On Wed, Dec 23, 2020 at 03:36:38PM +0100, Stefano Garzarella wrote: > This patch enables the IOTLB API support for vhost-vsock devices, > allowing the userspace to emulate an IOMMU for the guest. > > These changes were made following vhost-net, in details this patch: > - exposes VIRTIO_F_ACCESS_PLATFORM feature and inits the iotlb > device if the feature is acked > - implements VHOST_GET_BACKEND_FEATURES and > VHOST_SET_BACKEND_FEATURES ioctls > - calls vq_meta_prefetch() before vq processing to prefetch vq > metadata address in IOTLB > - provides .read_iter, .write_iter, and .poll callbacks for the > chardev; they are used by the userspace to exchange IOTLB messages > > This patch was tested specifying "intel_iommu=strict" in the guest > kernel command line. I used QEMU with a patch applied [1] to fix a > simple issue (that patch was merged in QEMU v5.2.0): > $ qemu -M q35,accel=kvm,kernel-irqchip=split \ > -drive file=fedora.qcow2,format=qcow2,if=virtio \ > -device intel-iommu,intremap=on,device-iotlb=on \ > -device vhost-vsock-pci,guest-cid=3,iommu_platform=on,ats=on > > [1] https://lists.gnu.org/archive/html/qemu-devel/2020-10/msg09077.html > > Reviewed-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx> > Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> > --- > > The patch is the same of v1, but I re-tested it with: > - QEMU v5.2.0-551-ga05f8ecd88 > - Linux 5.9.15 (host) > - Linux 5.9.15 and 5.10.0 (guest) > Now, enabling 'ats' it works well, there are just a few simple changes. > > v1: https://www.spinics.net/lists/kernel/msg3716022.html > v2: > - updated commit message about QEMU version and string used to test > - rebased on mst/vhost branch > > Thanks, > Stefano > --- > drivers/vhost/vsock.c | 68 +++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 65 insertions(+), 3 deletions(-) Acked-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
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