On Wed, Dec 12, 2018 at 11:35:45AM +0100, Joerg Roedel wrote: > Hi, > > to make progress on this, we should first agree on the protocol used > between guest and host. I have a few points to discuss on the protocol > first. > > On Tue, Dec 11, 2018 at 06:20:57PM +0000, Jean-Philippe Brucker wrote: > > [1] Virtio-iommu specification v0.9, sources and pdf > > git://linux-arm.org/virtio-iommu.git virtio-iommu/v0.9 > > http://jpbrucker.net/virtio-iommu/spec/v0.9/virtio-iommu-v0.9.pdf > > Looking at this I wonder why it doesn't make the IOTLB visible to the > guest. the UNMAP requests seem to require that the TLB is already > flushed to make the unmap visible. > > I think that will cost significant performance for both, vfio and > dma-iommu use-cases which both do (vfio at least to some degree), > deferred flushing. > > I also wonder whether the protocol should implement a > protocol version handshake virtio has a builtin version handshake so devices don't need to. > and iommu-feature set queries. > > > [3] git://linux-arm.org/linux-jpb.git virtio-iommu/v0.9.1 > > git://linux-arm.org/kvmtool-jpb.git virtio-iommu/v0.9 > > Unfortunatly gitweb seems to be broken on linux-arm.org. What is missing > in this patch-set to make this work on x86? And I wonder about pcc too. > Regards, > > Joerg
