[PATCH 2/2 v3] KVM: x86 emulator: add XADD instruction emulation

[Wei Yongjun]

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

Signed-off-by: Wei Yongjun <yj...@cn.fujitsu.com>
---
v2 -> v3: add Lock prefix to decode
---
 arch/x86/kvm/emulate.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 8bf80a9..e091718 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 | Lock), D(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 */
@@ -3532,6 +3533,10 @@ 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);
+               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


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