[libvirt-users] How to specify a x509-dir from XML config file?

Hi Everyone, I'd like to ask a question about libvirt xml config. I am using kvm with tls certification. For some reason I need to specify a unique certificate file for every instance, so my kvm command would be like: /usr/libexec/qemu-kvm -spice port=5900,tls-port=5901,addr=0.0.0.0,disable-ticketing,x509-dir=/openstack/etc/pki/libvirt-spice the argument x509-dir=/openstack/etc/pki/libvirt-spice is specified in /etc/libvirt/qemu.conf. It's a global argument. Can I specify it from xml? I searched the xml doc but unable to find useful infomation. BR Don