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Date:   Wed, 3 Mar 2021 18:18:49 +0100
From:   Jean-Philippe Brucker <jean-philippe@linaro.org>
To:     Vivek Gautam <vivek.gautam@arm.com>
Cc:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        iommu@lists.linux-foundation.org,
        virtualization@lists.linux-foundation.org, joro@8bytes.org,
        will.deacon@arm.com, mst@redhat.com, robin.murphy@arm.com,
        eric.auger@redhat.com, alex.williamson@redhat.com,
        kevin.tian@intel.com, jacob.jun.pan@linux.intel.com,
        yi.l.liu@intel.com, lorenzo.pieralisi@arm.com,
        shameerali.kolothum.thodi@huawei.com
Subject: Re: [PATCH RFC v1 08/15] iommu: Add asid_bits to arm smmu-v3 stage1
 table info
Message-ID: <YD/E+XASgn9PL9HM@myrica>
References: <20210115121342.15093-1-vivek.gautam@arm.com>
 <20210115121342.15093-9-vivek.gautam@arm.com>
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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@arm.com>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Robin Murphy <robin.murphy@arm.com>
> Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Cc: Eric Auger <eric.auger@redhat.com>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Cc: Kevin Tian <kevin.tian@intel.com>
> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Liu Yi L <yi.l.liu@intel.com>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> ---
>  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