On Thu, Oct 17, 2024 at 03:40:15PM -0300, Jason Gunthorpe wrote:
> 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.
Ack.
> > +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?
So long as a driver doesn't provide iommu_ops->default_viommu_ops,
it should be fine. We may also block DEFAULT viommu allocations in
the core if the driver doesn't provide that default_viommu_ops.
Nicolin
