translate-copy.c

qemu虚拟机代码

/*
 *  i386 on i386 translation
 * 
 *  Copyright (c) 2003 Fabrice Bellard
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include "config.h"

#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include <assert.h>

#include "cpu.h"
#include "exec-all.h"
#include "disas.h"

#ifdef USE_CODE_COPY

#include <signal.h>
#include <sys/mman.h>
#include <sys/ucontext.h>

extern char exec_loop;

/* operand size */
enum {
    OT_BYTE = 0,
    OT_WORD,
    OT_LONG, 
    OT_QUAD,
};

#define PREFIX_REPZ   0x01
#define PREFIX_REPNZ  0x02
#define PREFIX_LOCK   0x04
#define PREFIX_DATA   0x08
#define PREFIX_ADR    0x10

typedef struct DisasContext {
    /* current insn context */
    int override; /* -1 if no override */
    int prefix;
    int aflag, dflag;
    target_ulong pc; /* pc = eip + cs_base */
    int is_jmp; /* 1 = means jump (stop translation), 2 means CPU
                   static state change (stop translation) */
    /* code output */
    uint8_t *gen_code_ptr;
    uint8_t *gen_code_start;
    
    /* current block context */
    target_ulong cs_base; /* base of CS segment */
    int pe;     /* protected mode */
    int code32; /* 32 bit code segment */
    int f_st;   /* currently unused */
    int vm86;   /* vm86 mode */
    int cpl;
    int iopl;
    int flags;
    struct TranslationBlock *tb;
} DisasContext;

#define CPU_FIELD_OFFSET(field) offsetof(CPUState, field)

#define CPU_SEG 0x64 /* fs override */

static inline void gb(DisasContext *s, uint32_t val)
{
    *s->gen_code_ptr++ = val;
}

static inline void gw(DisasContext *s, uint32_t val)
{
    *s->gen_code_ptr++ = val;
    *s->gen_code_ptr++ = val >> 8;
}

static inline void gl(DisasContext *s, uint32_t val)
{
    *s->gen_code_ptr++ = val;
    *s->gen_code_ptr++ = val >> 8;
    *s->gen_code_ptr++ = val >> 16;
    *s->gen_code_ptr++ = val >> 24;
}

static inline void gjmp(DisasContext *s, long val)
{
    gb(s, 0xe9); /* jmp */
    gl(s, val - (long)(s->gen_code_ptr + 4));
}

static inline void gen_movl_addr_im(DisasContext *s, 
                                    uint32_t addr, uint32_t val)
{
    gb(s, CPU_SEG); /* seg movl im, addr */
    gb(s, 0xc7); 
    gb(s, 0x05);
    gl(s, addr);
    gl(s, val);
}

static inline void gen_movw_addr_im(DisasContext *s, 
                                    uint32_t addr, uint32_t val)
{
    gb(s, CPU_SEG); /* seg movl im, addr */
    gb(s, 0x66); 
    gb(s, 0xc7); 
    gb(s, 0x05);
    gl(s, addr);
    gw(s, val);
}


static void gen_jmp(DisasContext *s, uint32_t target_eip)
{
    TranslationBlock *tb = s->tb;

    gb(s, 0xe9); /* jmp */
    tb->tb_jmp_offset[0] = s->gen_code_ptr - s->gen_code_start;
    gl(s, 0);

    tb->tb_next_offset[0] = s->gen_code_ptr - s->gen_code_start;
    gen_movl_addr_im(s, CPU_FIELD_OFFSET(eip), target_eip);
    gen_movl_addr_im(s, CPU_FIELD_OFFSET(tmp0), (uint32_t)tb);
    gjmp(s, (long)&exec_loop);

    s->is_jmp = 1;
}

static void gen_jcc(DisasContext *s, int op,
                    uint32_t target_eip, uint32_t next_eip)
{
    TranslationBlock *tb = s->tb;

    gb(s, 0x0f); /* jcc */
    gb(s, 0x80 + op);
    tb->tb_jmp_offset[0] = s->gen_code_ptr - s->gen_code_start;
    gl(s, 0);
    gb(s, 0xe9); /* jmp */
    tb->tb_jmp_offset[1] = s->gen_code_ptr - s->gen_code_start;
    gl(s, 0);
    
    tb->tb_next_offset[0] = s->gen_code_ptr - s->gen_code_start;
    gen_movl_addr_im(s, CPU_FIELD_OFFSET(eip), target_eip);
    gen_movl_addr_im(s, CPU_FIELD_OFFSET(tmp0), (uint32_t)tb);
    gjmp(s, (long)&exec_loop);

    tb->tb_next_offset[1] = s->gen_code_ptr - s->gen_code_start;
    gen_movl_addr_im(s, CPU_FIELD_OFFSET(eip), next_eip);
    gen_movl_addr_im(s, CPU_FIELD_OFFSET(tmp0), (uint32_t)tb | 1);
    gjmp(s, (long)&exec_loop);

    s->is_jmp = 1;
}

static void gen_eob(DisasContext *s)
{
    gen_movl_addr_im(s, CPU_FIELD_OFFSET(tmp0), 0);
    gjmp(s, (long)&exec_loop);

    s->is_jmp = 1;
}

static inline void gen_lea_modrm(DisasContext *s, int modrm)
{
    int havesib;
    int base, disp;
    int index;
    int scale;
    int mod, rm, code;

    mod = (modrm >> 6) & 3;
    rm = modrm & 7;

    if (s->aflag) {

        havesib = 0;
        base = rm;
        index = 0;
        scale = 0;
        
        if (base == 4) {
            havesib = 1;
            code = ldub_code(s->pc++);
            scale = (code >> 6) & 3;
            index = (code >> 3) & 7;
            base = code & 7;
        }

        switch (mod) {
        case 0:
            if (base == 5) {
                base = -1;
                disp = ldl_code(s->pc);
                s->pc += 4;
            } else {
                disp = 0;
            }
            break;
        case 1:
            disp = (int8_t)ldub_code(s->pc++);
            break;
        default:
        case 2:
            disp = ldl_code(s->pc);
            s->pc += 4;
            break;
        }
        
    } else {
        switch (mod) {
        case 0:
            if (rm == 6) {
                disp = lduw_code(s->pc);
                s->pc += 2;
            } else {
                disp = 0;
            }
            break;
        case 1:
            disp = (int8_t)ldub_code(s->pc++);
            break;
        default:
        case 2:
            disp = lduw_code(s->pc);
            s->pc += 2;
            break;
        }
    }
}

static inline void parse_modrm(DisasContext *s, int modrm)
{
    if ((modrm & 0xc0) != 0xc0)
        gen_lea_modrm(s, modrm);        
}

static inline uint32_t insn_get(DisasContext *s, int ot)
{
    uint32_t ret;

    switch(ot) {
    case OT_BYTE:
        ret = ldub_code(s->pc);
        s->pc++;
        break;
    case OT_WORD:
        ret = lduw_code(s->pc);
        s->pc += 2;
        break;
    default:
    case OT_LONG:
        ret = ldl_code(s->pc);
        s->pc += 4;
        break;
    }
    return ret;
}

/* convert one instruction. s->is_jmp is set if the translation must
   be stopped.  */
static int disas_insn(DisasContext *s)
{
    target_ulong pc_start, pc_tmp, pc_start_insn;
    int b, prefixes, aflag, dflag, next_eip, val;
    int ot;
    int modrm, mod, op, rm;

    pc_start = s->pc;
    prefixes = 0;
    aflag = s->code32;
    dflag = s->code32;
    s->override = -1;
 next_byte:
    b = ldub_code(s->pc);
    s->pc++;
    /* check prefixes */
    switch (b) {
    case 0xf3:
        prefixes |= PREFIX_REPZ;
        goto next_byte;
    case 0xf2:
        prefixes |= PREFIX_REPNZ;
        goto next_byte;
    case 0xf0:
        prefixes |= PREFIX_LOCK;
        goto next_byte;
    case 0x2e:
        s->override = R_CS;
        goto next_byte;
    case 0x36:
        s->override = R_SS;
        goto next_byte;
    case 0x3e:
        s->override = R_DS;
        goto next_byte;
    case 0x26:
        s->override = R_ES;
        goto next_byte;
    case 0x64:
        s->override = R_FS;
        goto next_byte;
    case 0x65:
        s->override = R_GS;
        goto next_byte;
    case 0x66:
        prefixes |= PREFIX_DATA;
        goto next_byte;
    case 0x67:
        prefixes |= PREFIX_ADR;
        goto next_byte;
    }

    if (prefixes & PREFIX_DATA)
        dflag ^= 1;
    if (prefixes & PREFIX_ADR)
        aflag ^= 1;

    s->prefix = prefixes;
    s->aflag = aflag;
    s->dflag = dflag;

    /* lock generation */
    if (prefixes & PREFIX_LOCK)
        goto unsupported_op;
    if (s->override == R_FS || s->override == R_GS || s->override == R_CS)
        goto unsupported_op;

    pc_start_insn = s->pc - 1;
    /* now check op code */
 reswitch:
    switch(b) {
    case 0x0f:
        /**************************/
        /* extended op code */
        b = ldub_code(s->pc++) | 0x100;
        goto reswitch;
        
        /**************************/
        /* arith & logic */
    case 0x00 ... 0x05:
    case 0x08 ... 0x0d:
    case 0x10 ... 0x15:
    case 0x18 ... 0x1d:
    case 0x20 ... 0x25:
    case 0x28 ... 0x2d:
    case 0x30 ... 0x35:
    case 0x38 ... 0x3d:
        {
            int f;
            f = (b >> 1) & 3;

            if ((b & 1) == 0)
                ot = OT_BYTE;
            else
                ot = dflag ? OT_LONG : OT_WORD;
            
            switch(f) {
            case 0: /* OP Ev, Gv */
                modrm = ldub_code(s->pc++);
                parse_modrm(s, modrm);
                break;
            case 1: /* OP Gv, Ev */
                modrm = ldub_code(s->pc++);
                parse_modrm(s, modrm);
                break;
            case 2: /* OP A, Iv */
                insn_get(s, ot);
                break;
            }
        }
        break;

    case 0x80: /* GRP1 */
    case 0x81:
    case 0x82:
    case 0x83:
        {
            if ((b & 1) == 0)
                ot = OT_BYTE;
            else
                ot = dflag ? OT_LONG : OT_WORD;
            
            modrm = ldub_code(s->pc++);
            parse_modrm(s, modrm);

            switch(b) {
            default:
            case 0x80:
            case 0x81:
            case 0x82:
                insn_get(s, ot);
                break;
            case 0x83:
                insn_get(s, OT_BYTE);
                break;
            }
        }
        break;

        /**************************/
        /* inc, dec, and other misc arith */
    case 0x40 ... 0x47: /* inc Gv */
        break;
    case 0x48 ... 0x4f: /* dec Gv */
        break;
    case 0xf6: /* GRP3 */
    case 0xf7:
        if ((b & 1) == 0)
            ot = OT_BYTE;
        else
            ot = dflag ? OT_LONG : OT_WORD;

        modrm = ldub_code(s->pc++);
        op = (modrm >> 3) & 7;
        parse_modrm(s, modrm);

        switch(op) {
        case 0: /* test */
            insn_get(s, ot);
            break;
        case 2: /* not */
            break;
        case 3: /* neg */
            break;
        case 4: /* mul */