virtio-scsi: Forbid devices with different iothreads sharing a blockdev

This patch forbids attaching a disk to a SCSI device if its using a
different AioContext. Test case included.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index e1f7b208c7..eb90288f47 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -791,9 +791,16 @@ static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev,
     SCSIDevice *sd = SCSI_DEVICE(dev);
 
     if (s->ctx && !s->dataplane_fenced) {
+        AioContext *ctx;
         if (blk_op_is_blocked(sd->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
             return;
         }
+        ctx = blk_get_aio_context(sd->conf.blk);
+        if (ctx != s->ctx && ctx != qemu_get_aio_context()) {
+            error_setg(errp, "Cannot attach a blockdev that is using "
+                       "a different iothread");
+            return;
+        }
         virtio_scsi_acquire(s);
         blk_set_aio_context(sd->conf.blk, s->ctx);
         virtio_scsi_release(s);