Re: [PATCH RFC 1/4] vdpa: introduce .reset_map operation callback

[Jason Wang]

On Tue, Aug 15, 2023 at 9:46 AM Si-Wei Liu <si-wei.liu@xxxxxxxxxx> wrote:
>
> Signed-off-by: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
> ---
>  include/linux/vdpa.h | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index db1b0ea..3a3878d 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -314,6 +314,12 @@ struct vdpa_map_file {
>   *                             @iova: iova to be unmapped
>   *                             @size: size of the area
>   *                             Returns integer: success (0) or error (< 0)
> + * @reset_map:                 Reset device memory mapping (optional)
> + *                             Needed for device that using device
> + *                             specific DMA translation (on-chip IOMMU)

This exposes the device internal to the upper layer which is not optimal.

Btw, what's the difference between this and a simple

set_map(NULL)?

Thanks

> + *                             @vdev: vdpa device
> + *                             @asid: address space identifier
> + *                             Returns integer: success (0) or error (< 0)
>   * @get_vq_dma_dev:            Get the dma device for a specific
>   *                             virtqueue (optional)
>   *                             @vdev: vdpa device
> @@ -390,6 +396,7 @@ struct vdpa_config_ops {
>                        u64 iova, u64 size, u64 pa, u32 perm, void *opaque);
>         int (*dma_unmap)(struct vdpa_device *vdev, unsigned int asid,
>                          u64 iova, u64 size);
> +       int (*reset_map)(struct vdpa_device *vdev, unsigned int asid);
>         int (*set_group_asid)(struct vdpa_device *vdev, unsigned int group,
>                               unsigned int asid);
>         struct device *(*get_vq_dma_dev)(struct vdpa_device *vdev, u16 idx);
> --
> 1.8.3.1
>