reproduce (this is a W=1 build):
        # https://github.com/intel/tdx/commit/ae0b961d80ab90e43c6eff4a675e00ff80ab3b9f
        git remote add intel-tdx https://github.com/intel/tdx.git
        git fetch --no-tags intel-tdx kvm-upstream
        git checkout ae0b961d80ab90e43c6eff4a675e00ff80ab3b9f
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/coco/tdx/