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Commit d380a5e4 authored by Gleb Natapov's avatar Gleb Natapov Committed by Marcelo Tosatti
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KVM: x86 emulator: Add LOCK prefix validity checking 



Instructions which are not allowed to have LOCK prefix should
generate #UD if one is used.

[avi: fold opcode 82 fix from another patch]

Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent e92805ac

arch/x86/kvm/emulate.c

+56 −41
Original line number Diff line number Diff line
@@ -76,6 +76,7 @@ 
#define GroupDual   (1<<15)     /* Alternate decoding of mod == 3 */

#define GroupMask   0xff        /* Group number stored in bits 0:7 */

/* Misc flags */

#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 */
@@ -94,35 +95,35 @@ enum { 


static u32 opcode_table[256] = {

	/* 0x00 - 0x07 */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,

	ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,

	ImplicitOps | Stack | No64, ImplicitOps | Stack | No64,

	/* 0x08 - 0x0F */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,

	ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,

	ImplicitOps | Stack | No64, 0,

	/* 0x10 - 0x17 */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,

	ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,

	ImplicitOps | Stack | No64, ImplicitOps | Stack | No64,

	/* 0x18 - 0x1F */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,

	ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,

	ImplicitOps | Stack | No64, ImplicitOps | Stack | No64,

	/* 0x20 - 0x27 */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,

	DstAcc | SrcImmByte, DstAcc | SrcImm, 0, 0,

	/* 0x28 - 0x2F */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,

	0, 0, 0, 0,

	/* 0x30 - 0x37 */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,

	ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,

	0, 0, 0, 0,

	/* 0x38 - 0x3F */
@@ -158,7 +159,7 @@ static u32 opcode_table[256] = { 
	Group | Group1_80, Group | Group1_81,

	Group | Group1_82, Group | Group1_83,

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,

	ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,

	/* 0x88 - 0x8F */

	ByteOp | DstMem | SrcReg | ModRM | Mov, DstMem | SrcReg | ModRM | Mov,

	ByteOp | DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
@@ -263,17 +264,18 @@ static u32 twobyte_table[256] = { 
	DstMem | SrcReg | Src2CL | ModRM, 0, 0,

	/* 0xA8 - 0xAF */

	ImplicitOps | Stack, ImplicitOps | Stack,

	0, DstMem | SrcReg | ModRM | BitOp,

	0, DstMem | SrcReg | ModRM | BitOp | Lock,

	DstMem | SrcReg | Src2ImmByte | ModRM,

	DstMem | SrcReg | Src2CL | ModRM,

	ModRM, 0,

	/* 0xB0 - 0xB7 */

	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, 0,

	    DstMem | SrcReg | ModRM | BitOp,

	ByteOp | DstMem | SrcReg | ModRM | Lock, DstMem | SrcReg | ModRM | Lock,

	0, DstMem | SrcReg | ModRM | BitOp | Lock,

	0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov,

	    DstReg | SrcMem16 | ModRM | Mov,

	/* 0xB8 - 0xBF */

	0, 0, Group | Group8, DstMem | SrcReg | ModRM | BitOp,

	0, 0,

	Group | Group8, DstMem | SrcReg | ModRM | BitOp | Lock,

	0, 0, ByteOp | DstReg | SrcMem | ModRM | Mov,

	    DstReg | SrcMem16 | ModRM | Mov,

	/* 0xC0 - 0xCF */
@@ -290,25 +292,41 @@ static u32 twobyte_table[256] = { 


static u32 group_table[] = {

	[Group1_80*8] =

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

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

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

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

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM,

	[Group1_81*8] =

	DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,

	DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,

	DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,

	DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,

	DstMem | SrcImm | ModRM | Lock,

	DstMem | SrcImm | ModRM | Lock,

	DstMem | SrcImm | ModRM | Lock,

	DstMem | SrcImm | ModRM | Lock,

	DstMem | SrcImm | ModRM | Lock,

	DstMem | SrcImm | ModRM | Lock,

	DstMem | SrcImm | ModRM | Lock,

	DstMem | SrcImm | ModRM,

	[Group1_82*8] =

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

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

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

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

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM | Lock,

	ByteOp | DstMem | SrcImm | ModRM,

	[Group1_83*8] =

	DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,

	DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,

	DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,

	DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,

	DstMem | SrcImmByte | ModRM | Lock,

	DstMem | SrcImmByte | ModRM | Lock,

	DstMem | SrcImmByte | ModRM | Lock,

	DstMem | SrcImmByte | ModRM | Lock,

	DstMem | SrcImmByte | ModRM | Lock,

	DstMem | SrcImmByte | ModRM | Lock,

	DstMem | SrcImmByte | ModRM | Lock,

	DstMem | SrcImmByte | ModRM,

	[Group1A*8] =

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

	[Group3_Byte*8] =
@@ -332,10 +350,10 @@ static u32 group_table[] = { 
	SrcMem16 | ModRM | Mov | Priv, SrcMem | ModRM | ByteOp | Priv,

	[Group8*8] =

	0, 0, 0, 0,

	DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,

	DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,

	DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM | Lock,

	DstMem | SrcImmByte | ModRM | Lock, DstMem | SrcImmByte | ModRM | Lock,

	[Group9*8] =

	0, ImplicitOps | ModRM, 0, 0, 0, 0, 0, 0,

	0, ImplicitOps | ModRM | Lock, 0, 0, 0, 0, 0, 0,

};



static u32 group2_table[] = {
@@ -1580,8 +1598,7 @@ emulate_syscall(struct x86_emulate_ctxt *ctxt) 
	u64 msr_data;



	/* syscall is not available in real mode */

	if (c->lock_prefix || ctxt->mode == X86EMUL_MODE_REAL

	    || ctxt->mode == X86EMUL_MODE_VM86)

	if (ctxt->mode == X86EMUL_MODE_REAL || ctxt->mode == X86EMUL_MODE_VM86)

		return -1;



	setup_syscalls_segments(ctxt, &cs, &ss);
@@ -1629,10 +1646,6 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt) 
	struct kvm_segment cs, ss;

	u64 msr_data;



	/* inject #UD if LOCK prefix is used */

	if (c->lock_prefix)

		return -1;



	/* inject #GP if in real mode */

	if (ctxt->mode == X86EMUL_MODE_REAL) {

		kvm_inject_gp(ctxt->vcpu, 0);
@@ -1694,10 +1707,6 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt) 
	u64 msr_data;

	int usermode;



	/* inject #UD if LOCK prefix is used */

	if (c->lock_prefix)

		return -1;



	/* inject #GP if in real mode or Virtual 8086 mode */

	if (ctxt->mode == X86EMUL_MODE_REAL ||

	    ctxt->mode == X86EMUL_MODE_VM86) {
@@ -1819,6 +1828,12 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
	memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs);

	saved_eip = c->eip;



	/* LOCK prefix is allowed only with some instructions */

	if (c->lock_prefix && !(c->d & Lock)) {

		kvm_queue_exception(ctxt->vcpu, UD_VECTOR);

		goto done;

	}



	/* Privileged instruction can be executed only in CPL=0 */

	if ((c->d & Priv) && kvm_x86_ops->get_cpl(ctxt->vcpu)) {

		kvm_inject_gp(ctxt->vcpu, 0);