reproduce (this is a W=1 build):
        # https://github.com/sean-jc/linux/commit/3c2b47771dc542fbdb237bd5218112905717dfae
        git remote add sean-jc https://github.com/sean-jc/linux
        git fetch --no-tags sean-jc svm/sev_cache_opts
        git checkout 3c2b47771dc542fbdb237bd5218112905717dfae
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 prepare