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:
skip attempts to finalize features or set status.
virtio core will detect this and bail out.
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
drivers/s390/kvm/virtio_ccw.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 088bdf1..0ceeb25 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -65,6 +65,7 @@ struct virtio_ccw_device {
bool is_thinint;
bool going_away;
bool device_lost;
+ bool features_invalid;
void *airq_info;
};
@@ -746,6 +747,12 @@ static u64 virtio_ccw_get_features(struct virtio_device *vdev)
if (ret == 0)
rc |= (u64)le32_to_cpu(features->features) << 32;
+ /* Devices MUST set VIRTIO_F_VERSION_1 */
+ if (!(rc & BIT_ULL(VIRTIO_F_VERSION_1))) {
+ vcdev->features_invalid = true;
+ rc |= BIT_ULL(VIRTIO_F_VERSION_1);
+ }
+
out_free:
kfree(features);
kfree(ccw);
@@ -758,6 +765,10 @@ static void virtio_ccw_finalize_features(struct virtio_device *vdev)
struct virtio_feature_desc *features;
struct ccw1 *ccw;
+ /* Invalid features? Let's not try to drive this device. */
+ if (vcdev->features_invalid)
+ return;
+
ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
if (!ccw)
return;
@@ -869,6 +880,10 @@ static void virtio_ccw_set_status(struct virtio_device *vdev, u8 status)
struct ccw1 *ccw;
int ret;
+ /* Invalid features? Let's not try to drive this device. */
+ if (vcdev->features_invalid)
+ return;
+
ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
if (!ccw)
return;
--
MST
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