reproduce (this is a W=1 build):
        # https://github.com/intel/tdx/commit/90df00c4e488a8b5b6c837995706f3e101d75e9c
        git remote add intel-tdx https://github.com/intel/tdx.git
        git fetch --no-tags intel-tdx guest-debug
        git checkout 90df00c4e488a8b5b6c837995706f3e101d75e9c
        # 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/