For those of you who haven't seen it yet, there was a nice paper presented at USENIX on Wednesday on IOMMU protection strategies: "Protection Strategies for Direct Access to Virtualized I/O Devices", by Paul Willmann, Scott Rixner, and Alan L. Cox, Rice University. http://www.usenix.org/events/usenix08/tech/willmann.html Cheers, Muli