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bh=gpifSbnjYPCdwCNzWIyzHdufTbFFRRTIJ6we5pSJcKY=; b=JdT5dXnJ1a+uV7llNmTxifklaXovoas3UiGx+rXTQnupOoobB6RZH7EbQtHvuPdGwAHh7N Rs+dKxhuOaBE1oi2qBqkizKxpA4XJmislneJnSNHvR7SVoHEtPeKuOYIdP3lrXoKyomrHk imQif8q4DEhmnusLjYvjHbxaxyyaet4= X-MC-Unique: qwUDRcXxPt6kt1KNItsPIw-1 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= To: qemu-devel@nongnu.org Subject: [RFC v2 6/7] vhost: Route guest->host notification through shadow virtqueue Date: Tue, 9 Feb 2021 16:37:56 +0100 Message-Id: <20210209153757.1653598-7-eperezma@redhat.com> In-Reply-To: <20210209153757.1653598-1-eperezma@redhat.com> References: <20210209153757.1653598-1-eperezma@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.57, 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_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: , 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 , Rob Miller , Michael Lilja , Jim Harford , 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. 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 | 97 ++++++++++++++++++- hw/virtio/vhost.c | 148 ++++++++++++++++++++++++++++- 4 files changed, 253 insertions(+), 3 deletions(-) diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-vi= rtqueue.h index 6cc18d6acb..c45035c4b7 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_rcu(struct vhost_dev *dev, + unsigned idx, + VhostShadowVirtqueue *svq); +void vhost_shadow_vq_stop_rcu(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..884818b109 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 sw_lm_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 b5d2645ae0..01f282d434 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 { @@ -18,8 +21,95 @@ typedef struct VhostShadowVirtqueue { EventNotifier kick_notifier; /* Shadow call notifier, sent to vhost */ EventNotifier call_notifier; + + /* Borrowed virtqueue's guest to host notifier. */ + 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 (event_notifier_test_and_clear(n)) { + event_notifier_set(&svq->kick_notifier); + } +} + +/* + * Start shadow virtqueue operation. + * @dev vhost device + * @hidx vhost virtqueue index + * @svq Shadow Virtqueue + * + * Run in RCU context + */ +bool vhost_shadow_vq_start_rcu(struct vhost_dev *dev, + unsigned idx, + VhostShadowVirtqueue *svq) +{ + EventNotifier *vq_host_notifier =3D virtio_queue_get_host_notifier(svq= ->vq); + struct vhost_vring_file kick_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_host_notifier_status(svq->vq)); + + 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, &kick_file); + if (unlikely(r !=3D 0)) { + error_report("Couldn't set kick fd: %s", strerror(errno)); + goto err_set_vring_kick; + } + + /* Check for pending notifications from the guest */ + vhost_handle_guest_kick(&svq->host_notifier); + + 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 + * + * Run in RCU context + */ +void vhost_shadow_vq_stop_rcu(struct vhost_dev *dev, + unsigned idx, + VhostShadowVirtqueue *svq) +{ + EventNotifier *vq_host_notifier =3D virtio_queue_get_host_notifier(svq= ->vq); + struct vhost_vring_file kick_file =3D { + .index =3D idx, + .fd =3D event_notifier_get_fd(vq_host_notifier), + }; + int r; + + /* Restore vhost kick */ + r =3D dev->vhost_ops->vhost_set_vring_kick(dev, &kick_file); + /* Cannot do a lot of things */ + assert(r =3D=3D 0); + + 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. @@ -27,8 +117,11 @@ typedef struct VhostShadowVirtqueue { VhostShadowVirtqueue *vhost_shadow_vq_new(struct vhost_dev *dev, int idx) { g_autofree VhostShadowVirtqueue *svq =3D g_new0(VhostShadowVirtqueue, = 1); + int vq_idx =3D dev->vq_index + idx; int r; =20 + svq->vq =3D virtio_get_queue(dev->vdev, vq_idx); + r =3D event_notifier_init(&svq->kick_notifier, 0); if (r !=3D 0) { error_report("Couldn't create kick event notifier: %s", @@ -43,7 +136,7 @@ VhostShadowVirtqueue *vhost_shadow_vq_new(struct vhost_d= ev *dev, int idx) goto err_init_call_notifier; } =20 - return svq; + return g_steal_pointer(&svq); =20 err_init_call_notifier: event_notifier_cleanup(&svq->kick_notifier); diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index 8fbf14385e..9d4728e545 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" @@ -937,6 +938,84 @@ static void vhost_log_global_stop(MemoryListener *list= ener) } } =20 +static int vhost_sw_live_migration_stop(struct vhost_dev *dev) +{ + int idx; + + WITH_RCU_READ_LOCK_GUARD() { + dev->sw_lm_enabled =3D false; + + for (idx =3D 0; idx < dev->nvqs; ++idx) { + vhost_shadow_vq_stop_rcu(dev, idx, dev->shadow_vqs[idx]); + } + } + + for (idx =3D 0; idx < dev->nvqs; ++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; + + 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; + } + } + + WITH_RCU_READ_LOCK_GUARD() { + for (idx =3D 0; idx < dev->nvqs; ++idx) { + bool ok =3D vhost_shadow_vq_start_rcu(dev, idx, + dev->shadow_vqs[idx]); + + if (!ok) { + int stop_idx =3D idx; + + while (--stop_idx >=3D 0) { + vhost_shadow_vq_stop_rcu(dev, idx, + dev->shadow_vqs[stop_idx]); + } + + goto err; + } + } + } + + dev->sw_lm_enabled =3D true; + return 0; + +err: + for (; idx >=3D 0; --idx) { + vhost_shadow_vq_free(dev->shadow_vqs[idx]); + } + g_free(dev->shadow_vqs[idx]); + + return -1; +} + +static int vhost_sw_live_migration_enable(struct vhost_dev *dev, + bool enable_lm) +{ + int r; + + if (enable_lm =3D=3D dev->sw_lm_enabled) { + return 0; + } + + r =3D enable_lm ? vhost_sw_live_migration_start(dev) + : vhost_sw_live_migration_stop(dev); + + return r; +} + static void vhost_log_start(MemoryListener *listener, MemoryRegionSection *section, int old, int new) @@ -1381,6 +1460,7 @@ 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->sw_lm_enabled =3D false; hdev->started =3D false; memory_listener_register(&hdev->memory_listener, &address_space_memory= ); QLIST_INSERT_HEAD(&vhost_devices, hdev, entry); @@ -1486,6 +1566,10 @@ 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->sw_lm_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); @@ -1808,6 +1892,11 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODe= vice *vdev) hdev->vhost_ops->vhost_dev_start(hdev, false); } for (i =3D 0; i < hdev->nvqs; ++i) { + if (hdev->sw_lm_enabled) { + vhost_shadow_vq_stop_rcu(hdev, i, hdev->shadow_vqs[i]); + vhost_shadow_vq_free(hdev->shadow_vqs[i]); + } + vhost_virtqueue_stop(hdev, vdev, hdev->vqs + i, @@ -1821,6 +1910,8 @@ 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->sw_lm_enabled =3D false; hdev->started =3D false; hdev->vdev =3D NULL; } @@ -1837,5 +1928,60 @@ 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