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virtio-blk: add iothread-vq-mapping parameter
Add the iothread-vq-mapping parameter to assign virtqueues to IOThreads. Store the vq:AioContext mapping in the new struct VirtIOBlockDataPlane->vq_aio_context[] field and refactor the code to use the per-vq AioContext instead of the BlockDriverState's AioContext. Reimplement --device virtio-blk-pci,iothread= and non-IOThread mode by assigning all virtqueues to the IOThread and main loop's AioContext in vq_aio_context[], respectively. The comment in struct VirtIOBlockDataPlane about EventNotifiers is stale. Remove it. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20231220134755.814917-5-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi
Kevin Wolf
parent
cf03a152c5
commit
b6948ab01d
4 changed files with 202 additions and 50 deletions
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@ -32,13 +32,11 @@ struct VirtIOBlockDataPlane {
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VirtIOBlkConf *conf;
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VirtIODevice *vdev;
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/* Note that these EventNotifiers are assigned by value. This is
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* fine as long as you do not call event_notifier_cleanup on them
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* (because you don't own the file descriptor or handle; you just
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* use it).
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/*
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* The AioContext for each virtqueue. The BlockDriverState will use the
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* first element as its AioContext.
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*/
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IOThread *iothread;
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AioContext *ctx;
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AioContext **vq_aio_context;
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};
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/* Raise an interrupt to signal guest, if necessary */
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@ -47,6 +45,45 @@ void virtio_blk_data_plane_notify(VirtIOBlockDataPlane *s, VirtQueue *vq)
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virtio_notify_irqfd(s->vdev, vq);
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}
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/* Generate vq:AioContext mappings from a validated iothread-vq-mapping list */
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static void
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apply_vq_mapping(IOThreadVirtQueueMappingList *iothread_vq_mapping_list,
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AioContext **vq_aio_context, uint16_t num_queues)
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{
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IOThreadVirtQueueMappingList *node;
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size_t num_iothreads = 0;
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size_t cur_iothread = 0;
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for (node = iothread_vq_mapping_list; node; node = node->next) {
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num_iothreads++;
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}
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for (node = iothread_vq_mapping_list; node; node = node->next) {
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IOThread *iothread = iothread_by_id(node->value->iothread);
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AioContext *ctx = iothread_get_aio_context(iothread);
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/* Released in virtio_blk_data_plane_destroy() */
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object_ref(OBJECT(iothread));
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if (node->value->vqs) {
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uint16List *vq;
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/* Explicit vq:IOThread assignment */
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for (vq = node->value->vqs; vq; vq = vq->next) {
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vq_aio_context[vq->value] = ctx;
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}
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} else {
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/* Round-robin vq:IOThread assignment */
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for (unsigned i = cur_iothread; i < num_queues;
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i += num_iothreads) {
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vq_aio_context[i] = ctx;
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}
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}
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cur_iothread++;
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}
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}
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/* Context: QEMU global mutex held */
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bool virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf,
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VirtIOBlockDataPlane **dataplane,
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@ -58,7 +95,7 @@ bool virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf,
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*dataplane = NULL;
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if (conf->iothread) {
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if (conf->iothread || conf->iothread_vq_mapping_list) {
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if (!k->set_guest_notifiers || !k->ioeventfd_assign) {
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error_setg(errp,
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"device is incompatible with iothread "
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@ -86,13 +123,24 @@ bool virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf,
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s = g_new0(VirtIOBlockDataPlane, 1);
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s->vdev = vdev;
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s->conf = conf;
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s->vq_aio_context = g_new(AioContext *, conf->num_queues);
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if (conf->iothread) {
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s->iothread = conf->iothread;
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object_ref(OBJECT(s->iothread));
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s->ctx = iothread_get_aio_context(s->iothread);
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if (conf->iothread_vq_mapping_list) {
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apply_vq_mapping(conf->iothread_vq_mapping_list, s->vq_aio_context,
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conf->num_queues);
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} else if (conf->iothread) {
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AioContext *ctx = iothread_get_aio_context(conf->iothread);
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for (unsigned i = 0; i < conf->num_queues; i++) {
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s->vq_aio_context[i] = ctx;
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}
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/* Released in virtio_blk_data_plane_destroy() */
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object_ref(OBJECT(conf->iothread));
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} else {
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s->ctx = qemu_get_aio_context();
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AioContext *ctx = qemu_get_aio_context();
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for (unsigned i = 0; i < conf->num_queues; i++) {
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s->vq_aio_context[i] = ctx;
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}
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}
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*dataplane = s;
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@ -104,6 +152,7 @@ bool virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf,
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void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s)
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{
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VirtIOBlock *vblk;
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VirtIOBlkConf *conf = s->conf;
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if (!s) {
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return;
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@ -111,9 +160,21 @@ void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s)
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vblk = VIRTIO_BLK(s->vdev);
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assert(!vblk->dataplane_started);
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if (s->iothread) {
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object_unref(OBJECT(s->iothread));
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if (conf->iothread_vq_mapping_list) {
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IOThreadVirtQueueMappingList *node;
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for (node = conf->iothread_vq_mapping_list; node; node = node->next) {
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IOThread *iothread = iothread_by_id(node->value->iothread);
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object_unref(OBJECT(iothread));
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}
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}
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if (conf->iothread) {
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object_unref(OBJECT(conf->iothread));
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}
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g_free(s->vq_aio_context);
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g_free(s);
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}
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@ -177,19 +238,13 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
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trace_virtio_blk_data_plane_start(s);
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r = blk_set_aio_context(s->conf->conf.blk, s->ctx, &local_err);
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r = blk_set_aio_context(s->conf->conf.blk, s->vq_aio_context[0],
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&local_err);
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if (r < 0) {
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error_report_err(local_err);
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goto fail_aio_context;
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}
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/* Kick right away to begin processing requests already in vring */
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for (i = 0; i < nvqs; i++) {
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VirtQueue *vq = virtio_get_queue(s->vdev, i);
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event_notifier_set(virtio_queue_get_host_notifier(vq));
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}
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/*
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* These fields must be visible to the IOThread when it processes the
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* virtqueue, otherwise it will think dataplane has not started yet.
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@ -206,8 +261,12 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
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if (!blk_in_drain(s->conf->conf.blk)) {
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for (i = 0; i < nvqs; i++) {
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VirtQueue *vq = virtio_get_queue(s->vdev, i);
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AioContext *ctx = s->vq_aio_context[i];
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virtio_queue_aio_attach_host_notifier(vq, s->ctx);
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/* Kick right away to begin processing requests already in vring */
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event_notifier_set(virtio_queue_get_host_notifier(vq));
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virtio_queue_aio_attach_host_notifier(vq, ctx);
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}
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}
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return 0;
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@ -236,23 +295,18 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
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*
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* Context: BH in IOThread
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*/
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static void virtio_blk_data_plane_stop_bh(void *opaque)
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static void virtio_blk_data_plane_stop_vq_bh(void *opaque)
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{
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VirtIOBlockDataPlane *s = opaque;
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unsigned i;
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VirtQueue *vq = opaque;
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EventNotifier *host_notifier = virtio_queue_get_host_notifier(vq);
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for (i = 0; i < s->conf->num_queues; i++) {
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VirtQueue *vq = virtio_get_queue(s->vdev, i);
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EventNotifier *host_notifier = virtio_queue_get_host_notifier(vq);
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virtio_queue_aio_detach_host_notifier(vq, qemu_get_current_aio_context());
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virtio_queue_aio_detach_host_notifier(vq, s->ctx);
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/*
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* Test and clear notifier after disabling event, in case poll callback
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* didn't have time to run.
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*/
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virtio_queue_host_notifier_read(host_notifier);
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}
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/*
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* Test and clear notifier after disabling event, in case poll callback
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* didn't have time to run.
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*/
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virtio_queue_host_notifier_read(host_notifier);
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}
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/* Context: QEMU global mutex held */
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@ -279,7 +333,12 @@ void virtio_blk_data_plane_stop(VirtIODevice *vdev)
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trace_virtio_blk_data_plane_stop(s);
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if (!blk_in_drain(s->conf->conf.blk)) {
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aio_wait_bh_oneshot(s->ctx, virtio_blk_data_plane_stop_bh, s);
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for (i = 0; i < nvqs; i++) {
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VirtQueue *vq = virtio_get_queue(s->vdev, i);
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AioContext *ctx = s->vq_aio_context[i];
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aio_wait_bh_oneshot(ctx, virtio_blk_data_plane_stop_vq_bh, vq);
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}
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}
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/*
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@ -322,3 +381,23 @@ void virtio_blk_data_plane_stop(VirtIODevice *vdev)
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s->stopping = false;
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}
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void virtio_blk_data_plane_detach(VirtIOBlockDataPlane *s)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(s->vdev);
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for (uint16_t i = 0; i < s->conf->num_queues; i++) {
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VirtQueue *vq = virtio_get_queue(vdev, i);
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virtio_queue_aio_detach_host_notifier(vq, s->vq_aio_context[i]);
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}
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}
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void virtio_blk_data_plane_attach(VirtIOBlockDataPlane *s)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(s->vdev);
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for (uint16_t i = 0; i < s->conf->num_queues; i++) {
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VirtQueue *vq = virtio_get_queue(vdev, i);
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virtio_queue_aio_attach_host_notifier(vq, s->vq_aio_context[i]);
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}
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}
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@ -28,4 +28,7 @@ void virtio_blk_data_plane_notify(VirtIOBlockDataPlane *s, VirtQueue *vq);
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int virtio_blk_data_plane_start(VirtIODevice *vdev);
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void virtio_blk_data_plane_stop(VirtIODevice *vdev);
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void virtio_blk_data_plane_detach(VirtIOBlockDataPlane *s);
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void virtio_blk_data_plane_attach(VirtIOBlockDataPlane *s);
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#endif /* HW_DATAPLANE_VIRTIO_BLK_H */
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