reproduce (this is a W=1 build):
        # https://github.com/yiliu1765/iommufd/commit/c1a19e4695fca8f123793f427f4c10638ae0ac41
        git remote add yiliu1765-iommufd https://github.com/yiliu1765/iommufd.git
        git fetch --no-tags yiliu1765-iommufd wip/20250219-handle-refactor
        git checkout c1a19e4695fca8f123793f427f4c10638ae0ac41
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=um olddefconfig
        make W=1 O=build_dir ARCH=um SHELL=/bin/bash drivers/iommu/