Re: [PATCH v2 02/11] iommu/arm-smmu-v3: Pass in smmu/iommu_domain to __arm_smmu_tlb_inv_range()

[Will Deacon <will@kernel.org>]

On Mon, Apr 14, 2025 at 09:57:37PM -0700, Nicolin Chen wrote:
> What __arm_smmu_tlb_inv_range() really needs is the smmu and iommu_domain
> pointers from the smmu_domain.
> 
> For a nest_parent smmu_domain, it will no longer store an smmu pointer as
> it can be shared across vSMMU instances. A vSMMU structure sharing the S2
> smmu_domain instead would hold the smmu pointer.
> 
> Pass them in explicitly to fit both !nest_parent and nest_parent cases.
> 
> While changing it, share it in the header with arm-smmu-v3-iommmufd that
> will call it too.
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  4 ++++
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 17 +++++++++--------
>  2 files changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> index d4837a33fb81..5dbdc61558a9 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -955,6 +955,10 @@ void arm_smmu_tlb_inv_range_asid(unsigned long iova, size_t size, int asid,
>  				 struct arm_smmu_domain *smmu_domain);
>  int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain,
>  			    unsigned long iova, size_t size);
> +void __arm_smmu_tlb_inv_range(struct arm_smmu_device *smmu,
> +			      struct arm_smmu_cmdq_ent *cmd, unsigned long iova,
> +			      size_t size, size_t granule,
> +			      struct iommu_domain *domain);

I don't think this function makes a particularly good "public" API --
the caller even sets the cmd opcode!

Can we expose some TLB invalidation helpers instead rather than the
low-level helpers?

Will