Re: [PATCH v3 11/11] iommu/arm-smmu-v3: Add IOMMU_VIOMMU_TYPE_ARM_SMMUV3 support

On Wed, Oct 09, 2024 at 09:38:11AM -0700, Nicolin Chen wrote:

Add a new driver-type for ARM SMMUv3 to enum iommu_viommu_type. Implement +static inline struct iommufd_viommu * +arm_vsmmu_alloc(struct iommu_device *iommu_dev, struct iommu_domain *parent,

• struct iommufd_ctx *ictx, unsigned int viommu_type)
  

+{

• return ERR_PTR(-EOPNOTSUPP);

+}

Let's do #define NULL here instead so we don't get an op at all.

+struct iommufd_viommu * +arm_vsmmu_alloc(struct iommu_device *iommu_dev, struct iommu_domain *parent,

• struct iommufd_ctx *ictx, unsigned int viommu_type)
  

+{

• struct arm_smmu_device *smmu =

• container_of(iommu_dev, struct arm_smmu_device, iommu);
  

• struct arm_smmu_domain *s2_parent = to_smmu_domain(parent);
• struct arm_vsmmu *vsmmu;
• if (viommu_type != IOMMU_VIOMMU_TYPE_ARM_SMMUV3)

• return ERR_PTR(-EOPNOTSUPP);
  

So what happens if the user tries to create a default domain?

It skips this and just creates an normal viommu object

But then what? The driver needs to make sure it never casts that to a arm_vsmmu ? How?

Jason