | arch/x86/kvm/emulate.c | 33 | ||||
| -rw-r--r-- | arch/x86/kvm/kvm_emulate.h | 11 |
2 files changed, 31 insertions, 13 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 531dac5cf3dc..b636bca92ca4 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -239,6 +239,13 @@ enum x86_transfer_type { X86_TRANSFER_TASK_SWITCH, }; +enum rex_bits { + REX_B = 1, + REX_X = 2, + REX_R = 4, + REX_W = 8, +}; + static void writeback_registers(struct x86_emulate_ctxt *ctxt) { unsigned long dirty = ctxt->regs_dirty; @@ -919,7 +926,7 @@ static void *decode_register(struct x86_emulate_ctxt *ctxt, u8 modrm_reg, int byteop) { void *p; - int highbyte_regs = (ctxt->rex_prefix == 0) && byteop; + int highbyte_regs = (ctxt->rex_prefix == REX_NONE) && byteop; if (highbyte_regs && modrm_reg >= 4 && modrm_reg < 8) p = (unsigned char *)reg_rmw(ctxt, modrm_reg & 3) + 1; @@ -1110,7 +1117,7 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt, if (ctxt->d & ModRM) reg = ctxt->modrm_reg; else - reg = (ctxt->b & 7) | ((ctxt->rex_prefix & 1) << 3); + reg = (ctxt->b & 7) | (ctxt->rex_bits & REX_B ? 8 : 0); __decode_register_operand(ctxt, op, reg); } @@ -1129,9 +1136,9 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt, int rc = X86EMUL_CONTINUE; ulong modrm_ea = 0; - ctxt->modrm_reg = ((ctxt->rex_prefix << 1) & 8); /* REX.R */ - index_reg = (ctxt->rex_prefix << 2) & 8; /* REX.X */ - base_reg = (ctxt->rex_prefix << 3) & 8; /* REX.B */ + ctxt->modrm_reg = (ctxt->rex_bits & REX_R ? 8 : 0); + index_reg = (ctxt->rex_bits & REX_X ? 8 : 0); + base_reg = (ctxt->rex_bits & REX_B ? 8 : 0); ctxt->modrm_mod = (ctxt->modrm & 0xc0) >> 6; ctxt->modrm_reg |= (ctxt->modrm & 0x38) >> 3; @@ -2464,7 +2471,7 @@ static int em_sysexit(struct x86_emulate_ctxt *ctxt) setup_syscalls_segments(&cs, &ss); - if ((ctxt->rex_prefix & 0x8) != 0x0) + if (ctxt->rex_bits & REX_W) usermode = X86EMUL_MODE_PROT64; else usermode = X86EMUL_MODE_PROT32; @@ -4850,7 +4857,8 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len, int case 0x40 ... 0x4f: /* REX */ if (mode != X86EMUL_MODE_PROT64) goto done_prefixes; - ctxt->rex_prefix = ctxt->b; + ctxt->rex_prefix = REX_PREFIX; + ctxt->rex_bits = ctxt->b & 0xf; continue; case 0xf0: /* LOCK */ ctxt->lock_prefix = 1; @@ -4864,15 +4872,15 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len, int } /* Any legacy prefix after a REX prefix nullifies its effect. */ - - ctxt->rex_prefix = 0; + ctxt->rex_prefix = REX_NONE; + ctxt->rex_bits = 0; } done_prefixes: /* REX prefix. */ - if (ctxt->rex_prefix & 8) - ctxt->op_bytes = 8; /* REX.W */ + if (ctxt->rex_bits & REX_W) + ctxt->op_bytes = 8; /* Opcode byte(s). */ if (ctxt->b == 0x0f) { @@ -5138,7 +5146,8 @@ void init_decode_cache(struct x86_emulate_ctxt *ctxt) { /* Clear fields that are set conditionally but read without a guard. */ ctxt->rip_relative = false; - ctxt->rex_prefix = 0; + ctxt->rex_prefix = REX_NONE; + ctxt->rex_bits = 0; ctxt->lock_prefix = 0; ctxt->op_prefix = false; ctxt->rep_prefix = 0; diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index c526f46f5595..fb3dab4b5a53 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -319,6 +319,14 @@ typedef void (*fastop_t)(struct fastop *); #define NR_EMULATOR_GPRS 8 #endif +/* + * Distinguish between no prefix, REX, or in the future REX2. + */ +enum rex_type { + REX_NONE, + REX_PREFIX, +}; + struct x86_emulate_ctxt { void *vcpu; const struct x86_emulate_ops *ops; @@ -360,7 +368,8 @@ struct x86_emulate_ctxt { int (*check_perm)(struct x86_emulate_ctxt *ctxt); bool rip_relative; - u8 rex_prefix; + enum rex_type rex_prefix; + u8 rex_bits; u8 lock_prefix; u8 rep_prefix; /* bitmaps of registers in _regs[] that can be read */ |