Re: [PATCH v6 20/25] iommu/arm-smmu-v3-iommufd: Add hw_info to impl_ops

[Nicolin Chen <nicolinc@nvidia.com>]

On Fri, Jun 20, 2025 at 03:32:19AM +0000, Pranjal Shrivastava wrote:
> My point is that in-case someone passed INTEL_VTD type, we would end up
> calling impl_ops->hw_info and then the impl_ops->hw_info shall check for
> the type to return -EOPNOTSUPP. Either we should clearly mention that
> each impl_op implementing hw_info *must* add another type and check for
> it

Let's add this:

@@ -721,6 +721,11 @@ 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);
+       /*
+        * An implementation should define its own type other than the default
+        * IOMMU_HW_INFO_TYPE_ARM_SMMUV3. And it must validate the input @type
+        * to return its own structure.
+        */
        void *(*hw_info)(struct arm_smmu_device *smmu, u32 *length, u32 *type);
        const size_t vsmmu_size;
        const enum iommu_viommu_type vsmmu_type;

And I found that we could have another patch changing "u32 *type"
to "enum iommufd_hw_info_flags *type" to avoid some duplications
in the kdocs.

Thanks
Nicolin