[libvirt] How do I modify an existing network filter?

Hi All, We have a requirement to allow more than one IP connect to external network through one mac address. We suppose we need to modify the network filter but we can't find the python API or anything else to change the existing network filter. Does anyone know what I should do? We tried another way to add a parameter to 'filterref' in the instance xml file like below blue part and it worked. But we have to restart the instance to make this configufation effective. Can I make the xml change effective without restart the instance? Any help will be appreciated. <interface type='bridge'> <mac address='fa:16:3e:2f:00:09'/> <source bridge='br_vm'/> <model type='virtio'/> <filterref filter='nova-instance-instance-00000018-fa163e2f0009'> <parameter name='DHCPSERVER' value='50.1.1.1'/> <parameter name='IP' value='50.1.1.223'/> <parameter name='IP' value='50.1.1.222'/> </filterref> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> duyahong(a)kingsoft.com