[libvirt-users] ballooning option xml

Hi everybody, I need the ballooning option with kvm using libvirt xml file and virsh (virsh create domain.xml) kvm line must be appended with the -balloon virtio switch to enable ballooning. (can be disabled if there no option or with -balloon none ) I currently using Ubuntu Lucid How can I define this in the domain xml file, or what need I to do to get this option? is there any option like enabling with <balloon>virtio</balloon> or disabling with <balloon>none</balloon> Thanks in Advance Udo Attila Fischer