On Sat, Jun 14, 2025 at 12:14:45AM -0700, Nicolin Chen wrote:
> This will be used by Tegra241 CMDQV implementation to report a non-default
> HW info data.
>
> Reviewed-by: Jason Gunthorpe <j...@nvidia.com>
> Signed-off-by: Nicolin Chen <nicol...@nvidia.com>
> ---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 1 +
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 8 ++++++--
> 2 files changed, 7 insertions(+), 2 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 07589350b2a1..c408a035e65d 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -721,6 +721,7 @@ struct arm_smmu_impl_ops {
> int (*init_structures)(struct arm_smmu_device *smmu);
> struct arm_smmu_cmdq *(*get_secondary_cmdq)(
> struct arm_smmu_device *smmu, struct arm_smmu_cmdq_ent *ent);
> + void *(*hw_info)(struct arm_smmu_device *smmu, u32 *length, u32 *type);
> const size_t vsmmu_size;
> const enum iommu_viommu_type vsmmu_type;
> int (*vsmmu_init)(struct arm_vsmmu *vsmmu,
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> index 445365ae19e0..1c138aff73d1 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> @@ -10,13 +10,17 @@
> void *arm_smmu_hw_info(struct device *dev, u32 *length, u32 *type)
> {
> struct arm_smmu_master *master = dev_iommu_priv_get(dev);
> + const struct arm_smmu_impl_ops *impl_ops = master->smmu->impl_ops;
> struct iommu_hw_info_arm_smmuv3 *info;
> u32 __iomem *base_idr;
> unsigned int i;
>
> if (*type != IOMMU_HW_INFO_TYPE_DEFAULT &&
> - *type != IOMMU_HW_INFO_TYPE_ARM_SMMUV3)
> - return ERR_PTR(-EOPNOTSUPP);
> + *type != IOMMU_HW_INFO_TYPE_ARM_SMMUV3) {
> + if (!impl_ops || !impl_ops->hw_info)
> + return ERR_PTR(-EOPNOTSUPP);
> + return impl_ops->hw_info(master->smmu, length, type);
> + }
I'm not sure if I get this right.. if the user (while porting a VMM or
something) mistakenly passes *type == IOMMU_HW_INFO_TYPE_INTEL_VTD here,
they'll get impl-specific info? I agree in that case the impl-specific
driver needs to check the type, but shouldn't we simply return from here
itself if the type isn't arm-smmu-v3?
>
> info = kzalloc(sizeof(*info), GFP_KERNEL);
> if (!info)
> --
> 2.43.0
>
