Re: [PATCH 1/4] vdpa: introduce config op to get valid iova range

[Eli Cohen]

On Wed, Jun 17, 2020 at 06:29:44AM +0300, Jason Wang wrote:
> This patch introduce a config op to get valid iova range from the vDPA
> device.
> 
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
>  include/linux/vdpa.h | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index 239db794357c..b7633ed2500c 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -41,6 +41,16 @@ struct vdpa_device {
>  	unsigned int index;
>  };
>  
> +/**
> + * vDPA IOVA range - the IOVA range support by the device
> + * @start: start of the IOVA range
> + * @end: end of the IOVA range
> + */
> +struct vdpa_iova_range {
> +	u64 start;
> +	u64 end;
> +};
> +

What do you do with this information? Suppose some device tells you it
supports some limited range, say, from 0x40000000 to 0x80000000. What
does qemu do with this information?

>  /**
>   * vDPA_config_ops - operations for configuring a vDPA device.
>   * Note: vDPA device drivers are required to implement all of the
> @@ -134,6 +144,9 @@ struct vdpa_device {
>   * @get_generation:		Get device config generation (optional)
>   *				@vdev: vdpa device
>   *				Returns u32: device generation
> + * @get_iova_range:		Get supported iova range (on-chip IOMMU)
> + *				@vdev: vdpa device
> + *				Returns the iova range supported by the device
>   * @set_map:			Set device memory mapping (optional)
>   *				Needed for device that using device
>   *				specific DMA translation (on-chip IOMMU)
> @@ -195,6 +208,7 @@ struct vdpa_config_ops {
>  	void (*set_config)(struct vdpa_device *vdev, unsigned int offset,
>  			   const void *buf, unsigned int len);
>  	u32 (*get_generation)(struct vdpa_device *vdev);
> +	struct vdpa_iova_range (*get_iova_range)(struct vdpa_device *vdev);
>  
>  	/* DMA ops */
>  	int (*set_map)(struct vdpa_device *vdev, struct vhost_iotlb *iotlb);
> -- 
> 2.20.1
>