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Date:   Fri, 30 Oct 2020 09:10:57 +0000
From:   Stefan Hajnoczi <stefanha@redhat.com>
To:     Stefano Garzarella <sgarzare@redhat.com>
Cc:     mst@redhat.com, netdev@vger.kernel.org, kvm@vger.kernel.org,
        Jason Wang <jasowang@redhat.com>,
        virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] vhost/vsock: add IOTLB API support
Message-ID: <20201030091057.GB307361@stefanha-x1.localdomain>
References: <20201029174351.134173-1-sgarzare@redhat.com>
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On Thu, Oct 29, 2020 at 06:43:51PM +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.
>=20
> 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
>=20
> This patch was tested with QEMU and a patch applied [1] to fix a
> simple issue:
>     $ qemu -M q35,accel=3Dkvm,kernel-irqchip=3Dsplit \
>            -drive file=3Dfedora.qcow2,format=3Dqcow2,if=3Dvirtio \
>            -device intel-iommu,intremap=3Don \
>            -device vhost-vsock-pci,guest-cid=3D3,iommu_platform=3Don
>=20
> [1] https://lists.gnu.org/archive/html/qemu-devel/2020-10/msg09077.html
>=20
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>  drivers/vhost/vsock.c | 68 +++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 65 insertions(+), 3 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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