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Subject: Re: [PATCH 2/2] iommu: arm-smmu-v3: Report domain nesting info
 reuqired for stage1
To:     Vivek Gautam <vivek.gautam@arm.com>, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        iommu@lists.linux-foundation.org,
        virtualization@lists.linux-foundation.org
Cc:     joro@8bytes.org, will.deacon@arm.com, mst@redhat.com,
        robin.murphy@arm.com, jean-philippe@linaro.org,
        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
References: <20210212105859.8445-1-vivek.gautam@arm.com>
 <20210212105859.8445-3-vivek.gautam@arm.com>
From:   Auger Eric <eric.auger@redhat.com>
Message-ID: <0708b0b2-78f7-e55c-21a7-3c49eb5141df@redhat.com>
Date:   Fri, 12 Feb 2021 19:13:43 +0100
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Hi Vivek,

On 2/12/21 11:58 AM, Vivek Gautam wrote:
> Update nested domain information required for stage1 page table.

s/reuqired/required in the commit title
> 
> Signed-off-by: Vivek Gautam <vivek.gautam@arm.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index c11dd3940583..728018921fae 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -2555,6 +2555,7 @@ static int arm_smmu_domain_nesting_info(struct arm_smmu_domain *smmu_domain,
>  					void *data)
>  {
>  	struct iommu_nesting_info *info = (struct iommu_nesting_info *)data;
> +	struct arm_smmu_device *smmu = smmu_domain->smmu;
>  	unsigned int size;
>  
>  	if (!info || smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED)
> @@ -2571,9 +2572,20 @@ static int arm_smmu_domain_nesting_info(struct arm_smmu_domain *smmu_domain,
>  		return 0;
>  	}
>  
> -	/* report an empty iommu_nesting_info for now */
> -	memset(info, 0x0, size);
> +	/* Update the nesting info as required for stage1 page tables */
> +	info->addr_width = smmu->ias;
> +	info->format = IOMMU_PASID_FORMAT_ARM_SMMU_V3;
> +	info->features = IOMMU_NESTING_FEAT_BIND_PGTBL |
I understood IOMMU_NESTING_FEAT_BIND_PGTBL advertises the requirement to
bind tables per PASID, ie. passing iommu_gpasid_bind_data.
In ARM case I guess you plan to use attach/detach_pasid_table API with
iommu_pasid_table_config struct. So I understood we should add a new
feature here.
> +			 IOMMU_NESTING_FEAT_PAGE_RESP |
> +			 IOMMU_NESTING_FEAT_CACHE_INVLD;
> +	info->pasid_bits = smmu->ssid_bits;
> +	info->vendor.smmuv3.asid_bits = smmu->asid_bits;
> +	info->vendor.smmuv3.pgtbl_fmt = ARM_64_LPAE_S1;
> +	memset(&info->padding, 0x0, 12);
> +	memset(&info->vendor.smmuv3.padding, 0x0, 9);
> +
>  	info->argsz = size;
> +
spurious new line
>  	return 0;
>  }
>  
>