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linux/drivers/kvm/x86_emulate.c
Avi Kivity c7e75a3db4 KVM: x86 emulator: don't depend on cr2 for mov abs emulation 
The 'mov abs' instruction family (opcodes 0xa0 - 0xa3) still depends on cr2
provided by the page fault handler.  This is wrong for several reasons:

- if an instruction accessed misaligned data that crosses a page boundary,
  and if the fault happened on the second page, cr2 will point at the
  second page, not the data itself.

- if we're emulating in real mode, or due to a FlexPriority exit, there
  is no cr2 generated.

So, this change adds decoding for this instruction form and drops reliance
on cr2.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-01-30 17:52:57 +02:00

1833 lines
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/******************************************************************************
* x86_emulate.c
*
* Generic x86 (32-bit and 64-bit) instruction decoder and emulator.
*
* Copyright (c) 2005 Keir Fraser
*
* Linux coding style, mod r/m decoder, segment base fixes, real-mode
* privileged instructions:
*
* Copyright (C) 2006 Qumranet
*
* Avi Kivity <avi@qumranet.com>
* Yaniv Kamay <yaniv@qumranet.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4
*/
#ifndef __KERNEL__
#include <stdio.h>
#include <stdint.h>
#include <public/xen.h>
#define DPRINTF(_f, _a ...) printf(_f , ## _a)
#else
#include "kvm.h"
#include "x86.h"
#define DPRINTF(x...) do {} while (0)
#endif
#include "x86_emulate.h"
#include <linux/module.h>
/*
* 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)
#define MemAbs (1<<9) /* Memory operand is absolute displacement */
static u16 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,
SrcImmByte, SrcImm, 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 - 0x47 */
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
/* 0x48 - 0x4F */
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
/* 0x50 - 0x57 */
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
/* 0x58 - 0x5F */
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
/* 0x60 - 0x67 */
0, 0, 0, DstReg | SrcMem32 | ModRM | Mov /* movsxd (x86/64) */ ,
0, 0, 0, 0,
/* 0x68 - 0x6F */
0, 0, ImplicitOps|Mov, 0,
SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps, /* insb, insw/insd */
SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps, /* outsb, outsw/outsd */
/* 0x70 - 0x77 */
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
/* 0x78 - 0x7F */
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
/* 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, ModRM | DstReg, 0, DstMem | SrcNone | ModRM | Mov,
/* 0x90 - 0x9F */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ImplicitOps, ImplicitOps, 0, 0,
/* 0xA0 - 0xA7 */
ByteOp | DstReg | SrcMem | Mov | MemAbs, DstReg | SrcMem | Mov | MemAbs,
ByteOp | DstMem | SrcReg | Mov | MemAbs, DstMem | SrcReg | Mov | MemAbs,
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, ImplicitOps, 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 - 0xE7 */
0, 0, 0, 0, 0, 0, 0, 0,
/* 0xE8 - 0xEF */
ImplicitOps, SrcImm|ImplicitOps, 0, SrcImmByte|ImplicitOps, 0, 0, 0, 0,
/* 0xF0 - 0xF7 */
0, 0, 0, 0,
ImplicitOps, ImplicitOps,
ByteOp | DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM,
/* 0xF8 - 0xFF */
ImplicitOps, 0, ImplicitOps, ImplicitOps,
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,
ImplicitOps, ImplicitOps, 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 */
ImplicitOps, 0, ImplicitOps, 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 */
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
/* 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, DstMem | SrcReg | ModRM | Mov, 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
};
/* 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"; "
/* Raw emulation: instruction has two explicit operands. */
#define __emulate_2op_nobyte(_op,_src,_dst,_eflags,_wx,_wy,_lx,_ly,_qx,_qy) \
do { \
unsigned long _tmp; \
\
switch ((_dst).bytes) { \
case 2: \
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "4", "2") \
_op"w %"_wx"3,%1; " \
_POST_EFLAGS("0", "4", "2") \
: "=m" (_eflags), "=m" ((_dst).val), \
"=&r" (_tmp) \
: _wy ((_src).val), "i" (EFLAGS_MASK)); \
break; \
case 4: \
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "4", "2") \
_op"l %"_lx"3,%1; " \
_POST_EFLAGS("0", "4", "2") \
: "=m" (_eflags), "=m" ((_dst).val), \
"=&r" (_tmp) \
: _ly ((_src).val), "i" (EFLAGS_MASK)); \
break; \
case 8: \
__emulate_2op_8byte(_op, _src, _dst, \
_eflags, _qx, _qy); \
break; \
} \
} while (0)
#define __emulate_2op(_op,_src,_dst,_eflags,_bx,_by,_wx,_wy,_lx,_ly,_qx,_qy) \
do { \
unsigned long _tmp; \
switch ((_dst).bytes) { \
case 1: \
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "4", "2") \
_op"b %"_bx"3,%1; " \
_POST_EFLAGS("0", "4", "2") \
: "=m" (_eflags), "=m" ((_dst).val), \
"=&r" (_tmp) \
: _by ((_src).val), "i" (EFLAGS_MASK)); \
break; \
default: \
__emulate_2op_nobyte(_op, _src, _dst, _eflags, \
_wx, _wy, _lx, _ly, _qx, _qy); \
break; \
} \
} while (0)
/* Source operand is byte-sized and may be restricted to just %cl. */
#define emulate_2op_SrcB(_op, _src, _dst, _eflags) \
__emulate_2op(_op, _src, _dst, _eflags, \
"b", "c", "b", "c", "b", "c", "b", "c")
/* Source operand is byte, word, long or quad sized. */
#define emulate_2op_SrcV(_op, _src, _dst, _eflags) \
__emulate_2op(_op, _src, _dst, _eflags, \
"b", "q", "w", "r", _LO32, "r", "", "r")
/* Source operand is word, long or quad sized. */
#define emulate_2op_SrcV_nobyte(_op, _src, _dst, _eflags) \
__emulate_2op_nobyte(_op, _src, _dst, _eflags, \
"w", "r", _LO32, "r", "", "r")
/* Instruction has only one explicit operand (no source operand). */
#define emulate_1op(_op, _dst, _eflags) \
do { \
unsigned long _tmp; \
\
switch ((_dst).bytes) { \
case 1: \
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "3", "2") \
_op"b %1; " \
_POST_EFLAGS("0", "3", "2") \
: "=m" (_eflags), "=m" ((_dst).val), \
"=&r" (_tmp) \
: "i" (EFLAGS_MASK)); \
break; \
case 2: \
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "3", "2") \
_op"w %1; " \
_POST_EFLAGS("0", "3", "2") \
: "=m" (_eflags), "=m" ((_dst).val), \
"=&r" (_tmp) \
: "i" (EFLAGS_MASK)); \
break; \
case 4: \
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "3", "2") \
_op"l %1; " \
_POST_EFLAGS("0", "3", "2") \
: "=m" (_eflags), "=m" ((_dst).val), \
"=&r" (_tmp) \
: "i" (EFLAGS_MASK)); \
break; \
case 8: \
__emulate_1op_8byte(_op, _dst, _eflags); \
break; \
} \
} while (0)
/* Emulate an instruction with quadword operands (x86/64 only). */
#if defined(CONFIG_X86_64)
#define __emulate_2op_8byte(_op, _src, _dst, _eflags, _qx, _qy) \
do { \
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "4", "2") \
_op"q %"_qx"3,%1; " \
_POST_EFLAGS("0", "4", "2") \
: "=m" (_eflags), "=m" ((_dst).val), "=&r" (_tmp) \
: _qy ((_src).val), "i" (EFLAGS_MASK)); \
} while (0)
#define __emulate_1op_8byte(_op, _dst, _eflags) \
do { \
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "3", "2") \
_op"q %1; " \
_POST_EFLAGS("0", "3", "2") \
: "=m" (_eflags), "=m" ((_dst).val), "=&r" (_tmp) \
: "i" (EFLAGS_MASK)); \
} while (0)
#elif defined(__i386__)
#define __emulate_2op_8byte(_op, _src, _dst, _eflags, _qx, _qy)
#define __emulate_1op_8byte(_op, _dst, _eflags)
#endif /* __i386__ */
/* Fetch next part of the instruction being emulated. */
#define insn_fetch(_type, _size, _eip) \
({ unsigned long _x; \
rc = ops->read_std((unsigned long)(_eip) + ctxt->cs_base, &_x, \
(_size), ctxt->vcpu); \
if (rc != 0) \
goto done; \
(_eip) += (_size); \
(_type)_x; \
})
/* Access/update address held in a register, based on addressing mode. */
#define address_mask(reg) \
((c->ad_bytes == sizeof(unsigned long)) ? \
(reg) : ((reg) & ((1UL << (c->ad_bytes << 3)) - 1)))
#define register_address(base, reg) \
((base) + address_mask(reg))
#define register_address_increment(reg, inc) \
do { \
/* signed type ensures sign extension to long */ \
int _inc = (inc); \
if (c->ad_bytes == sizeof(unsigned long)) \
(reg) += _inc; \
else \
(reg) = ((reg) & \
~((1UL << (c->ad_bytes << 3)) - 1)) | \
(((reg) + _inc) & \
((1UL << (c->ad_bytes << 3)) - 1)); \
} while (0)
#define JMP_REL(rel) \
do { \
register_address_increment(c->eip, rel); \
} while (0)
/*
* Given the 'reg' portion of a ModRM byte, and a register block, return a
* pointer into the block that addresses the relevant register.
* @highbyte_regs specifies whether to decode AH,CH,DH,BH.
*/
static void *decode_register(u8 modrm_reg, unsigned long *regs,
int highbyte_regs)
{
void *p;
p = &regs[modrm_reg];
if (highbyte_regs && modrm_reg >= 4 && modrm_reg < 8)
p = (unsigned char *)&regs[modrm_reg & 3] + 1;
return p;
}
static int read_descriptor(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
void *ptr,
u16 *size, unsigned long *address, int op_bytes)
{
int rc;
if (op_bytes == 2)
op_bytes = 3;
*address = 0;
rc = ops->read_std((unsigned long)ptr, (unsigned long *)size, 2,
ctxt->vcpu);
if (rc)
return rc;
rc = ops->read_std((unsigned long)ptr + 2, address, op_bytes,
ctxt->vcpu);
return rc;
}
static int test_cc(unsigned int condition, unsigned int flags)
{
int rc = 0;
switch ((condition & 15) >> 1) {
case 0: /* o */
rc |= (flags & EFLG_OF);
break;
case 1: /* b/c/nae */
rc |= (flags & EFLG_CF);
break;
case 2: /* z/e */
rc |= (flags & EFLG_ZF);
break;
case 3: /* be/na */
rc |= (flags & (EFLG_CF|EFLG_ZF));
break;
case 4: /* s */
rc |= (flags & EFLG_SF);
break;
case 5: /* p/pe */
rc |= (flags & EFLG_PF);
break;
case 7: /* le/ng */
rc |= (flags & EFLG_ZF);
/* fall through */
case 6: /* l/nge */
rc |= (!(flags & EFLG_SF) != !(flags & EFLG_OF));
break;
}
/* Odd condition identifiers (lsb == 1) have inverted sense. */
return (!!rc ^ (condition & 1));
}
int
x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
u8 sib, rex_prefix = 0;
int rc = 0;
int mode = ctxt->mode;
int index_reg = 0, base_reg = 0, scale, rip_relative = 0;
/* Shadow copy of register state. Committed on successful emulation. */
memset(c, 0, sizeof(struct decode_cache));
c->eip = ctxt->vcpu->rip;
memcpy(c->regs, ctxt->vcpu->regs, sizeof c->regs);
switch (mode) {
case X86EMUL_MODE_REAL:
case X86EMUL_MODE_PROT16:
c->op_bytes = c->ad_bytes = 2;
break;
case X86EMUL_MODE_PROT32:
c->op_bytes = c->ad_bytes = 4;
break;
#ifdef CONFIG_X86_64
case X86EMUL_MODE_PROT64:
c->op_bytes = 4;
c->ad_bytes = 8;
break;
#endif
default:
return -1;
}
/* Legacy prefixes. */
for (;;) {
switch (c->b = insn_fetch(u8, 1, c->eip)) {
case 0x66: /* operand-size override */
c->op_bytes ^= 6; /* switch between 2/4 bytes */
break;
case 0x67: /* address-size override */
if (mode == X86EMUL_MODE_PROT64)
/* switch between 4/8 bytes */
c->ad_bytes ^= 12;
else
/* switch between 2/4 bytes */
c->ad_bytes ^= 6;
break;
case 0x2e: /* CS override */
c->override_base = &ctxt->cs_base;
break;
case 0x3e: /* DS override */
c->override_base = &ctxt->ds_base;
break;
case 0x26: /* ES override */
c->override_base = &ctxt->es_base;
break;
case 0x64: /* FS override */
c->override_base = &ctxt->fs_base;
break;
case 0x65: /* GS override */
c->override_base = &ctxt->gs_base;
break;
case 0x36: /* SS override */
c->override_base = &ctxt->ss_base;
break;
case 0x40 ... 0x4f: /* REX */
if (mode != X86EMUL_MODE_PROT64)
goto done_prefixes;
rex_prefix = c->b;
continue;
case 0xf0: /* LOCK */
c->lock_prefix = 1;
break;
case 0xf2: /* REPNE/REPNZ */
case 0xf3: /* REP/REPE/REPZ */
c->rep_prefix = 1;
break;
default:
goto done_prefixes;
}
/* Any legacy prefix after a REX prefix nullifies its effect. */
rex_prefix = 0;
}
done_prefixes:
/* REX prefix. */
if (rex_prefix) {
if (rex_prefix & 8)
c->op_bytes = 8; /* REX.W */
c->modrm_reg = (rex_prefix & 4) << 1; /* REX.R */
index_reg = (rex_prefix & 2) << 2; /* REX.X */
c->modrm_rm = base_reg = (rex_prefix & 1) << 3; /* REG.B */
}
/* Opcode byte(s). */
c->d = opcode_table[c->b];
if (c->d == 0) {
/* Two-byte opcode? */
if (c->b == 0x0f) {
c->twobyte = 1;
c->b = insn_fetch(u8, 1, c->eip);
c->d = twobyte_table[c->b];
}
/* Unrecognised? */
if (c->d == 0) {
DPRINTF("Cannot emulate %02x\n", c->b);
return -1;
}
}
/* ModRM and SIB bytes. */
if (c->d & ModRM) {
c->modrm = insn_fetch(u8, 1, c->eip);
c->modrm_mod |= (c->modrm & 0xc0) >> 6;
c->modrm_reg |= (c->modrm & 0x38) >> 3;
c->modrm_rm |= (c->modrm & 0x07);
c->modrm_ea = 0;
c->use_modrm_ea = 1;
if (c->modrm_mod == 3) {
c->modrm_val = *(unsigned long *)
decode_register(c->modrm_rm, c->regs, c->d & ByteOp);
goto modrm_done;
}
if (c->ad_bytes == 2) {
unsigned bx = c->regs[VCPU_REGS_RBX];
unsigned bp = c->regs[VCPU_REGS_RBP];
unsigned si = c->regs[VCPU_REGS_RSI];
unsigned di = c->regs[VCPU_REGS_RDI];
/* 16-bit ModR/M decode. */
switch (c->modrm_mod) {
case 0:
if (c->modrm_rm == 6)
c->modrm_ea +=
insn_fetch(u16, 2, c->eip);
break;
case 1:
c->modrm_ea += insn_fetch(s8, 1, c->eip);
break;
case 2:
c->modrm_ea += insn_fetch(u16, 2, c->eip);
break;
}
switch (c->modrm_rm) {
case 0:
c->modrm_ea += bx + si;
break;
case 1:
c->modrm_ea += bx + di;
break;
case 2:
c->modrm_ea += bp + si;
break;
case 3:
c->modrm_ea += bp + di;
break;
case 4:
c->modrm_ea += si;
break;
case 5:
c->modrm_ea += di;
break;
case 6:
if (c->modrm_mod != 0)
c->modrm_ea += bp;
break;
case 7:
c->modrm_ea += bx;
break;
}
if (c->modrm_rm == 2 || c->modrm_rm == 3 ||
(c->modrm_rm == 6 && c->modrm_mod != 0))
if (!c->override_base)
c->override_base = &ctxt->ss_base;
c->modrm_ea = (u16)c->modrm_ea;
} else {
/* 32/64-bit ModR/M decode. */
switch (c->modrm_rm) {
case 4:
case 12:
sib = insn_fetch(u8, 1, c->eip);
index_reg |= (sib >> 3) & 7;
base_reg |= sib & 7;
scale = sib >> 6;
switch (base_reg) {
case 5:
if (c->modrm_mod != 0)
c->modrm_ea +=
c->regs[base_reg];
else
c->modrm_ea +=
insn_fetch(s32, 4, c->eip);
break;
default:
c->modrm_ea += c->regs[base_reg];
}
switch (index_reg) {
case 4:
break;
default:
c->modrm_ea +=
c->regs[index_reg] << scale;
}
break;
case 5:
if (c->modrm_mod != 0)
c->modrm_ea += c->regs[c->modrm_rm];
else if (mode == X86EMUL_MODE_PROT64)
rip_relative = 1;
break;
default:
c->modrm_ea += c->regs[c->modrm_rm];
break;
}
switch (c->modrm_mod) {
case 0:
if (c->modrm_rm == 5)
c->modrm_ea +=
insn_fetch(s32, 4, c->eip);
break;
case 1:
c->modrm_ea += insn_fetch(s8, 1, c->eip);
break;
case 2:
c->modrm_ea += insn_fetch(s32, 4, c->eip);
break;
}
}
if (rip_relative) {
c->modrm_ea += c->eip;
switch (c->d & SrcMask) {
case SrcImmByte:
c->modrm_ea += 1;
break;
case SrcImm:
if (c->d & ByteOp)
c->modrm_ea += 1;
else
if (c->op_bytes == 8)
c->modrm_ea += 4;
else
c->modrm_ea += c->op_bytes;
}
}
modrm_done:
;
} else if (c->d & MemAbs) {
switch (c->ad_bytes) {
case 2:
c->modrm_ea = insn_fetch(u16, 2, c->eip);
break;
case 4:
c->modrm_ea = insn_fetch(u32, 4, c->eip);
break;
case 8:
c->modrm_ea = insn_fetch(u64, 8, c->eip);
break;
}
}
if (!c->override_base)
c->override_base = &ctxt->ds_base;
if (mode == X86EMUL_MODE_PROT64 &&
c->override_base != &ctxt->fs_base &&
c->override_base != &ctxt->gs_base)
c->override_base = NULL;
if (c->override_base)
c->modrm_ea += *c->override_base;
if (c->ad_bytes != 8)
c->modrm_ea = (u32)c->modrm_ea;
/*
* Decode and fetch the source operand: register, memory
* or immediate.
*/
switch (c->d & SrcMask) {
case SrcNone:
break;
case SrcReg:
c->src.type = OP_REG;
if (c->d & ByteOp) {
c->src.ptr =
decode_register(c->modrm_reg, c->regs,
(rex_prefix == 0));
c->src.val = c->src.orig_val = *(u8 *)c->src.ptr;
c->src.bytes = 1;
} else {
c->src.ptr =
decode_register(c->modrm_reg, c->regs, 0);
switch ((c->src.bytes = c->op_bytes)) {
case 2:
c->src.val = c->src.orig_val =
*(u16 *) c->src.ptr;
break;
case 4:
c->src.val = c->src.orig_val =
*(u32 *) c->src.ptr;
break;
case 8:
c->src.val = c->src.orig_val =
*(u64 *) c->src.ptr;
break;
}
}
break;
case SrcMem16:
c->src.bytes = 2;
goto srcmem_common;
case SrcMem32:
c->src.bytes = 4;
goto srcmem_common;
case SrcMem:
c->src.bytes = (c->d & ByteOp) ? 1 :
c->op_bytes;
/* Don't fetch the address for invlpg: it could be unmapped. */
if (c->twobyte && c->b == 0x01 && c->modrm_reg == 7)
break;
srcmem_common:
/*
* For instructions with a ModR/M byte, switch to register
* access if Mod = 3.
*/
if ((c->d & ModRM) && c->modrm_mod == 3) {
c->src.type = OP_REG;
break;
}
c->src.type = OP_MEM;
break;
case SrcImm:
c->src.type = OP_IMM;
c->src.ptr = (unsigned long *)c->eip;
c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
if (c->src.bytes == 8)
c->src.bytes = 4;
/* NB. Immediates are sign-extended as necessary. */
switch (c->src.bytes) {
case 1:
c->src.val = insn_fetch(s8, 1, c->eip);
break;
case 2:
c->src.val = insn_fetch(s16, 2, c->eip);
break;
case 4:
c->src.val = insn_fetch(s32, 4, c->eip);
break;
}
break;
case SrcImmByte:
c->src.type = OP_IMM;
c->src.ptr = (unsigned long *)c->eip;
c->src.bytes = 1;
c->src.val = insn_fetch(s8, 1, c->eip);
break;
}
/* Decode and fetch the destination operand: register or memory. */
switch (c->d & DstMask) {
case ImplicitOps:
/* Special instructions do their own operand decoding. */
return 0;
case DstReg:
c->dst.type = OP_REG;
if ((c->d & ByteOp)
&& !(c->twobyte &&
(c->b == 0xb6 || c->b == 0xb7))) {
c->dst.ptr =
decode_register(c->modrm_reg, c->regs,
(rex_prefix == 0));
c->dst.val = *(u8 *) c->dst.ptr;
c->dst.bytes = 1;
} else {
c->dst.ptr =
decode_register(c->modrm_reg, c->regs, 0);
switch ((c->dst.bytes = c->op_bytes)) {
case 2:
c->dst.val = *(u16 *)c->dst.ptr;
break;
case 4:
c->dst.val = *(u32 *)c->dst.ptr;
break;
case 8:
c->dst.val = *(u64 *)c->dst.ptr;
break;
}
}
break;
case DstMem:
if ((c->d & ModRM) && c->modrm_mod == 3) {
c->dst.type = OP_REG;
break;
}
c->dst.type = OP_MEM;
break;
}
done:
return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
}
static inline void emulate_push(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
c->dst.type = OP_MEM;
c->dst.bytes = c->op_bytes;
c->dst.val = c->src.val;
register_address_increment(c->regs[VCPU_REGS_RSP], -c->op_bytes);
c->dst.ptr = (void *) register_address(ctxt->ss_base,
c->regs[VCPU_REGS_RSP]);
}
static inline int emulate_grp1a(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
int rc;
/* 64-bit mode: POP always pops a 64-bit operand. */
if (ctxt->mode == X86EMUL_MODE_PROT64)
c->dst.bytes = 8;
rc = ops->read_std(register_address(ctxt->ss_base,
c->regs[VCPU_REGS_RSP]),
&c->dst.val, c->dst.bytes, ctxt->vcpu);
if (rc != 0)
return rc;
register_address_increment(c->regs[VCPU_REGS_RSP], c->dst.bytes);
return 0;
}
static inline void emulate_grp2(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
switch (c->modrm_reg) {
case 0: /* rol */
emulate_2op_SrcB("rol", c->src, c->dst, ctxt->eflags);
break;
case 1: /* ror */
emulate_2op_SrcB("ror", c->src, c->dst, ctxt->eflags);
break;
case 2: /* rcl */
emulate_2op_SrcB("rcl", c->src, c->dst, ctxt->eflags);
break;
case 3: /* rcr */
emulate_2op_SrcB("rcr", c->src, c->dst, ctxt->eflags);
break;
case 4: /* sal/shl */
case 6: /* sal/shl */
emulate_2op_SrcB("sal", c->src, c->dst, ctxt->eflags);
break;
case 5: /* shr */
emulate_2op_SrcB("shr", c->src, c->dst, ctxt->eflags);
break;
case 7: /* sar */
emulate_2op_SrcB("sar", c->src, c->dst, ctxt->eflags);
break;
}
}
static inline int emulate_grp3(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
int rc = 0;
switch (c->modrm_reg) {
case 0 ... 1: /* test */
/*
* Special case in Grp3: test has an immediate
* source operand.
*/
c->src.type = OP_IMM;
c->src.ptr = (unsigned long *)c->eip;
c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
if (c->src.bytes == 8)
c->src.bytes = 4;
switch (c->src.bytes) {
case 1:
c->src.val = insn_fetch(s8, 1, c->eip);
break;
case 2:
c->src.val = insn_fetch(s16, 2, c->eip);
break;
case 4:
c->src.val = insn_fetch(s32, 4, c->eip);
break;
}
emulate_2op_SrcV("test", c->src, c->dst, ctxt->eflags);
break;
case 2: /* not */
c->dst.val = ~c->dst.val;
break;
case 3: /* neg */
emulate_1op("neg", c->dst, ctxt->eflags);
break;
default:
DPRINTF("Cannot emulate %02x\n", c->b);
rc = X86EMUL_UNHANDLEABLE;
break;
}
done:
return rc;
}
static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
int rc;
switch (c->modrm_reg) {
case 0: /* inc */
emulate_1op("inc", c->dst, ctxt->eflags);
break;
case 1: /* dec */
emulate_1op("dec", c->dst, ctxt->eflags);
break;
case 4: /* jmp abs */
if (c->b == 0xff)
c->eip = c->dst.val;
else {
DPRINTF("Cannot emulate %02x\n", c->b);
return X86EMUL_UNHANDLEABLE;
}
break;
case 6: /* push */
/* 64-bit mode: PUSH always pushes a 64-bit operand. */
if (ctxt->mode == X86EMUL_MODE_PROT64) {
c->dst.bytes = 8;
rc = ops->read_std((unsigned long)c->dst.ptr,
&c->dst.val, 8, ctxt->vcpu);
if (rc != 0)
return rc;
}
register_address_increment(c->regs[VCPU_REGS_RSP],
-c->dst.bytes);
rc = ops->write_emulated(register_address(ctxt->ss_base,
c->regs[VCPU_REGS_RSP]), &c->dst.val,
c->dst.bytes, ctxt->vcpu);
if (rc != 0)
return rc;
c->dst.type = OP_NONE;
break;
default:
DPRINTF("Cannot emulate %02x\n", c->b);
return X86EMUL_UNHANDLEABLE;
}
return 0;
}
static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
unsigned long cr2)
{
struct decode_cache *c = &ctxt->decode;
u64 old, new;
int rc;
rc = ops->read_emulated(cr2, &old, 8, ctxt->vcpu);
if (rc != 0)
return rc;
if (((u32) (old >> 0) != (u32) c->regs[VCPU_REGS_RAX]) ||
((u32) (old >> 32) != (u32) c->regs[VCPU_REGS_RDX])) {
c->regs[VCPU_REGS_RAX] = (u32) (old >> 0);
c->regs[VCPU_REGS_RDX] = (u32) (old >> 32);
ctxt->eflags &= ~EFLG_ZF;
} else {
new = ((u64)c->regs[VCPU_REGS_RCX] << 32) |
(u32) c->regs[VCPU_REGS_RBX];
rc = ops->cmpxchg_emulated(cr2, &old, &new, 8, ctxt->vcpu);
if (rc != 0)
return rc;
ctxt->eflags |= EFLG_ZF;
}
return 0;
}
static inline int writeback(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
int rc;
struct decode_cache *c = &ctxt->decode;
switch (c->dst.type) {
case OP_REG:
/* The 4-byte case *is* correct:
* in 64-bit mode we zero-extend.
*/
switch (c->dst.bytes) {
case 1:
*(u8 *)c->dst.ptr = (u8)c->dst.val;
break;
case 2:
*(u16 *)c->dst.ptr = (u16)c->dst.val;
break;
case 4:
*c->dst.ptr = (u32)c->dst.val;
break; /* 64b: zero-ext */
case 8:
*c->dst.ptr = c->dst.val;
break;
}
break;
case OP_MEM:
if (c->lock_prefix)
rc = ops->cmpxchg_emulated(
(unsigned long)c->dst.ptr,
&c->dst.orig_val,
&c->dst.val,
c->dst.bytes,
ctxt->vcpu);
else
rc = ops->write_emulated(
(unsigned long)c->dst.ptr,
&c->dst.val,
c->dst.bytes,
ctxt->vcpu);
if (rc != 0)
return rc;
break;
case OP_NONE:
/* no writeback */
break;
default:
break;
}
return 0;
}
int
x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
{
unsigned long cr2 = ctxt->cr2;
u64 msr_data;
unsigned long saved_eip = 0;
struct decode_cache *c = &ctxt->decode;
int rc = 0;
/* Shadow copy of register state. Committed on successful emulation.
* NOTE: we can copy them from vcpu as x86_decode_insn() doesn't
* modify them.
*/
memcpy(c->regs, ctxt->vcpu->regs, sizeof c->regs);
saved_eip = c->eip;
if (((c->d & ModRM) && (c->modrm_mod != 3)) || (c->d & MemAbs))
cr2 = c->modrm_ea;
if (c->src.type == OP_MEM) {
c->src.ptr = (unsigned long *)cr2;
c->src.val = 0;
rc = ops->read_emulated((unsigned long)c->src.ptr,
&c->src.val,
c->src.bytes,
ctxt->vcpu);
if (rc != 0)
goto done;
c->src.orig_val = c->src.val;
}
if ((c->d & DstMask) == ImplicitOps)
goto special_insn;
if (c->dst.type == OP_MEM) {
c->dst.ptr = (unsigned long *)cr2;
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->dst.val = 0;
if (c->d & BitOp) {
unsigned long mask = ~(c->dst.bytes * 8 - 1);
c->dst.ptr = (void *)c->dst.ptr +
(c->src.val & mask) / 8;
}
if (!(c->d & Mov) &&
/* optimisation - avoid slow emulated read */
((rc = ops->read_emulated((unsigned long)c->dst.ptr,
&c->dst.val,
c->dst.bytes, ctxt->vcpu)) != 0))
goto done;
}
c->dst.orig_val = c->dst.val;
if (c->twobyte)
goto twobyte_insn;
switch (c->b) {
case 0x00 ... 0x05:
add: /* add */
emulate_2op_SrcV("add", c->src, c->dst, ctxt->eflags);
break;
case 0x08 ... 0x0d:
or: /* or */
emulate_2op_SrcV("or", c->src, c->dst, ctxt->eflags);
break;
case 0x10 ... 0x15:
adc: /* adc */
emulate_2op_SrcV("adc", c->src, c->dst, ctxt->eflags);
break;
case 0x18 ... 0x1d:
sbb: /* sbb */
emulate_2op_SrcV("sbb", c->src, c->dst, ctxt->eflags);
break;
case 0x20 ... 0x23:
and: /* and */
emulate_2op_SrcV("and", c->src, c->dst, ctxt->eflags);
break;
case 0x24: /* and al imm8 */
c->dst.type = OP_REG;
c->dst.ptr = &c->regs[VCPU_REGS_RAX];
c->dst.val = *(u8 *)c->dst.ptr;
c->dst.bytes = 1;
c->dst.orig_val = c->dst.val;
goto and;
case 0x25: /* and ax imm16, or eax imm32 */
c->dst.type = OP_REG;
c->dst.bytes = c->op_bytes;
c->dst.ptr = &c->regs[VCPU_REGS_RAX];
if (c->op_bytes == 2)
c->dst.val = *(u16 *)c->dst.ptr;
else
c->dst.val = *(u32 *)c->dst.ptr;
c->dst.orig_val = c->dst.val;
goto and;
case 0x28 ... 0x2d:
sub: /* sub */
emulate_2op_SrcV("sub", c->src, c->dst, ctxt->eflags);
break;
case 0x30 ... 0x35:
xor: /* xor */
emulate_2op_SrcV("xor", c->src, c->dst, ctxt->eflags);
break;
case 0x38 ... 0x3d:
cmp: /* cmp */
emulate_2op_SrcV("cmp", c->src, c->dst, ctxt->eflags);
break;
case 0x63: /* movsxd */
if (ctxt->mode != X86EMUL_MODE_PROT64)
goto cannot_emulate;
c->dst.val = (s32) c->src.val;
break;
case 0x80 ... 0x83: /* Grp1 */
switch (c->modrm_reg) {
case 0:
goto add;
case 1:
goto or;
case 2:
goto adc;
case 3:
goto sbb;
case 4:
goto and;
case 5:
goto sub;
case 6:
goto xor;
case 7:
goto cmp;
}
break;
case 0x84 ... 0x85:
emulate_2op_SrcV("test", c->src, c->dst, ctxt->eflags);
break;
case 0x86 ... 0x87: /* xchg */
/* Write back the register source. */
switch (c->dst.bytes) {
case 1:
*(u8 *) c->src.ptr = (u8) c->dst.val;
break;
case 2:
*(u16 *) c->src.ptr = (u16) c->dst.val;
break;
case 4:
*c->src.ptr = (u32) c->dst.val;
break; /* 64b reg: zero-extend */
case 8:
*c->src.ptr = c->dst.val;
break;
}
/*
* Write back the memory destination with implicit LOCK
* prefix.
*/
c->dst.val = c->src.val;
c->lock_prefix = 1;
break;
case 0x88 ... 0x8b: /* mov */
goto mov;
case 0x8d: /* lea r16/r32, m */
c->dst.val = c->modrm_val;
break;
case 0x8f: /* pop (sole member of Grp1a) */
rc = emulate_grp1a(ctxt, ops);
if (rc != 0)
goto done;
break;
case 0xa0 ... 0xa1: /* mov */
c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
c->dst.val = c->src.val;
break;
case 0xa2 ... 0xa3: /* mov */
c->dst.val = (unsigned long)c->regs[VCPU_REGS_RAX];
break;
case 0xc0 ... 0xc1:
emulate_grp2(ctxt);
break;
case 0xc6 ... 0xc7: /* mov (sole member of Grp11) */
mov:
c->dst.val = c->src.val;
break;
case 0xd0 ... 0xd1: /* Grp2 */
c->src.val = 1;
emulate_grp2(ctxt);
break;
case 0xd2 ... 0xd3: /* Grp2 */
c->src.val = c->regs[VCPU_REGS_RCX];
emulate_grp2(ctxt);
break;
case 0xf6 ... 0xf7: /* Grp3 */
rc = emulate_grp3(ctxt, ops);
if (rc != 0)
goto done;
break;
case 0xfe ... 0xff: /* Grp4/Grp5 */
rc = emulate_grp45(ctxt, ops);
if (rc != 0)
goto done;
break;
}
writeback:
rc = writeback(ctxt, ops);
if (rc != 0)
goto done;
/* Commit shadow register state. */
memcpy(ctxt->vcpu->regs, c->regs, sizeof c->regs);
ctxt->vcpu->rip = c->eip;
done:
if (rc == X86EMUL_UNHANDLEABLE) {
c->eip = saved_eip;
return -1;
}
return 0;
special_insn:
if (c->twobyte)
goto twobyte_special_insn;
switch (c->b) {
case 0x40 ... 0x47: /* inc r16/r32 */
c->dst.bytes = c->op_bytes;
c->dst.ptr = (unsigned long *)&c->regs[c->b & 0x7];
c->dst.val = *c->dst.ptr;
emulate_1op("inc", c->dst, ctxt->eflags);
break;
case 0x48 ... 0x4f: /* dec r16/r32 */
c->dst.bytes = c->op_bytes;
c->dst.ptr = (unsigned long *)&c->regs[c->b & 0x7];
c->dst.val = *c->dst.ptr;
emulate_1op("dec", c->dst, ctxt->eflags);
break;
case 0x50 ... 0x57: /* push reg */
if (c->op_bytes == 2)
c->src.val = (u16) c->regs[c->b & 0x7];
else
c->src.val = (u32) c->regs[c->b & 0x7];
c->dst.type = OP_MEM;
c->dst.bytes = c->op_bytes;
c->dst.val = c->src.val;
register_address_increment(c->regs[VCPU_REGS_RSP],
-c->op_bytes);
c->dst.ptr = (void *) register_address(
ctxt->ss_base, c->regs[VCPU_REGS_RSP]);
break;
case 0x58 ... 0x5f: /* pop reg */
c->dst.ptr = (unsigned long *)&c->regs[c->b & 0x7];
pop_instruction:
if ((rc = ops->read_std(register_address(ctxt->ss_base,
c->regs[VCPU_REGS_RSP]), c->dst.ptr,
c->op_bytes, ctxt->vcpu)) != 0)
goto done;
register_address_increment(c->regs[VCPU_REGS_RSP],
c->op_bytes);
c->dst.type = OP_NONE; /* Disable writeback. */
break;
case 0x6a: /* push imm8 */
c->src.val = 0L;
c->src.val = insn_fetch(s8, 1, c->eip);
emulate_push(ctxt);
break;
case 0x6c: /* insb */
case 0x6d: /* insw/insd */
if (kvm_emulate_pio_string(ctxt->vcpu, NULL,
1,
(c->d & ByteOp) ? 1 : c->op_bytes,
c->rep_prefix ?
address_mask(c->regs[VCPU_REGS_RCX]) : 1,
(ctxt->eflags & EFLG_DF),
register_address(ctxt->es_base,
c->regs[VCPU_REGS_RDI]),
c->rep_prefix,
c->regs[VCPU_REGS_RDX]) == 0) {
c->eip = saved_eip;
return -1;
}
return 0;
case 0x6e: /* outsb */
case 0x6f: /* outsw/outsd */
if (kvm_emulate_pio_string(ctxt->vcpu, NULL,
0,
(c->d & ByteOp) ? 1 : c->op_bytes,
c->rep_prefix ?
address_mask(c->regs[VCPU_REGS_RCX]) : 1,
(ctxt->eflags & EFLG_DF),
register_address(c->override_base ?
*c->override_base :
ctxt->ds_base,
c->regs[VCPU_REGS_RSI]),
c->rep_prefix,
c->regs[VCPU_REGS_RDX]) == 0) {
c->eip = saved_eip;
return -1;
}
return 0;
case 0x70 ... 0x7f: /* jcc (short) */ {
int rel = insn_fetch(s8, 1, c->eip);
if (test_cc(c->b, ctxt->eflags))
JMP_REL(rel);
break;
}
case 0x9c: /* pushf */
c->src.val = (unsigned long) ctxt->eflags;
emulate_push(ctxt);
break;
case 0x9d: /* popf */
c->dst.ptr = (unsigned long *) &ctxt->eflags;
goto pop_instruction;
case 0xc3: /* ret */
c->dst.ptr = &c->eip;
goto pop_instruction;
case 0xf4: /* hlt */
ctxt->vcpu->halt_request = 1;
goto done;
case 0xf5: /* cmc */
/* complement carry flag from eflags reg */
ctxt->eflags ^= EFLG_CF;
c->dst.type = OP_NONE; /* Disable writeback. */
break;
case 0xf8: /* clc */
ctxt->eflags &= ~EFLG_CF;
c->dst.type = OP_NONE; /* Disable writeback. */
break;
case 0xfa: /* cli */
ctxt->eflags &= ~X86_EFLAGS_IF;
c->dst.type = OP_NONE; /* Disable writeback. */
break;
case 0xfb: /* sti */
ctxt->eflags |= X86_EFLAGS_IF;
c->dst.type = OP_NONE; /* Disable writeback. */
break;
}
if (c->rep_prefix) {
if (c->regs[VCPU_REGS_RCX] == 0) {
ctxt->vcpu->rip = c->eip;
goto done;
}
c->regs[VCPU_REGS_RCX]--;
c->eip = ctxt->vcpu->rip;
}
switch (c->b) {
case 0xa4 ... 0xa5: /* movs */
c->dst.type = OP_MEM;
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->dst.ptr = (unsigned long *)register_address(
ctxt->es_base,
c->regs[VCPU_REGS_RDI]);
if ((rc = ops->read_emulated(register_address(
c->override_base ? *c->override_base :
ctxt->ds_base,
c->regs[VCPU_REGS_RSI]),
&c->dst.val,
c->dst.bytes, ctxt->vcpu)) != 0)
goto done;
register_address_increment(c->regs[VCPU_REGS_RSI],
(ctxt->eflags & EFLG_DF) ? -c->dst.bytes
: c->dst.bytes);
register_address_increment(c->regs[VCPU_REGS_RDI],
(ctxt->eflags & EFLG_DF) ? -c->dst.bytes
: c->dst.bytes);
break;
case 0xa6 ... 0xa7: /* cmps */
DPRINTF("Urk! I don't handle CMPS.\n");
goto cannot_emulate;
case 0xaa ... 0xab: /* stos */
c->dst.type = OP_MEM;
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->dst.ptr = (unsigned long *)cr2;
c->dst.val = c->regs[VCPU_REGS_RAX];
register_address_increment(c->regs[VCPU_REGS_RDI],
(ctxt->eflags & EFLG_DF) ? -c->dst.bytes
: c->dst.bytes);
break;
case 0xac ... 0xad: /* lods */
c->dst.type = OP_REG;
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
if ((rc = ops->read_emulated(cr2, &c->dst.val,
c->dst.bytes,
ctxt->vcpu)) != 0)
goto done;
register_address_increment(c->regs[VCPU_REGS_RSI],
(ctxt->eflags & EFLG_DF) ? -c->dst.bytes
: c->dst.bytes);
break;
case 0xae ... 0xaf: /* scas */
DPRINTF("Urk! I don't handle SCAS.\n");
goto cannot_emulate;
case 0xe8: /* call (near) */ {
long int rel;
switch (c->op_bytes) {
case 2:
rel = insn_fetch(s16, 2, c->eip);
break;
case 4:
rel = insn_fetch(s32, 4, c->eip);
break;
case 8:
rel = insn_fetch(s64, 8, c->eip);
break;
default:
DPRINTF("Call: Invalid op_bytes\n");
goto cannot_emulate;
}
c->src.val = (unsigned long) c->eip;
JMP_REL(rel);
c->op_bytes = c->ad_bytes;
emulate_push(ctxt);
break;
}
case 0xe9: /* jmp rel */
case 0xeb: /* jmp rel short */
JMP_REL(c->src.val);
c->dst.type = OP_NONE; /* Disable writeback. */
break;
}
goto writeback;
twobyte_insn:
switch (c->b) {
case 0x01: /* lgdt, lidt, lmsw */
switch (c->modrm_reg) {
u16 size;
unsigned long address;
case 0: /* vmcall */
if (c->modrm_mod != 3 || c->modrm_rm != 1)
goto cannot_emulate;
rc = kvm_fix_hypercall(ctxt->vcpu);
if (rc)
goto done;
kvm_emulate_hypercall(ctxt->vcpu);
break;
case 2: /* lgdt */
rc = read_descriptor(ctxt, ops, c->src.ptr,
&size, &address, c->op_bytes);
if (rc)
goto done;
realmode_lgdt(ctxt->vcpu, size, address);
break;
case 3: /* lidt/vmmcall */
if (c->modrm_mod == 3 && c->modrm_rm == 1) {
rc = kvm_fix_hypercall(ctxt->vcpu);
if (rc)
goto done;
kvm_emulate_hypercall(ctxt->vcpu);
} else {
rc = read_descriptor(ctxt, ops, c->src.ptr,
&size, &address,
c->op_bytes);
if (rc)
goto done;
realmode_lidt(ctxt->vcpu, size, address);
}
break;
case 4: /* smsw */
if (c->modrm_mod != 3)
goto cannot_emulate;
*(u16 *)&c->regs[c->modrm_rm]
= realmode_get_cr(ctxt->vcpu, 0);
break;
case 6: /* lmsw */
if (c->modrm_mod != 3)
goto cannot_emulate;
realmode_lmsw(ctxt->vcpu, (u16)c->modrm_val,
&ctxt->eflags);
break;
case 7: /* invlpg*/
emulate_invlpg(ctxt->vcpu, cr2);
break;
default:
goto cannot_emulate;
}
/* Disable writeback. */
c->dst.type = OP_NONE;
break;
case 0x21: /* mov from dr to reg */
if (c->modrm_mod != 3)
goto cannot_emulate;
rc = emulator_get_dr(ctxt, c->modrm_reg, &c->regs[c->modrm_rm]);
if (rc)
goto cannot_emulate;
c->dst.type = OP_NONE; /* no writeback */
break;
case 0x23: /* mov from reg to dr */
if (c->modrm_mod != 3)
goto cannot_emulate;
rc = emulator_set_dr(ctxt, c->modrm_reg,
c->regs[c->modrm_rm]);
if (rc)
goto cannot_emulate;
c->dst.type = OP_NONE; /* no writeback */
break;
case 0x40 ... 0x4f: /* cmov */
c->dst.val = c->dst.orig_val = c->src.val;
if (!test_cc(c->b, ctxt->eflags))
c->dst.type = OP_NONE; /* no writeback */
break;
case 0xa3:
bt: /* bt */
c->dst.type = OP_NONE;
/* only subword offset */
c->src.val &= (c->dst.bytes << 3) - 1;
emulate_2op_SrcV_nobyte("bt", c->src, c->dst, ctxt->eflags);
break;
case 0xab:
bts: /* bts */
/* only subword offset */
c->src.val &= (c->dst.bytes << 3) - 1;
emulate_2op_SrcV_nobyte("bts", c->src, c->dst, ctxt->eflags);
break;
case 0xb0 ... 0xb1: /* cmpxchg */
/*
* Save real source value, then compare EAX against
* destination.
*/
c->src.orig_val = c->src.val;
c->src.val = c->regs[VCPU_REGS_RAX];
emulate_2op_SrcV("cmp", c->src, c->dst, ctxt->eflags);
if (ctxt->eflags & EFLG_ZF) {
/* Success: write back to memory. */
c->dst.val = c->src.orig_val;
} else {
/* Failure: write the value we saw to EAX. */
c->dst.type = OP_REG;
c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
}
break;
case 0xb3:
btr: /* btr */
/* only subword offset */
c->src.val &= (c->dst.bytes << 3) - 1;
emulate_2op_SrcV_nobyte("btr", c->src, c->dst, ctxt->eflags);
break;
case 0xb6 ... 0xb7: /* movzx */
c->dst.bytes = c->op_bytes;
c->dst.val = (c->d & ByteOp) ? (u8) c->src.val
: (u16) c->src.val;
break;
case 0xba: /* Grp8 */
switch (c->modrm_reg & 3) {
case 0:
goto bt;
case 1:
goto bts;
case 2:
goto btr;
case 3:
goto btc;
}
break;
case 0xbb:
btc: /* btc */
/* only subword offset */
c->src.val &= (c->dst.bytes << 3) - 1;
emulate_2op_SrcV_nobyte("btc", c->src, c->dst, ctxt->eflags);
break;
case 0xbe ... 0xbf: /* movsx */
c->dst.bytes = c->op_bytes;
c->dst.val = (c->d & ByteOp) ? (s8) c->src.val :
(s16) c->src.val;
break;
case 0xc3: /* movnti */
c->dst.bytes = c->op_bytes;
c->dst.val = (c->op_bytes == 4) ? (u32) c->src.val :
(u64) c->src.val;
break;
}
goto writeback;
twobyte_special_insn:
switch (c->b) {
case 0x06:
emulate_clts(ctxt->vcpu);
break;
case 0x08: /* invd */
break;
case 0x09: /* wbinvd */
break;
case 0x0d: /* GrpP (prefetch) */
case 0x18: /* Grp16 (prefetch/nop) */
break;
case 0x20: /* mov cr, reg */
if (c->modrm_mod != 3)
goto cannot_emulate;
c->regs[c->modrm_rm] =
realmode_get_cr(ctxt->vcpu, c->modrm_reg);
break;
case 0x22: /* mov reg, cr */
if (c->modrm_mod != 3)
goto cannot_emulate;
realmode_set_cr(ctxt->vcpu,
c->modrm_reg, c->modrm_val, &ctxt->eflags);
break;
case 0x30:
/* wrmsr */
msr_data = (u32)c->regs[VCPU_REGS_RAX]
| ((u64)c->regs[VCPU_REGS_RDX] << 32);
rc = kvm_set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data);
if (rc) {
kvm_x86_ops->inject_gp(ctxt->vcpu, 0);
c->eip = ctxt->vcpu->rip;
}
rc = X86EMUL_CONTINUE;
break;
case 0x32:
/* rdmsr */
rc = kvm_get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], &msr_data);
if (rc) {
kvm_x86_ops->inject_gp(ctxt->vcpu, 0);
c->eip = ctxt->vcpu->rip;
} else {
c->regs[VCPU_REGS_RAX] = (u32)msr_data;
c->regs[VCPU_REGS_RDX] = msr_data >> 32;
}
rc = X86EMUL_CONTINUE;
break;
case 0x80 ... 0x8f: /* jnz rel, etc*/ {
long int rel;
switch (c->op_bytes) {
case 2:
rel = insn_fetch(s16, 2, c->eip);
break;
case 4:
rel = insn_fetch(s32, 4, c->eip);
break;
case 8:
rel = insn_fetch(s64, 8, c->eip);
break;
default:
DPRINTF("jnz: Invalid op_bytes\n");
goto cannot_emulate;
}
if (test_cc(c->b, ctxt->eflags))
JMP_REL(rel);
break;
}
case 0xc7: /* Grp9 (cmpxchg8b) */
rc = emulate_grp9(ctxt, ops, cr2);
if (rc != 0)
goto done;
break;
}
/* Disable writeback. */
c->dst.type = OP_NONE;
goto writeback;
cannot_emulate:
DPRINTF("Cannot emulate %02x\n", c->b);
c->eip = saved_eip;
return -1;
}
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