Re: [PATCH v3 10/16] iommu/amd: Modify logic for checking GT and PPR features

[Jason Gunthorpe <jgg@ziepe.ca>]

On Fri, Aug 04, 2023 at 06:42:10AM +0000, Vasant Hegde wrote:
> From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> 
> In order to support v2 page table, IOMMU driver need to check if the
> hardware can support Guest Translation (GT) and Peripheral Page Requet
> (PPR) features. Currently, IOMMU driver uses global (amd_iommu_v2_present)
> and per-iommu (struct amd_iommu.is_iommu_v2) variables to track the
> features. There variables area redundant since we could simply just check
> the global EFR mask.
> 
> Therefore, replace it with a helper function with appropriate name.
> 
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> Co-developed-by: Vasant Hegde <vasant.hegde@amd.com>
> Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
> ---
>  drivers/iommu/amd/amd_iommu.h       | 11 +++++++++++
>  drivers/iommu/amd/amd_iommu_types.h |  9 ++++-----
>  drivers/iommu/amd/init.c            | 14 +-------------
>  drivers/iommu/amd/iommu.c           |  2 +-
>  4 files changed, 17 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
> index a5a350ee36fe..0605f02fa711 100644
> --- a/drivers/iommu/amd/amd_iommu.h
> +++ b/drivers/iommu/amd/amd_iommu.h
> @@ -95,6 +95,17 @@ static inline bool iommu_feature(struct amd_iommu *iommu, u64 mask)
>  	return !!(iommu->features & mask);
>  }
>  
> +static inline bool check_feature_on_all_iommus(u64 mask)
> +{
> +	return !!(amd_iommu_efr & mask);
> +}
> +
> +static inline bool amd_iommu_gt_ppr_supported(void)
> +{
> +	return (check_feature_on_all_iommus(FEATURE_GT) &&
> +		check_feature_on_all_iommus(FEATURE_PPR));
> +}
> +

I'm still against adding more globals, the iommu struct was available,
just use it directly in this patch.

Jason