platform.c

xen 3.2.2 源码

/*
 * platform.c: handling x86 platform related MMIO instructions
 *
 * Copyright (c) 2004, Intel Corporation.
 * Copyright (c) 2005, International Business Machines Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 */

#include <xen/config.h>
#include <xen/types.h>
#include <xen/mm.h>
#include <xen/domain_page.h>
#include <asm/page.h>
#include <xen/event.h>
#include <xen/trace.h>
#include <xen/sched.h>
#include <asm/regs.h>
#include <asm/x86_emulate.h>
#include <asm/paging.h>
#include <asm/hvm/hvm.h>
#include <asm/hvm/support.h>
#include <asm/hvm/io.h>
#include <public/hvm/ioreq.h>

#include <xen/lib.h>
#include <xen/sched.h>
#include <asm/current.h>

#define DECODE_success  1
#define DECODE_failure  0

#define mk_operand(size_reg, index, seg, flag) \
    (((size_reg) << 24) | ((index) << 16) | ((seg) << 8) | (flag))

#if defined (__x86_64__)
static inline long __get_reg_value(unsigned long reg, int size)
{
    switch ( size ) {
    case BYTE_64:
        return (char)(reg & 0xFF);
    case WORD:
        return (short)(reg & 0xFFFF);
    case LONG:
        return (int)(reg & 0xFFFFFFFF);
    case QUAD:
        return (long)(reg);
    default:
        printk("Error: (__get_reg_value) Invalid reg size\n");
        domain_crash_synchronous();
    }
}

long get_reg_value(int size, int index, int seg, struct cpu_user_regs *regs)
{
    if ( size == BYTE ) {
        switch ( index ) {
        case 0: /* %al */
            return (char)(regs->rax & 0xFF);
        case 1: /* %cl */
            return (char)(regs->rcx & 0xFF);
        case 2: /* %dl */
            return (char)(regs->rdx & 0xFF);
        case 3: /* %bl */
            return (char)(regs->rbx & 0xFF);
        case 4: /* %ah */
            return (char)((regs->rax & 0xFF00) >> 8);
        case 5: /* %ch */
            return (char)((regs->rcx & 0xFF00) >> 8);
        case 6: /* %dh */
            return (char)((regs->rdx & 0xFF00) >> 8);
        case 7: /* %bh */
            return (char)((regs->rbx & 0xFF00) >> 8);
        default:
            printk("Error: (get_reg_value) Invalid index value\n");
            domain_crash_synchronous();
        }
        /* NOTREACHED */
    }

    switch ( index ) {
    case 0: return __get_reg_value(regs->rax, size);
    case 1: return __get_reg_value(regs->rcx, size);
    case 2: return __get_reg_value(regs->rdx, size);
    case 3: return __get_reg_value(regs->rbx, size);
    case 4: return __get_reg_value(regs->rsp, size);
    case 5: return __get_reg_value(regs->rbp, size);
    case 6: return __get_reg_value(regs->rsi, size);
    case 7: return __get_reg_value(regs->rdi, size);
    case 8: return __get_reg_value(regs->r8, size);
    case 9: return __get_reg_value(regs->r9, size);
    case 10: return __get_reg_value(regs->r10, size);
    case 11: return __get_reg_value(regs->r11, size);
    case 12: return __get_reg_value(regs->r12, size);
    case 13: return __get_reg_value(regs->r13, size);
    case 14: return __get_reg_value(regs->r14, size);
    case 15: return __get_reg_value(regs->r15, size);
    default:
        printk("Error: (get_reg_value) Invalid index value\n");
        domain_crash_synchronous();
    }
}
#elif defined (__i386__)
static inline long __get_reg_value(unsigned long reg, int size)
{
    switch ( size ) {
    case WORD:
        return (short)(reg & 0xFFFF);
    case LONG:
        return (int)(reg & 0xFFFFFFFF);
    default:
        printk("Error: (__get_reg_value) Invalid reg size\n");
        domain_crash_synchronous();
    }
}

long get_reg_value(int size, int index, int seg, struct cpu_user_regs *regs)
{
    if ( size == BYTE ) {
        switch ( index ) {
        case 0: /* %al */
            return (char)(regs->eax & 0xFF);
        case 1: /* %cl */
            return (char)(regs->ecx & 0xFF);
        case 2: /* %dl */
            return (char)(regs->edx & 0xFF);
        case 3: /* %bl */
            return (char)(regs->ebx & 0xFF);
        case 4: /* %ah */
            return (char)((regs->eax & 0xFF00) >> 8);
        case 5: /* %ch */
            return (char)((regs->ecx & 0xFF00) >> 8);
        case 6: /* %dh */
            return (char)((regs->edx & 0xFF00) >> 8);
        case 7: /* %bh */
            return (char)((regs->ebx & 0xFF00) >> 8);
        default:
            printk("Error: (get_reg_value) Invalid index value\n");
            domain_crash_synchronous();
        }
    }

    switch ( index ) {
    case 0: return __get_reg_value(regs->eax, size);
    case 1: return __get_reg_value(regs->ecx, size);
    case 2: return __get_reg_value(regs->edx, size);
    case 3: return __get_reg_value(regs->ebx, size);
    case 4: return __get_reg_value(regs->esp, size);
    case 5: return __get_reg_value(regs->ebp, size);
    case 6: return __get_reg_value(regs->esi, size);
    case 7: return __get_reg_value(regs->edi, size);
    default:
        printk("Error: (get_reg_value) Invalid index value\n");
        domain_crash_synchronous();
    }
}
#endif

static inline unsigned char *check_prefix(unsigned char *inst,
                                          struct hvm_io_op *mmio_op,
                                          unsigned char *ad_size,
                                          unsigned char *op_size,
                                          unsigned char *seg_sel,
                                          unsigned char *rex_p)
{
    while ( 1 ) {
        switch ( *inst ) {
            /* rex prefix for em64t instructions */
        case 0x40 ... 0x4f:
            *rex_p = *inst;
            break;
        case 0xf3: /* REPZ */
            mmio_op->flags = REPZ;
            break;
        case 0xf2: /* REPNZ */
            mmio_op->flags = REPNZ;
            break;
        case 0xf0: /* LOCK */
            break;
        case 0x2e: /* CS */
        case 0x36: /* SS */
        case 0x3e: /* DS */
        case 0x26: /* ES */
        case 0x64: /* FS */
        case 0x65: /* GS */
            *seg_sel = *inst;
            break;
        case 0x66: /* 32bit->16bit */
            *op_size = WORD;
            break;
        case 0x67:
            *ad_size = WORD;
            break;
        default:
            return inst;
        }
        inst++;
    }
}

static inline unsigned long get_immediate(int ad_size, const unsigned char *inst, int op_size)
{
    int mod, reg, rm;
    unsigned long val = 0;
    int i;

    mod = (*inst >> 6) & 3;
    reg = (*inst >> 3) & 7;
    rm = *inst & 7;

    inst++; //skip ModR/M byte
    if ( ad_size != WORD && mod != 3 && rm == 4 ) {
        rm = *inst & 7;
        inst++; //skip SIB byte
    }

    switch ( mod ) {
    case 0:
        if ( ad_size == WORD ) {
            if ( rm == 6 )
                inst = inst + 2; //disp16, skip 2 bytes
        }
        else {
            if ( rm == 5 )
                inst = inst + 4; //disp32, skip 4 bytes
        }
        break;
    case 1:
        inst++; //disp8, skip 1 byte
        break;
    case 2:
        if ( ad_size == WORD )
            inst = inst + 2; //disp16, skip 2 bytes
        else
            inst = inst + 4; //disp32, skip 4 bytes
        break;
    }

    if ( op_size == QUAD )
        op_size = LONG;

    for ( i = 0; i < op_size; i++ ) {
        val |= (*inst++ & 0xff) << (8 * i);
    }

    return val;
}

static inline unsigned long get_immediate_sign_ext(
    int ad_size, const unsigned char *inst, int op_size)
{
    unsigned long result = get_immediate(ad_size, inst, op_size);
    if ( op_size == BYTE )
        return (int8_t)result;
    if ( op_size == WORD )
        return (int16_t)result;
    return (int32_t)result;
}

static inline int get_index(const unsigned char *inst, unsigned char rex)
{
    int mod, reg, rm;
    int rex_r, rex_b;

    mod = (*inst >> 6) & 3;
    reg = (*inst >> 3) & 7;
    rm = *inst & 7;

    rex_r = (rex >> 2) & 1;
    rex_b = rex & 1;

    //Only one operand in the instruction is register
    if ( mod == 3 ) {
        return (rm + (rex_b << 3));
    } else {
        return (reg + (rex_r << 3));
    }
    return 0;
}

static void init_instruction(struct hvm_io_op *mmio_op)
{
    mmio_op->instr = 0;

    mmio_op->flags = 0;

    mmio_op->operand[0] = 0;
    mmio_op->operand[1] = 0;
    mmio_op->immediate = 0;
}

#define GET_OP_SIZE_FOR_BYTE(size_reg)      \
    do {                                    \
        if ( rex )                          \
            (size_reg) = BYTE_64;           \
        else                                \
            (size_reg) = BYTE;              \
    } while( 0 )

#define GET_OP_SIZE_FOR_NONEBYTE(op_size)   \
    do {                                    \
        if ( rex & 0x8 )                    \
            (op_size) = QUAD;               \
        else if ( (op_size) != WORD )       \
            (op_size) = LONG;               \
    } while( 0 )


/*
 * Decode mem,accumulator operands (as in <opcode> m8/m16/m32, al,ax,eax)
 */
static inline int mem_acc(unsigned char size, struct hvm_io_op *mmio)
{
    mmio->operand[0] = mk_operand(size, 0, 0, MEMORY);
    mmio->operand[1] = mk_operand(size, 0, 0, REGISTER);
    return DECODE_success;
}

/*
 * Decode accumulator,mem operands (as in <opcode> al,ax,eax, m8/m16/m32)
 */
static inline int acc_mem(unsigned char size, struct hvm_io_op *mmio)
{
    mmio->operand[0] = mk_operand(size, 0, 0, REGISTER);
    mmio->operand[1] = mk_operand(size, 0, 0, MEMORY);
    return DECODE_success;
}

/*
 * Decode mem,reg operands (as in <opcode> r32/16, m32/16)
 */
static int mem_reg(unsigned char size, unsigned char *opcode,
                   struct hvm_io_op *mmio_op, unsigned char rex)
{
    int index = get_index(opcode + 1, rex);

    mmio_op->operand[0] = mk_operand(size, 0, 0, MEMORY);
    mmio_op->operand[1] = mk_operand(size, index, 0, REGISTER);
    return DECODE_success;
}

/*
 * Decode reg,mem operands (as in <opcode> m32/16, r32/16)
 */
static int reg_mem(unsigned char size, unsigned char *opcode,
                   struct hvm_io_op *mmio_op, unsigned char rex)
{
    int index = get_index(opcode + 1, rex);

    mmio_op->operand[0] = mk_operand(size, index, 0, REGISTER);
    mmio_op->operand[1] = mk_operand(size, 0, 0, MEMORY);
    return DECODE_success;
}

static int mmio_decode(int address_bytes, unsigned char *opcode,
                       struct hvm_io_op *mmio_op,
                       unsigned char *ad_size, unsigned char *op_size,
                       unsigned char *seg_sel)
{
    unsigned char size_reg = 0;
    unsigned char rex = 0;
    int index;

    *ad_size = 0;
    *op_size = 0;
    *seg_sel = 0;
    init_instruction(mmio_op);

    opcode = check_prefix(opcode, mmio_op, ad_size, op_size, seg_sel, &rex);

    switch ( address_bytes )
    {
    case 2:
        if ( *op_size == WORD )
            *op_size = LONG;
        else if ( *op_size == LONG )
            *op_size = WORD;
        else if ( *op_size == 0 )
            *op_size = WORD;
        if ( *ad_size == WORD )
            *ad_size = LONG;
        else if ( *ad_size == LONG )
            *ad_size = WORD;
        else if ( *ad_size == 0 )
            *ad_size = WORD;
        break;
    case 4:
        if ( *op_size == 0 )
            *op_size = LONG;
        if ( *ad_size == 0 )
            *ad_size = LONG;
        break;
#ifdef __x86_64__
    case 8:
        if ( *op_size == 0 )
            *op_size = rex & 0x8 ? QUAD : LONG;
        if ( *ad_size == WORD )
            *ad_size = LONG;
        else if ( *ad_size == 0 )
            *ad_size = QUAD;
        break;
#endif
    }

    /* the operands order in comments conforms to AT&T convention */

    switch ( *opcode ) {

    case 0x00: /* add r8, m8 */
        mmio_op->instr = INSTR_ADD;
        *op_size = BYTE;
        GET_OP_SIZE_FOR_BYTE(size_reg);
        return reg_mem(size_reg, opcode, mmio_op, rex);

    case 0x03: /* add m32/16, r32/16 */
        mmio_op->instr = INSTR_ADD;
        GET_OP_SIZE_FOR_NONEBYTE(*op_size);
        return mem_reg(*op_size, opcode, mmio_op, rex);

    case 0x08: /* or r8, m8 */	
        mmio_op->instr = INSTR_OR;
        *op_size = BYTE;
        GET_OP_SIZE_FOR_BYTE(size_reg);
        return reg_mem(size_reg, opcode, mmio_op, rex);

    case 0x09: /* or r32/16, m32/16 */
        mmio_op->instr = INSTR_OR;
        GET_OP_SIZE_FOR_NONEBYTE(*op_size);
        return reg_mem(*op_size, opcode, mmio_op, rex);

    case 0x0A: /* or m8, r8 */
        mmio_op->instr = INSTR_OR;
        *op_size = BYTE;
        GET_OP_SIZE_FOR_BYTE(size_reg);
        return mem_reg(size_reg, opcode, mmio_op, rex);

    case 0x0B: /* or m32/16, r32/16 */
        mmio_op->instr = INSTR_OR;
        GET_OP_SIZE_FOR_NONEBYTE(*op_size);