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/7b4624b4ef6957706b9925831c9d5968c1cd9173
        git remote add sean-jc https://github.com/sean-jc/linux
        git fetch --no-tags sean-jc x86/xfer_to_guest_mode
        git checkout 7b4624b4ef6957706b9925831c9d5968c1cd9173
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-15.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=loongarch olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-15.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=loongarch SHELL=/bin/bash arch/loongarch/kvm/