There is a new xen kernel (2.6.32.23-170.1.xendom0.fc12) available to download at http://koji.fedoraproject.org/koji/taskinfo?taskID=2547470 and at the repository http://repos.fedorapeople.org/repos/myoung/dom0-kernel/ It contains some patches added added to xen/stable-2.6.32.x since the last build, including an event channels fix. Michael Young