[PATCH 3/6] virtio/console: verify device has config space

["Michael S. Tsirkin" <mst@redhat.com>]

Some devices might not implement config space access
(e.g. remoteproc used not to - before 3.9).
virtio/console needs config space access so make it
fail gracefully if not there.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/char/virtio_console.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index de03df9..26afb56 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1986,6 +1986,12 @@ static int virtcons_probe(struct virtio_device *vdev)
 	bool multiport;
 	bool early = early_put_chars != NULL;
 
+	if (!vdev->config->get) {
+		dev_err(&vdev->dev, "%s failure: config access disabled\n",
+			__func__);
+		return -EINVAL;
+	}
+
 	/* Ensure to read early_put_chars now */
 	barrier();
 
-- 
MST