[libvirt] libvirt label qemu process problem

I found that when using souce code to install libvirt,it labeled qemu process with label "unconfined_u:unconfined_r:svirt_t:s0:c53,c366" instead of "system_u:system_r:svirt_t:s0:c53,c366",is this a bug??can anyone explain it ?? thanks! zhunxun@gmail.com