RE: [PATCH v4 1/4] vdpa: Add stop operation

Eli Cohen
2022-06-01T05:35:12Z

> From: Eugenio Pérez <eperezma@redhat.com>
> Sent: Thursday, May 26, 2022 3:44 PM
> To: Michael S. Tsirkin <mst@redhat.com>; kvm@vger.kernel.org; virtualization@lists.linux-foundation.org; linux-kernel@vger.kernel.org;
> Jason Wang <jasowang@redhat.com>; netdev@vger.kernel.org
> Cc: martinh@xilinx.com; Stefano Garzarella <sgarzare@redhat.com>; martinpo@xilinx.com; lvivier@redhat.com; pabloc@xilinx.com;
> Parav Pandit <parav@nvidia.com>; Eli Cohen <elic@nvidia.com>; Dan Carpenter <dan.carpenter@oracle.com>; Xie Yongji
> <xieyongji@bytedance.com>; Christophe JAILLET <christophe.jaillet@wanadoo.fr>; Zhang Min <zhang.min9@zte.com.cn>; Wu Zongyong
> <wuzongyong@linux.alibaba.com>; lulu@redhat.com; Zhu Lingshan <lingshan.zhu@intel.com>; Piotr.Uminski@intel.com; Si-Wei Liu <si-
> wei.liu@oracle.com>; ecree.xilinx@gmail.com; gautam.dawar@amd.com; habetsm.xilinx@gmail.com; tanuj.kamde@amd.com;
> hanand@xilinx.com; dinang@xilinx.com; Longpeng <longpeng2@huawei.com>
> Subject: [PATCH v4 1/4] vdpa: Add stop operation
>
> This operation is optional: It it's not implemented, backend feature bit
> will not be exposed.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> ---
> include/linux/vdpa.h | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index 15af802d41c4..ddfebc4e1e01 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -215,6 +215,11 @@ struct vdpa_map_file {
> * @reset: Reset device
> * @vdev: vdpa device
> * Returns integer: success (0) or error (< 0)
> + * @stop: Stop or resume the device (optional, but it must
> + * be implemented if require device stop)
> + * @vdev: vdpa device
> + * @stop: stop (true), not stop (false)
> + * Returns integer: success (0) or error (< 0)

I assume after successful "stop" the device is guaranteed to stop processing descriptors and after resume it may process descriptors?
If that is so, I think it should be clear in the change log.

> * @get_config_size: Get the size of the configuration space includes
> * fields that are conditional on feature bits.
> * @vdev: vdpa device
> @@ -316,6 +321,7 @@ struct vdpa_config_ops {
> u8 (*get_status)(struct vdpa_device *vdev);
> void (*set_status)(struct vdpa_device *vdev, u8 status);
> int (*reset)(struct vdpa_device *vdev);
> + int (*stop)(struct vdpa_device *vdev, bool stop);
> size_t (*get_config_size)(struct vdpa_device *vdev);
> void (*get_config)(struct vdpa_device *vdev, unsigned int offset,
> void *buf, unsigned int len);
> --
> 2.31.1