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To: Stefan Hajnoczi References: <20210127111938.GH299797@stefanha-x1.localdomain> From: =?UTF-8?Q?Leonardo_Augusto_Guimar=c3=a3es_Garcia?= Organization: IBM Message-ID: Date: Wed, 27 Jan 2021 09:30:35 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20210127111938.GH299797@stefanha-x1.localdomain> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.343, 18.0.737 definitions=2021-01-27_05:2021-01-27, 2021-01-27 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 impostorscore=0 adultscore=0 mlxlogscore=999 suspectscore=0 priorityscore=1501 mlxscore=0 phishscore=0 lowpriorityscore=0 bulkscore=0 clxscore=1015 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101270063 Received-SPF: pass client-ip=148.163.158.5; envelope-from=lagarcia@linux.ibm.com; helo=mx0a-001b2d01.pphosted.com X-Spam_score_int: -26 X-Spam_score: -2.7 X-Spam_bar: -- X-Spam_report: (-2.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=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: , Reply-To: lagarcia@br.ibm.com Cc: qemu-devel@nongnu.org, dgilbert@redhat.com, "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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? I don't know if VIRTIO_PCI_FLAG_ATS should depend on VIRTIO_F_IOMMU_PLATFORM. At least from a code perspective today, they are completely independent. A user can specify one or the other or both. And if a user specifies VIRTIO_PCI_FLAG_ATS without specifying VIRTIO_F_IOMMU_PLATFORM, the same issue described in the original message will happen inside the guest. > > What needs to be added to support ATS? Unfortunately I don't know the answer for this question. Hopefully someone else can help with this one. > >> + >> 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. Sure, I can do that. I wasn't sure whether this restriction was only for vhost-user-fs or whether it was generic for all vhost-user devices. I will include this in a next version of the patch. Cheers, Leo > > Stefan