virtio: assert 32 bit features in transports
At this point, no transports set any of the high 32 feature bits.
Since transports generally can't (yet) cope with such bits, add BUG_ON
checks to make sure they are not set by mistake.
Based on rproc patch by Rusty.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index 2336c7e..f5575cc 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -103,6 +103,9 @@
/* Give virtio_ring a chance to accept features. */
vring_transport_features(vdev);
+ /* Make sure we don't have any features > 32 bits! */
+ BUG_ON((u32)vdev->features != vdev->features);
+
memset(out_features, 0, desc->feature_len);
bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
for (i = 0; i < bits; i++) {