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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: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
This commit is contained in:
Michael S. Tsirkin 2014-12-04 18:59:50 +02:00
parent b6098c3042
commit ce15408f35
1 changed files with 13 additions and 3 deletions
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16
drivers/s390/kvm/virtio_ccw.c
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@ -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;
ret = virtio_ccw_set_transport_rev(vcdev);
if (ret)
goto out_free;
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) {