virtio-scsi: use aio handler for data plane

In addition to handling IO in vcpu thread and in io thread, dataplane
introduces yet another mode: handling it by AioContext.

This reuses the same handler as previous modes, which triggers races as
these were not designed to be reentrant.  Use a separate handler just
for aio, and disable regular handlers when dataplane is active.

Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 39 insertions, 4 deletions

diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index b44ac5dfa0..39ad086db7 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -38,7 +38,35 @@ void virtio_scsi_set_iothread(VirtIOSCSI *s, IOThread *iothread)
     }
 }
 
-static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n)
+static void virtio_scsi_data_plane_handle_cmd(VirtIODevice *vdev,
+                                              VirtQueue *vq)
+{
+    VirtIOSCSI *s = (VirtIOSCSI *)vdev;
+
+    assert(s->ctx && s->dataplane_started);
+    virtio_scsi_handle_cmd_vq(s, vq);
+}
+
+static void virtio_scsi_data_plane_handle_ctrl(VirtIODevice *vdev,
+                                               VirtQueue *vq)
+{
+    VirtIOSCSI *s = VIRTIO_SCSI(vdev);
+
+    assert(s->ctx && s->dataplane_started);
+    virtio_scsi_handle_ctrl_vq(s, vq);
+}
+
+static void virtio_scsi_data_plane_handle_event(VirtIODevice *vdev,
+                                                VirtQueue *vq)
+{
+    VirtIOSCSI *s = VIRTIO_SCSI(vdev);
+
+    assert(s->ctx && s->dataplane_started);
+    virtio_scsi_handle_event_vq(s, vq);
+}
+
+static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n,
+                                  void (*fn)(VirtIODevice *vdev, VirtQueue *vq))
 {
     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s)));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
@@ -54,6 +82,7 @@ static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n)
     }
 
     virtio_queue_aio_set_host_notifier_handler(vq, s->ctx, true, true);
+    virtio_set_queue_aio(vq, fn);
     return 0;
 }
 
@@ -71,9 +100,12 @@ static void virtio_scsi_clear_aio(VirtIOSCSI *s)
     int i;
 
     virtio_queue_aio_set_host_notifier_handler(vs->ctrl_vq, s->ctx, false, false);
+    virtio_set_queue_aio(vs->ctrl_vq, NULL);
     virtio_queue_aio_set_host_notifier_handler(vs->event_vq, s->ctx, false, false);
+    virtio_set_queue_aio(vs->event_vq, NULL);
     for (i = 0; i < vs->conf.num_queues; i++) {
         virtio_queue_aio_set_host_notifier_handler(vs->cmd_vqs[i], s->ctx, false, false);
+        virtio_set_queue_aio(vs->cmd_vqs[i], NULL);
     }
 }
 
@@ -104,16 +136,19 @@ void virtio_scsi_dataplane_start(VirtIOSCSI *s)
     }
 
     aio_context_acquire(s->ctx);
-    rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0);
+    rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0,
+                                virtio_scsi_data_plane_handle_ctrl);
     if (rc) {
         goto fail_vrings;
     }
-    rc = virtio_scsi_vring_init(s, vs->event_vq, 1);
+    rc = virtio_scsi_vring_init(s, vs->event_vq, 1,
+                                virtio_scsi_data_plane_handle_event);
     if (rc) {
         goto fail_vrings;
     }
     for (i = 0; i < vs->conf.num_queues; i++) {
-        rc = virtio_scsi_vring_init(s, vs->cmd_vqs[i], i + 2);
+        rc = virtio_scsi_vring_init(s, vs->cmd_vqs[i], i + 2,
+                                    virtio_scsi_data_plane_handle_cmd);
         if (rc) {
             goto fail_vrings;
         }