virtio-blk now listens to op blocker change of the associated block
backend.
Up on setting op blocker on BLOCK_OP_TYPE_DEVICE_IO:
non-dataplane:
1) Set VirtIOBlock.paused
2) In virtio_blk_handle_output, do nothing if VirtIOBlock.paused
dataplane:
1) Clear the host event notifier
2) In handle_notify, do nothing if VirtIOBlock.paused
Up on removing the op blocker:
non-dataplane:
1) Clear VirtIOBlock.paused
2) Schedule a BH on the AioContext of the backend, which calls
virtio_blk_handle_output, so that the previous unhandled kicks can
make progress
dataplane:
1) Set the host event notifier
2) Notify the host event notifier so that unhandled events are
processed
Signed-off-by: Fam Zheng
---
hw/block/dataplane/virtio-blk.c | 25 +++-
hw/block/virtio-blk.c | 63 +++--
include/hw/virtio/virtio-blk.h | 8 +-
3 files changed, 92 insertions(+), 4 deletions(-)
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index ec0c8f4..d6c943c 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -87,8 +87,28 @@ static void complete_request_vring(VirtIOBlockReq *req,
unsigned char status)
qemu_bh_schedule(s->bh);
}
+static void virtio_blk_data_plane_pause(VirtIOBlock *vblk)
+{
+VirtIOBlockDataPlane *s = vblk->dataplane;
+
+event_notifier_test_and_clear(&s->host_notifier);
+aio_set_event_notifier(s->ctx, &s->host_notifier, NULL);
+}
+
+static void handle_notify(EventNotifier *e);
+static void virtio_blk_data_plane_resume(VirtIOBlock *vblk)
+{
+VirtIOBlockDataPlane *s = vblk->dataplane;
+
+aio_set_event_notifier(s->ctx, &s->host_notifier, handle_notify);
+
+event_notifier_set(&s->host_notifier);
+}
+
static const VirtIOBlockOps virtio_blk_data_plane_ops = {
-.complete_request = complete_request_vring,
+.complete_request = complete_request_vring,
+.pause = virtio_blk_data_plane_pause,
+.resume = virtio_blk_data_plane_resume,
};
static void handle_notify(EventNotifier *e)
@@ -98,6 +118,9 @@ static void handle_notify(EventNotifier *e)
VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
event_notifier_test_and_clear(&s->host_notifier);
+if (vblk->paused) {
+return;
+}
blk_io_plug(s->conf->conf.blk);
for (;;) {
MultiReqBuffer mrb = {};
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index f4a9d19..4bc1b2a 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -59,8 +59,38 @@ static void virtio_blk_complete_request(VirtIOBlockReq *req,
virtio_notify(vdev, s->vq);
}
+typedef struct {
+QEMUBH *bh;
+VirtIOBlock *s;
+} VirtIOBlockResumeData;
+
+static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq);
+static void virtio_blk_resume_bh_cb(void *opaque)
+{
+VirtIOBlockResumeData *data = opaque;
+qemu_bh_delete(data->bh);
+virtio_blk_handle_output(VIRTIO_DEVICE(data->s), data->s->vq);
+}
+
+static void virtio_blk_pause(VirtIOBlock *vblk)
+{
+/* TODO: stop ioeventfd */
+}
+
+static void virtio_blk_resume(VirtIOBlock *vblk)
+{
+VirtIOBlockResumeData *data = g_new(VirtIOBlockResumeData, 1);
+data->bh = aio_bh_new(blk_get_aio_context(vblk->blk),
+virtio_blk_resume_bh_cb, data);
+data->s = vblk;
+data->s->paused = false;
+qemu_bh_schedule(data->bh);
+}
+
static const VirtIOBlockOps virtio_blk_ops = (VirtIOBlockOps) {
-.complete_request = virtio_blk_complete_request,
+.complete_request = virtio_blk_complete_request,
+.pause = virtio_blk_pause,
+.resume = virtio_blk_resume,
};
static void virtio_blk_req_complete(VirtIOBlockReq *req, unsigned char status)
@@ -597,6 +627,9 @@ static void virtio_blk_handle_output(VirtIODevice *vdev,
VirtQueue *vq)
VirtIOBlockReq *req;
MultiReqBuffer mrb = {};
+if (s->paused) {
+return;
+}
/* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
* dataplane here instead of waiting for .set_status().
*/
@@ -787,7 +820,7 @@ static void virtio_blk_save(QEMUFile *f, void *opaque)
virtio_save(vdev, f);
}
-
+
static void virtio_blk_save_device(VirtIODevice *vdev, QEMUFile *f)
{
VirtIOBlock *s = VIRTIO_BLK(vdev);
@@ -875,6 +908,29 @@ static void virtio_blk_migration_state_changed(Notifier
*notifier, void *data)
}
}
+static void virtio_blk_op_blocker_changed(Notifier *notifier, void *opaque)
+{
+BlockOpEvent *event = opaque;
+VirtIOBlock *s = container_of(notifier, VirtIOBlock,
+ op_blocker_notifier);
+bool pause;
+
+if (event->type != BLOCK_OP_TYPE_DEVICE_IO) {
+return;
+}
+pause = event->blocking || blk_op_is_blocked(s->blk,
+BLOCK_OP_TYPE_DEVICE
