On 17 April 2015 at 13:13, Shannon Zhao <shannon.z...@linaro.org> wrote:
> Add virtio_ccw_device_plugged, it can be used to get backend's features.
>
> Signed-off-by: Shannon Zhao <zhaoshengl...@huawei.com>
> Signed-off-by: Shannon Zhao <shannon.z...@linaro.org>
> ---
> hw/s390x/virtio-ccw.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
> index 130535c..30ca377 100644
> --- a/hw/s390x/virtio-ccw.c
> +++ b/hw/s390x/virtio-ccw.c
> @@ -1395,6 +1395,16 @@ static int virtio_ccw_load_config(DeviceState *d,
> QEMUFile *f)
> return 0;
> }
>
> +/* This is called by virtio-bus just after the device is plugged. */
> +static void virtio_ccw_device_plugged(DeviceState *d)
> +{
> + VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
> +
> + /* Only the first 32 feature bits are used. */
> + dev->host_features[0] = virtio_bus_get_vdev_features(&dev->bus,
> +
> dev->host_features[0]);
> +}
This means that this transport now calls virtio_bus_get_vdev_features
twice, which doesn't look right. In particular, we call it from
realize to set dev->host_features[0], and then add some features to
dev->host_features[0]. Then I think we will call the 'plugged'
method which will throw away those extra features.
So I think that if we need to call this from 'plugged'
rather than 'realize' we need to move all the code for
setting host_features from 'realize' to here.
But I'm confused about why this change is necessary --
don't the blk backends already use the "properties are
on the backend" approach, and they work with this transport?
-- PMM
