reproduce (this is a W=1 build):
        # https://github.com/jgunthorpe/linux/commit/ca213f193f2c2aa9b43a653bc6466e1216f6e767
        git remote add jgunthorpe https://github.com/jgunthorpe/linux
        git fetch --no-tags jgunthorpe iommufd_noiommu
        git checkout ca213f193f2c2aa9b43a653bc6466e1216f6e767

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=parisc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=parisc SHELL=/bin/bash drivers/iommu/iommufd/