On Fri, Mar 17, 2023 at 03:02:26AM +0000, Tian, Kevin wrote: > > +/** > > + * struct iommu_hwpt_alloc - ioctl(IOMMU_HWPT_ALLOC) > > + * @size: sizeof(struct iommu_hwpt_alloc) > > + * @flags: Must be 0 > > + * @dev_id: The device to allocate this HWPT for > > + * @pt_id: The IOAS to connect this HWPT to > > + * @out_hwpt_id: The ID of the new HWPT > > + * @__reserved: Must be 0 > > + * > > + * Explicitly allocate a hardware page table object. This is the same object > > + * type that is returned by iommufd_device_attach() and represents the > > + * underlying iommu driver's iommu_domain kernel object. > > + * > > + * A normal HWPT will be created with the mappings from the given IOAS. > > + */ > > 'normal' is a confusing word in this context. Yea, Eric was asking about a related question in another thread, because he couldn't get this part. I think we could replace this "normal" with just "kernel-managed", so eventually it would look like the following narrative after adding user_data and nesting: * A kernel-managed HWPT will be created with the mappings from the given IOAS. * The @data_type for its allocation can be set to IOMMU_HWPT_TYPE_DEFAULT, or * another type (being listed below) to customize the allocation. * * A user-managed HWPT will be created from a given parent HWPT via @pt_id, in * which the parent HWPT must be allocated previously via the same ioctl from a * given IOAS. The @data_type must not be set to IOMMU_HWPT_TYPE_DEFAULT but a * pre-defined type corresponding to the underlying IOMMU hardware. Thanks Nic
