virtio: Complete feature negotation before updating status

lguest (in rusty's use-tun-ringfd patch) assumes that the
guest has updated its feature bits before setting its status
to VIRTIO_CONFIG_S_DRIVER_OK.

That's pretty reasonable, so let's make it so.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 0f3c2bb..7084e7e 100644 (file)
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -124,9 +124,9 @@ static int virtio_dev_probe(struct device *_d)
        if (err)
                add_status(dev, VIRTIO_CONFIG_S_FAILED);
        else {
-               add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
                /* They should never have set feature bits beyond 32 */
                dev->config->set_features(dev, dev->features[0]);
+               add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
        }
        return err;
 }