polkit

Para não pedir senha ao abrir VirtManager:

# vim /etc/polkit-1/rules.d/80-libvirt.rules

polkit.addRule(function(action, subject) {
  if (action.id == "org.libvirt.unix.manage" && subject.local && subject.active && subject.isInGroup("libvirt")) {
      return polkit.Result.YES;
  }
});

# ls /usr/share/polkit-1/actions/