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Tsirkin" , Stefan Hajnoczi , Parav Pandit , Juan Quintela , David Gilbert , Maxime Coquelin References: <20230112172434.760850-1-eperezma@redhat.com> <20230112172434.760850-12-eperezma@redhat.com> From: Jason Wang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org 在 2023/1/13 17:00, Eugenio Perez Martin 写道: > On Fri, Jan 13, 2023 at 5:55 AM Jason Wang wrote: >> On Fri, Jan 13, 2023 at 1:25 AM Eugenio Pérez wrote: >>> This allows net to restart the device backend to configure SVQ on it. >>> >>> Ideally, these changes should not be net specific. However, the vdpa net >>> backend is the one with enough knowledge to configure everything because >>> of some reasons: >>> * Queues might need to be shadowed or not depending on its kind (control >>> vs data). >>> * Queues need to share the same map translations (iova tree). >>> >>> Because of that it is cleaner to restart the whole net backend and >>> configure again as expected, similar to how vhost-kernel moves between >>> userspace and passthrough. >>> >>> If more kinds of devices need dynamic switching to SVQ we can create a >>> callback struct like VhostOps and move most of the code there. >>> VhostOps cannot be reused since all vdpa backend share them, and to >>> personalize just for networking would be too heavy. >>> >>> Signed-off-by: Eugenio Pérez >>> --- >>> net/vhost-vdpa.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 84 insertions(+) >>> >>> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c >>> index 5d7ad6e4d7..f38532b1df 100644 >>> --- a/net/vhost-vdpa.c >>> +++ b/net/vhost-vdpa.c >>> @@ -26,6 +26,8 @@ >>> #include >>> #include "standard-headers/linux/virtio_net.h" >>> #include "monitor/monitor.h" >>> +#include "migration/migration.h" >>> +#include "migration/misc.h" >>> #include "migration/blocker.h" >>> #include "hw/virtio/vhost.h" >>> >>> @@ -33,6 +35,7 @@ >>> typedef struct VhostVDPAState { >>> NetClientState nc; >>> struct vhost_vdpa vhost_vdpa; >>> + Notifier migration_state; >>> Error *migration_blocker; >>> VHostNetState *vhost_net; >>> >>> @@ -243,10 +246,86 @@ static VhostVDPAState *vhost_vdpa_net_first_nc_vdpa(VhostVDPAState *s) >>> return DO_UPCAST(VhostVDPAState, nc, nc0); >>> } >>> >>> +static void vhost_vdpa_net_log_global_enable(VhostVDPAState *s, bool enable) >>> +{ >>> + struct vhost_vdpa *v = &s->vhost_vdpa; >>> + VirtIONet *n; >>> + VirtIODevice *vdev; >>> + int data_queue_pairs, cvq, r; >>> + NetClientState *peer; >>> + >>> + /* We are only called on the first data vqs and only if x-svq is not set */ >>> + if (s->vhost_vdpa.shadow_vqs_enabled == enable) { >>> + return; >>> + } >>> + >>> + vdev = v->dev->vdev; >>> + n = VIRTIO_NET(vdev); >>> + if (!n->vhost_started) { >>> + return; >>> + } >>> + >>> + if (enable) { >>> + ioctl(v->device_fd, VHOST_VDPA_SUSPEND); >> Do we need to check if the device is started or not here? >> > v->vhost_started is checked right above, right? Right, I miss that. > >>> + } >> I'm not sure I understand the reason for vhost_net_stop() after a >> VHOST_VDPA_SUSPEND. It looks to me those functions are duplicated. >> > I think this is really worth exploring, and it would have been clearer > if I didn't squash the vhost_reset_status commit by mistake :). > > Looking at qemu master vhost.c:vhost_dev_stop: > if (hdev->vhost_ops->vhost_dev_start) { > hdev->vhost_ops->vhost_dev_start(hdev, false); > } > if (vrings) { > vhost_dev_set_vring_enable(hdev, false); > } > for (i = 0; i < hdev->nvqs; ++i) { > vhost_virtqueue_stop(hdev, > vdev, > hdev->vqs + i, > hdev->vq_index + i); > } > > Both vhost-used and vhost-vdpa set_status(0) at > ->vhost_dev_start(hdev, false). It cleans virtqueue state in vdpa so > they are not recoverable at vhost_virtqueue_stop->get_vring_base, and > I think it is too late for vdpa devices to change it. I guess > vhost-user devices do not lose the state there, but I did not test. > > I call VHOST_VDPA_SUSPEND here so vhost_vdpa_dev_start looks more > similar to vhost_user_dev_start. We can make > vhost_vdpa_dev_start(false) to suspend the device instead. But then we > need to reset it after getting the indexes. That's why I added > vhost_vdpa_reset_status, but I admit it is neither the cleanest > approach nor the best name to it. I wonder if we can simply suspend in vhost_net_stop() if we know the parent can stop? Thanks > > Adding Maxime, RFC here so we can make -vdpa and -user not to divert too much. > >>> + data_queue_pairs = n->multiqueue ? n->max_queue_pairs : 1; >>> + cvq = virtio_vdev_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) ? >>> + n->max_ncs - n->max_queue_pairs : 0; >>> + vhost_net_stop(vdev, n->nic->ncs, data_queue_pairs, cvq); >>> + >>> + peer = s->nc.peer; >>> + for (int i = 0; i < data_queue_pairs + cvq; i++) { >>> + VhostVDPAState *vdpa_state; >>> + NetClientState *nc; >>> + >>> + if (i < data_queue_pairs) { >>> + nc = qemu_get_peer(peer, i); >>> + } else { >>> + nc = qemu_get_peer(peer, n->max_queue_pairs); >>> + } >>> + >>> + vdpa_state = DO_UPCAST(VhostVDPAState, nc, nc); >>> + vdpa_state->vhost_vdpa.shadow_data = enable; >>> + >>> + if (i < data_queue_pairs) { >>> + /* Do not override CVQ shadow_vqs_enabled */ >>> + vdpa_state->vhost_vdpa.shadow_vqs_enabled = enable; >>> + } >>> + } >>> + >>> + r = vhost_net_start(vdev, n->nic->ncs, data_queue_pairs, cvq); >>> + if (unlikely(r < 0)) { >>> + error_report("unable to start vhost net: %s(%d)", g_strerror(-r), -r); >>> + } >>> +} >>> + >>> +static void vdpa_net_migration_state_notifier(Notifier *notifier, void *data) >>> +{ >>> + MigrationState *migration = data; >>> + VhostVDPAState *s = container_of(notifier, VhostVDPAState, >>> + migration_state); >>> + >>> + switch (migration->state) { >>> + case MIGRATION_STATUS_SETUP: >>> + vhost_vdpa_net_log_global_enable(s, true); >>> + return; >>> + >>> + case MIGRATION_STATUS_CANCELLING: >>> + case MIGRATION_STATUS_CANCELLED: >>> + case MIGRATION_STATUS_FAILED: >>> + vhost_vdpa_net_log_global_enable(s, false); >> Do we need to recover here? >> > I may be missing something, but the device is fully reset and restored > in these cases. > > CCing Juan and D. Gilbert, a review would be appreciated to check if > this covers all the cases. > > Thanks! > > >> Thanks >> >>> + return; >>> + }; >>> +} >>> + >>> static void vhost_vdpa_net_data_start_first(VhostVDPAState *s) >>> { >>> struct vhost_vdpa *v = &s->vhost_vdpa; >>> >>> + if (v->feature_log) { >>> + add_migration_state_change_notifier(&s->migration_state); >>> + } >>> + >>> if (v->shadow_vqs_enabled) { >>> v->iova_tree = vhost_iova_tree_new(v->iova_range.first, >>> v->iova_range.last); >>> @@ -280,6 +359,10 @@ static void vhost_vdpa_net_client_stop(NetClientState *nc) >>> >>> assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA); >>> >>> + if (s->vhost_vdpa.index == 0 && s->vhost_vdpa.feature_log) { >>> + remove_migration_state_change_notifier(&s->migration_state); >>> + } >>> + >>> dev = s->vhost_vdpa.dev; >>> if (dev->vq_index + dev->nvqs == dev->vq_index_end) { >>> g_clear_pointer(&s->vhost_vdpa.iova_tree, vhost_iova_tree_delete); >>> @@ -767,6 +850,7 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer, >>> s->vhost_vdpa.device_fd = vdpa_device_fd; >>> s->vhost_vdpa.index = queue_pair_index; >>> s->always_svq = svq; >>> + s->migration_state.notify = vdpa_net_migration_state_notifier; >>> s->vhost_vdpa.shadow_vqs_enabled = svq; >>> s->vhost_vdpa.iova_range = iova_range; >>> s->vhost_vdpa.shadow_data = svq; >>> -- >>> 2.31.1 >>> >>