You can clone with
Kyle Fransham suggested enabling virtio for KVM instances in this workspace-user post: http://lists.globus.org/pipermail/workspace-user/2011-March/001630.html
This should be integrated. And more generally, can we make libvirt XML more of a template that can be edited by admins to suit their needs?
Note that virtio requires specific guest drivers. We can't enable it by default without breaking support for many systems (old Linux distributions, Windows without the virtio drivers installed, other OSes...).
A middle ground would be to switch to e1000 instead of the default rtl8139.
e1000 has better performance than the default NIC, while having better support from the various OSes out there.
I made it so that the xml handed to libvirt is generated from a template. This would allow a site admin to modify the template with virtio if their system could handle it. This puts the configuration in the hands of the site admin but it makes it global for all users. Is that a reasonable solution to this?
Sounds good to me. I expect virtio is a common need, so we should probably have a section in the admin reference guide explaining how to set that up specifically.
I added documentation to the admin/reference.html page.