On Fri, 2012-03-09 at 21:58 +1100, David Gibson wrote: > > What about virtio? > > virtio doesn't use virtualized PCI DMA, it uses direct hypervisor > access to guest memory, by guest physical address. It *shouldn't*, > but it does - that's the way it's specced and that's the way the guest > kernel expects it to be. It could be fixed with a new feature bit, > but that's a project for another day.
More precisely, the patch don't break virtio as virtio just bypasses this all. Also having virtio go through the iommu might not be such a great idea, it should definitely remain optional. The ability of virtio to go straight to guest memory has some significant performance advantages. Cheers, Ben.
