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>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 0037130..0c08bff 100644 (file)
--- 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 :