virtio_balloon: add legacy_only flag

We have no plans to support virtio 1.0 in balloon driver.  Add an
explicit flag to mark it legacy only.

This will be used by follow-up patches.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

2 files changed, 3 insertions, 0 deletions

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index c9703d4d6f67..4497def48dae 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -518,6 +518,7 @@ static unsigned int features[] = {
 };
 
 static struct virtio_driver virtio_balloon_driver = {
+        .legacy_only = true,
         .feature_table = features,
         .feature_table_size = ARRAY_SIZE(features),
         .driver.name =  KBUILD_MODNAME,
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index f70411eb9d27..2bbf62697671 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -132,6 +132,7 @@ int virtio_device_restore(struct virtio_device *dev);
  * @feature_table_size: number of entries in the feature table array.
  * @feature_table_legacy: same as feature_table but when working in legacy mode.
  * @feature_table_size_legacy: number of entries in feature table legacy array.
+ * @legacy_only: driver does not support virtio 1.0.
  * @probe: the function to call when a device is found.  Returns 0 or -errno.
  * @remove: the function to call when a device is removed.
  * @config_changed: optional function to call when the device configuration
@@ -144,6 +145,7 @@ struct virtio_driver {
         unsigned int feature_table_size;
         const unsigned int *feature_table_legacy;
         unsigned int feature_table_size_legacy;
+        bool legacy_only;
         int (*probe)(struct virtio_device *dev);
         void (*scan)(struct virtio_device *dev);
         void (*remove)(struct virtio_device *dev);