[libvirt-users] How to run qemu with root permission from libvirt.

Hi all, My platform is qemu 1.5.1 and libvirt 1.2.0. How to lauch the qemu with root permission, since in the qemu I would like to access the hardware directly. I actually check the runing /usr/bin/kvm process, it indicated that this process is from a root user, but it still failed to act as with root permission. Thanks! Ed