virtio: add API to detect legacy devices
transports need to be able to detect legacy-only
devices (ATM balloon only) to use legacy path
to drive them.
Add a core API to do just that.
The implementation just blacklists balloon:
not too pretty, but let's not over-engineer.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index fa6b75d..224f854 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -3,6 +3,7 @@
#include <linux/virtio_config.h>
#include <linux/module.h>
#include <linux/idr.h>
+#include <uapi/linux/virtio_ids.h>
/* Unique numbering for virtio devices. */
static DEFINE_IDA(virtio_index_ida);
@@ -267,6 +268,12 @@
.remove = virtio_dev_remove,
};
+bool virtio_device_is_legacy_only(struct virtio_device_id id)
+{
+ return id.device == VIRTIO_ID_BALLOON;
+}
+EXPORT_SYMBOL_GPL(virtio_device_is_legacy_only);
+
int register_virtio_driver(struct virtio_driver *driver)
{
/* Catch this early. */
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 2bbf626..d666bcb 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -108,6 +108,8 @@
void *priv;
};
+bool virtio_device_is_legacy_only(struct virtio_device_id id);
+
static inline struct virtio_device *dev_to_virtio(struct device *_dev)
{
return container_of(_dev, struct virtio_device, dev);