reproduce (this is a W=1 build):
        # https://github.com/kvm-riscv/linux/commit/6e5f032951fccd717d1e5b7ca967d6fc20c8bdef
        git remote add kvm-riscv https://github.com/kvm-riscv/linux.git
        git fetch --no-tags kvm-riscv riscv_kvm_nested_v1
        git checkout 6e5f032951fccd717d1e5b7ca967d6fc20c8bdef

        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv-linux-gnu
        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=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash arch/riscv/kvm/