[PATCH v3 4/6] virtio_ccw: rev 1 devices set VIRTIO_F_VERSION_1

Michael S. Tsirkin
2014-12-08T13:06:03Z

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>
---
drivers/s390/kvm/virtio_ccw.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 789275f..f9f87ba 100644
--- 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;
--
MST