Jason Wang
2023-Mar-03 03:34 UTC
[PATCH v4 09/15] vdpa: add vdpa net migration state notifier
? 2023/3/2 03:26, Eugenio Perez Martin ??:> On Mon, Feb 27, 2023 at 9:08 AM Jason Wang <jasowang at redhat.com> wrote: >> >> ? 2023/2/24 23:54, Eugenio P?rez ??: >>> 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> >>> --- >>> v4: >>> * Delete duplication of set shadow_data and shadow_vqs_enabled moving it >>> to data / cvq net start functions. >>> >>> v3: >>> * Check for migration state at vdpa device start to enable SVQ in data >>> vqs. >>> >>> v1 from RFC: >>> * 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 | 72 ++++++++++++++++++++++++++++++++++++++++++++++-- >>> 1 file changed, 69 insertions(+), 3 deletions(-) >>> >>> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c >>> index b89c99066a..c5512ddf10 100644 >>> --- a/net/vhost-vdpa.c >>> +++ b/net/vhost-vdpa.c >>> @@ -26,12 +26,15 @@ >>> #include <err.h> >>> #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); >>> + } >> >> This should work but I just realize that vhost support >> vhost_dev_set_log(), I wonder if it would be simpler to go with that way. >> >> Using vhost_virtqueue_set_addr(, enable_log = true)? >> > We can do that but it has the same problem as with checking _F_LOG_ALL > in set_features: > > 1. We're tearing down a vhost device using a listener registered > against that device, at start / stop. > 2. We need to traverse all the devices many times to first get all the > vqs state and then transverse them again to set them up properly. > > My two ideas to solve the recursiveness of 1 are: > a. Duplicating vhost_dev_start / vhost_dev_stop at > vhost_vdpa_set_features / vhost_vdpa_set_vring_addr. > > This has the same problem as all duplications: It will get out of sync > eventually. For example, the latest changes about configure interrupt > would need to be duplicated in this new call. > > b. Add a new parameter to vhost_dev_start/stop to skip the > set_features / set_vring_address step. > Now that the virtio queue reset changes have exposed these functions > it is also possible to call them from vhost-vdpa. > > Maybe we can store that parameter in vhost_vdpa so we don't call > vhost_dev_start / stop there instead of affecting all backends, but > the idea is the same. > > For problem 2 I still do not have a solution. CVQ / MQ Is out of the > scope for this series but I think it will bite us when we add it > (hopefully soon).Thanks for the clarification, I'd suggest to document the above in the changlog.> > Thanks! > >> Thanks >> >> >>> + >>> 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 @@ out: >>> 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;