Si-Wei Liu
2023-Feb-13 06:50 UTC
[PATCH v2 07/13] vdpa: add vdpa net migration state notifier
On 2/8/2023 1:42 AM, Eugenio P?rez 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 P?rez <eperezma at redhat.com> > --- > v3: > * Add TODO to use the resume operation in the future. > * Use migration_in_setup and migration_has_failed instead of a > complicated switch case. > --- > net/vhost-vdpa.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 76 insertions(+) > > diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c > index dd686b4514..bca13f97fd 100644 > --- a/net/vhost-vdpa.c > +++ b/net/vhost-vdpa.c > @@ -26,12 +26,14 @@ > #include <err.h> > #include "standard-headers/linux/virtio_net.h" > #include "monitor/monitor.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 */ > @@ -241,10 +243,79 @@ 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;What if vhost gets started after migration is started, will svq still be (dynamically) enabled during vhost_dev_start()? I don't see relevant code to deal with it?> + } > + > + 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); > + > + 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;Don't get why shadow_data is set on cvq's vhost_vdpa? This may result in address space collision: data vq's iova getting improperly allocated on cvq's address space in vhost_vdpa_listener_region_{add,del}(). Noted currently there's an issue where guest VM's memory listener registration is always hooked to the last vq, which could be on the cvq in a different iova address space VHOST_VDPA_NET_CVQ_ASID. Thanks, -Siwei> + > + 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); > + > + 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); > @@ -278,6 +349,10 @@ 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); > @@ -741,6 +816,7 @@ 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;