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linux-pinenote/arch/x86/kvm/emulate.c
Andre Przywara dc25e89e07 KVM: SVM: copy instruction bytes from VMCB 
In case of a nested page fault or an intercepted #PF newer SVM
implementations provide a copy of the faulting instruction bytes
in the VMCB.
Use these bytes to feed the instruction emulator and avoid the costly
guest instruction fetch in this case.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-01-12 11:31:07 +02:00

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/******************************************************************************
* 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
* Copyright 2010 Red Hat, Inc. and/or its affiliates.
*
* 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
*/
#include <linux/kvm_host.h>
#include "kvm_cache_regs.h"
#include <linux/module.h>
#include <asm/kvm_emulate.h>
#include "x86.h"
#include "tss.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 DstAcc (4<<1) /* Destination Accumulator */
#define DstDI (5<<1) /* Destination is in ES:(E)DI */
#define DstMem64 (6<<1) /* 64bit memory operand */
#define DstImmUByte (7<<1) /* 8-bit unsigned immediate operand */
#define DstMask (7<<1)
/* Source operand type. */
#define SrcNone (0<<4) /* No source operand. */
#define SrcReg (1<<4) /* Register operand. */
#define SrcMem (2<<4) /* Memory operand. */
#define SrcMem16 (3<<4) /* Memory operand (16-bit). */
#define SrcMem32 (4<<4) /* Memory operand (32-bit). */
#define SrcImm (5<<4) /* Immediate operand. */
#define SrcImmByte (6<<4) /* 8-bit sign-extended immediate operand. */
#define SrcOne (7<<4) /* Implied '1' */
#define SrcImmUByte (8<<4) /* 8-bit unsigned immediate operand. */
#define SrcImmU (9<<4) /* Immediate operand, unsigned */
#define SrcSI (0xa<<4) /* Source is in the DS:RSI */
#define SrcImmFAddr (0xb<<4) /* Source is immediate far address */
#define SrcMemFAddr (0xc<<4) /* Source is far address in memory */
#define SrcAcc (0xd<<4) /* Source Accumulator */
#define SrcImmU16 (0xe<<4) /* Immediate operand, unsigned, 16 bits */
#define SrcMask (0xf<<4)
/* Generic ModRM decode. */
#define ModRM (1<<8)
/* Destination is only written; never read. */
#define Mov (1<<9)
#define BitOp (1<<10)
#define MemAbs (1<<11) /* Memory operand is absolute displacement */
#define String (1<<12) /* String instruction (rep capable) */
#define Stack (1<<13) /* Stack instruction (push/pop) */
#define Group (1<<14) /* Bits 3:5 of modrm byte extend opcode */
#define GroupDual (1<<15) /* Alternate decoding of mod == 3 */
/* Misc flags */
#define NoAccess (1<<23) /* Don't access memory (lea/invlpg/verr etc) */
#define Op3264 (1<<24) /* Operand is 64b in long mode, 32b otherwise */
#define Undefined (1<<25) /* No Such Instruction */
#define Lock (1<<26) /* lock prefix is allowed for the instruction */
#define Priv (1<<27) /* instruction generates #GP if current CPL != 0 */
#define No64 (1<<28)
/* Source 2 operand type */
#define Src2None (0<<29)
#define Src2CL (1<<29)
#define Src2ImmByte (2<<29)
#define Src2One (3<<29)
#define Src2Imm (4<<29)
#define Src2Mask (7<<29)
#define X2(x...) x, x
#define X3(x...) X2(x), x
#define X4(x...) X2(x), X2(x)
#define X5(x...) X4(x), x
#define X6(x...) X4(x), X2(x)
#define X7(x...) X4(x), X3(x)
#define X8(x...) X4(x), X4(x)
#define X16(x...) X8(x), X8(x)
struct opcode {
u32 flags;
union {
int (*execute)(struct x86_emulate_ctxt *ctxt);
struct opcode *group;
struct group_dual *gdual;
} u;
};
struct group_dual {
struct opcode mod012[8];
struct opcode mod3[8];
};
/* EFLAGS bit definitions. */
#define EFLG_ID (1<<21)
#define EFLG_VIP (1<<20)
#define EFLG_VIF (1<<19)
#define EFLG_AC (1<<18)
#define EFLG_VM (1<<17)
#define EFLG_RF (1<<16)
#define EFLG_IOPL (3<<12)
#define EFLG_NT (1<<14)
#define EFLG_OF (1<<11)
#define EFLG_DF (1<<10)
#define EFLG_IF (1<<9)
#define EFLG_TF (1<<8)
#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)
#define EFLG_RESERVED_ZEROS_MASK 0xffc0802a
#define EFLG_RESERVED_ONE_MASK 2
/*
* 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); _sav &= ~_msk; */ \
"movl %"_sav",%"_LO32 _tmp"; " \
"push %"_tmp"; " \
"push %"_tmp"; " \
"movl %"_msk",%"_LO32 _tmp"; " \
"andl %"_LO32 _tmp",("_STK"); " \
"pushf; " \
"notl %"_LO32 _tmp"; " \
"andl %"_LO32 _tmp",("_STK"); " \
"andl %"_LO32 _tmp","__stringify(BITS_PER_LONG/4)"("_STK"); " \
"pop %"_tmp"; " \
"orl %"_LO32 _tmp",("_STK"); " \
"popf; " \
"pop %"_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 CONFIG_X86_64
#define ON64(x) x
#else
#define ON64(x)
#endif
#define ____emulate_2op(_op, _src, _dst, _eflags, _x, _y, _suffix, _dsttype) \
do { \
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "4", "2") \
_op _suffix " %"_x"3,%1; " \
_POST_EFLAGS("0", "4", "2") \
: "=m" (_eflags), "+q" (*(_dsttype*)&(_dst).val),\
"=&r" (_tmp) \
: _y ((_src).val), "i" (EFLAGS_MASK)); \
} while (0)
/* 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: \
____emulate_2op(_op,_src,_dst,_eflags,_wx,_wy,"w",u16);\
break; \
case 4: \
____emulate_2op(_op,_src,_dst,_eflags,_lx,_ly,"l",u32);\
break; \
case 8: \
ON64(____emulate_2op(_op,_src,_dst,_eflags,_qx,_qy,"q",u64)); \
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: \
____emulate_2op(_op,_src,_dst,_eflags,_bx,_by,"b",u8); \
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 three operands and one operand is stored in ECX register */
#define __emulate_2op_cl(_op, _cl, _src, _dst, _eflags, _suffix, _type) \
do { \
unsigned long _tmp; \
_type _clv = (_cl).val; \
_type _srcv = (_src).val; \
_type _dstv = (_dst).val; \
\
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "5", "2") \
_op _suffix " %4,%1 \n" \
_POST_EFLAGS("0", "5", "2") \
: "=m" (_eflags), "+r" (_dstv), "=&r" (_tmp) \
: "c" (_clv) , "r" (_srcv), "i" (EFLAGS_MASK) \
); \
\
(_cl).val = (unsigned long) _clv; \
(_src).val = (unsigned long) _srcv; \
(_dst).val = (unsigned long) _dstv; \
} while (0)
#define emulate_2op_cl(_op, _cl, _src, _dst, _eflags) \
do { \
switch ((_dst).bytes) { \
case 2: \
__emulate_2op_cl(_op, _cl, _src, _dst, _eflags, \
"w", unsigned short); \
break; \
case 4: \
__emulate_2op_cl(_op, _cl, _src, _dst, _eflags, \
"l", unsigned int); \
break; \
case 8: \
ON64(__emulate_2op_cl(_op, _cl, _src, _dst, _eflags, \
"q", unsigned long)); \
break; \
} \
} while (0)
#define __emulate_1op(_op, _dst, _eflags, _suffix) \
do { \
unsigned long _tmp; \
\
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "3", "2") \
_op _suffix " %1; " \
_POST_EFLAGS("0", "3", "2") \
: "=m" (_eflags), "+m" ((_dst).val), \
"=&r" (_tmp) \
: "i" (EFLAGS_MASK)); \
} while (0)
/* Instruction has only one explicit operand (no source operand). */
#define emulate_1op(_op, _dst, _eflags) \
do { \
switch ((_dst).bytes) { \
case 1: __emulate_1op(_op, _dst, _eflags, "b"); break; \
case 2: __emulate_1op(_op, _dst, _eflags, "w"); break; \
case 4: __emulate_1op(_op, _dst, _eflags, "l"); break; \
case 8: ON64(__emulate_1op(_op, _dst, _eflags, "q")); break; \
} \
} while (0)
#define __emulate_1op_rax_rdx(_op, _src, _rax, _rdx, _eflags, _suffix) \
do { \
unsigned long _tmp; \
\
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "4", "1") \
_op _suffix " %5; " \
_POST_EFLAGS("0", "4", "1") \
: "=m" (_eflags), "=&r" (_tmp), \
"+a" (_rax), "+d" (_rdx) \
: "i" (EFLAGS_MASK), "m" ((_src).val), \
"a" (_rax), "d" (_rdx)); \
} while (0)
#define __emulate_1op_rax_rdx_ex(_op, _src, _rax, _rdx, _eflags, _suffix, _ex) \
do { \
unsigned long _tmp; \
\
__asm__ __volatile__ ( \
_PRE_EFLAGS("0", "5", "1") \
"1: \n\t" \
_op _suffix " %6; " \
"2: \n\t" \
_POST_EFLAGS("0", "5", "1") \
".pushsection .fixup,\"ax\" \n\t" \
"3: movb $1, %4 \n\t" \
"jmp 2b \n\t" \
".popsection \n\t" \
_ASM_EXTABLE(1b, 3b) \
: "=m" (_eflags), "=&r" (_tmp), \
"+a" (_rax), "+d" (_rdx), "+qm"(_ex) \
: "i" (EFLAGS_MASK), "m" ((_src).val), \
"a" (_rax), "d" (_rdx)); \
} while (0)
/* instruction has only one source operand, destination is implicit (e.g. mul, div, imul, idiv) */
#define emulate_1op_rax_rdx(_op, _src, _rax, _rdx, _eflags) \
do { \
switch((_src).bytes) { \
case 1: __emulate_1op_rax_rdx(_op, _src, _rax, _rdx, _eflags, "b"); break; \
case 2: __emulate_1op_rax_rdx(_op, _src, _rax, _rdx, _eflags, "w"); break; \
case 4: __emulate_1op_rax_rdx(_op, _src, _rax, _rdx, _eflags, "l"); break; \
case 8: ON64(__emulate_1op_rax_rdx(_op, _src, _rax, _rdx, _eflags, "q")); break; \
} \
} while (0)
#define emulate_1op_rax_rdx_ex(_op, _src, _rax, _rdx, _eflags, _ex) \
do { \
switch((_src).bytes) { \
case 1: \
__emulate_1op_rax_rdx_ex(_op, _src, _rax, _rdx, \
_eflags, "b", _ex); \
break; \
case 2: \
__emulate_1op_rax_rdx_ex(_op, _src, _rax, _rdx, \
_eflags, "w", _ex); \
break; \
case 4: \
__emulate_1op_rax_rdx_ex(_op, _src, _rax, _rdx, \
_eflags, "l", _ex); \
break; \
case 8: ON64( \
__emulate_1op_rax_rdx_ex(_op, _src, _rax, _rdx, \
_eflags, "q", _ex)); \
break; \
} \
} while (0)
/* Fetch next part of the instruction being emulated. */
#define insn_fetch(_type, _size, _eip) \
({ unsigned long _x; \
rc = do_insn_fetch(ctxt, ops, (_eip), &_x, (_size)); \
if (rc != X86EMUL_CONTINUE) \
goto done; \
(_eip) += (_size); \
(_type)_x; \
})
#define insn_fetch_arr(_arr, _size, _eip) \
({ rc = do_insn_fetch(ctxt, ops, (_eip), _arr, (_size)); \
if (rc != X86EMUL_CONTINUE) \
goto done; \
(_eip) += (_size); \
})
static inline unsigned long ad_mask(struct decode_cache *c)
{
return (1UL << (c->ad_bytes << 3)) - 1;
}
/* Access/update address held in a register, based on addressing mode. */
static inline unsigned long
address_mask(struct decode_cache *c, unsigned long reg)
{
if (c->ad_bytes == sizeof(unsigned long))
return reg;
else
return reg & ad_mask(c);
}
static inline unsigned long
register_address(struct decode_cache *c, unsigned long reg)
{
return address_mask(c, reg);
}
static inline void
register_address_increment(struct decode_cache *c, unsigned long *reg, int inc)
{
if (c->ad_bytes == sizeof(unsigned long))
*reg += inc;
else
*reg = (*reg & ~ad_mask(c)) | ((*reg + inc) & ad_mask(c));
}
static inline void jmp_rel(struct decode_cache *c, int rel)
{
register_address_increment(c, &c->eip, rel);
}
static void set_seg_override(struct decode_cache *c, int seg)
{
c->has_seg_override = true;
c->seg_override = seg;
}
static unsigned long seg_base(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops, int seg)
{
if (ctxt->mode == X86EMUL_MODE_PROT64 && seg < VCPU_SREG_FS)
return 0;
return ops->get_cached_segment_base(seg, ctxt->vcpu);
}
static unsigned seg_override(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
struct decode_cache *c)
{
if (!c->has_seg_override)
return 0;
return c->seg_override;
}
static ulong linear(struct x86_emulate_ctxt *ctxt,
struct segmented_address addr)
{
struct decode_cache *c = &ctxt->decode;
ulong la;
la = seg_base(ctxt, ctxt->ops, addr.seg) + addr.ea;
if (c->ad_bytes != 8)
la &= (u32)-1;
return la;
}
static int emulate_exception(struct x86_emulate_ctxt *ctxt, int vec,
u32 error, bool valid)
{
ctxt->exception.vector = vec;
ctxt->exception.error_code = error;
ctxt->exception.error_code_valid = valid;
return X86EMUL_PROPAGATE_FAULT;
}
static int emulate_gp(struct x86_emulate_ctxt *ctxt, int err)
{
return emulate_exception(ctxt, GP_VECTOR, err, true);
}
static int emulate_ud(struct x86_emulate_ctxt *ctxt)
{
return emulate_exception(ctxt, UD_VECTOR, 0, false);
}
static int emulate_ts(struct x86_emulate_ctxt *ctxt, int err)
{
return emulate_exception(ctxt, TS_VECTOR, err, true);
}
static int emulate_de(struct x86_emulate_ctxt *ctxt)
{
return emulate_exception(ctxt, DE_VECTOR, 0, false);
}
static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
unsigned long eip, u8 *dest)
{
struct fetch_cache *fc = &ctxt->decode.fetch;
int rc;
int size, cur_size;
if (eip == fc->end) {
cur_size = fc->end - fc->start;
size = min(15UL - cur_size, PAGE_SIZE - offset_in_page(eip));
rc = ops->fetch(ctxt->cs_base + eip, fc->data + cur_size,
size, ctxt->vcpu, &ctxt->exception);
if (rc != X86EMUL_CONTINUE)
return rc;
fc->end += size;
}
*dest = fc->data[eip - fc->start];
return X86EMUL_CONTINUE;
}
static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
unsigned long eip, void *dest, unsigned size)
{
int rc;
/* x86 instructions are limited to 15 bytes. */
if (eip + size - ctxt->eip > 15)
return X86EMUL_UNHANDLEABLE;
while (size--) {
rc = do_fetch_insn_byte(ctxt, ops, eip++, dest++);
if (rc != X86EMUL_CONTINUE)
return rc;
}
return X86EMUL_CONTINUE;
}
/*
* 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,
struct segmented_address addr,
u16 *size, unsigned long *address, int op_bytes)
{
int rc;
if (op_bytes == 2)
op_bytes = 3;
*address = 0;
rc = ops->read_std(linear(ctxt, addr), (unsigned long *)size, 2,
ctxt->vcpu, &ctxt->exception);
if (rc != X86EMUL_CONTINUE)
return rc;
addr.ea += 2;
rc = ops->read_std(linear(ctxt, addr), address, op_bytes,
ctxt->vcpu, &ctxt->exception);
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));
}
static void fetch_register_operand(struct operand *op)
{
switch (op->bytes) {
case 1:
op->val = *(u8 *)op->addr.reg;
break;
case 2:
op->val = *(u16 *)op->addr.reg;
break;
case 4:
op->val = *(u32 *)op->addr.reg;
break;
case 8:
op->val = *(u64 *)op->addr.reg;
break;
}
}
static void decode_register_operand(struct operand *op,
struct decode_cache *c,
int inhibit_bytereg)
{
unsigned reg = c->modrm_reg;
int highbyte_regs = c->rex_prefix == 0;
if (!(c->d & ModRM))
reg = (c->b & 7) | ((c->rex_prefix & 1) << 3);
op->type = OP_REG;
if ((c->d & ByteOp) && !inhibit_bytereg) {
op->addr.reg = decode_register(reg, c->regs, highbyte_regs);
op->bytes = 1;
} else {
op->addr.reg = decode_register(reg, c->regs, 0);
op->bytes = c->op_bytes;
}
fetch_register_operand(op);
op->orig_val = op->val;
}
static int decode_modrm(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
struct operand *op)
{
struct decode_cache *c = &ctxt->decode;
u8 sib;
int index_reg = 0, base_reg = 0, scale;
int rc = X86EMUL_CONTINUE;
ulong modrm_ea = 0;
if (c->rex_prefix) {
c->modrm_reg = (c->rex_prefix & 4) << 1; /* REX.R */
index_reg = (c->rex_prefix & 2) << 2; /* REX.X */
c->modrm_rm = base_reg = (c->rex_prefix & 1) << 3; /* REG.B */
}
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_seg = VCPU_SREG_DS;
if (c->modrm_mod == 3) {
op->type = OP_REG;
op->bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
op->addr.reg = decode_register(c->modrm_rm,
c->regs, c->d & ByteOp);
fetch_register_operand(op);
return rc;
}
op->type = OP_MEM;
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)
modrm_ea += insn_fetch(u16, 2, c->eip);
break;
case 1:
modrm_ea += insn_fetch(s8, 1, c->eip);
break;
case 2:
modrm_ea += insn_fetch(u16, 2, c->eip);
break;
}
switch (c->modrm_rm) {
case 0:
modrm_ea += bx + si;
break;
case 1:
modrm_ea += bx + di;
break;
case 2:
modrm_ea += bp + si;
break;
case 3:
modrm_ea += bp + di;
break;
case 4:
modrm_ea += si;
break;
case 5:
modrm_ea += di;
break;
case 6:
if (c->modrm_mod != 0)
modrm_ea += bp;
break;
case 7:
modrm_ea += bx;
break;
}
if (c->modrm_rm == 2 || c->modrm_rm == 3 ||
(c->modrm_rm == 6 && c->modrm_mod != 0))
c->modrm_seg = VCPU_SREG_SS;
modrm_ea = (u16)modrm_ea;
} else {
/* 32/64-bit ModR/M decode. */
if ((c->modrm_rm & 7) == 4) {
sib = insn_fetch(u8, 1, c->eip);
index_reg |= (sib >> 3) & 7;
base_reg |= sib & 7;
scale = sib >> 6;
if ((base_reg & 7) == 5 && c->modrm_mod == 0)
modrm_ea += insn_fetch(s32, 4, c->eip);
else
modrm_ea += c->regs[base_reg];
if (index_reg != 4)
modrm_ea += c->regs[index_reg] << scale;
} else if ((c->modrm_rm & 7) == 5 && c->modrm_mod == 0) {
if (ctxt->mode == X86EMUL_MODE_PROT64)
c->rip_relative = 1;
} else
modrm_ea += c->regs[c->modrm_rm];
switch (c->modrm_mod) {
case 0:
if (c->modrm_rm == 5)
modrm_ea += insn_fetch(s32, 4, c->eip);
break;
case 1:
modrm_ea += insn_fetch(s8, 1, c->eip);
break;
case 2:
modrm_ea += insn_fetch(s32, 4, c->eip);
break;
}
}
op->addr.mem.ea = modrm_ea;
done:
return rc;
}
static int decode_abs(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
struct operand *op)
{
struct decode_cache *c = &ctxt->decode;
int rc = X86EMUL_CONTINUE;
op->type = OP_MEM;
switch (c->ad_bytes) {
case 2:
op->addr.mem.ea = insn_fetch(u16, 2, c->eip);
break;
case 4:
op->addr.mem.ea = insn_fetch(u32, 4, c->eip);
break;
case 8:
op->addr.mem.ea = insn_fetch(u64, 8, c->eip);
break;
}
done:
return rc;
}
static void fetch_bit_operand(struct decode_cache *c)
{
long sv = 0, mask;
if (c->dst.type == OP_MEM && c->src.type == OP_REG) {
mask = ~(c->dst.bytes * 8 - 1);
if (c->src.bytes == 2)
sv = (s16)c->src.val & (s16)mask;
else if (c->src.bytes == 4)
sv = (s32)c->src.val & (s32)mask;
c->dst.addr.mem.ea += (sv >> 3);
}
/* only subword offset */
c->src.val &= (c->dst.bytes << 3) - 1;
}
static int read_emulated(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
unsigned long addr, void *dest, unsigned size)
{
int rc;
struct read_cache *mc = &ctxt->decode.mem_read;
while (size) {
int n = min(size, 8u);
size -= n;
if (mc->pos < mc->end)
goto read_cached;
rc = ops->read_emulated(addr, mc->data + mc->end, n,
&ctxt->exception, ctxt->vcpu);
if (rc != X86EMUL_CONTINUE)
return rc;
mc->end += n;
read_cached:
memcpy(dest, mc->data + mc->pos, n);
mc->pos += n;
dest += n;
addr += n;
}
return X86EMUL_CONTINUE;
}
static int pio_in_emulated(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
unsigned int size, unsigned short port,
void *dest)
{
struct read_cache *rc = &ctxt->decode.io_read;
if (rc->pos == rc->end) { /* refill pio read ahead */
struct decode_cache *c = &ctxt->decode;
unsigned int in_page, n;
unsigned int count = c->rep_prefix ?
address_mask(c, c->regs[VCPU_REGS_RCX]) : 1;
in_page = (ctxt->eflags & EFLG_DF) ?
offset_in_page(c->regs[VCPU_REGS_RDI]) :
PAGE_SIZE - offset_in_page(c->regs[VCPU_REGS_RDI]);
n = min(min(in_page, (unsigned int)sizeof(rc->data)) / size,
count);
if (n == 0)
n = 1;
rc->pos = rc->end = 0;
if (!ops->pio_in_emulated(size, port, rc->data, n, ctxt->vcpu))
return 0;
rc->end = n * size;
}
memcpy(dest, rc->data + rc->pos, size);
rc->pos += size;
return 1;
}
static u32 desc_limit_scaled(struct desc_struct *desc)
{
u32 limit = get_desc_limit(desc);
return desc->g ? (limit << 12) | 0xfff : limit;
}
static void get_descriptor_table_ptr(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
u16 selector, struct desc_ptr *dt)
{
if (selector & 1 << 2) {
struct desc_struct desc;
memset (dt, 0, sizeof *dt);
if (!ops->get_cached_descriptor(&desc, VCPU_SREG_LDTR, ctxt->vcpu))
return;
dt->size = desc_limit_scaled(&desc); /* what if limit > 65535? */
dt->address = get_desc_base(&desc);
} else
ops->get_gdt(dt, ctxt->vcpu);
}
/* allowed just for 8 bytes segments */
static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
u16 selector, struct desc_struct *desc)
{
struct desc_ptr dt;
u16 index = selector >> 3;
int ret;
ulong addr;
get_descriptor_table_ptr(ctxt, ops, selector, &dt);
if (dt.size < index * 8 + 7)
return emulate_gp(ctxt, selector & 0xfffc);
addr = dt.address + index * 8;
ret = ops->read_std(addr, desc, sizeof *desc, ctxt->vcpu,
&ctxt->exception);
return ret;
}
/* allowed just for 8 bytes segments */
static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
u16 selector, struct desc_struct *desc)
{
struct desc_ptr dt;
u16 index = selector >> 3;
ulong addr;
int ret;
get_descriptor_table_ptr(ctxt, ops, selector, &dt);
if (dt.size < index * 8 + 7)
return emulate_gp(ctxt, selector & 0xfffc);
addr = dt.address + index * 8;
ret = ops->write_std(addr, desc, sizeof *desc, ctxt->vcpu,
&ctxt->exception);
return ret;
}
static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
u16 selector, int seg)
{
struct desc_struct seg_desc;
u8 dpl, rpl, cpl;
unsigned err_vec = GP_VECTOR;
u32 err_code = 0;
bool null_selector = !(selector & ~0x3); /* 0000-0003 are null */
int ret;
memset(&seg_desc, 0, sizeof seg_desc);
if ((seg <= VCPU_SREG_GS && ctxt->mode == X86EMUL_MODE_VM86)
|| ctxt->mode == X86EMUL_MODE_REAL) {
/* set real mode segment descriptor */
set_desc_base(&seg_desc, selector << 4);
set_desc_limit(&seg_desc, 0xffff);
seg_desc.type = 3;
seg_desc.p = 1;
seg_desc.s = 1;
goto load;
}
/* NULL selector is not valid for TR, CS and SS */
if ((seg == VCPU_SREG_CS || seg == VCPU_SREG_SS || seg == VCPU_SREG_TR)
&& null_selector)
goto exception;
/* TR should be in GDT only */
if (seg == VCPU_SREG_TR && (selector & (1 << 2)))
goto exception;
if (null_selector) /* for NULL selector skip all following checks */
goto load;
ret = read_segment_descriptor(ctxt, ops, selector, &seg_desc);
if (ret != X86EMUL_CONTINUE)
return ret;
err_code = selector & 0xfffc;
err_vec = GP_VECTOR;
/* can't load system descriptor into segment selecor */
if (seg <= VCPU_SREG_GS && !seg_desc.s)
goto exception;
if (!seg_desc.p) {
err_vec = (seg == VCPU_SREG_SS) ? SS_VECTOR : NP_VECTOR;
goto exception;
}
rpl = selector & 3;
dpl = seg_desc.dpl;
cpl = ops->cpl(ctxt->vcpu);
switch (seg) {
case VCPU_SREG_SS:
/*
* segment is not a writable data segment or segment
* selector's RPL != CPL or segment selector's RPL != CPL
*/
if (rpl != cpl || (seg_desc.type & 0xa) != 0x2 || dpl != cpl)
goto exception;
break;
case VCPU_SREG_CS:
if (!(seg_desc.type & 8))
goto exception;
if (seg_desc.type & 4) {
/* conforming */
if (dpl > cpl)
goto exception;
} else {
/* nonconforming */
if (rpl > cpl || dpl != cpl)
goto exception;
}
/* CS(RPL) <- CPL */
selector = (selector & 0xfffc) | cpl;
break;
case VCPU_SREG_TR:
if (seg_desc.s || (seg_desc.type != 1 && seg_desc.type != 9))
goto exception;
break;
case VCPU_SREG_LDTR:
if (seg_desc.s || seg_desc.type != 2)
goto exception;
break;
default: /* DS, ES, FS, or GS */
/*
* segment is not a data or readable code segment or
* ((segment is a data or nonconforming code segment)
* and (both RPL and CPL > DPL))
*/
if ((seg_desc.type & 0xa) == 0x8 ||
(((seg_desc.type & 0xc) != 0xc) &&
(rpl > dpl && cpl > dpl)))
goto exception;
break;
}
if (seg_desc.s) {
/* mark segment as accessed */
seg_desc.type |= 1;
ret = write_segment_descriptor(ctxt, ops, selector, &seg_desc);
if (ret != X86EMUL_CONTINUE)
return ret;
}
load:
ops->set_segment_selector(selector, seg, ctxt->vcpu);
ops->set_cached_descriptor(&seg_desc, seg, ctxt->vcpu);
return X86EMUL_CONTINUE;
exception:
emulate_exception(ctxt, err_vec, err_code, true);
return X86EMUL_PROPAGATE_FAULT;
}
static void write_register_operand(struct operand *op)
{
/* The 4-byte case *is* correct: in 64-bit mode we zero-extend. */
switch (op->bytes) {
case 1:
*(u8 *)op->addr.reg = (u8)op->val;
break;
case 2:
*(u16 *)op->addr.reg = (u16)op->val;
break;
case 4:
*op->addr.reg = (u32)op->val;
break; /* 64b: zero-extend */
case 8:
*op->addr.reg = op->val;
break;
}
}
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:
write_register_operand(&c->dst);
break;
case OP_MEM:
if (c->lock_prefix)
rc = ops->cmpxchg_emulated(
linear(ctxt, c->dst.addr.mem),
&c->dst.orig_val,
&c->dst.val,
c->dst.bytes,
&ctxt->exception,
ctxt->vcpu);
else
rc = ops->write_emulated(
linear(ctxt, c->dst.addr.mem),
&c->dst.val,
c->dst.bytes,
&ctxt->exception,
ctxt->vcpu);
if (rc != X86EMUL_CONTINUE)
return rc;
break;
case OP_NONE:
/* no writeback */
break;
default:
break;
}
return X86EMUL_CONTINUE;
}
static inline void emulate_push(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
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, &c->regs[VCPU_REGS_RSP], -c->op_bytes);
c->dst.addr.mem.ea = register_address(c, c->regs[VCPU_REGS_RSP]);
c->dst.addr.mem.seg = VCPU_SREG_SS;
}
static int emulate_pop(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
void *dest, int len)
{
struct decode_cache *c = &ctxt->decode;
int rc;
struct segmented_address addr;
addr.ea = register_address(c, c->regs[VCPU_REGS_RSP]);
addr.seg = VCPU_SREG_SS;
rc = read_emulated(ctxt, ops, linear(ctxt, addr), dest, len);
if (rc != X86EMUL_CONTINUE)
return rc;
register_address_increment(c, &c->regs[VCPU_REGS_RSP], len);
return rc;
}
static int emulate_popf(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
void *dest, int len)
{
int rc;
unsigned long val, change_mask;
int iopl = (ctxt->eflags & X86_EFLAGS_IOPL) >> IOPL_SHIFT;
int cpl = ops->cpl(ctxt->vcpu);
rc = emulate_pop(ctxt, ops, &val, len);
if (rc != X86EMUL_CONTINUE)
return rc;
change_mask = EFLG_CF | EFLG_PF | EFLG_AF | EFLG_ZF | EFLG_SF | EFLG_OF
| EFLG_TF | EFLG_DF | EFLG_NT | EFLG_RF | EFLG_AC | EFLG_ID;
switch(ctxt->mode) {
case X86EMUL_MODE_PROT64:
case X86EMUL_MODE_PROT32:
case X86EMUL_MODE_PROT16:
if (cpl == 0)
change_mask |= EFLG_IOPL;
if (cpl <= iopl)
change_mask |= EFLG_IF;
break;
case X86EMUL_MODE_VM86:
if (iopl < 3)
return emulate_gp(ctxt, 0);
change_mask |= EFLG_IF;
break;
default: /* real mode */
change_mask |= (EFLG_IOPL | EFLG_IF);
break;
}
*(unsigned long *)dest =
(ctxt->eflags & ~change_mask) | (val & change_mask);
return rc;
}
static void emulate_push_sreg(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops, int seg)
{
struct decode_cache *c = &ctxt->decode;
c->src.val = ops->get_segment_selector(seg, ctxt->vcpu);
emulate_push(ctxt, ops);
}
static int emulate_pop_sreg(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops, int seg)
{
struct decode_cache *c = &ctxt->decode;
unsigned long selector;
int rc;
rc = emulate_pop(ctxt, ops, &selector, c->op_bytes);
if (rc != X86EMUL_CONTINUE)
return rc;
rc = load_segment_descriptor(ctxt, ops, (u16)selector, seg);
return rc;
}
static int emulate_pusha(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
unsigned long old_esp = c->regs[VCPU_REGS_RSP];
int rc = X86EMUL_CONTINUE;
int reg = VCPU_REGS_RAX;
while (reg <= VCPU_REGS_RDI) {
(reg == VCPU_REGS_RSP) ?
(c->src.val = old_esp) : (c->src.val = c->regs[reg]);
emulate_push(ctxt, ops);
rc = writeback(ctxt, ops);
if (rc != X86EMUL_CONTINUE)
return rc;
++reg;
}
/* Disable writeback. */
c->dst.type = OP_NONE;
return rc;
}
static int emulate_popa(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
int rc = X86EMUL_CONTINUE;
int reg = VCPU_REGS_RDI;
while (reg >= VCPU_REGS_RAX) {
if (reg == VCPU_REGS_RSP) {
register_address_increment(c, &c->regs[VCPU_REGS_RSP],
c->op_bytes);
--reg;
}
rc = emulate_pop(ctxt, ops, &c->regs[reg], c->op_bytes);
if (rc != X86EMUL_CONTINUE)
break;
--reg;
}
return rc;
}
int emulate_int_real(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops, int irq)
{
struct decode_cache *c = &ctxt->decode;
int rc;
struct desc_ptr dt;
gva_t cs_addr;
gva_t eip_addr;
u16 cs, eip;
/* TODO: Add limit checks */
c->src.val = ctxt->eflags;
emulate_push(ctxt, ops);
rc = writeback(ctxt, ops);
if (rc != X86EMUL_CONTINUE)
return rc;
ctxt->eflags &= ~(EFLG_IF | EFLG_TF | EFLG_AC);
c->src.val = ops->get_segment_selector(VCPU_SREG_CS, ctxt->vcpu);
emulate_push(ctxt, ops);
rc = writeback(ctxt, ops);
if (rc != X86EMUL_CONTINUE)
return rc;
c->src.val = c->eip;
emulate_push(ctxt, ops);
rc = writeback(ctxt, ops);
if (rc != X86EMUL_CONTINUE)
return rc;
c->dst.type = OP_NONE;
ops->get_idt(&dt, ctxt->vcpu);
eip_addr = dt.address + (irq << 2);
cs_addr = dt.address + (irq << 2) + 2;
rc = ops->read_std(cs_addr, &cs, 2, ctxt->vcpu, &ctxt->exception);
if (rc != X86EMUL_CONTINUE)
return rc;
rc = ops->read_std(eip_addr, &eip, 2, ctxt->vcpu, &ctxt->exception);
if (rc != X86EMUL_CONTINUE)
return rc;
rc = load_segment_descriptor(ctxt, ops, cs, VCPU_SREG_CS);
if (rc != X86EMUL_CONTINUE)
return rc;
c->eip = eip;
return rc;
}
static int emulate_int(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops, int irq)
{
switch(ctxt->mode) {
case X86EMUL_MODE_REAL:
return emulate_int_real(ctxt, ops, irq);
case X86EMUL_MODE_VM86:
case X86EMUL_MODE_PROT16:
case X86EMUL_MODE_PROT32:
case X86EMUL_MODE_PROT64:
default:
/* Protected mode interrupts unimplemented yet */
return X86EMUL_UNHANDLEABLE;
}
}
static int emulate_iret_real(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
int rc = X86EMUL_CONTINUE;
unsigned long temp_eip = 0;
unsigned long temp_eflags = 0;
unsigned long cs = 0;
unsigned long mask = EFLG_CF | EFLG_PF | EFLG_AF | EFLG_ZF | EFLG_SF | EFLG_TF |
EFLG_IF | EFLG_DF | EFLG_OF | EFLG_IOPL | EFLG_NT | EFLG_RF |
EFLG_AC | EFLG_ID | (1 << 1); /* Last one is the reserved bit */
unsigned long vm86_mask = EFLG_VM | EFLG_VIF | EFLG_VIP;
/* TODO: Add stack limit check */
rc = emulate_pop(ctxt, ops, &temp_eip, c->op_bytes);
if (rc != X86EMUL_CONTINUE)
return rc;
if (temp_eip & ~0xffff)
return emulate_gp(ctxt, 0);
rc = emulate_pop(ctxt, ops, &cs, c->op_bytes);
if (rc != X86EMUL_CONTINUE)
return rc;
rc = emulate_pop(ctxt, ops, &temp_eflags, c->op_bytes);
if (rc != X86EMUL_CONTINUE)
return rc;
rc = load_segment_descriptor(ctxt, ops, (u16)cs, VCPU_SREG_CS);
if (rc != X86EMUL_CONTINUE)
return rc;
c->eip = temp_eip;
if (c->op_bytes == 4)
ctxt->eflags = ((temp_eflags & mask) | (ctxt->eflags & vm86_mask));
else if (c->op_bytes == 2) {
ctxt->eflags &= ~0xffff;
ctxt->eflags |= temp_eflags;
}
ctxt->eflags &= ~EFLG_RESERVED_ZEROS_MASK; /* Clear reserved zeros */
ctxt->eflags |= EFLG_RESERVED_ONE_MASK;
return rc;
}
static inline int emulate_iret(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops* ops)
{
switch(ctxt->mode) {
case X86EMUL_MODE_REAL:
return emulate_iret_real(ctxt, ops);
case X86EMUL_MODE_VM86:
case X86EMUL_MODE_PROT16:
case X86EMUL_MODE_PROT32:
case X86EMUL_MODE_PROT64:
default:
/* iret from protected mode unimplemented yet */
return X86EMUL_UNHANDLEABLE;
}
}
static inline int emulate_grp1a(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
return emulate_pop(ctxt, ops, &c->dst.val, c->dst.bytes);
}
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;
unsigned long *rax = &c->regs[VCPU_REGS_RAX];
unsigned long *rdx = &c->regs[VCPU_REGS_RDX];
u8 de = 0;
switch (c->modrm_reg) {
case 0 ... 1: /* test */
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;
case 4: /* mul */
emulate_1op_rax_rdx("mul", c->src, *rax, *rdx, ctxt->eflags);
break;
case 5: /* imul */
emulate_1op_rax_rdx("imul", c->src, *rax, *rdx, ctxt->eflags);
break;
case 6: /* div */
emulate_1op_rax_rdx_ex("div", c->src, *rax, *rdx,
ctxt->eflags, de);
break;
case 7: /* idiv */
emulate_1op_rax_rdx_ex("idiv", c->src, *rax, *rdx,
ctxt->eflags, de);
break;
default:
return X86EMUL_UNHANDLEABLE;
}
if (de)
return emulate_de(ctxt);
return X86EMUL_CONTINUE;
}
static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
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 2: /* call near abs */ {
long int old_eip;
old_eip = c->eip;
c->eip = c->src.val;
c->src.val = old_eip;
emulate_push(ctxt, ops);
break;
}
case 4: /* jmp abs */
c->eip = c->src.val;
break;
case 6: /* push */
emulate_push(ctxt, ops);
break;
}
return X86EMUL_CONTINUE;
}
static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
u64 old = c->dst.orig_val64;
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 {
c->dst.val64 = ((u64)c->regs[VCPU_REGS_RCX] << 32) |
(u32) c->regs[VCPU_REGS_RBX];
ctxt->eflags |= EFLG_ZF;
}
return X86EMUL_CONTINUE;
}
static int emulate_ret_far(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
int rc;
unsigned long cs;
rc = emulate_pop(ctxt, ops, &c->eip, c->op_bytes);
if (rc != X86EMUL_CONTINUE)
return rc;
if (c->op_bytes == 4)
c->eip = (u32)c->eip;
rc = emulate_pop(ctxt, ops, &cs, c->op_bytes);
if (rc != X86EMUL_CONTINUE)
return rc;
rc = load_segment_descriptor(ctxt, ops, (u16)cs, VCPU_SREG_CS);
return rc;
}
static int emulate_load_segment(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops, int seg)
{
struct decode_cache *c = &ctxt->decode;
unsigned short sel;
int rc;
memcpy(&sel, c->src.valptr + c->op_bytes, 2);
rc = load_segment_descriptor(ctxt, ops, sel, seg);
if (rc != X86EMUL_CONTINUE)
return rc;
c->dst.val = c->src.val;
return rc;
}
static inline void
setup_syscalls_segments(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops, struct desc_struct *cs,
struct desc_struct *ss)
{
memset(cs, 0, sizeof(struct desc_struct));
ops->get_cached_descriptor(cs, VCPU_SREG_CS, ctxt->vcpu);
memset(ss, 0, sizeof(struct desc_struct));
cs->l = 0; /* will be adjusted later */
set_desc_base(cs, 0); /* flat segment */
cs->g = 1; /* 4kb granularity */
set_desc_limit(cs, 0xfffff); /* 4GB limit */
cs->type = 0x0b; /* Read, Execute, Accessed */
cs->s = 1;
cs->dpl = 0; /* will be adjusted later */
cs->p = 1;
cs->d = 1;
set_desc_base(ss, 0); /* flat segment */
set_desc_limit(ss, 0xfffff); /* 4GB limit */
ss->g = 1; /* 4kb granularity */
ss->s = 1;
ss->type = 0x03; /* Read/Write, Accessed */
ss->d = 1; /* 32bit stack segment */
ss->dpl = 0;
ss->p = 1;
}
static int
emulate_syscall(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
struct desc_struct cs, ss;
u64 msr_data;
u16 cs_sel, ss_sel;
/* syscall is not available in real mode */
if (ctxt->mode == X86EMUL_MODE_REAL ||
ctxt->mode == X86EMUL_MODE_VM86)
return emulate_ud(ctxt);
setup_syscalls_segments(ctxt, ops, &cs, &ss);
ops->get_msr(ctxt->vcpu, MSR_STAR, &msr_data);
msr_data >>= 32;
cs_sel = (u16)(msr_data & 0xfffc);
ss_sel = (u16)(msr_data + 8);
if (is_long_mode(ctxt->vcpu)) {
cs.d = 0;
cs.l = 1;
}
ops->set_cached_descriptor(&cs, VCPU_SREG_CS, ctxt->vcpu);
ops->set_segment_selector(cs_sel, VCPU_SREG_CS, ctxt->vcpu);
ops->set_cached_descriptor(&ss, VCPU_SREG_SS, ctxt->vcpu);
ops->set_segment_selector(ss_sel, VCPU_SREG_SS, ctxt->vcpu);
c->regs[VCPU_REGS_RCX] = c->eip;
if (is_long_mode(ctxt->vcpu)) {
#ifdef CONFIG_X86_64
c->regs[VCPU_REGS_R11] = ctxt->eflags & ~EFLG_RF;
ops->get_msr(ctxt->vcpu,
ctxt->mode == X86EMUL_MODE_PROT64 ?
MSR_LSTAR : MSR_CSTAR, &msr_data);
c->eip = msr_data;
ops->get_msr(ctxt->vcpu, MSR_SYSCALL_MASK, &msr_data);
ctxt->eflags &= ~(msr_data | EFLG_RF);
#endif
} else {
/* legacy mode */
ops->get_msr(ctxt->vcpu, MSR_STAR, &msr_data);
c->eip = (u32)msr_data;
ctxt->eflags &= ~(EFLG_VM | EFLG_IF | EFLG_RF);
}
return X86EMUL_CONTINUE;
}
static int
emulate_sysenter(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
struct desc_struct cs, ss;
u64 msr_data;
u16 cs_sel, ss_sel;
/* inject #GP if in real mode */
if (ctxt->mode == X86EMUL_MODE_REAL)
return emulate_gp(ctxt, 0);
/* XXX sysenter/sysexit have not been tested in 64bit mode.
* Therefore, we inject an #UD.
*/
if (ctxt->mode == X86EMUL_MODE_PROT64)
return emulate_ud(ctxt);
setup_syscalls_segments(ctxt, ops, &cs, &ss);
ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_CS, &msr_data);
switch (ctxt->mode) {
case X86EMUL_MODE_PROT32:
if ((msr_data & 0xfffc) == 0x0)
return emulate_gp(ctxt, 0);
break;
case X86EMUL_MODE_PROT64:
if (msr_data == 0x0)
return emulate_gp(ctxt, 0);
break;
}
ctxt->eflags &= ~(EFLG_VM | EFLG_IF | EFLG_RF);
cs_sel = (u16)msr_data;
cs_sel &= ~SELECTOR_RPL_MASK;
ss_sel = cs_sel + 8;
ss_sel &= ~SELECTOR_RPL_MASK;
if (ctxt->mode == X86EMUL_MODE_PROT64
|| is_long_mode(ctxt->vcpu)) {
cs.d = 0;
cs.l = 1;
}
ops->set_cached_descriptor(&cs, VCPU_SREG_CS, ctxt->vcpu);
ops->set_segment_selector(cs_sel, VCPU_SREG_CS, ctxt->vcpu);
ops->set_cached_descriptor(&ss, VCPU_SREG_SS, ctxt->vcpu);
ops->set_segment_selector(ss_sel, VCPU_SREG_SS, ctxt->vcpu);
ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_EIP, &msr_data);
c->eip = msr_data;
ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_ESP, &msr_data);
c->regs[VCPU_REGS_RSP] = msr_data;
return X86EMUL_CONTINUE;
}
static int
emulate_sysexit(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
struct desc_struct cs, ss;
u64 msr_data;
int usermode;
u16 cs_sel, ss_sel;
/* inject #GP if in real mode or Virtual 8086 mode */
if (ctxt->mode == X86EMUL_MODE_REAL ||
ctxt->mode == X86EMUL_MODE_VM86)
return emulate_gp(ctxt, 0);
setup_syscalls_segments(ctxt, ops, &cs, &ss);
if ((c->rex_prefix & 0x8) != 0x0)
usermode = X86EMUL_MODE_PROT64;
else
usermode = X86EMUL_MODE_PROT32;
cs.dpl = 3;
ss.dpl = 3;
ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_CS, &msr_data);
switch (usermode) {
case X86EMUL_MODE_PROT32:
cs_sel = (u16)(msr_data + 16);
if ((msr_data & 0xfffc) == 0x0)
return emulate_gp(ctxt, 0);
ss_sel = (u16)(msr_data + 24);
break;
case X86EMUL_MODE_PROT64:
cs_sel = (u16)(msr_data + 32);
if (msr_data == 0x0)
return emulate_gp(ctxt, 0);
ss_sel = cs_sel + 8;
cs.d = 0;
cs.l = 1;
break;
}
cs_sel |= SELECTOR_RPL_MASK;
ss_sel |= SELECTOR_RPL_MASK;
ops->set_cached_descriptor(&cs, VCPU_SREG_CS, ctxt->vcpu);
ops->set_segment_selector(cs_sel, VCPU_SREG_CS, ctxt->vcpu);
ops->set_cached_descriptor(&ss, VCPU_SREG_SS, ctxt->vcpu);
ops->set_segment_selector(ss_sel, VCPU_SREG_SS, ctxt->vcpu);
c->eip = c->regs[VCPU_REGS_RDX];
c->regs[VCPU_REGS_RSP] = c->regs[VCPU_REGS_RCX];
return X86EMUL_CONTINUE;
}
static bool emulator_bad_iopl(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
int iopl;
if (ctxt->mode == X86EMUL_MODE_REAL)
return false;
if (ctxt->mode == X86EMUL_MODE_VM86)
return true;
iopl = (ctxt->eflags & X86_EFLAGS_IOPL) >> IOPL_SHIFT;
return ops->cpl(ctxt->vcpu) > iopl;
}
static bool emulator_io_port_access_allowed(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
u16 port, u16 len)
{
struct desc_struct tr_seg;
int r;
u16 io_bitmap_ptr;
u8 perm, bit_idx = port & 0x7;
unsigned mask = (1 << len) - 1;
ops->get_cached_descriptor(&tr_seg, VCPU_SREG_TR, ctxt->vcpu);
if (!tr_seg.p)
return false;
if (desc_limit_scaled(&tr_seg) < 103)
return false;
r = ops->read_std(get_desc_base(&tr_seg) + 102, &io_bitmap_ptr, 2,
ctxt->vcpu, NULL);
if (r != X86EMUL_CONTINUE)
return false;
if (io_bitmap_ptr + port/8 > desc_limit_scaled(&tr_seg))
return false;
r = ops->read_std(get_desc_base(&tr_seg) + io_bitmap_ptr + port/8,
&perm, 1, ctxt->vcpu, NULL);
if (r != X86EMUL_CONTINUE)
return false;
if ((perm >> bit_idx) & mask)
return false;
return true;
}
static bool emulator_io_permited(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
u16 port, u16 len)
{
if (ctxt->perm_ok)
return true;
if (emulator_bad_iopl(ctxt, ops))
if (!emulator_io_port_access_allowed(ctxt, ops, port, len))
return false;
ctxt->perm_ok = true;
return true;
}
static void save_state_to_tss16(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
struct tss_segment_16 *tss)
{
struct decode_cache *c = &ctxt->decode;
tss->ip = c->eip;
tss->flag = ctxt->eflags;
tss->ax = c->regs[VCPU_REGS_RAX];
tss->cx = c->regs[VCPU_REGS_RCX];
tss->dx = c->regs[VCPU_REGS_RDX];
tss->bx = c->regs[VCPU_REGS_RBX];
tss->sp = c->regs[VCPU_REGS_RSP];
tss->bp = c->regs[VCPU_REGS_RBP];
tss->si = c->regs[VCPU_REGS_RSI];
tss->di = c->regs[VCPU_REGS_RDI];
tss->es = ops->get_segment_selector(VCPU_SREG_ES, ctxt->vcpu);
tss->cs = ops->get_segment_selector(VCPU_SREG_CS, ctxt->vcpu);
tss->ss = ops->get_segment_selector(VCPU_SREG_SS, ctxt->vcpu);
tss->ds = ops->get_segment_selector(VCPU_SREG_DS, ctxt->vcpu);
tss->ldt = ops->get_segment_selector(VCPU_SREG_LDTR, ctxt->vcpu);
}
static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
struct tss_segment_16 *tss)
{
struct decode_cache *c = &ctxt->decode;
int ret;
c->eip = tss->ip;
ctxt->eflags = tss->flag | 2;
c->regs[VCPU_REGS_RAX] = tss->ax;
c->regs[VCPU_REGS_RCX] = tss->cx;
c->regs[VCPU_REGS_RDX] = tss->dx;
c->regs[VCPU_REGS_RBX] = tss->bx;
c->regs[VCPU_REGS_RSP] = tss->sp;
c->regs[VCPU_REGS_RBP] = tss->bp;
c->regs[VCPU_REGS_RSI] = tss->si;
c->regs[VCPU_REGS_RDI] = tss->di;
/*
* SDM says that segment selectors are loaded before segment
* descriptors
*/
ops->set_segment_selector(tss->ldt, VCPU_SREG_LDTR, ctxt->vcpu);
ops->set_segment_selector(tss->es, VCPU_SREG_ES, ctxt->vcpu);
ops->set_segment_selector(tss->cs, VCPU_SREG_CS, ctxt->vcpu);
ops->set_segment_selector(tss->ss, VCPU_SREG_SS, ctxt->vcpu);
ops->set_segment_selector(tss->ds, VCPU_SREG_DS, ctxt->vcpu);
/*
* Now load segment descriptors. If fault happenes at this stage
* it is handled in a context of new task
*/
ret = load_segment_descriptor(ctxt, ops, tss->ldt, VCPU_SREG_LDTR);
if (ret != X86EMUL_CONTINUE)
return ret;
ret = load_segment_descriptor(ctxt, ops, tss->es, VCPU_SREG_ES);
if (ret != X86EMUL_CONTINUE)
return ret;
ret = load_segment_descriptor(ctxt, ops, tss->cs, VCPU_SREG_CS);
if (ret != X86EMUL_CONTINUE)
return ret;
ret = load_segment_descriptor(ctxt, ops, tss->ss, VCPU_SREG_SS);
if (ret != X86EMUL_CONTINUE)
return ret;
ret = load_segment_descriptor(ctxt, ops, tss->ds, VCPU_SREG_DS);
if (ret != X86EMUL_CONTINUE)
return ret;
return X86EMUL_CONTINUE;
}
static int task_switch_16(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
u16 tss_selector, u16 old_tss_sel,
ulong old_tss_base, struct desc_struct *new_desc)
{
struct tss_segment_16 tss_seg;
int ret;
u32 new_tss_base = get_desc_base(new_desc);
ret = ops->read_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
&ctxt->exception);
if (ret != X86EMUL_CONTINUE)
/* FIXME: need to provide precise fault address */
return ret;
save_state_to_tss16(ctxt, ops, &tss_seg);
ret = ops->write_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
&ctxt->exception);
if (ret != X86EMUL_CONTINUE)
/* FIXME: need to provide precise fault address */
return ret;
ret = ops->read_std(new_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
&ctxt->exception);
if (ret != X86EMUL_CONTINUE)
/* FIXME: need to provide precise fault address */
return ret;
if (old_tss_sel != 0xffff) {
tss_seg.prev_task_link = old_tss_sel;
ret = ops->write_std(new_tss_base,
&tss_seg.prev_task_link,
sizeof tss_seg.prev_task_link,
ctxt->vcpu, &ctxt->exception);
if (ret != X86EMUL_CONTINUE)
/* FIXME: need to provide precise fault address */
return ret;
}
return load_state_from_tss16(ctxt, ops, &tss_seg);
}
static void save_state_to_tss32(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
struct tss_segment_32 *tss)
{
struct decode_cache *c = &ctxt->decode;
tss->cr3 = ops->get_cr(3, ctxt->vcpu);
tss->eip = c->eip;
tss->eflags = ctxt->eflags;
tss->eax = c->regs[VCPU_REGS_RAX];
tss->ecx = c->regs[VCPU_REGS_RCX];
tss->edx = c->regs[VCPU_REGS_RDX];
tss->ebx = c->regs[VCPU_REGS_RBX];
tss->esp = c->regs[VCPU_REGS_RSP];
tss->ebp = c->regs[VCPU_REGS_RBP];
tss->esi = c->regs[VCPU_REGS_RSI];
tss->edi = c->regs[VCPU_REGS_RDI];
tss->es = ops->get_segment_selector(VCPU_SREG_ES, ctxt->vcpu);
tss->cs = ops->get_segment_selector(VCPU_SREG_CS, ctxt->vcpu);
tss->ss = ops->get_segment_selector(VCPU_SREG_SS, ctxt->vcpu);
tss->ds = ops->get_segment_selector(VCPU_SREG_DS, ctxt->vcpu);
tss->fs = ops->get_segment_selector(VCPU_SREG_FS, ctxt->vcpu);
tss->gs = ops->get_segment_selector(VCPU_SREG_GS, ctxt->vcpu);
tss->ldt_selector = ops->get_segment_selector(VCPU_SREG_LDTR, ctxt->vcpu);
}
static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
struct tss_segment_32 *tss)
{
struct decode_cache *c = &ctxt->decode;
int ret;
if (ops->set_cr(3, tss->cr3, ctxt->vcpu))
return emulate_gp(ctxt, 0);
c->eip = tss->eip;
ctxt->eflags = tss->eflags | 2;
c->regs[VCPU_REGS_RAX] = tss->eax;
c->regs[VCPU_REGS_RCX] = tss->ecx;
c->regs[VCPU_REGS_RDX] = tss->edx;
c->regs[VCPU_REGS_RBX] = tss->ebx;
c->regs[VCPU_REGS_RSP] = tss->esp;
c->regs[VCPU_REGS_RBP] = tss->ebp;
c->regs[VCPU_REGS_RSI] = tss->esi;
c->regs[VCPU_REGS_RDI] = tss->edi;
/*
* SDM says that segment selectors are loaded before segment
* descriptors
*/
ops->set_segment_selector(tss->ldt_selector, VCPU_SREG_LDTR, ctxt->vcpu);
ops->set_segment_selector(tss->es, VCPU_SREG_ES, ctxt->vcpu);
ops->set_segment_selector(tss->cs, VCPU_SREG_CS, ctxt->vcpu);
ops->set_segment_selector(tss->ss, VCPU_SREG_SS, ctxt->vcpu);
ops->set_segment_selector(tss->ds, VCPU_SREG_DS, ctxt->vcpu);
ops->set_segment_selector(tss->fs, VCPU_SREG_FS, ctxt->vcpu);
ops->set_segment_selector(tss->gs, VCPU_SREG_GS, ctxt->vcpu);
/*
* Now load segment descriptors. If fault happenes at this stage
* it is handled in a context of new task
*/
ret = load_segment_descriptor(ctxt, ops, tss->ldt_selector, VCPU_SREG_LDTR);
if (ret != X86EMUL_CONTINUE)
return ret;
ret = load_segment_descriptor(ctxt, ops, tss->es, VCPU_SREG_ES);
if (ret != X86EMUL_CONTINUE)
return ret;
ret = load_segment_descriptor(ctxt, ops, tss->cs, VCPU_SREG_CS);
if (ret != X86EMUL_CONTINUE)
return ret;
ret = load_segment_descriptor(ctxt, ops, tss->ss, VCPU_SREG_SS);
if (ret != X86EMUL_CONTINUE)
return ret;
ret = load_segment_descriptor(ctxt, ops, tss->ds, VCPU_SREG_DS);
if (ret != X86EMUL_CONTINUE)
return ret;
ret = load_segment_descriptor(ctxt, ops, tss->fs, VCPU_SREG_FS);
if (ret != X86EMUL_CONTINUE)
return ret;
ret = load_segment_descriptor(ctxt, ops, tss->gs, VCPU_SREG_GS);
if (ret != X86EMUL_CONTINUE)
return ret;
return X86EMUL_CONTINUE;
}
static int task_switch_32(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
u16 tss_selector, u16 old_tss_sel,
ulong old_tss_base, struct desc_struct *new_desc)
{
struct tss_segment_32 tss_seg;
int ret;
u32 new_tss_base = get_desc_base(new_desc);
ret = ops->read_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
&ctxt->exception);
if (ret != X86EMUL_CONTINUE)
/* FIXME: need to provide precise fault address */
return ret;
save_state_to_tss32(ctxt, ops, &tss_seg);
ret = ops->write_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
&ctxt->exception);
if (ret != X86EMUL_CONTINUE)
/* FIXME: need to provide precise fault address */
return ret;
ret = ops->read_std(new_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
&ctxt->exception);
if (ret != X86EMUL_CONTINUE)
/* FIXME: need to provide precise fault address */
return ret;
if (old_tss_sel != 0xffff) {
tss_seg.prev_task_link = old_tss_sel;
ret = ops->write_std(new_tss_base,
&tss_seg.prev_task_link,
sizeof tss_seg.prev_task_link,
ctxt->vcpu, &ctxt->exception);
if (ret != X86EMUL_CONTINUE)
/* FIXME: need to provide precise fault address */
return ret;
}
return load_state_from_tss32(ctxt, ops, &tss_seg);
}
static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
u16 tss_selector, int reason,
bool has_error_code, u32 error_code)
{
struct desc_struct curr_tss_desc, next_tss_desc;
int ret;
u16 old_tss_sel = ops->get_segment_selector(VCPU_SREG_TR, ctxt->vcpu);
ulong old_tss_base =
ops->get_cached_segment_base(VCPU_SREG_TR, ctxt->vcpu);
u32 desc_limit;
/* FIXME: old_tss_base == ~0 ? */
ret = read_segment_descriptor(ctxt, ops, tss_selector, &next_tss_desc);
if (ret != X86EMUL_CONTINUE)
return ret;
ret = read_segment_descriptor(ctxt, ops, old_tss_sel, &curr_tss_desc);
if (ret != X86EMUL_CONTINUE)
return ret;
/* FIXME: check that next_tss_desc is tss */
if (reason != TASK_SWITCH_IRET) {
if ((tss_selector & 3) > next_tss_desc.dpl ||
ops->cpl(ctxt->vcpu) > next_tss_desc.dpl)
return emulate_gp(ctxt, 0);
}
desc_limit = desc_limit_scaled(&next_tss_desc);
if (!next_tss_desc.p ||
((desc_limit < 0x67 && (next_tss_desc.type & 8)) ||
desc_limit < 0x2b)) {
emulate_ts(ctxt, tss_selector & 0xfffc);
return X86EMUL_PROPAGATE_FAULT;
}
if (reason == TASK_SWITCH_IRET || reason == TASK_SWITCH_JMP) {
curr_tss_desc.type &= ~(1 << 1); /* clear busy flag */
write_segment_descriptor(ctxt, ops, old_tss_sel,
&curr_tss_desc);
}
if (reason == TASK_SWITCH_IRET)
ctxt->eflags = ctxt->eflags & ~X86_EFLAGS_NT;
/* set back link to prev task only if NT bit is set in eflags
note that old_tss_sel is not used afetr this point */
if (reason != TASK_SWITCH_CALL && reason != TASK_SWITCH_GATE)
old_tss_sel = 0xffff;
if (next_tss_desc.type & 8)
ret = task_switch_32(ctxt, ops, tss_selector, old_tss_sel,
old_tss_base, &next_tss_desc);
else
ret = task_switch_16(ctxt, ops, tss_selector, old_tss_sel,
old_tss_base, &next_tss_desc);
if (ret != X86EMUL_CONTINUE)
return ret;
if (reason == TASK_SWITCH_CALL || reason == TASK_SWITCH_GATE)
ctxt->eflags = ctxt->eflags | X86_EFLAGS_NT;
if (reason != TASK_SWITCH_IRET) {
next_tss_desc.type |= (1 << 1); /* set busy flag */
write_segment_descriptor(ctxt, ops, tss_selector,
&next_tss_desc);
}
ops->set_cr(0, ops->get_cr(0, ctxt->vcpu) | X86_CR0_TS, ctxt->vcpu);
ops->set_cached_descriptor(&next_tss_desc, VCPU_SREG_TR, ctxt->vcpu);
ops->set_segment_selector(tss_selector, VCPU_SREG_TR, ctxt->vcpu);
if (has_error_code) {
struct decode_cache *c = &ctxt->decode;
c->op_bytes = c->ad_bytes = (next_tss_desc.type & 8) ? 4 : 2;
c->lock_prefix = 0;
c->src.val = (unsigned long) error_code;
emulate_push(ctxt, ops);
}
return ret;
}
int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
u16 tss_selector, int reason,
bool has_error_code, u32 error_code)
{
struct x86_emulate_ops *ops = ctxt->ops;
struct decode_cache *c = &ctxt->decode;
int rc;
c->eip = ctxt->eip;
c->dst.type = OP_NONE;
rc = emulator_do_task_switch(ctxt, ops, tss_selector, reason,
has_error_code, error_code);
if (rc == X86EMUL_CONTINUE) {
rc = writeback(ctxt, ops);
if (rc == X86EMUL_CONTINUE)
ctxt->eip = c->eip;
}
return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
}
static void string_addr_inc(struct x86_emulate_ctxt *ctxt, unsigned seg,
int reg, struct operand *op)
{
struct decode_cache *c = &ctxt->decode;
int df = (ctxt->eflags & EFLG_DF) ? -1 : 1;
register_address_increment(c, &c->regs[reg], df * op->bytes);
op->addr.mem.ea = register_address(c, c->regs[reg]);
op->addr.mem.seg = seg;
}
static int em_push(struct x86_emulate_ctxt *ctxt)
{
emulate_push(ctxt, ctxt->ops);
return X86EMUL_CONTINUE;
}
static int em_das(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
u8 al, old_al;
bool af, cf, old_cf;
cf = ctxt->eflags & X86_EFLAGS_CF;
al = c->dst.val;
old_al = al;
old_cf = cf;
cf = false;
af = ctxt->eflags & X86_EFLAGS_AF;
if ((al & 0x0f) > 9 || af) {
al -= 6;
cf = old_cf | (al >= 250);
af = true;
} else {
af = false;
}
if (old_al > 0x99 || old_cf) {
al -= 0x60;
cf = true;
}
c->dst.val = al;
/* Set PF, ZF, SF */
c->src.type = OP_IMM;
c->src.val = 0;
c->src.bytes = 1;
emulate_2op_SrcV("or", c->src, c->dst, ctxt->eflags);
ctxt->eflags &= ~(X86_EFLAGS_AF | X86_EFLAGS_CF);
if (cf)
ctxt->eflags |= X86_EFLAGS_CF;
if (af)
ctxt->eflags |= X86_EFLAGS_AF;
return X86EMUL_CONTINUE;
}
static int em_call_far(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
u16 sel, old_cs;
ulong old_eip;
int rc;
old_cs = ctxt->ops->get_segment_selector(VCPU_SREG_CS, ctxt->vcpu);
old_eip = c->eip;
memcpy(&sel, c->src.valptr + c->op_bytes, 2);
if (load_segment_descriptor(ctxt, ctxt->ops, sel, VCPU_SREG_CS))
return X86EMUL_CONTINUE;
c->eip = 0;
memcpy(&c->eip, c->src.valptr, c->op_bytes);
c->src.val = old_cs;
emulate_push(ctxt, ctxt->ops);
rc = writeback(ctxt, ctxt->ops);
if (rc != X86EMUL_CONTINUE)
return rc;
c->src.val = old_eip;
emulate_push(ctxt, ctxt->ops);
rc = writeback(ctxt, ctxt->ops);
if (rc != X86EMUL_CONTINUE)
return rc;
c->dst.type = OP_NONE;
return X86EMUL_CONTINUE;
}
static int em_ret_near_imm(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
int rc;
c->dst.type = OP_REG;
c->dst.addr.reg = &c->eip;
c->dst.bytes = c->op_bytes;
rc = emulate_pop(ctxt, ctxt->ops, &c->dst.val, c->op_bytes);
if (rc != X86EMUL_CONTINUE)
return rc;
register_address_increment(c, &c->regs[VCPU_REGS_RSP], c->src.val);
return X86EMUL_CONTINUE;
}
static int em_imul(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
emulate_2op_SrcV_nobyte("imul", c->src, c->dst, ctxt->eflags);
return X86EMUL_CONTINUE;
}
static int em_imul_3op(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
c->dst.val = c->src2.val;
return em_imul(ctxt);
}
static int em_cwd(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
c->dst.type = OP_REG;
c->dst.bytes = c->src.bytes;
c->dst.addr.reg = &c->regs[VCPU_REGS_RDX];
c->dst.val = ~((c->src.val >> (c->src.bytes * 8 - 1)) - 1);
return X86EMUL_CONTINUE;
}
static int em_rdtsc(struct x86_emulate_ctxt *ctxt)
{
unsigned cpl = ctxt->ops->cpl(ctxt->vcpu);
struct decode_cache *c = &ctxt->decode;
u64 tsc = 0;
if (cpl > 0 && (ctxt->ops->get_cr(4, ctxt->vcpu) & X86_CR4_TSD))
return emulate_gp(ctxt, 0);
ctxt->ops->get_msr(ctxt->vcpu, MSR_IA32_TSC, &tsc);
c->regs[VCPU_REGS_RAX] = (u32)tsc;
c->regs[VCPU_REGS_RDX] = tsc >> 32;
return X86EMUL_CONTINUE;
}
static int em_mov(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
c->dst.val = c->src.val;
return X86EMUL_CONTINUE;
}
#define D(_y) { .flags = (_y) }
#define N D(0)
#define G(_f, _g) { .flags = ((_f) | Group), .u.group = (_g) }
#define GD(_f, _g) { .flags = ((_f) | Group | GroupDual), .u.gdual = (_g) }
#define I(_f, _e) { .flags = (_f), .u.execute = (_e) }
#define D2bv(_f) D((_f) | ByteOp), D(_f)
#define I2bv(_f, _e) I((_f) | ByteOp, _e), I(_f, _e)
#define D6ALU(_f) D2bv((_f) | DstMem | SrcReg | ModRM), \
D2bv(((_f) | DstReg | SrcMem | ModRM) & ~Lock), \
D2bv(((_f) & ~Lock) | DstAcc | SrcImm)
static struct opcode group1[] = {
X7(D(Lock)), N
};
static struct opcode group1A[] = {
D(DstMem | SrcNone | ModRM | Mov | Stack), N, N, N, N, N, N, N,
};
static struct opcode group3[] = {
D(DstMem | SrcImm | ModRM), D(DstMem | SrcImm | ModRM),
D(DstMem | SrcNone | ModRM | Lock), D(DstMem | SrcNone | ModRM | Lock),
X4(D(SrcMem | ModRM)),
};
static struct opcode group4[] = {
D(ByteOp | DstMem | SrcNone | ModRM | Lock), D(ByteOp | DstMem | SrcNone | ModRM | Lock),
N, N, N, N, N, N,
};
static struct opcode group5[] = {
D(DstMem | SrcNone | ModRM | Lock), D(DstMem | SrcNone | ModRM | Lock),
D(SrcMem | ModRM | Stack),
I(SrcMemFAddr | ModRM | ImplicitOps | Stack, em_call_far),
D(SrcMem | ModRM | Stack), D(SrcMemFAddr | ModRM | ImplicitOps),
D(SrcMem | ModRM | Stack), N,
};
static struct group_dual group7 = { {
N, N, D(ModRM | SrcMem | Priv), D(ModRM | SrcMem | Priv),
D(SrcNone | ModRM | DstMem | Mov), N,
D(SrcMem16 | ModRM | Mov | Priv),
D(SrcMem | ModRM | ByteOp | Priv | NoAccess),
}, {
D(SrcNone | ModRM | Priv), N, N, D(SrcNone | ModRM | Priv),
D(SrcNone | ModRM | DstMem | Mov), N,
D(SrcMem16 | ModRM | Mov | Priv), N,
} };
static struct opcode group8[] = {
N, N, N, N,
D(DstMem | SrcImmByte | ModRM), D(DstMem | SrcImmByte | ModRM | Lock),
D(DstMem | SrcImmByte | ModRM | Lock), D(DstMem | SrcImmByte | ModRM | Lock),
};
static struct group_dual group9 = { {
N, D(DstMem64 | ModRM | Lock), N, N, N, N, N, N,
}, {
N, N, N, N, N, N, N, N,
} };
static struct opcode group11[] = {
I(DstMem | SrcImm | ModRM | Mov, em_mov), X7(D(Undefined)),
};
static struct opcode opcode_table[256] = {
/* 0x00 - 0x07 */
D6ALU(Lock),
D(ImplicitOps | Stack | No64), D(ImplicitOps | Stack | No64),
/* 0x08 - 0x0F */
D6ALU(Lock),
D(ImplicitOps | Stack | No64), N,
/* 0x10 - 0x17 */
D6ALU(Lock),
D(ImplicitOps | Stack | No64), D(ImplicitOps | Stack | No64),
/* 0x18 - 0x1F */
D6ALU(Lock),
D(ImplicitOps | Stack | No64), D(ImplicitOps | Stack | No64),
/* 0x20 - 0x27 */
D6ALU(Lock), N, N,
/* 0x28 - 0x2F */
D6ALU(Lock), N, I(ByteOp | DstAcc | No64, em_das),
/* 0x30 - 0x37 */
D6ALU(Lock), N, N,
/* 0x38 - 0x3F */
D6ALU(0), N, N,
/* 0x40 - 0x4F */
X16(D(DstReg)),
/* 0x50 - 0x57 */
X8(I(SrcReg | Stack, em_push)),
/* 0x58 - 0x5F */
X8(D(DstReg | Stack)),
/* 0x60 - 0x67 */
D(ImplicitOps | Stack | No64), D(ImplicitOps | Stack | No64),
N, D(DstReg | SrcMem32 | ModRM | Mov) /* movsxd (x86/64) */ ,
N, N, N, N,
/* 0x68 - 0x6F */
I(SrcImm | Mov | Stack, em_push),
I(DstReg | SrcMem | ModRM | Src2Imm, em_imul_3op),
I(SrcImmByte | Mov | Stack, em_push),
I(DstReg | SrcMem | ModRM | Src2ImmByte, em_imul_3op),
D2bv(DstDI | Mov | String), /* insb, insw/insd */
D2bv(SrcSI | ImplicitOps | String), /* outsb, outsw/outsd */
/* 0x70 - 0x7F */
X16(D(SrcImmByte)),
/* 0x80 - 0x87 */
G(ByteOp | DstMem | SrcImm | ModRM | Group, group1),
G(DstMem | SrcImm | ModRM | Group, group1),
G(ByteOp | DstMem | SrcImm | ModRM | No64 | Group, group1),
G(DstMem | SrcImmByte | ModRM | Group, group1),
D2bv(DstMem | SrcReg | ModRM), D2bv(DstMem | SrcReg | ModRM | Lock),
/* 0x88 - 0x8F */
I2bv(DstMem | SrcReg | ModRM | Mov, em_mov),
I2bv(DstReg | SrcMem | ModRM | Mov, em_mov),
D(DstMem | SrcNone | ModRM | Mov), D(ModRM | SrcMem | NoAccess | DstReg),
D(ImplicitOps | SrcMem16 | ModRM), G(0, group1A),
/* 0x90 - 0x97 */
X8(D(SrcAcc | DstReg)),
/* 0x98 - 0x9F */
D(DstAcc | SrcNone), I(ImplicitOps | SrcAcc, em_cwd),
I(SrcImmFAddr | No64, em_call_far), N,
D(ImplicitOps | Stack), D(ImplicitOps | Stack), N, N,
/* 0xA0 - 0xA7 */
I2bv(DstAcc | SrcMem | Mov | MemAbs, em_mov),
I2bv(DstMem | SrcAcc | Mov | MemAbs, em_mov),
I2bv(SrcSI | DstDI | Mov | String, em_mov),
D2bv(SrcSI | DstDI | String),
/* 0xA8 - 0xAF */
D2bv(DstAcc | SrcImm),
I2bv(SrcAcc | DstDI | Mov | String, em_mov),
I2bv(SrcSI | DstAcc | Mov | String, em_mov),
D2bv(SrcAcc | DstDI | String),
/* 0xB0 - 0xB7 */
X8(I(ByteOp | DstReg | SrcImm | Mov, em_mov)),
/* 0xB8 - 0xBF */
X8(I(DstReg | SrcImm | Mov, em_mov)),
/* 0xC0 - 0xC7 */
D2bv(DstMem | SrcImmByte | ModRM),
I(ImplicitOps | Stack | SrcImmU16, em_ret_near_imm),
D(ImplicitOps | Stack),
D(DstReg | SrcMemFAddr | ModRM | No64), D(DstReg | SrcMemFAddr | ModRM | No64),
G(ByteOp, group11), G(0, group11),
/* 0xC8 - 0xCF */
N, N, N, D(ImplicitOps | Stack),
D(ImplicitOps), D(SrcImmByte), D(ImplicitOps | No64), D(ImplicitOps),
/* 0xD0 - 0xD7 */
D2bv(DstMem | SrcOne | ModRM), D2bv(DstMem | ModRM),
N, N, N, N,
/* 0xD8 - 0xDF */
N, N, N, N, N, N, N, N,
/* 0xE0 - 0xE7 */
X4(D(SrcImmByte)),
D2bv(SrcImmUByte | DstAcc), D2bv(SrcAcc | DstImmUByte),
/* 0xE8 - 0xEF */
D(SrcImm | Stack), D(SrcImm | ImplicitOps),
D(SrcImmFAddr | No64), D(SrcImmByte | ImplicitOps),
D2bv(SrcNone | DstAcc), D2bv(SrcAcc | ImplicitOps),
/* 0xF0 - 0xF7 */
N, N, N, N,
D(ImplicitOps | Priv), D(ImplicitOps), G(ByteOp, group3), G(0, group3),
/* 0xF8 - 0xFF */
D(ImplicitOps), D(ImplicitOps), D(ImplicitOps), D(ImplicitOps),
D(ImplicitOps), D(ImplicitOps), G(0, group4), G(0, group5),
};
static struct opcode twobyte_table[256] = {
/* 0x00 - 0x0F */
N, GD(0, &group7), N, N,
N, D(ImplicitOps), D(ImplicitOps | Priv), N,
D(ImplicitOps | Priv), D(ImplicitOps | Priv), N, N,
N, D(ImplicitOps | ModRM), N, N,
/* 0x10 - 0x1F */
N, N, N, N, N, N, N, N, D(ImplicitOps | ModRM), N, N, N, N, N, N, N,
/* 0x20 - 0x2F */
D(ModRM | DstMem | Priv | Op3264), D(ModRM | DstMem | Priv | Op3264),
D(ModRM | SrcMem | Priv | Op3264), D(ModRM | SrcMem | Priv | Op3264),
N, N, N, N,
N, N, N, N, N, N, N, N,
/* 0x30 - 0x3F */
D(ImplicitOps | Priv), I(ImplicitOps, em_rdtsc),
D(ImplicitOps | Priv), N,
D(ImplicitOps), D(ImplicitOps | Priv), N, N,
N, N, N, N, N, N, N, N,
/* 0x40 - 0x4F */
X16(D(DstReg | SrcMem | ModRM | Mov)),
/* 0x50 - 0x5F */
N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N,
/* 0x60 - 0x6F */
N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N,
/* 0x70 - 0x7F */
N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N,
/* 0x80 - 0x8F */
X16(D(SrcImm)),
/* 0x90 - 0x9F */
X16(D(ByteOp | DstMem | SrcNone | ModRM| Mov)),
/* 0xA0 - 0xA7 */
D(ImplicitOps | Stack), D(ImplicitOps | Stack),
N, D(DstMem | SrcReg | ModRM | BitOp),
D(DstMem | SrcReg | Src2ImmByte | ModRM),
D(DstMem | SrcReg | Src2CL | ModRM), N, N,
/* 0xA8 - 0xAF */
D(ImplicitOps | Stack), D(ImplicitOps | Stack),
N, D(DstMem | SrcReg | ModRM | BitOp | Lock),
D(DstMem | SrcReg | Src2ImmByte | ModRM),
D(DstMem | SrcReg | Src2CL | ModRM),
D(ModRM), I(DstReg | SrcMem | ModRM, em_imul),
/* 0xB0 - 0xB7 */
D2bv(DstMem | SrcReg | ModRM | Lock),
D(DstReg | SrcMemFAddr | ModRM), D(DstMem | SrcReg | ModRM | BitOp | Lock),
D(DstReg | SrcMemFAddr | ModRM), D(DstReg | SrcMemFAddr | ModRM),
D(ByteOp | DstReg | SrcMem | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
/* 0xB8 - 0xBF */
N, N,
G(BitOp, group8), D(DstMem | SrcReg | ModRM | BitOp | Lock),
D(DstReg | SrcMem | ModRM), D(DstReg | SrcMem | ModRM),
D(ByteOp | DstReg | SrcMem | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
/* 0xC0 - 0xCF */
D2bv(DstMem | SrcReg | ModRM | Lock),
N, D(DstMem | SrcReg | ModRM | Mov),
N, N, N, GD(0, &group9),
N, N, N, N, N, N, N, N,
/* 0xD0 - 0xDF */
N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N,
/* 0xE0 - 0xEF */
N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N,
/* 0xF0 - 0xFF */
N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N
};
#undef D
#undef N
#undef G
#undef GD
#undef I
#undef D2bv
#undef I2bv
#undef D6ALU
static unsigned imm_size(struct decode_cache *c)
{
unsigned size;
size = (c->d & ByteOp) ? 1 : c->op_bytes;
if (size == 8)
size = 4;
return size;
}
static int decode_imm(struct x86_emulate_ctxt *ctxt, struct operand *op,
unsigned size, bool sign_extension)
{
struct decode_cache *c = &ctxt->decode;
struct x86_emulate_ops *ops = ctxt->ops;
int rc = X86EMUL_CONTINUE;
op->type = OP_IMM;
op->bytes = size;
op->addr.mem.ea = c->eip;
/* NB. Immediates are sign-extended as necessary. */
switch (op->bytes) {
case 1:
op->val = insn_fetch(s8, 1, c->eip);
break;
case 2:
op->val = insn_fetch(s16, 2, c->eip);
break;
case 4:
op->val = insn_fetch(s32, 4, c->eip);
break;
}
if (!sign_extension) {
switch (op->bytes) {
case 1:
op->val &= 0xff;
break;
case 2:
op->val &= 0xffff;
break;
case 4:
op->val &= 0xffffffff;
break;
}
}
done:
return rc;
}
int
x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
{
struct x86_emulate_ops *ops = ctxt->ops;
struct decode_cache *c = &ctxt->decode;
int rc = X86EMUL_CONTINUE;
int mode = ctxt->mode;
int def_op_bytes, def_ad_bytes, dual, goffset;
struct opcode opcode, *g_mod012, *g_mod3;
struct operand memop = { .type = OP_NONE };
c->eip = ctxt->eip;
c->fetch.start = c->eip;
c->fetch.end = c->fetch.start + insn_len;
if (insn_len > 0)
memcpy(c->fetch.data, insn, insn_len);
ctxt->cs_base = seg_base(ctxt, ops, VCPU_SREG_CS);
switch (mode) {
case X86EMUL_MODE_REAL:
case X86EMUL_MODE_VM86:
case X86EMUL_MODE_PROT16:
def_op_bytes = def_ad_bytes = 2;
break;
case X86EMUL_MODE_PROT32:
def_op_bytes = def_ad_bytes = 4;
break;
#ifdef CONFIG_X86_64
case X86EMUL_MODE_PROT64:
def_op_bytes = 4;
def_ad_bytes = 8;
break;
#endif
default:
return -1;
}
c->op_bytes = def_op_bytes;
c->ad_bytes = def_ad_bytes;
/* Legacy prefixes. */
for (;;) {
switch (c->b = insn_fetch(u8, 1, c->eip)) {
case 0x66: /* operand-size override */
/* switch between 2/4 bytes */
c->op_bytes = def_op_bytes ^ 6;
break;
case 0x67: /* address-size override */
if (mode == X86EMUL_MODE_PROT64)
/* switch between 4/8 bytes */
c->ad_bytes = def_ad_bytes ^ 12;
else
/* switch between 2/4 bytes */
c->ad_bytes = def_ad_bytes ^ 6;
break;
case 0x26: /* ES override */
case 0x2e: /* CS override */
case 0x36: /* SS override */
case 0x3e: /* DS override */
set_seg_override(c, (c->b >> 3) & 3);
break;
case 0x64: /* FS override */
case 0x65: /* GS override */
set_seg_override(c, c->b & 7);
break;
case 0x40 ... 0x4f: /* REX */
if (mode != X86EMUL_MODE_PROT64)
goto done_prefixes;
c->rex_prefix = c->b;
continue;
case 0xf0: /* LOCK */
c->lock_prefix = 1;
break;
case 0xf2: /* REPNE/REPNZ */
c->rep_prefix = REPNE_PREFIX;
break;
case 0xf3: /* REP/REPE/REPZ */
c->rep_prefix = REPE_PREFIX;
break;
default:
goto done_prefixes;
}
/* Any legacy prefix after a REX prefix nullifies its effect. */
c->rex_prefix = 0;
}
done_prefixes:
/* REX prefix. */
if (c->rex_prefix & 8)
c->op_bytes = 8; /* REX.W */
/* Opcode byte(s). */
opcode = opcode_table[c->b];
/* Two-byte opcode? */
if (c->b == 0x0f) {
c->twobyte = 1;
c->b = insn_fetch(u8, 1, c->eip);
opcode = twobyte_table[c->b];
}
c->d = opcode.flags;
if (c->d & Group) {
dual = c->d & GroupDual;
c->modrm = insn_fetch(u8, 1, c->eip);
--c->eip;
if (c->d & GroupDual) {
g_mod012 = opcode.u.gdual->mod012;
g_mod3 = opcode.u.gdual->mod3;
} else
g_mod012 = g_mod3 = opcode.u.group;
c->d &= ~(Group | GroupDual);
goffset = (c->modrm >> 3) & 7;
if ((c->modrm >> 6) == 3)
opcode = g_mod3[goffset];
else
opcode = g_mod012[goffset];
c->d |= opcode.flags;
}
c->execute = opcode.u.execute;
/* Unrecognised? */
if (c->d == 0 || (c->d & Undefined))
return -1;
if (mode == X86EMUL_MODE_PROT64 && (c->d & Stack))
c->op_bytes = 8;
if (c->d & Op3264) {
if (mode == X86EMUL_MODE_PROT64)
c->op_bytes = 8;
else
c->op_bytes = 4;
}
/* ModRM and SIB bytes. */
if (c->d & ModRM) {
rc = decode_modrm(ctxt, ops, &memop);
if (!c->has_seg_override)
set_seg_override(c, c->modrm_seg);
} else if (c->d & MemAbs)
rc = decode_abs(ctxt, ops, &memop);
if (rc != X86EMUL_CONTINUE)
goto done;
if (!c->has_seg_override)
set_seg_override(c, VCPU_SREG_DS);
memop.addr.mem.seg = seg_override(ctxt, ops, c);
if (memop.type == OP_MEM && c->ad_bytes != 8)
memop.addr.mem.ea = (u32)memop.addr.mem.ea;
if (memop.type == OP_MEM && c->rip_relative)
memop.addr.mem.ea += c->eip;
/*
* Decode and fetch the source operand: register, memory
* or immediate.
*/
switch (c->d & SrcMask) {
case SrcNone:
break;
case SrcReg:
decode_register_operand(&c->src, c, 0);
break;
case SrcMem16:
memop.bytes = 2;
goto srcmem_common;
case SrcMem32:
memop.bytes = 4;
goto srcmem_common;
case SrcMem:
memop.bytes = (c->d & ByteOp) ? 1 :
c->op_bytes;
srcmem_common:
c->src = memop;
break;
case SrcImmU16:
rc = decode_imm(ctxt, &c->src, 2, false);
break;
case SrcImm:
rc = decode_imm(ctxt, &c->src, imm_size(c), true);
break;
case SrcImmU:
rc = decode_imm(ctxt, &c->src, imm_size(c), false);
break;
case SrcImmByte:
rc = decode_imm(ctxt, &c->src, 1, true);
break;
case SrcImmUByte:
rc = decode_imm(ctxt, &c->src, 1, false);
break;
case SrcAcc:
c->src.type = OP_REG;
c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->src.addr.reg = &c->regs[VCPU_REGS_RAX];
fetch_register_operand(&c->src);
break;
case SrcOne:
c->src.bytes = 1;
c->src.val = 1;
break;
case SrcSI:
c->src.type = OP_MEM;
c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->src.addr.mem.ea =
register_address(c, c->regs[VCPU_REGS_RSI]);
c->src.addr.mem.seg = seg_override(ctxt, ops, c),
c->src.val = 0;
break;
case SrcImmFAddr:
c->src.type = OP_IMM;
c->src.addr.mem.ea = c->eip;
c->src.bytes = c->op_bytes + 2;
insn_fetch_arr(c->src.valptr, c->src.bytes, c->eip);
break;
case SrcMemFAddr:
memop.bytes = c->op_bytes + 2;
goto srcmem_common;
break;
}
if (rc != X86EMUL_CONTINUE)
goto done;
/*
* Decode and fetch the second source operand: register, memory
* or immediate.
*/
switch (c->d & Src2Mask) {
case Src2None:
break;
case Src2CL:
c->src2.bytes = 1;
c->src2.val = c->regs[VCPU_REGS_RCX] & 0x8;
break;
case Src2ImmByte:
rc = decode_imm(ctxt, &c->src2, 1, true);
break;
case Src2One:
c->src2.bytes = 1;
c->src2.val = 1;
break;
case Src2Imm:
rc = decode_imm(ctxt, &c->src2, imm_size(c), true);
break;
}
if (rc != X86EMUL_CONTINUE)
goto done;
/* Decode and fetch the destination operand: register or memory. */
switch (c->d & DstMask) {
case DstReg:
decode_register_operand(&c->dst, c,
c->twobyte && (c->b == 0xb6 || c->b == 0xb7));
break;
case DstImmUByte:
c->dst.type = OP_IMM;
c->dst.addr.mem.ea = c->eip;
c->dst.bytes = 1;
c->dst.val = insn_fetch(u8, 1, c->eip);
break;
case DstMem:
case DstMem64:
c->dst = memop;
if ((c->d & DstMask) == DstMem64)
c->dst.bytes = 8;
else
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
if (c->d & BitOp)
fetch_bit_operand(c);
c->dst.orig_val = c->dst.val;
break;
case DstAcc:
c->dst.type = OP_REG;
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->dst.addr.reg = &c->regs[VCPU_REGS_RAX];
fetch_register_operand(&c->dst);
c->dst.orig_val = c->dst.val;
break;
case DstDI:
c->dst.type = OP_MEM;
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
c->dst.addr.mem.ea =
register_address(c, c->regs[VCPU_REGS_RDI]);
c->dst.addr.mem.seg = VCPU_SREG_ES;
c->dst.val = 0;
break;
case ImplicitOps:
/* Special instructions do their own operand decoding. */
default:
c->dst.type = OP_NONE; /* Disable writeback. */
return 0;
}
done:
return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
}
static bool string_insn_completed(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
/* The second termination condition only applies for REPE
* and REPNE. Test if the repeat string operation prefix is
* REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
* corresponding termination condition according to:
* - if REPE/REPZ and ZF = 0 then done
* - if REPNE/REPNZ and ZF = 1 then done
*/
if (((c->b == 0xa6) || (c->b == 0xa7) ||
(c->b == 0xae) || (c->b == 0xaf))
&& (((c->rep_prefix == REPE_PREFIX) &&
((ctxt->eflags & EFLG_ZF) == 0))
|| ((c->rep_prefix == REPNE_PREFIX) &&
((ctxt->eflags & EFLG_ZF) == EFLG_ZF))))
return true;
return false;
}
int
x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
{
struct x86_emulate_ops *ops = ctxt->ops;
u64 msr_data;
struct decode_cache *c = &ctxt->decode;
int rc = X86EMUL_CONTINUE;
int saved_dst_type = c->dst.type;
int irq; /* Used for int 3, int, and into */
ctxt->decode.mem_read.pos = 0;
if (ctxt->mode == X86EMUL_MODE_PROT64 && (c->d & No64)) {
rc = emulate_ud(ctxt);
goto done;
}
/* LOCK prefix is allowed only with some instructions */
if (c->lock_prefix && (!(c->d & Lock) || c->dst.type != OP_MEM)) {
rc = emulate_ud(ctxt);
goto done;
}
if ((c->d & SrcMask) == SrcMemFAddr && c->src.type != OP_MEM) {
rc = emulate_ud(ctxt);
goto done;
}
/* Privileged instruction can be executed only in CPL=0 */
if ((c->d & Priv) && ops->cpl(ctxt->vcpu)) {
rc = emulate_gp(ctxt, 0);
goto done;
}
if (c->rep_prefix && (c->d & String)) {
/* All REP prefixes have the same first termination condition */
if (address_mask(c, c->regs[VCPU_REGS_RCX]) == 0) {
ctxt->eip = c->eip;
goto done;
}
}
if ((c->src.type == OP_MEM) && !(c->d & NoAccess)) {
rc = read_emulated(ctxt, ops, linear(ctxt, c->src.addr.mem),
c->src.valptr, c->src.bytes);
if (rc != X86EMUL_CONTINUE)
goto done;
c->src.orig_val64 = c->src.val64;
}
if (c->src2.type == OP_MEM) {
rc = read_emulated(ctxt, ops, linear(ctxt, c->src2.addr.mem),
&c->src2.val, c->src2.bytes);
if (rc != X86EMUL_CONTINUE)
goto done;
}
if ((c->d & DstMask) == ImplicitOps)
goto special_insn;
if ((c->dst.type == OP_MEM) && !(c->d & Mov)) {
/* optimisation - avoid slow emulated read if Mov */
rc = read_emulated(ctxt, ops, linear(ctxt, c->dst.addr.mem),
&c->dst.val, c->dst.bytes);
if (rc != X86EMUL_CONTINUE)
goto done;
}
c->dst.orig_val = c->dst.val;
special_insn:
if (c->execute) {
rc = c->execute(ctxt);
if (rc != X86EMUL_CONTINUE)
goto done;
goto writeback;
}
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 0x06: /* push es */
emulate_push_sreg(ctxt, ops, VCPU_SREG_ES);
break;
case 0x07: /* pop es */
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_ES);
break;
case 0x08 ... 0x0d:
or: /* or */
emulate_2op_SrcV("or", c->src, c->dst, ctxt->eflags);
break;
case 0x0e: /* push cs */
emulate_push_sreg(ctxt, ops, VCPU_SREG_CS);
break;
case 0x10 ... 0x15:
adc: /* adc */
emulate_2op_SrcV("adc", c->src, c->dst, ctxt->eflags);
break;
case 0x16: /* push ss */
emulate_push_sreg(ctxt, ops, VCPU_SREG_SS);
break;
case 0x17: /* pop ss */
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_SS);
break;
case 0x18 ... 0x1d:
sbb: /* sbb */
emulate_2op_SrcV("sbb", c->src, c->dst, ctxt->eflags);
break;
case 0x1e: /* push ds */
emulate_push_sreg(ctxt, ops, VCPU_SREG_DS);
break;
case 0x1f: /* pop ds */
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_DS);
break;
case 0x20 ... 0x25:
and: /* and */
emulate_2op_SrcV("and", c->src, c->dst, ctxt->eflags);
break;
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 0x40 ... 0x47: /* inc r16/r32 */
emulate_1op("inc", c->dst, ctxt->eflags);
break;
case 0x48 ... 0x4f: /* dec r16/r32 */
emulate_1op("dec", c->dst, ctxt->eflags);
break;
case 0x58 ... 0x5f: /* pop reg */
pop_instruction:
rc = emulate_pop(ctxt, ops, &c->dst.val, c->op_bytes);
break;
case 0x60: /* pusha */
rc = emulate_pusha(ctxt, ops);
break;
case 0x61: /* popa */
rc = emulate_popa(ctxt, ops);
break;
case 0x63: /* movsxd */
if (ctxt->mode != X86EMUL_MODE_PROT64)
goto cannot_emulate;
c->dst.val = (s32) c->src.val;
break;
case 0x6c: /* insb */
case 0x6d: /* insw/insd */
c->src.val = c->regs[VCPU_REGS_RDX];
goto do_io_in;
case 0x6e: /* outsb */
case 0x6f: /* outsw/outsd */
c->dst.val = c->regs[VCPU_REGS_RDX];
goto do_io_out;
break;
case 0x70 ... 0x7f: /* jcc (short) */
if (test_cc(c->b, ctxt->eflags))
jmp_rel(c, 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:
test:
emulate_2op_SrcV("test", c->src, c->dst, ctxt->eflags);
break;
case 0x86 ... 0x87: /* xchg */
xchg:
/* Write back the register source. */
c->src.val = c->dst.val;
write_register_operand(&c->src);
/*
* Write back the memory destination with implicit LOCK
* prefix.
*/
c->dst.val = c->src.orig_val;
c->lock_prefix = 1;
break;
case 0x8c: /* mov r/m, sreg */
if (c->modrm_reg > VCPU_SREG_GS) {
rc = emulate_ud(ctxt);
goto done;
}
c->dst.val = ops->get_segment_selector(c->modrm_reg, ctxt->vcpu);
break;
case 0x8d: /* lea r16/r32, m */
c->dst.val = c->src.addr.mem.ea;
break;
case 0x8e: { /* mov seg, r/m16 */
uint16_t sel;
sel = c->src.val;
if (c->modrm_reg == VCPU_SREG_CS ||
c->modrm_reg > VCPU_SREG_GS) {
rc = emulate_ud(ctxt);
goto done;
}
if (c->modrm_reg == VCPU_SREG_SS)
ctxt->interruptibility = KVM_X86_SHADOW_INT_MOV_SS;
rc = load_segment_descriptor(ctxt, ops, sel, c->modrm_reg);
c->dst.type = OP_NONE; /* Disable writeback. */
break;
}
case 0x8f: /* pop (sole member of Grp1a) */
rc = emulate_grp1a(ctxt, ops);
break;
case 0x90 ... 0x97: /* nop / xchg reg, rax */
if (c->dst.addr.reg == &c->regs[VCPU_REGS_RAX])
break;
goto xchg;
case 0x98: /* cbw/cwde/cdqe */
switch (c->op_bytes) {
case 2: c->dst.val = (s8)c->dst.val; break;
case 4: c->dst.val = (s16)c->dst.val; break;
case 8: c->dst.val = (s32)c->dst.val; break;
}
break;
case 0x9c: /* pushf */
c->src.val = (unsigned long) ctxt->eflags;
emulate_push(ctxt, ops);
break;
case 0x9d: /* popf */
c->dst.type = OP_REG;
c->dst.addr.reg = &ctxt->eflags;
c->dst.bytes = c->op_bytes;
rc = emulate_popf(ctxt, ops, &c->dst.val, c->op_bytes);
break;
case 0xa6 ... 0xa7: /* cmps */
c->dst.type = OP_NONE; /* Disable writeback. */
goto cmp;
case 0xa8 ... 0xa9: /* test ax, imm */
goto test;
case 0xae ... 0xaf: /* scas */
goto cmp;
case 0xc0 ... 0xc1:
emulate_grp2(ctxt);
break;
case 0xc3: /* ret */
c->dst.type = OP_REG;
c->dst.addr.reg = &c->eip;
c->dst.bytes = c->op_bytes;
goto pop_instruction;
case 0xc4: /* les */
rc = emulate_load_segment(ctxt, ops, VCPU_SREG_ES);
break;
case 0xc5: /* lds */
rc = emulate_load_segment(ctxt, ops, VCPU_SREG_DS);
break;
case 0xcb: /* ret far */
rc = emulate_ret_far(ctxt, ops);
break;
case 0xcc: /* int3 */
irq = 3;
goto do_interrupt;
case 0xcd: /* int n */
irq = c->src.val;
do_interrupt:
rc = emulate_int(ctxt, ops, irq);
break;
case 0xce: /* into */
if (ctxt->eflags & EFLG_OF) {
irq = 4;
goto do_interrupt;
}
break;
case 0xcf: /* iret */
rc = emulate_iret(ctxt, ops);
break;
case 0xd0 ... 0xd1: /* Grp2 */
emulate_grp2(ctxt);
break;
case 0xd2 ... 0xd3: /* Grp2 */
c->src.val = c->regs[VCPU_REGS_RCX];
emulate_grp2(ctxt);
break;
case 0xe0 ... 0xe2: /* loop/loopz/loopnz */
register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
if (address_mask(c, c->regs[VCPU_REGS_RCX]) != 0 &&
(c->b == 0xe2 || test_cc(c->b ^ 0x5, ctxt->eflags)))
jmp_rel(c, c->src.val);
break;
case 0xe3: /* jcxz/jecxz/jrcxz */
if (address_mask(c, c->regs[VCPU_REGS_RCX]) == 0)
jmp_rel(c, c->src.val);
break;
case 0xe4: /* inb */
case 0xe5: /* in */
goto do_io_in;
case 0xe6: /* outb */
case 0xe7: /* out */
goto do_io_out;
case 0xe8: /* call (near) */ {
long int rel = c->src.val;
c->src.val = (unsigned long) c->eip;
jmp_rel(c, rel);
emulate_push(ctxt, ops);
break;
}
case 0xe9: /* jmp rel */
goto jmp;
case 0xea: { /* jmp far */
unsigned short sel;
jump_far:
memcpy(&sel, c->src.valptr + c->op_bytes, 2);
if (load_segment_descriptor(ctxt, ops, sel, VCPU_SREG_CS))
goto done;
c->eip = 0;
memcpy(&c->eip, c->src.valptr, c->op_bytes);
break;
}
case 0xeb:
jmp: /* jmp rel short */
jmp_rel(c, c->src.val);
c->dst.type = OP_NONE; /* Disable writeback. */
break;
case 0xec: /* in al,dx */
case 0xed: /* in (e/r)ax,dx */
c->src.val = c->regs[VCPU_REGS_RDX];
do_io_in:
c->dst.bytes = min(c->dst.bytes, 4u);
if (!emulator_io_permited(ctxt, ops, c->src.val, c->dst.bytes)) {
rc = emulate_gp(ctxt, 0);
goto done;
}
if (!pio_in_emulated(ctxt, ops, c->dst.bytes, c->src.val,
&c->dst.val))
goto done; /* IO is needed */
break;
case 0xee: /* out dx,al */
case 0xef: /* out dx,(e/r)ax */
c->dst.val = c->regs[VCPU_REGS_RDX];
do_io_out:
c->src.bytes = min(c->src.bytes, 4u);
if (!emulator_io_permited(ctxt, ops, c->dst.val,
c->src.bytes)) {
rc = emulate_gp(ctxt, 0);
goto done;
}
ops->pio_out_emulated(c->src.bytes, c->dst.val,
&c->src.val, 1, ctxt->vcpu);
c->dst.type = OP_NONE; /* Disable writeback. */
break;
case 0xf4: /* hlt */
ctxt->vcpu->arch.halt_request = 1;
break;
case 0xf5: /* cmc */
/* complement carry flag from eflags reg */
ctxt->eflags ^= EFLG_CF;
break;
case 0xf6 ... 0xf7: /* Grp3 */
rc = emulate_grp3(ctxt, ops);
break;
case 0xf8: /* clc */
ctxt->eflags &= ~EFLG_CF;
break;
case 0xf9: /* stc */
ctxt->eflags |= EFLG_CF;
break;
case 0xfa: /* cli */
if (emulator_bad_iopl(ctxt, ops)) {
rc = emulate_gp(ctxt, 0);
goto done;
} else
ctxt->eflags &= ~X86_EFLAGS_IF;
break;
case 0xfb: /* sti */
if (emulator_bad_iopl(ctxt, ops)) {
rc = emulate_gp(ctxt, 0);
goto done;
} else {
ctxt->interruptibility = KVM_X86_SHADOW_INT_STI;
ctxt->eflags |= X86_EFLAGS_IF;
}
break;
case 0xfc: /* cld */
ctxt->eflags &= ~EFLG_DF;
break;
case 0xfd: /* std */
ctxt->eflags |= EFLG_DF;
break;
case 0xfe: /* Grp4 */
grp45:
rc = emulate_grp45(ctxt, ops);
break;
case 0xff: /* Grp5 */
if (c->modrm_reg == 5)
goto jump_far;
goto grp45;
default:
goto cannot_emulate;
}
if (rc != X86EMUL_CONTINUE)
goto done;
writeback:
rc = writeback(ctxt, ops);
if (rc != X86EMUL_CONTINUE)
goto done;
/*
* restore dst type in case the decoding will be reused
* (happens for string instruction )
*/
c->dst.type = saved_dst_type;
if ((c->d & SrcMask) == SrcSI)
string_addr_inc(ctxt, seg_override(ctxt, ops, c),
VCPU_REGS_RSI, &c->src);
if ((c->d & DstMask) == DstDI)
string_addr_inc(ctxt, VCPU_SREG_ES, VCPU_REGS_RDI,
&c->dst);
if (c->rep_prefix && (c->d & String)) {
struct read_cache *r = &ctxt->decode.io_read;
register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
if (!string_insn_completed(ctxt)) {
/*
* Re-enter guest when pio read ahead buffer is empty
* or, if it is not used, after each 1024 iteration.
*/
if ((r->end != 0 || c->regs[VCPU_REGS_RCX] & 0x3ff) &&
(r->end == 0 || r->end != r->pos)) {
/*
* Reset read cache. Usually happens before
* decode, but since instruction is restarted
* we have to do it here.
*/
ctxt->decode.mem_read.end = 0;
return EMULATION_RESTART;
}
goto done; /* skip rip writeback */
}
}
ctxt->eip = c->eip;
done:
if (rc == X86EMUL_PROPAGATE_FAULT)
ctxt->have_exception = true;
return (rc == X86EMUL_UNHANDLEABLE) ? EMULATION_FAILED : EMULATION_OK;
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 != X86EMUL_CONTINUE)
goto done;
/* Let the processor re-execute the fixed hypercall */
c->eip = ctxt->eip;
/* Disable writeback. */
c->dst.type = OP_NONE;
break;
case 2: /* lgdt */
rc = read_descriptor(ctxt, ops, c->src.addr.mem,
&size, &address, c->op_bytes);
if (rc != X86EMUL_CONTINUE)
goto done;
realmode_lgdt(ctxt->vcpu, size, address);
/* Disable writeback. */
c->dst.type = OP_NONE;
break;
case 3: /* lidt/vmmcall */
if (c->modrm_mod == 3) {
switch (c->modrm_rm) {
case 1:
rc = kvm_fix_hypercall(ctxt->vcpu);
break;
default:
goto cannot_emulate;
}
} else {
rc = read_descriptor(ctxt, ops, c->src.addr.mem,
&size, &address,
c->op_bytes);
if (rc != X86EMUL_CONTINUE)
goto done;
realmode_lidt(ctxt->vcpu, size, address);
}
/* Disable writeback. */
c->dst.type = OP_NONE;
break;
case 4: /* smsw */
c->dst.bytes = 2;
c->dst.val = ops->get_cr(0, ctxt->vcpu);
break;
case 6: /* lmsw */
ops->set_cr(0, (ops->get_cr(0, ctxt->vcpu) & ~0x0eul) |
(c->src.val & 0x0f), ctxt->vcpu);
c->dst.type = OP_NONE;
break;
case 5: /* not defined */
emulate_ud(ctxt);
rc = X86EMUL_PROPAGATE_FAULT;
goto done;
case 7: /* invlpg*/
emulate_invlpg(ctxt->vcpu,
linear(ctxt, c->src.addr.mem));
/* Disable writeback. */
c->dst.type = OP_NONE;
break;
default:
goto cannot_emulate;
}
break;
case 0x05: /* syscall */
rc = emulate_syscall(ctxt, ops);
break;
case 0x06:
emulate_clts(ctxt->vcpu);
break;
case 0x09: /* wbinvd */
kvm_emulate_wbinvd(ctxt->vcpu);
break;
case 0x08: /* invd */
case 0x0d: /* GrpP (prefetch) */
case 0x18: /* Grp16 (prefetch/nop) */
break;
case 0x20: /* mov cr, reg */
switch (c->modrm_reg) {
case 1:
case 5 ... 7:
case 9 ... 15:
emulate_ud(ctxt);
rc = X86EMUL_PROPAGATE_FAULT;
goto done;
}
c->dst.val = ops->get_cr(c->modrm_reg, ctxt->vcpu);
break;
case 0x21: /* mov from dr to reg */
if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
(c->modrm_reg == 4 || c->modrm_reg == 5)) {
emulate_ud(ctxt);
rc = X86EMUL_PROPAGATE_FAULT;
goto done;
}
ops->get_dr(c->modrm_reg, &c->dst.val, ctxt->vcpu);
break;
case 0x22: /* mov reg, cr */
if (ops->set_cr(c->modrm_reg, c->src.val, ctxt->vcpu)) {
emulate_gp(ctxt, 0);
rc = X86EMUL_PROPAGATE_FAULT;
goto done;
}
c->dst.type = OP_NONE;
break;
case 0x23: /* mov from reg to dr */
if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
(c->modrm_reg == 4 || c->modrm_reg == 5)) {
emulate_ud(ctxt);
rc = X86EMUL_PROPAGATE_FAULT;
goto done;
}
if (ops->set_dr(c->modrm_reg, c->src.val &
((ctxt->mode == X86EMUL_MODE_PROT64) ?
~0ULL : ~0U), ctxt->vcpu) < 0) {
/* #UD condition is already handled by the code above */
emulate_gp(ctxt, 0);
rc = X86EMUL_PROPAGATE_FAULT;
goto done;
}
c->dst.type = OP_NONE; /* no writeback */
break;
case 0x30:
/* wrmsr */
msr_data = (u32)c->regs[VCPU_REGS_RAX]
| ((u64)c->regs[VCPU_REGS_RDX] << 32);
if (ops->set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data)) {
emulate_gp(ctxt, 0);
rc = X86EMUL_PROPAGATE_FAULT;
goto done;
}
rc = X86EMUL_CONTINUE;
break;
case 0x32:
/* rdmsr */
if (ops->get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], &msr_data)) {
emulate_gp(ctxt, 0);
rc = X86EMUL_PROPAGATE_FAULT;
goto done;
} else {
c->regs[VCPU_REGS_RAX] = (u32)msr_data;
c->regs[VCPU_REGS_RDX] = msr_data >> 32;
}
rc = X86EMUL_CONTINUE;
break;
case 0x34: /* sysenter */
rc = emulate_sysenter(ctxt, ops);
break;
case 0x35: /* sysexit */
rc = emulate_sysexit(ctxt, ops);
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 0x80 ... 0x8f: /* jnz rel, etc*/
if (test_cc(c->b, ctxt->eflags))
jmp_rel(c, c->src.val);
break;
case 0x90 ... 0x9f: /* setcc r/m8 */
c->dst.val = test_cc(c->b, ctxt->eflags);
break;
case 0xa0: /* push fs */
emulate_push_sreg(ctxt, ops, VCPU_SREG_FS);
break;
case 0xa1: /* pop fs */
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_FS);
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 0xa4: /* shld imm8, r, r/m */
case 0xa5: /* shld cl, r, r/m */
emulate_2op_cl("shld", c->src2, c->src, c->dst, ctxt->eflags);
break;
case 0xa8: /* push gs */
emulate_push_sreg(ctxt, ops, VCPU_SREG_GS);
break;
case 0xa9: /* pop gs */
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_GS);
break;
case 0xab:
bts: /* bts */
emulate_2op_SrcV_nobyte("bts", c->src, c->dst, ctxt->eflags);
break;
case 0xac: /* shrd imm8, r, r/m */
case 0xad: /* shrd cl, r, r/m */
emulate_2op_cl("shrd", c->src2, c->src, c->dst, ctxt->eflags);
break;
case 0xae: /* clflush */
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.addr.reg = (unsigned long *)&c->regs[VCPU_REGS_RAX];
}
break;
case 0xb2: /* lss */
rc = emulate_load_segment(ctxt, ops, VCPU_SREG_SS);
break;
case 0xb3:
btr: /* btr */
emulate_2op_SrcV_nobyte("btr", c->src, c->dst, ctxt->eflags);
break;
case 0xb4: /* lfs */
rc = emulate_load_segment(ctxt, ops, VCPU_SREG_FS);
break;
case 0xb5: /* lgs */
rc = emulate_load_segment(ctxt, ops, VCPU_SREG_GS);
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 */
emulate_2op_SrcV_nobyte("btc", c->src, c->dst, ctxt->eflags);
break;
case 0xbc: { /* bsf */
u8 zf;
__asm__ ("bsf %2, %0; setz %1"
: "=r"(c->dst.val), "=q"(zf)
: "r"(c->src.val));
ctxt->eflags &= ~X86_EFLAGS_ZF;
if (zf) {
ctxt->eflags |= X86_EFLAGS_ZF;
c->dst.type = OP_NONE; /* Disable writeback. */
}
break;
}
case 0xbd: { /* bsr */
u8 zf;
__asm__ ("bsr %2, %0; setz %1"
: "=r"(c->dst.val), "=q"(zf)
: "r"(c->src.val));
ctxt->eflags &= ~X86_EFLAGS_ZF;
if (zf) {
ctxt->eflags |= X86_EFLAGS_ZF;
c->dst.type = OP_NONE; /* Disable writeback. */
}
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 0xc0 ... 0xc1: /* xadd */
emulate_2op_SrcV("add", c->src, c->dst, ctxt->eflags);
/* Write back the register source. */
c->src.val = c->dst.orig_val;
write_register_operand(&c->src);
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;
case 0xc7: /* Grp9 (cmpxchg8b) */
rc = emulate_grp9(ctxt, ops);
break;
default:
goto cannot_emulate;
}
if (rc != X86EMUL_CONTINUE)
goto done;
goto writeback;
cannot_emulate:
return -1;
}
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