If LOCK prefix is used dest arg should be memory, otherwise instruction should generate #UD. Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx> --- arch/x86/kvm/emulate.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) 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 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) } /* 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; } -- 1.6.5 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html