reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/sean-jc/linux/commit/c90e655590a56d8697a4e8b1b44f17cb4e7b01cb
        git remote add sean-jc https://github.com/sean-jc/linux
        git fetch --no-tags sean-jc x86/mmu_follow_pfn
        git checkout c90e655590a56d8697a4e8b1b44f17cb4e7b01cb
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-13.2.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-13.2.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/kvm/ virt/