On Wed, Oct 30, 2024 at 02:34:33PM -0700, Nicolin Chen wrote: > +static struct iommufd_hwpt_nested * > +iommufd_viommu_alloc_hwpt_nested(struct iommufd_viommu *viommu, u32 flags, > + const struct iommu_user_data *user_data) > +{ > + struct iommufd_hwpt_nested *hwpt_nested; > + struct iommufd_hw_pagetable *hwpt; > + int rc; > + > + if ((flags & ~IOMMU_HWPT_FAULT_ID_VALID) || !user_data->len) > + return ERR_PTR(-EOPNOTSUPP); Now that flags exists we are expecting the driver to validate it, so this check on flags should be dropped? Or we go back to hiding FAULT_ID_VALID from the driver (and keep the flags)? Jason