■x86_emulate.c

□概要
　汎用x86(32/64bit)命令のデコーダ＆エミュレータ

□ヘッダ（システムフォルダ配下以外）
#include "kvm.h"
#include "x86_emulate.h"

□変数・マクロ・構造体
/*

* Opcode effective-address decode tables. * Note that we only emulate instructions that have at least one memory * operand (excluding implicit stack references). We assume that stack * references and instruction fetches will never occur in special memory * areas that require emulation. So, for example, 'mov <imm>,<reg>' need * not be handled. */

/* Operand sizes: 8-bit operands or specified/overridden size. */
#define ByteOp (1<<0) /* 8-bit operands. */
/* Destination operand type. */
#define ImplicitOps (1<<1) /* Implicit in opcode. No generic decode. */
#define DstReg (2<<1) /* Register operand. */
#define DstMem (3<<1) /* Memory operand. */
#define DstMask (3<<1)
/* Source operand type. */
#define SrcNone (0<<3) /* No source operand. */
#define SrcImplicit (0<<3) /* Source operand is implicit in the opcode. */
#define SrcReg (1<<3) /* Register operand. */
#define SrcMem (2<<3) /* Memory operand. */
#define SrcMem16 (3<<3) /* Memory operand (16-bit). */
#define SrcMem32 (4<<3) /* Memory operand (32-bit). */
#define SrcImm (5<<3) /* Immediate operand. */
#define SrcImmByte (6<<3) /* 8-bit sign-extended immediate operand. */
#define SrcMask (7<<3)
/* Generic ModRM decode. */
#define ModRM (1<<6)
/* Destination is only written; never read. */
#define Mov (1<<7)
#define BitOp (1<<8)

static u8 opcode_table[256] = {

/* 0x00 - 0x07 */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, 0, 0, 0, 0, /* 0x08 - 0x0F */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, 0, 0, 0, 0, /* 0x10 - 0x17 */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, 0, 0, 0, 0, /* 0x18 - 0x1F */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, 0, 0, 0, 0, /* 0x20 - 0x27 */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, 0, 0, 0, 0, /* 0x28 - 0x2F */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, 0, 0, 0, 0, /* 0x30 - 0x37 */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, 0, 0, 0, 0, /* 0x38 - 0x3F */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, 0, 0, 0, 0, /* 0x40 - 0x4F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x50 - 0x5F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x60 - 0x6F */ 0, 0, 0, DstReg | SrcMem32 | ModRM | Mov /* movsxd (x86/64) */ , 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x70 - 0x7F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x80 - 0x87 */ ByteOp | DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM, DstMem | SrcImmByte | ModRM, ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, /* 0x88 - 0x8F */ ByteOp | DstMem | SrcReg | ModRM | Mov, DstMem | SrcReg | ModRM | Mov, ByteOp | DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, 0, 0, 0, DstMem | SrcNone | ModRM | Mov, /* 0x90 - 0x9F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xA0 - 0xA7 */ ByteOp | DstReg | SrcMem | Mov, DstReg | SrcMem | Mov, ByteOp | DstMem | SrcReg | Mov, DstMem | SrcReg | Mov, ByteOp | ImplicitOps | Mov, ImplicitOps | Mov, ByteOp | ImplicitOps, ImplicitOps, /* 0xA8 - 0xAF */ 0, 0, ByteOp | ImplicitOps | Mov, ImplicitOps | Mov, ByteOp | ImplicitOps | Mov, ImplicitOps | Mov, ByteOp | ImplicitOps, ImplicitOps, /* 0xB0 - 0xBF */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xC0 - 0xC7 */ ByteOp | DstMem | SrcImm | ModRM, DstMem | SrcImmByte | ModRM, 0, 0, 0, 0, ByteOp | DstMem | SrcImm | ModRM | Mov, DstMem | SrcImm | ModRM | Mov, /* 0xC8 - 0xCF */ 0, 0, 0, 0, 0, 0, 0, 0, /* 0xD0 - 0xD7 */ ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM, ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM, 0, 0, 0, 0, /* 0xD8 - 0xDF */ 0, 0, 0, 0, 0, 0, 0, 0, /* 0xE0 - 0xEF */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xF0 - 0xF7 */ 0, 0, 0, 0, 0, 0, ByteOp | DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM, /* 0xF8 - 0xFF */ 0, 0, 0, 0, 0, 0, ByteOp | DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM

};

static u16 twobyte_table[256] = {

/* 0x00 - 0x0F */ 0, SrcMem | ModRM | DstReg, 0, 0, 0, 0, ImplicitOps, 0, 0, 0, 0, 0, 0, ImplicitOps | ModRM, 0, 0, /* 0x10 - 0x1F */ 0, 0, 0, 0, 0, 0, 0, 0, ImplicitOps | ModRM, 0, 0, 0, 0, 0, 0, 0, /* 0x20 - 0x2F */ ModRM | ImplicitOps, ModRM, ModRM | ImplicitOps, ModRM, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x30 - 0x3F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x40 - 0x47 */ DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, /* 0x48 - 0x4F */ DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov, /* 0x50 - 0x5F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x60 - 0x6F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x70 - 0x7F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x80 - 0x8F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x90 - 0x9F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xA0 - 0xA7 */ 0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0, /* 0xA8 - 0xAF */ 0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0, /* 0xB0 - 0xB7 */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem16 | ModRM | Mov, /* 0xB8 - 0xBF */ 0, 0, DstMem | SrcImmByte | ModRM, DstMem | SrcReg | ModRM | BitOp, 0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem16 | ModRM | Mov, /* 0xC0 - 0xCF */ 0, 0, 0, 0, 0, 0, 0, ImplicitOps | ModRM, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xD0 - 0xDF */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xE0 - 0xEF */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xF0 - 0xFF */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

};

/* Type, address-of, and value of an instruction's operand. */
struct operand {

enum { OP_REG, OP_MEM, OP_IMM } type; unsigned int bytes; unsigned long val, orig_val, *ptr;

};

/* EFLAGS bit definitions. */
#define EFLG_OF (1<<11)
#define EFLG_DF (1<<10)
#define EFLG_SF (1<<7)
#define EFLG_ZF (1<<6)
#define EFLG_AF (1<<4)
#define EFLG_PF (1<<2)
#define EFLG_CF (1<<0)

/*

* Instruction emulation: * Most instructions are emulated directly via a fragment of inline assembly * code. This allows us to save/restore EFLAGS and thus very easily pick up * any modified flags. */

#if defined(CONFIG_X86_64)
#define _LO32 "k" /* force 32-bit operand */
#define _STK "%%rsp" /* stack pointer */
#elif defined(_i386)
#define _LO32 "" /* force 32-bit operand */
#define _STK "%%esp" /* stack pointer */
#endif

/*

* These EFLAGS bits are restored from saved value during emulation, and * any changes are written back to the saved value after emulation. */

#define EFLAGS_MASK (EFLG_OF|EFLG_SF|EFLG_ZF|EFLG_AF|EFLG_PF|EFLG_CF)

/* Before executing instruction: restore necessary bits in EFLAGS. */
#define _PRE_EFLAGS(_sav, _msk, _tmp) \

/* EFLAGS = (_sav & _msk) | (EFLAGS & ~_msk); */ \ "push %"_sav"; " \ "movl %"_msk",%"_LO32 _tmp"; " \ "andl %"_LO32 _tmp",("_STK"); " \ "pushf; " \ "notl %"_LO32 _tmp"; " \ "andl %"_LO32 _tmp",("_STK"); " \ "pop %"_tmp"; " \ "orl %"_LO32 _tmp",("_STK"); " \ "popf; " \ /* _sav &= ~msk; */ \ "movl %"_msk",%"_LO32 _tmp"; " \ "notl %"_LO32 _tmp"; " \ "andl %"_LO32 _tmp",%"_sav"; "

/* After executing instruction: write-back necessary bits in EFLAGS. */
#define _POST_EFLAGS(_sav, _msk, _tmp) \

/* _sav |= EFLAGS & _msk; */ \ "pushf; " \ "pop %"_tmp"; " \ "andl %"_msk",%"_LO32 _tmp"; " \ "orl %"_LO32 _tmp",%"_sav"; "

□ifdef
_KERNEL
CONFIG_X86_64
_i386
XEN

□関数
kvm_emulator_want_group7_invlpg
decode_register
read_descriptor
x86_emulate_memop
x86_emulate_read_std
x86_emulate_write_std