KVM: x86 emulator: use SrcAcc to simplify xchg decoding

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 4 insertions, 11 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c7176df9ced5..b7da0e3e0cc0 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2147,7 +2147,7 @@ static struct opcode opcode_table[256] = {
         D(DstMem | SrcNone | ModRM | Mov), D(ModRM | DstReg),
         D(ImplicitOps | SrcMem16 | ModRM), G(0, group1A),
         /* 0x90 - 0x97 */
-        X8(D(DstReg)),
+        X8(D(SrcAcc | DstReg)),
         /* 0x98 - 0x9F */
         N, N, D(SrcImmFAddr | No64), N,
         D(ImplicitOps | Stack), D(ImplicitOps | Stack), N, N,
@@ -2932,16 +2932,9 @@ special_insn:
                 if (rc != X86EMUL_CONTINUE)
                         goto done;
                 break;
-        case 0x90: /* nop / xchg r8,rax */
-                if (c->dst.addr.reg == &c->regs[VCPU_REGS_RAX]) {
-                        c->dst.type = OP_NONE;  /* nop */
-                        break;
-                }
-        case 0x91 ... 0x97: /* xchg reg,rax */
-                c->src.type = OP_REG;
-                c->src.bytes = c->op_bytes;
-                c->src.addr.reg = &c->regs[VCPU_REGS_RAX];
-                c->src.val = *(c->src.addr.reg);
+        case 0x90 ... 0x97: /* nop / xchg reg, rax */
+                if (c->dst.addr.reg == &c->regs[VCPU_REGS_RAX])
+                        goto done;
                 goto xchg;
         case 0x9c: /* pushf */
                 c->src.val =  (unsigned long) ctxt->eflags;