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Commit 6e3d5dfb authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: x86 emulator: Fix stack instructions on 64-bit mode 



Stack instructions are always 64-bit on 64-bit mode; many of the
emulated stack instructions did not take that into account.  Fix by
adding a 'Stack' bitflag and setting the operand size appropriately
during the decode stage (except for 'push r/m', which is in a group
with a few other instructions, so it gets its own treatment).

This fixes random crashes on Vista x64.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 152ff9be

drivers/kvm/x86_emulate.c

+15 −12
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ 
#define BitOp       (1<<8)

#define MemAbs      (1<<9)      /* Memory operand is absolute displacement */

#define String      (1<<10)     /* String instruction (rep capable) */

#define Stack       (1<<11)     /* Stack instruction (push/pop) */



static u16 opcode_table[256] = {

	/* 0x00 - 0x07 */
@@ -104,14 +105,16 @@ static u16 opcode_table[256] = { 
	/* 0x48 - 0x4F */

	DstReg, DstReg, DstReg, DstReg,	DstReg, DstReg, DstReg, DstReg,

	/* 0x50 - 0x57 */

	SrcReg, SrcReg, SrcReg, SrcReg, SrcReg, SrcReg, SrcReg, SrcReg,

	SrcReg | Stack, SrcReg | Stack, SrcReg | Stack, SrcReg | Stack,

	SrcReg | Stack, SrcReg | Stack, SrcReg | Stack, SrcReg | Stack,

	/* 0x58 - 0x5F */

	DstReg, DstReg, DstReg, DstReg,	DstReg, DstReg, DstReg, DstReg,

	DstReg | Stack, DstReg | Stack, DstReg | Stack, DstReg | Stack,

	DstReg | Stack, DstReg | Stack, DstReg | Stack, DstReg | Stack,

	/* 0x60 - 0x67 */

	0, 0, 0, DstReg | SrcMem32 | ModRM | Mov /* movsxd (x86/64) */ ,

	0, 0, 0, 0,

	/* 0x68 - 0x6F */

	0, 0, ImplicitOps|Mov, 0,

	0, 0, ImplicitOps | Mov | Stack, 0,

	SrcNone  | ByteOp  | ImplicitOps, SrcNone  | ImplicitOps, /* insb, insw/insd */

	SrcNone  | ByteOp  | ImplicitOps, SrcNone  | ImplicitOps, /* outsb, outsw/outsd */

	/* 0x70 - 0x77 */
@@ -128,9 +131,10 @@ static u16 opcode_table[256] = { 
	/* 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,

	0, ModRM | DstReg, 0, DstMem | SrcNone | ModRM | Mov | Stack,

	/* 0x90 - 0x9F */

	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ImplicitOps, ImplicitOps, 0, 0,

	0, 0, 0, 0, 0, 0, 0, 0,

	0, 0, 0, 0, ImplicitOps | Stack, ImplicitOps | Stack, 0, 0,

	/* 0xA0 - 0xA7 */

	ByteOp | DstReg | SrcMem | Mov | MemAbs, DstReg | SrcMem | Mov | MemAbs,

	ByteOp | DstMem | SrcReg | Mov | MemAbs, DstMem | SrcReg | Mov | MemAbs,
@@ -144,7 +148,7 @@ static u16 opcode_table[256] = { 
	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,

	0, ImplicitOps | Stack, 0, 0,

	ByteOp | DstMem | SrcImm | ModRM | Mov, DstMem | SrcImm | ModRM | Mov,

	/* 0xC8 - 0xCF */

	0, 0, 0, 0, 0, 0, 0, 0,
@@ -157,7 +161,8 @@ static u16 opcode_table[256] = { 
	/* 0xE0 - 0xE7 */

	0, 0, 0, 0, 0, 0, 0, 0,

	/* 0xE8 - 0xEF */

	ImplicitOps, SrcImm|ImplicitOps, 0, SrcImmByte|ImplicitOps, 0, 0, 0, 0,

	ImplicitOps | Stack, SrcImm|ImplicitOps, 0, SrcImmByte|ImplicitOps,

	0, 0, 0, 0,

	/* 0xF0 - 0xF7 */

	0, 0, 0, 0,

	ImplicitOps, ImplicitOps,
@@ -868,6 +873,9 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
		}

	}



	if (mode == X86EMUL_MODE_PROT64 && (c->d & Stack))

		c->op_bytes = 8;



	/* ModRM and SIB bytes. */

	if (c->d & ModRM)

		rc = decode_modrm(ctxt, ops);
@@ -988,11 +996,6 @@ static inline int emulate_grp1a(struct x86_emulate_ctxt *ctxt, 
	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);