[libvirt-users] virtio and encryption

Greetings, I am trying to use virtio and encryption. My setup is: host and guest: ubuntu 10.04 server (libvirt 0.7.5-5ubuntu27, qemu-kvm 0.12.3+noroms-0ubuntu9.2) I have secret defined and disk in domain xml referencing that secret. When I start using "<target dev='hda' bus='ide'/>" in HDD config, it works. When I start using "<target dev='vda' bus='virtio'/>" I get following in syslog: qemuMonitorCommandWithHandler:240 : cannot send monitor command 'cont': Unknown error 8446744073709551594 running with "<target dev='vda' bus='virtio'/>" works fine if format is raw and there is no encryption. Is storing raw images on encrypted loop device the only way to have both virtio and ecryption?