KVM: x86: smsw emulation is incorrect in 64-bit mode

In 64-bit mode, when the destination is a register, the assignment is done
according to the operand size. Otherwise (memory operand or no 64-bit mode), a
16-bit assignment is performed.

Currently, 16-bit assignment is always done to the destination.
Signed-off-by: NNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/emulate.c

@@ -3235,7 +3235,8 @@ static int em_lidt(struct x86_emulate_ctxt *ctxt)
 
 static int em_smsw(struct x86_emulate_ctxt *ctxt)
 {
-	ctxt->dst.bytes = 2;
+	if (ctxt->dst.type == OP_MEM)
+		ctxt->dst.bytes = 2;
 	ctxt->dst.val = ctxt->ops->get_cr(ctxt, 0);
 	return X86EMUL_CONTINUE;
 }