KVM: x86 emulator: cleanup nop emulation

Make it more explicit what we are checking for.

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

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a99d49c..03a7291 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2799,8 +2799,8 @@ special_insn:
                        goto done;
                break;
        case 0x90: /* nop / xchg r8,rax */
-               if (!(c->rex_prefix & 1)) { /* nop */
-                       c->dst.type = OP_NONE;
+               if (c->dst.ptr == (unsigned long *)&c->regs[VCPU_REGS_RAX]) {
+                       c->dst.type = OP_NONE;  /* nop */
                        break;
                }
        case 0x91 ... 0x97: /* xchg reg,rax */