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Message-ID: <20210127163423.GI3052@work-vm> References: <20210127111938.GH299797@stefanha-x1.localdomain> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.308, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: maxime.coquelin@redhat.com, qemu-devel@nongnu.org, Stefan Hajnoczi , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Leonardo Augusto Guimarães Garcia (lagarcia@linux.ibm.com) wrote: > On 1/27/21 8:19 AM, Stefan Hajnoczi wrote: > > On Tue, Jan 26, 2021 at 03:23:38PM -0300, lagarcia@linux.ibm.com wrote: > > > From: Leonardo Garcia > > > > > > Currently, as IOMMU and ATS are not supported, if a user mistakenly set > > > any of them and tries to mount the vhost-user filesystem inside the > > > guest, whenever the user tries to access the mount point, the system > > > will hang forever. > > > > > > Signed-off-by: Leonardo Garcia > > > --- > > > hw/virtio/vhost-user-fs-pci.c | 7 +++++++ > > > hw/virtio/vhost-user-fs.c | 5 +++++ > > > 2 files changed, 12 insertions(+) > > > > > > diff --git a/hw/virtio/vhost-user-fs-pci.c b/hw/virtio/vhost-user-fs-pci.c > > > index 2ed8492b3f..564d1fd108 100644 > > > --- a/hw/virtio/vhost-user-fs-pci.c > > > +++ b/hw/virtio/vhost-user-fs-pci.c > > > @@ -11,6 +11,8 @@ > > > * top-level directory. > > > */ > > > +#include "qemu/osdep.h" > > > +#include "qapi/error.h" > > > #include "qemu/osdep.h" > > > #include "hw/qdev-properties.h" > > > #include "hw/virtio/vhost-user-fs.h" > > > @@ -45,6 +47,11 @@ static void vhost_user_fs_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp) > > > vpci_dev->nvectors = dev->vdev.conf.num_request_queues + 2; > > > } > > > + if (vpci_dev->flags & VIRTIO_PCI_FLAG_ATS) { > > > + error_setg(errp, "ATS is currently not supported with vhost-user-fs-pci"); > > > + return; > > > + } > > Why is this check needed in addition to VIRTIO_F_IOMMU_PLATFORM? > > > > What needs to be added to support ATS? > > > > > + > > > qdev_realize(vdev, BUS(&vpci_dev->bus), errp); > > > } > > > diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c > > > index ac4fc34b36..914d68b3ee 100644 > > > --- a/hw/virtio/vhost-user-fs.c > > > +++ b/hw/virtio/vhost-user-fs.c > > > @@ -203,6 +203,11 @@ static void vuf_device_realize(DeviceState *dev, Error **errp) > > > return; > > > } > > > + if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) { > > > + error_setg(errp, "IOMMU is currently not supported with vhost-user-fs"); > > > + return; > > > + } > > > + > > > if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) { > > I thought IOMMU support depends on the vhost-user device backend (e.g. > > virtiofsd), so the vhost-user backend should participate in advertising > > this feature. > > > > Perhaps the check should be: > > > > ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user, > > VHOST_BACKEND_TYPE_USER, 0); > > if (ret < 0) { > > error_setg_errno(errp, -ret, "vhost_dev_init failed"); > > goto err_virtio; > > } > > + > > + if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM) && > > + !(fs->vhost_dev.hdev_features & (1ull << VIRTIO_F_IOMMU_PLATFORM))) { > > + error_setg(errp, "IOMMU is not supported by the vhost-user device backend"); > > + goto err_iommu_needed; > > + } > > > > Also, can this logic be made generic for all vhost-user devices? It's > > not really specific to vhost-user-fs. > > Further analyzing this, on vhost-user.c, I see: > >         if (virtio_has_feature(features, VIRTIO_F_IOMMU_PLATFORM) && >                 !(virtio_has_feature(dev->protocol_features, >                     VHOST_USER_PROTOCOL_F_SLAVE_REQ) && >                  virtio_has_feature(dev->protocol_features, >                     VHOST_USER_PROTOCOL_F_REPLY_ACK))) { >             error_report("IOMMU support requires reply-ack and " >                          "slave-req protocol features."); >             return -1; >         } > > This code was included by commit 6dcdd06. It included support for > VIRTIO_F_IOMMU_PLATFORM with vhost_net devices. So, the restriction is not > generic for all vhost-user devices. That test is a slightly different test; that's checking that the vhost-user device has two underlying features that are needed to make iommu work; it's not a full test though; it doesn't actually check the vhost-user device also wants to do iommu. Dave > Cheers, > > Leo > > > > > Stefan > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK