Re: [RFC PATCH 01/10] vdpa: add get_config_size callback in vdpa_config_ops

[Jason Wang <jasowang@redhat.com>]

On 2021/2/16 5:44 下午, Stefano Garzarella wrote:
> This new callback is used to get the size of the configuration space
> of vDPA devices.
>
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>   include/linux/vdpa.h              | 4 ++++
>   drivers/vdpa/ifcvf/ifcvf_main.c   | 6 ++++++
>   drivers/vdpa/mlx5/net/mlx5_vnet.c | 6 ++++++
>   drivers/vdpa/vdpa_sim/vdpa_sim.c  | 9 +++++++++
>   4 files changed, 25 insertions(+)
>
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index 4ab5494503a8..fddf42b17573 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -150,6 +150,9 @@ struct vdpa_iova_range {
>    * @set_status:			Set the device status
>    *				@vdev: vdpa device
>    *				@status: virtio device status
> + * @get_config_size:		Get the size of the configuration space
> + *				@vdev: vdpa device
> + *				Returns size_t: configuration size


Rethink about this, how much we could gain by introducing a dedicated 
ops here? E.g would it be simpler if we simply introduce a 
max_config_size to vdpa device?

Thanks


>    * @get_config:			Read from device specific configuration space
>    *				@vdev: vdpa device
>    *				@offset: offset from the beginning of
> @@ -231,6 +234,7 @@ struct vdpa_config_ops {
>   	u32 (*get_vendor_id)(struct vdpa_device *vdev);
>   	u8 (*get_status)(struct vdpa_device *vdev);
>   	void (*set_status)(struct vdpa_device *vdev, u8 status);
> +	size_t (*get_config_size)(struct vdpa_device *vdev);
>   	void (*get_config)(struct vdpa_device *vdev, unsigned int offset,
>   			   void *buf, unsigned int len);
>   	void (*set_config)(struct vdpa_device *vdev, unsigned int offset,
> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
> index 7c8bbfcf6c3e..2443271e17d2 100644
> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
> @@ -332,6 +332,11 @@ static u32 ifcvf_vdpa_get_vq_align(struct vdpa_device *vdpa_dev)
>   	return IFCVF_QUEUE_ALIGNMENT;
>   }
>   
> +static size_t ifcvf_vdpa_get_config_size(struct vdpa_device *vdpa_dev)
> +{
> +	return sizeof(struct virtio_net_config);
> +}
> +
>   static void ifcvf_vdpa_get_config(struct vdpa_device *vdpa_dev,
>   				  unsigned int offset,
>   				  void *buf, unsigned int len)
> @@ -392,6 +397,7 @@ static const struct vdpa_config_ops ifc_vdpa_ops = {
>   	.get_device_id	= ifcvf_vdpa_get_device_id,
>   	.get_vendor_id	= ifcvf_vdpa_get_vendor_id,
>   	.get_vq_align	= ifcvf_vdpa_get_vq_align,
> +	.get_config_size	= ifcvf_vdpa_get_config_size,
>   	.get_config	= ifcvf_vdpa_get_config,
>   	.set_config	= ifcvf_vdpa_set_config,
>   	.set_config_cb  = ifcvf_vdpa_set_config_cb,
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 10e9b09932eb..78043ee567b6 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1814,6 +1814,11 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status)
>   	ndev->mvdev.status |= VIRTIO_CONFIG_S_FAILED;
>   }
>   
> +static size_t mlx5_vdpa_get_config_size(struct vdpa_device *vdev)
> +{
> +	return sizeof(struct virtio_net_config);
> +}
> +
>   static void mlx5_vdpa_get_config(struct vdpa_device *vdev, unsigned int offset, void *buf,
>   				 unsigned int len)
>   {
> @@ -1900,6 +1905,7 @@ static const struct vdpa_config_ops mlx5_vdpa_ops = {
>   	.get_vendor_id = mlx5_vdpa_get_vendor_id,
>   	.get_status = mlx5_vdpa_get_status,
>   	.set_status = mlx5_vdpa_set_status,
> +	.get_config_size = mlx5_vdpa_get_config_size,
>   	.get_config = mlx5_vdpa_get_config,
>   	.set_config = mlx5_vdpa_set_config,
>   	.get_generation = mlx5_vdpa_get_generation,
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index d5942842432d..779ae6c144d7 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -439,6 +439,13 @@ static void vdpasim_set_status(struct vdpa_device *vdpa, u8 status)
>   	spin_unlock(&vdpasim->lock);
>   }
>   
> +static size_t vdpasim_get_config_size(struct vdpa_device *vdpa)
> +{
> +	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> +
> +	return vdpasim->dev_attr.config_size;
> +}
> +
>   static void vdpasim_get_config(struct vdpa_device *vdpa, unsigned int offset,
>   			     void *buf, unsigned int len)
>   {
> @@ -566,6 +573,7 @@ static const struct vdpa_config_ops vdpasim_config_ops = {
>   	.get_vendor_id          = vdpasim_get_vendor_id,
>   	.get_status             = vdpasim_get_status,
>   	.set_status             = vdpasim_set_status,
> +	.get_config_size        = vdpasim_get_config_size,
>   	.get_config             = vdpasim_get_config,
>   	.set_config             = vdpasim_set_config,
>   	.get_generation         = vdpasim_get_generation,
> @@ -593,6 +601,7 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = {
>   	.get_vendor_id          = vdpasim_get_vendor_id,
>   	.get_status             = vdpasim_get_status,
>   	.set_status             = vdpasim_set_status,
> +	.get_config_size        = vdpasim_get_config_size,
>   	.get_config             = vdpasim_get_config,
>   	.set_config             = vdpasim_set_config,
>   	.get_generation         = vdpasim_get_generation,