[libvirt] How can I attach a network interface to KVM machine

Hi. When I am trying to attach an interface <interface type='bridge'> <mac address='52:54:00:db:1a:bb'/> <source bridge='mkvebr0'/> </interface> libvirt reports me, that libvirt.libvirtError: this function is not supported by the hypervisor: this device type cannot be attached Is there a legal way to attach a network interface to QEMU/KVM machine?