reproduce (this is a W=1 build):
        # https://github.com/sean-jc/linux/commit/b783b064073844d4db8ca790ce101798658b60bc
        git remote add sean-jc https://github.com/sean-jc/linux
        git fetch --no-tags sean-jc x86/dynamic_mmu_page_hash
        git checkout b783b064073844d4db8ca790ce101798658b60bc
        # 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 SHELL=/bin/bash arch/x86/kvm/