From e21737ab150c2742dd94089017db96c472dd4b87 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Tue, 21 Jun 2016 13:13:11 +0100 Subject: virtio-blk: multiqueue batch notify The batch notification BH needs to know which virtqueues to notify when multiqueue is enabled. Use a bitmap to track the virtqueues with pending notifications. At this point there is only one virtqueue so hard-code virtqueue index 0. A later patch will switch to real virtqueue indices. Signed-off-by: Stefan Hajnoczi Reviewed-by: Fam Zheng Message-id: 1466511196-12612-3-git-send-email-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi --- hw/block/dataplane/virtio-blk.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-) (limited to 'hw/block') diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c index 2041b0400b..c20a195eb5 100644 --- a/hw/block/dataplane/virtio-blk.c +++ b/hw/block/dataplane/virtio-blk.c @@ -34,8 +34,8 @@ struct VirtIOBlockDataPlane { VirtIODevice *vdev; VirtQueue *vq; /* virtqueue vring */ - EventNotifier *guest_notifier; /* irq */ QEMUBH *bh; /* bh for guest notification */ + unsigned long *batch_notify_vqs; /* Note that these EventNotifiers are assigned by value. This is * fine as long as you do not call event_notifier_cleanup on them @@ -49,18 +49,34 @@ struct VirtIOBlockDataPlane { /* Raise an interrupt to signal guest, if necessary */ void virtio_blk_data_plane_notify(VirtIOBlockDataPlane *s) { + set_bit(0, s->batch_notify_vqs); qemu_bh_schedule(s->bh); } static void notify_guest_bh(void *opaque) { VirtIOBlockDataPlane *s = opaque; + unsigned nvqs = s->conf->num_queues; + unsigned long bitmap[BITS_TO_LONGS(nvqs)]; + unsigned j; - if (!virtio_should_notify(s->vdev, s->vq)) { - return; - } + memcpy(bitmap, s->batch_notify_vqs, sizeof(bitmap)); + memset(s->batch_notify_vqs, 0, sizeof(bitmap)); + + for (j = 0; j < nvqs; j += BITS_PER_LONG) { + unsigned long bits = bitmap[j]; - event_notifier_set(s->guest_notifier); + while (bits != 0) { + unsigned i = j + ctzl(bits); + VirtQueue *vq = virtio_get_queue(s->vdev, i); + + if (virtio_should_notify(s->vdev, vq)) { + event_notifier_set(virtio_queue_get_guest_notifier(vq)); + } + + bits &= bits - 1; /* clear right-most bit */ + } + } } /* Context: QEMU global mutex held */ @@ -104,6 +120,7 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf, } s->ctx = iothread_get_aio_context(s->iothread); s->bh = aio_bh_new(s->ctx, notify_guest_bh, s); + s->batch_notify_vqs = bitmap_new(conf->num_queues); *dataplane = s; } @@ -116,6 +133,7 @@ void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s) } virtio_blk_data_plane_stop(s); + g_free(s->batch_notify_vqs); qemu_bh_delete(s->bh); object_unref(OBJECT(s->iothread)); g_free(s); @@ -154,7 +172,6 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s) "ensure -enable-kvm is set\n", r); goto fail_guest_notifiers; } - s->guest_notifier = virtio_queue_get_guest_notifier(s->vq); /* Set up virtqueue notify */ r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), 0, true); -- cgit v1.2.3