add: migration for xen

            raise VMError('deletion of VM `%s` failed' % self.get_name())

        self._hv_handle._cache_vm_rebuild()

    def migrate(self, host, port):

    def migrate(self, libvirt_addr, hv_addr):

        '''

        '''

        # special case for xen

        if self.hypervisor().get_hv_type() == 'xen':

            flags = (libvirt.VIR_MIGRATE_LIVE ^

                    libvirt.VIR_MIGRATE_PERSIST_DEST ^

                    libvirt.VIR_MIGRATE_UNDEFINE_SOURCE)

            uri = 'xenmigr://%s:%d' % (host, port)

            lv_uri  = 'xen+tcp://%s:%d' % libvirt_addr

            mig_uri = 'xenmigr://%s:%d' % hv_addr

        # kvm and others

        else:

            flags = (libvirt.VIR_MIGRATE_LIVE ^

                    libvirt.VIR_MIGRATE_PERSIST_DEST ^

                    libvirt.VIR_MIGRATE_UNDEFINE_SOURCE ^

                    libvirt.VIR_MIGRATE_PEER2PEER ^

                    libvirt.VIR_MIGRATE_TUNNELLED)

            uri = 'qemu+tcp://%s:%d/system' % (host, port)

            lv_uri  = 'qemu+tcp://%s:%d/system' % libvirt_addr

            mig_uri = 'qemu+tcp://%s:%d/system' % hv_addr

        # establish the connection with remote libvirt

        rconn = libvirt.open(lv_uri)

        # migrate !

        try:

            self._domain.migrate(self._hv_handle._lvcon_handle, flags, None, uri, 0)

            self._domain.migrate(rconn, flags, None, mig_uri, 0)

        except libvirt.libvirtError as err:

            # FIXME ignore bogus exception properly

            # maybe no more needed since real remote connection is provided

            if not ('no domain with matching name' in err.message

                    or 'Domain not found' in err.message):

                raise err

        finally:

            # close the libvirt connection

            rconn.close()

    def power_on(self):

        '''