> From: Liu, Yi L <yi.l.liu@xxxxxxxxx> > Sent: Thursday, May 11, 2023 10:39 PM > @@ -229,6 +238,15 @@ struct iommu_iotlb_gather { > * after use. Return the data buffer if success, or ERR_PTR on > * failure. > * @domain_alloc: allocate iommu domain > + * @domain_alloc_user: allocate user iommu domain > + * @domain_alloc_user_data_len: return the required length of the user > data > + * to allocate a specific type user iommu domain. > + * @hwpt_type is defined as enum iommu_hwpt_type > + * in include/uapi/linux/iommufd.h. The returned > + * length is the corresponding sizeof driver data > + * structures in include/uapi/linux/iommufd.h. > + * -EOPNOTSUPP would be returned if the input > + * @hwpt_type is not supported by the driver. Can this be merged with earlier @hw_info callback? That will already report a list of supported hwpt types. is there a problem to further describe the data length for each type in that interface?