KVM: x86 emulator: add XADD instruction emulation

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

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 003713041ce6..0c08bffe6cb4 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2385,7 +2385,8 @@ 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 */
@@ -3531,6 +3532,12 @@ twobyte_insn:
                 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 :