[Qemu-devel] [PATCH 5/9] virtio-blk: multiqueue batch notify

[Stefan Hajnoczi <stefanha@redhat.com>]

The batch notification BH needs to know which virtqueues to notify when
multiqueue is enabled.  Use a bitmap to track the virtqueues that with
pending notifications.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/block/virtio-blk.c          | 20 ++++++++++++++++----
 include/hw/virtio/virtio-blk.h |  1 +
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index d16a1b7..ab0f589 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -54,11 +54,19 @@ static void virtio_blk_batch_notify_bh(void *opaque)
 {
     VirtIOBlock *s = opaque;
     VirtIODevice *vdev = VIRTIO_DEVICE(s);
+    unsigned nvqs = s->conf.num_queues;
+    unsigned i = 0;
 
-    if (s->dataplane_started && !s->dataplane_disabled) {
-        virtio_blk_data_plane_notify(s->dataplane, s->vq);
-    } else {
-        virtio_notify(vdev, s->vq);
+    while ((i = find_next_bit(s->batch_notify_vqs, nvqs, i)) < nvqs) {
+        VirtQueue *vq = virtio_get_queue(vdev, i);
+
+        bitmap_clear(s->batch_notify_vqs, i, 1);
+
+        if (s->dataplane_started && !s->dataplane_disabled) {
+            virtio_blk_data_plane_notify(s->dataplane, vq);
+        } else {
+            virtio_notify(vdev, vq);
+        }
     }
 }
 
@@ -77,6 +85,8 @@ static void virtio_blk_req_complete(VirtIOBlockReq *req, unsigned char status)
 
     stb_p(&req->in->status, status);
     virtqueue_push(req->vq, &req->elem, req->in_len);
+
+    bitmap_set(s->batch_notify_vqs, virtio_queue_get_id(req->vq), 1);
     qemu_bh_schedule(s->batch_notify_bh);
 }
 
@@ -922,6 +932,7 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
 
     s->batch_notify_bh = aio_bh_new(blk_get_aio_context(s->blk),
                                     virtio_blk_batch_notify_bh, s);
+    s->batch_notify_vqs = bitmap_new(conf->num_queues);
 
     s->change = qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
     register_savevm(dev, "virtio-blk", virtio_blk_id++, 2,
@@ -938,6 +949,7 @@ static void virtio_blk_device_unrealize(DeviceState *dev, Error **errp)
     VirtIOBlock *s = VIRTIO_BLK(dev);
 
     qemu_bh_delete(s->batch_notify_bh);
+    g_free(s->batch_notify_vqs);
     virtio_blk_data_plane_destroy(s->dataplane);
     s->dataplane = NULL;
     qemu_del_vm_change_state_handler(s->change);
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index 487b28d..b6e7860 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -51,6 +51,7 @@ typedef struct VirtIOBlock {
     void *rq;
     QEMUBH *bh;
     QEMUBH *batch_notify_bh;
+    unsigned long *batch_notify_vqs;
     VirtIOBlkConf conf;
     unsigned short sector_mask;
     bool original_wce;
-- 
2.5.5