reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/agraf/linux-2.6/commit/3c9cb25fc553cc12e4cca8f313472e567f41f128
        git remote add agraf-2.6 https://github.com/agraf/linux-2.6.git
        git fetch --no-tags agraf-2.6 kvm-kho-gmem-test
        git checkout 3c9cb25fc553cc12e4cca8f313472e567f41f128
        # 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