From 6949843046b6f9c4c6cd28922d5427a17414dfc9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= Date: Fri, 3 Mar 2023 18:24:39 +0100 Subject: [PATCH] vdpa: add vdpa net migration state notifier MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This allows net to restart the device backend to configure SVQ on it. Ideally, these changes should not be net specific and they could be done in: * vhost_vdpa_set_features (with VHOST_F_LOG_ALL) * vhost_vdpa_set_vring_addr (with .enable_log) * vhost_vdpa_set_log_base. 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). Also, there are other problems that may have solutions but complicates the implementation at this stage: * We're basically duplicating vhost_dev_start and vhost_dev_stop, and they could go out of sync. If we want to reuse them, we need a way to skip some function calls to avoid recursiveness (either vhost_ops -> vhost_set_features, vhost_set_vring_addr, ...). * We need to traverse all vhost_dev of a given net device twice: one to stop and get the vq state and another one after the reset to configure properties like address, fd, etc. 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. * Add a parent struct or link all the vhost_vdpa or vhost_dev structs so we can traverse them. Signed-off-by: Eugenio Pérez Message-Id: <20230303172445.1089785-9-eperezma@redhat.com> Tested-by: Lei Yang Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- net/vhost-vdpa.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 69 insertions(+), 3 deletions(-) diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c index d195f48776fe..167b43679d9f 100644 --- a/net/vhost-vdpa.c +++ b/net/vhost-vdpa.c @@ -26,12 +26,15 @@ #include #include "standard-headers/linux/virtio_net.h" #include "monitor/monitor.h" +#include "migration/migration.h" +#include "migration/misc.h" #include "hw/virtio/vhost.h" /* Todo:need to add the multiqueue support here */ typedef struct VhostVDPAState { NetClientState nc; struct vhost_vdpa vhost_vdpa; + Notifier migration_state; VHostNetState *vhost_net; /* Control commands shadow buffers */ @@ -239,10 +242,59 @@ 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; + + /* 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; + } + + 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; + /* + * TODO: vhost_net_stop does suspend, get_base and reset. We can be smarter + * in the future and resume the device if read-only operations between + * suspend and reset goes wrong. + */ + vhost_net_stop(vdev, n->nic->ncs, data_queue_pairs, cvq); + + /* Start will check migration setup_or_active to configure or not SVQ */ + 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); + + if (migration_in_setup(migration)) { + vhost_vdpa_net_log_global_enable(s, true); + } else if (migration_has_failed(migration)) { + vhost_vdpa_net_log_global_enable(s, false); + } +} + static void vhost_vdpa_net_data_start_first(VhostVDPAState *s) { struct vhost_vdpa *v = &s->vhost_vdpa; + 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); @@ -256,6 +308,15 @@ static int vhost_vdpa_net_data_start(NetClientState *nc) assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA); + if (s->always_svq || + migration_is_setup_or_active(migrate_get_current()->state)) { + v->shadow_vqs_enabled = true; + v->shadow_data = true; + } else { + v->shadow_vqs_enabled = false; + v->shadow_data = false; + } + if (v->index == 0) { vhost_vdpa_net_data_start_first(s); return 0; @@ -276,6 +337,10 @@ static void vhost_vdpa_net_client_stop(NetClientState *nc) assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA); + if (s->vhost_vdpa.index == 0) { + 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); @@ -412,11 +477,12 @@ static int vhost_vdpa_net_cvq_start(NetClientState *nc) s = DO_UPCAST(VhostVDPAState, nc, nc); v = &s->vhost_vdpa; - v->shadow_data = s->always_svq; + s0 = vhost_vdpa_net_first_nc_vdpa(s); + v->shadow_data = s0->vhost_vdpa.shadow_vqs_enabled; v->shadow_vqs_enabled = s->always_svq; s->vhost_vdpa.address_space_id = VHOST_VDPA_GUEST_PA_ASID; - if (s->always_svq) { + if (s->vhost_vdpa.shadow_data) { /* SVQ is already configured for all virtqueues */ goto out; } @@ -473,7 +539,6 @@ static int vhost_vdpa_net_cvq_start(NetClientState *nc) return 0; } - s0 = vhost_vdpa_net_first_nc_vdpa(s); if (s0->vhost_vdpa.iova_tree) { /* * SVQ is already configured for all virtqueues. Reuse IOVA tree for @@ -749,6 +814,7 @@ 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;