reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=571c1813cb0a092c17b74e1c9b929cf7769a8e79
        git remote add kvm https://git.kernel.org/pub/scm/virt/kvm/kvm.git
        git fetch --no-tags kvm kvm-coco-queue
        git checkout 571c1813cb0a092c17b74e1c9b929cf7769a8e79
        # 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