Re: [RFC 6/8] virtio-ccw: Lock ioeventfd state with VIRTIO_F_NOTIFICATION_DATA

On 01/03/2024 14.43, Jonah Palmer wrote:
> Prevent ioeventfd from being enabled/disabled when a virtio-ccw device
> has negotiated the VIRTIO_F_NOTIFICATION_DATA transport feature.
> 
> Due to the ioeventfd not being able to carry the extra data associated
> with this feature, the ioeventfd should be left in a disabled state for
> emulated virtio-ccw devices using this feature.
> 
> Signed-off-by: Jonah Palmer <[email protected]>
> ---
>   hw/s390x/virtio-ccw.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
> index b4676909dd..936ba78fda 100644
> --- a/hw/s390x/virtio-ccw.c
> +++ b/hw/s390x/virtio-ccw.c
> @@ -530,14 +530,16 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
>               if (ret) {
>                   break;
>               }
> -            if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
> +            if (!(status & VIRTIO_CONFIG_S_DRIVER_OK) &&
> +                !virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFICATION_DATA)) {
>                   virtio_ccw_stop_ioeventfd(dev);
>               }
>               if (virtio_set_status(vdev, status) == 0) {
>                   if (vdev->status == 0) {
>                       virtio_ccw_reset_virtio(dev);
>                   }
> -                if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
> +                if ((status & VIRTIO_CONFIG_S_DRIVER_OK) &&
> +                    !virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFICATION_DATA)) {
>                       virtio_ccw_start_ioeventfd(dev);
>                   }
>                   sch->curr_status.scsw.count = ccw.count - sizeof(status);

Acked-by: Thomas Huth <[email protected]>