commit d3f5f065603705cd4275d57324c49e391f786b5e
author Michael S. Tsirkin <mst@redhat.com> Tue Jan 13 16:34:58 2015 +0200
committer Rusty Russell <rusty@rustcorp.com.au> Wed Jan 21 16:28:55 2015 +1030
tree 8bf7e4230355ec31f9d96d727a4a0b4a42e8acf9
parent 3909213cfd9224cb1827d557fb6eb5ebdb8ddcbe

virtio_pci_modern: support devices with no config

Virtio 1.0 spec lists device config as optional.
Set get/set callbacks to NULL. Drivers can check that
and fail gracefully.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/virtio/virtio_pci_modern.c

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 0e54cc8..68ebc20 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -422,6 +422,21 @@
 	free_pages_exact(info->queue, vring_pci_size(info->num));
 }
 
+static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
+	.get		= NULL,
+	.set		= NULL,
+	.generation	= vp_generation,
+	.get_status	= vp_get_status,
+	.set_status	= vp_set_status,
+	.reset		= vp_reset,
+	.find_vqs	= vp_modern_find_vqs,
+	.del_vqs	= vp_del_vqs,
+	.get_features	= vp_get_features,
+	.finalize_features = vp_finalize_features,
+	.bus_name	= vp_bus_name,
+	.set_vq_affinity = vp_set_vq_affinity,
+};
+
 static const struct virtio_config_ops virtio_pci_config_ops = {
 	.get		= vp_get,
 	.set		= vp_set,
@@ -652,9 +667,11 @@
 						&vp_dev->device_len);
 		if (!vp_dev->device)
 			goto err_map_device;
-	}
 
-	vp_dev->vdev.config = &virtio_pci_config_ops;
+		vp_dev->vdev.config = &virtio_pci_config_ops;
+	} else {
+		vp_dev->vdev.config = &virtio_pci_config_nodev_ops;
+	}
 
 	vp_dev->config_vector = vp_config_vector;
 	vp_dev->setup_vq = setup_vq;