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bh=/nDkxBDtSYmLMz+5vg4uCbwepfBk8wkLkW97MdIYV4Y=; b=D8L7JTY3ssURct4a8YndakfxlUmax8hGS2t40Qqp97L5jshHVcFZztLeQwaEtixb5I0+9o h698G9sVqsvqu4LeW3rZiL8wHD6WPpWR4V4FXk7w8jhqUndVrTw2zJpO1nexvG5DJMOwEp DQiUeXWcdIQd3MwItyTV2VylYpE0M7E= X-MC-Unique: nflRJF1DNla5xrJ-BBYlxQ-1 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= To: qemu-devel@nongnu.org Subject: [RFC v3 07/29] vhost: Route guest->host notification through shadow virtqueue Date: Wed, 19 May 2021 18:28:41 +0200 Message-Id: <20210519162903.1172366-8-eperezma@redhat.com> In-Reply-To: <20210519162903.1172366-1-eperezma@redhat.com> References: <20210519162903.1172366-1-eperezma@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eperezma@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=216.205.24.124; envelope-from=eperezma@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.39, 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: Parav Pandit , "Michael S. Tsirkin" , Jason Wang , Juan Quintela , Markus Armbruster , virtualization@lists.linux-foundation.org, Harpreet Singh Anand , Xiao W Wang , Stefan Hajnoczi , Eli Cohen , Michael Lilja , Stefano Garzarella Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Shadow virtqueue notifications forwarding is disabled when vhost_dev stops, so code flow follows usual cleanup. Signed-off-by: Eugenio P=C3=A9rez --- hw/virtio/vhost-shadow-virtqueue.h | 7 ++ include/hw/virtio/vhost.h | 4 + hw/virtio/vhost-shadow-virtqueue.c | 113 ++++++++++++++++++++++- hw/virtio/vhost.c | 143 ++++++++++++++++++++++++++++- 4 files changed, 265 insertions(+), 2 deletions(-) diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-vi= rtqueue.h index 6cc18d6acb..c891c6510d 100644 --- a/hw/virtio/vhost-shadow-virtqueue.h +++ b/hw/virtio/vhost-shadow-virtqueue.h @@ -17,6 +17,13 @@ =20 typedef struct VhostShadowVirtqueue VhostShadowVirtqueue; =20 +bool vhost_shadow_vq_start(struct vhost_dev *dev, + unsigned idx, + VhostShadowVirtqueue *svq); +void vhost_shadow_vq_stop(struct vhost_dev *dev, + unsigned idx, + VhostShadowVirtqueue *svq); + VhostShadowVirtqueue *vhost_shadow_vq_new(struct vhost_dev *dev, int idx); =20 void vhost_shadow_vq_free(VhostShadowVirtqueue *vq); diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h index ac963bf23d..7ffdf9aea0 100644 --- a/include/hw/virtio/vhost.h +++ b/include/hw/virtio/vhost.h @@ -55,6 +55,8 @@ struct vhost_iommu { QLIST_ENTRY(vhost_iommu) iommu_next; }; =20 +typedef struct VhostShadowVirtqueue VhostShadowVirtqueue; + typedef struct VhostDevConfigOps { /* Vhost device config space changed callback */ @@ -83,7 +85,9 @@ struct vhost_dev { uint64_t backend_cap; bool started; bool log_enabled; + bool shadow_vqs_enabled; uint64_t log_size; + VhostShadowVirtqueue **shadow_vqs; Error *migration_blocker; const VhostOps *vhost_ops; void *opaque; diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-vi= rtqueue.c index 4512e5b058..3e43399e9c 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -8,9 +8,12 @@ */ =20 #include "hw/virtio/vhost-shadow-virtqueue.h" +#include "hw/virtio/vhost.h" + +#include "standard-headers/linux/vhost_types.h" =20 #include "qemu/error-report.h" -#include "qemu/event_notifier.h" +#include "qemu/main-loop.h" =20 /* Shadow virtqueue to relay notifications */ typedef struct VhostShadowVirtqueue { @@ -18,14 +21,121 @@ typedef struct VhostShadowVirtqueue { EventNotifier kick_notifier; /* Shadow call notifier, sent to vhost */ EventNotifier call_notifier; + + /* + * Borrowed virtqueue's guest to host notifier. + * To borrow it in this event notifier allows to register on the event + * loop and access the associated shadow virtqueue easily. If we use t= he + * VirtQueue, we don't have an easy way to retrieve it. + * + * So shadow virtqueue must not clean it, or we would lose VirtQueue o= ne. + */ + EventNotifier host_notifier; + + /* Virtio queue shadowing */ + VirtQueue *vq; } VhostShadowVirtqueue; =20 +/* Forward guest notifications */ +static void vhost_handle_guest_kick(EventNotifier *n) +{ + VhostShadowVirtqueue *svq =3D container_of(n, VhostShadowVirtqueue, + host_notifier); + + if (unlikely(!event_notifier_test_and_clear(n))) { + return; + } + + event_notifier_set(&svq->kick_notifier); +} + +/* + * Restore the vhost guest to host notifier, i.e., disables svq effect. + */ +static int vhost_shadow_vq_restore_vdev_host_notifier(struct vhost_dev *de= v, + unsigned vhost_index, + VhostShadowVirtqueue = *svq) +{ + EventNotifier *vq_host_notifier =3D virtio_queue_get_host_notifier(svq= ->vq); + struct vhost_vring_file file =3D { + .index =3D vhost_index, + .fd =3D event_notifier_get_fd(vq_host_notifier), + }; + int r; + + /* Restore vhost kick */ + r =3D dev->vhost_ops->vhost_set_vring_kick(dev, &file); + return r ? -errno : 0; +} + +/* + * Start shadow virtqueue operation. + * @dev vhost device + * @hidx vhost virtqueue index + * @svq Shadow Virtqueue + */ +bool vhost_shadow_vq_start(struct vhost_dev *dev, + unsigned idx, + VhostShadowVirtqueue *svq) +{ + EventNotifier *vq_host_notifier =3D virtio_queue_get_host_notifier(svq= ->vq); + struct vhost_vring_file file =3D { + .index =3D idx, + .fd =3D event_notifier_get_fd(&svq->kick_notifier), + }; + int r; + + /* Check that notifications are still going directly to vhost dev */ + assert(virtio_queue_is_host_notifier_enabled(svq->vq)); + + /* + * event_notifier_set_handler already checks for guest's notifications= if + * they arrive in the switch, so there is no need to explicitely check= for + * them. + */ + event_notifier_init_fd(&svq->host_notifier, + event_notifier_get_fd(vq_host_notifier)); + event_notifier_set_handler(&svq->host_notifier, vhost_handle_guest_kic= k); + + r =3D dev->vhost_ops->vhost_set_vring_kick(dev, &file); + if (unlikely(r !=3D 0)) { + error_report("Couldn't set kick fd: %s", strerror(errno)); + goto err_set_vring_kick; + } + + return true; + +err_set_vring_kick: + event_notifier_set_handler(&svq->host_notifier, NULL); + + return false; +} + +/* + * Stop shadow virtqueue operation. + * @dev vhost device + * @idx vhost queue index + * @svq Shadow Virtqueue + */ +void vhost_shadow_vq_stop(struct vhost_dev *dev, + unsigned idx, + VhostShadowVirtqueue *svq) +{ + int r =3D vhost_shadow_vq_restore_vdev_host_notifier(dev, idx, svq); + if (unlikely(r < 0)) { + error_report("Couldn't restore vq kick fd: %s", strerror(-r)); + } + + event_notifier_set_handler(&svq->host_notifier, NULL); +} + /* * Creates vhost shadow virtqueue, and instruct vhost device to use the sh= adow * methods and file descriptors. */ VhostShadowVirtqueue *vhost_shadow_vq_new(struct vhost_dev *dev, int idx) { + int vq_idx =3D dev->vq_index + idx; g_autofree VhostShadowVirtqueue *svq =3D g_new0(VhostShadowVirtqueue, = 1); int r; =20 @@ -43,6 +153,7 @@ VhostShadowVirtqueue *vhost_shadow_vq_new(struct vhost_d= ev *dev, int idx) goto err_init_call_notifier; } =20 + svq->vq =3D virtio_get_queue(dev->vdev, vq_idx); return g_steal_pointer(&svq); =20 err_init_call_notifier: diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index c4c1f80661..84091b5251 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -25,6 +25,7 @@ #include "exec/address-spaces.h" #include "hw/virtio/virtio-bus.h" #include "hw/virtio/virtio-access.h" +#include "hw/virtio/vhost-shadow-virtqueue.h" #include "migration/blocker.h" #include "migration/qemu-file-types.h" #include "sysemu/dma.h" @@ -1219,6 +1220,74 @@ static void vhost_virtqueue_stop(struct vhost_dev *d= ev, 0, virtio_queue_get_desc_size(vdev, idx)); } =20 +static int vhost_sw_live_migration_stop(struct vhost_dev *dev) +{ + int idx; + + dev->shadow_vqs_enabled =3D false; + + for (idx =3D 0; idx < dev->nvqs; ++idx) { + vhost_shadow_vq_stop(dev, idx, dev->shadow_vqs[idx]); + vhost_shadow_vq_free(dev->shadow_vqs[idx]); + } + + g_free(dev->shadow_vqs); + dev->shadow_vqs =3D NULL; + return 0; +} + +static int vhost_sw_live_migration_start(struct vhost_dev *dev) +{ + int idx, stop_idx; + + dev->shadow_vqs =3D g_new0(VhostShadowVirtqueue *, dev->nvqs); + for (idx =3D 0; idx < dev->nvqs; ++idx) { + dev->shadow_vqs[idx] =3D vhost_shadow_vq_new(dev, idx); + if (unlikely(dev->shadow_vqs[idx] =3D=3D NULL)) { + goto err_new; + } + } + + dev->shadow_vqs_enabled =3D true; + for (idx =3D 0; idx < dev->nvqs; ++idx) { + bool ok =3D vhost_shadow_vq_start(dev, idx, dev->shadow_vqs[idx]); + if (unlikely(!ok)) { + goto err_start; + } + } + + return 0; + +err_start: + dev->shadow_vqs_enabled =3D false; + for (stop_idx =3D 0; stop_idx < idx; stop_idx++) { + vhost_shadow_vq_stop(dev, idx, dev->shadow_vqs[stop_idx]); + } + +err_new: + for (idx =3D 0; idx < dev->nvqs; ++idx) { + vhost_shadow_vq_free(dev->shadow_vqs[idx]); + } + g_free(dev->shadow_vqs); + + return -1; +} + +static int vhost_sw_live_migration_enable(struct vhost_dev *dev, + bool enable_lm) +{ + int r; + + if (enable_lm =3D=3D dev->shadow_vqs_enabled) { + return 0; + } + + r =3D enable_lm ? vhost_sw_live_migration_start(dev) + : vhost_sw_live_migration_stop(dev); + + return r; +} + static void vhost_eventfd_add(MemoryListener *listener, MemoryRegionSection *section, bool match_data, uint64_t data, EventNotifie= r *e) @@ -1381,6 +1450,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaq= ue, hdev->log =3D NULL; hdev->log_size =3D 0; hdev->log_enabled =3D false; + hdev->shadow_vqs_enabled =3D false; hdev->started =3D false; memory_listener_register(&hdev->memory_listener, &address_space_memory= ); QLIST_INSERT_HEAD(&vhost_devices, hdev, entry); @@ -1484,6 +1554,10 @@ void vhost_dev_disable_notifiers(struct vhost_dev *h= dev, VirtIODevice *vdev) BusState *qbus =3D BUS(qdev_get_parent_bus(DEVICE(vdev))); int i, r; =20 + if (hdev->shadow_vqs_enabled) { + vhost_sw_live_migration_enable(hdev, false); + } + for (i =3D 0; i < hdev->nvqs; ++i) { r =3D virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_inde= x + i, false); @@ -1798,6 +1872,7 @@ fail_features: void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev) { int i; + bool is_shadow_vqs_enabled =3D hdev->shadow_vqs_enabled; =20 /* should only be called after backend is connected */ assert(hdev->vhost_ops); @@ -1805,7 +1880,16 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODe= vice *vdev) if (hdev->vhost_ops->vhost_dev_start) { hdev->vhost_ops->vhost_dev_start(hdev, false); } + if (is_shadow_vqs_enabled) { + /* Shadow virtqueue will be stopped */ + hdev->shadow_vqs_enabled =3D false; + } for (i =3D 0; i < hdev->nvqs; ++i) { + if (is_shadow_vqs_enabled) { + vhost_shadow_vq_stop(hdev, i, hdev->shadow_vqs[i]); + vhost_shadow_vq_free(hdev->shadow_vqs[i]); + } + vhost_virtqueue_stop(hdev, vdev, hdev->vqs + i, @@ -1819,6 +1903,8 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODev= ice *vdev) memory_listener_unregister(&hdev->iommu_listener); } vhost_log_put(hdev, true); + g_free(hdev->shadow_vqs); + hdev->shadow_vqs_enabled =3D false; hdev->started =3D false; hdev->vdev =3D NULL; } @@ -1835,5 +1921,60 @@ int vhost_net_set_backend(struct vhost_dev *hdev, =20 void qmp_x_vhost_enable_shadow_vq(const char *name, bool enable, Error **e= rrp) { - error_setg(errp, "Shadow virtqueue still not implemented"); + struct vhost_dev *hdev, *hdev_err; + VirtIODevice *vdev; + const char *err_cause =3D NULL; + int r; + ErrorClass err_class =3D ERROR_CLASS_GENERIC_ERROR; + + QLIST_FOREACH(hdev, &vhost_devices, entry) { + if (hdev->vdev && 0 =3D=3D strcmp(hdev->vdev->name, name)) { + vdev =3D hdev->vdev; + break; + } + } + + if (!hdev) { + err_class =3D ERROR_CLASS_DEVICE_NOT_FOUND; + err_cause =3D "Device not found"; + goto not_found_err; + } + + for ( ; hdev; hdev =3D QLIST_NEXT(hdev, entry)) { + if (vdev !=3D hdev->vdev) { + continue; + } + + if (!hdev->started) { + err_cause =3D "Device is not started"; + goto err; + } + + r =3D vhost_sw_live_migration_enable(hdev, enable); + if (unlikely(r)) { + err_cause =3D "Error enabling (see monitor)"; + goto err; + } + } + + return; + +err: + QLIST_FOREACH(hdev_err, &vhost_devices, entry) { + if (hdev_err =3D=3D hdev) { + break; + } + + if (vdev !=3D hdev->vdev) { + continue; + } + + vhost_sw_live_migration_enable(hdev, !enable); + } + +not_found_err: + if (err_cause) { + error_set(errp, err_class, + "Can't enable shadow vq on %s: %s", name, err_cause); + } } --=20 2.27.0