Re: [PATCH RFC v1 08/15] iommu: Add asid_bits to arm smmu-v3 stage1 table info

[Jean-Philippe Brucker]

On Fri, Jan 15, 2021 at 05:43:35PM +0530, Vivek Gautam wrote:
> aisd_bits data is required to prepare stage-1 tables for arm-smmu-v3.
> 
> Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxx>
> Cc: Joerg Roedel <joro@xxxxxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Cc: Robin Murphy <robin.murphy@xxxxxxx>
> Cc: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
> Cc: Eric Auger <eric.auger@xxxxxxxxxx>
> Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Cc: Liu Yi L <yi.l.liu@xxxxxxxxx>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Cc: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx>
> ---
>  include/uapi/linux/iommu.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
> index 082d758dd016..96abbfc7c643 100644
> --- a/include/uapi/linux/iommu.h
> +++ b/include/uapi/linux/iommu.h
> @@ -357,7 +357,7 @@ struct iommu_pasid_smmuv3 {
>  	__u32	version;
>  	__u8	s1fmt;
>  	__u8	s1dss;
> -	__u8	padding[2];
> +	__u16	asid_bits;

Is this used anywhere?  This struct is passed from host userspace to host
kernel to attach the PASID table, so I don't think it needs an asid_bits
field.

Thanks,
Jean