KVM: x86 emulator: If LOCK prefix is used dest arg should be memory.
If LOCK prefix is used dest arg should be memory, otherwise instruction
should generate #UD.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b89a8f2..46a7ee3 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1842,7 +1842,7 @@
}
/* LOCK prefix is allowed only with some instructions */
- if (c->lock_prefix && !(c->d & Lock)) {
+ if (c->lock_prefix && (!(c->d & Lock) || c->dst.type != OP_MEM)) {
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
goto done;
}