[PATCH 2/2] KVM: x86 emulator: add XADD instruction emulation

[Wei Yongjun <yjwei@cn.fujitsu.com>]

Add XADD instruction emulation (opcode 0x0f 0xc0~0xc1)

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
---
 arch/x86/kvm/emulate.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 8bf80a9..7c47e37 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2387,7 +2387,8 @@ static struct opcode twobyte_table[256] = {
 	D(DstReg | SrcMem | ModRM), D(DstReg | SrcMem | ModRM),
 	D(ByteOp | DstReg | SrcMem | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
 	/* 0xC0 - 0xCF */
-	N, N, N, D(DstMem | SrcReg | ModRM | Mov),
+	D(ByteOp | DstMem | SrcReg | ModRM), D(DstMem | SrcReg | ModRM),
+	N, D(DstMem | SrcReg | ModRM | Mov),
 	N, N, N, GD(0, &group9),
 	N, N, N, N, N, N, N, N,
 	/* 0xD0 - 0xDF */
@@ -3532,6 +3533,12 @@ twobyte_insn:
 		c->dst.val = (c->d & ByteOp) ? (s8) c->src.val :
 							(s16) c->src.val;
 		break;
+	case 0xc0 ... 0xc1:	/* xadd */
+		/* Write back the register source. */
+		write_register_operand(&c->src, c->dst.val, c->dst.bytes);
+		/* Write back the memory destination with implicit LOCK prefix. */
+		c->lock_prefix = 1;
+		goto add;
 	case 0xc3:		/* movnti */
 		c->dst.bytes = c->op_bytes;
 		c->dst.val = (c->op_bytes == 4) ? (u32) c->src.val :
-- 
1.7.0.4