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Commit ce15408f authored by Michael S. Tsirkin's avatar Michael S. Tsirkin
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virtio_ccw: legacy: don't negotiate rev 1/features 



Legacy balloon device doesn't pretend to support revision 1 or 64 bit
features.

But just in case someone implements a broken one that does, let's not
even try to drive legacy only devices using revision 1, and let's not
give them a chance to say they support VIRTIO_F_VERSION_1 by not reading
or writing high feature bits.

Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent b6098c30

drivers/s390/kvm/virtio_ccw.c

+13 −3
Original line number Diff line number Diff line
@@ -733,6 +733,9 @@ static u64 virtio_ccw_get_features(struct virtio_device *vdev) 


	rc = le32_to_cpu(features->features);



	if (vcdev->revision == 0)

		goto out_free;



	/* Read second half of the feature bits from the host. */

	features->index = 1;

	ccw->cmd_code = CCW_CMD_READ_FEAT;
@@ -775,6 +778,9 @@ static void virtio_ccw_finalize_features(struct virtio_device *vdev) 
	ccw->cda = (__u32)(unsigned long)features;

	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);



	if (vcdev->revision == 0)

		goto out_free;



	features->index = 1;

	features->features = cpu_to_le32(vdev->features >> 32);

	/* Write the second half of the feature bits to the host. */
@@ -1182,9 +1188,13 @@ static int virtio_ccw_online(struct ccw_device *cdev) 
	vcdev->vdev.id.vendor = cdev->id.cu_type;

	vcdev->vdev.id.device = cdev->id.cu_model;



	if (virtio_device_is_legacy_only(vcdev->vdev.id)) {

		vcdev->revision = 0;

	} else {

		ret = virtio_ccw_set_transport_rev(vcdev);

		if (ret)

			goto out_free;

	}



	ret = register_virtio_device(&vcdev->vdev);

	if (ret) {