virtio: Dont add "config" to list for !per_vq_vector

For the MSI but non-per_vq_vector case, the config/change vq
also gets added to the list of vqs that need to process the
MSI interrupt. This is not needed as config has it's own
handler (vp_config_changed). In any case, vring_interrupt()
finds nothing needs to be done on this vq.

I tested this patch by testing the "Fallback:" and "Finally
fall back" cases in vp_find_vqs(). Please review.

Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 7 insertions, 3 deletions

diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 4bcc8b82640b..79a31e5b4b68 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -415,9 +415,13 @@ static struct virtqueue *setup_vq(struct virtio_device *vdev, unsigned index,
                 }
         }
 
-        spin_lock_irqsave(&vp_dev->lock, flags);
-        list_add(&info->node, &vp_dev->virtqueues);
-        spin_unlock_irqrestore(&vp_dev->lock, flags);
+        if (callback) {
+                spin_lock_irqsave(&vp_dev->lock, flags);
+                list_add(&info->node, &vp_dev->virtqueues);
+                spin_unlock_irqrestore(&vp_dev->lock, flags);
+        } else {
+                INIT_LIST_HEAD(&info->node);
+        }
 
         return vq;