virtio_ccw: rev 1 devices set VIRTIO_F_VERSION_1

What does it mean if rev 1 device does not set
VIRTIO_F_VERSION_1? E.g. is it native endian?

Let's not even try to drive such devices:
fail attempts to finalize features.
virtio core will detect this and bail out.

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

diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 789275f..f9f87ba 100644 (file)
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -758,6 +758,13 @@ static int virtio_ccw_finalize_features(struct virtio_device *vdev)
        struct virtio_feature_desc *features;
        struct ccw1 *ccw;
 
+       if (vcdev->revision == 1 &&
+           !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
+               dev_err(&vdev->dev, "virtio: device uses revision 1 "
+                       "but does not have VIRTIO_F_VERSION_1\n");
+               return -EINVAL;
+       }
+
        ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
        if (!ccw)
                return 0;