reproduce (this is a W=1 build):
        # https://github.com/sean-jc/linux/commit/d9373d770b41ab420ff2c59d39cbbac60915a06e
        git remote add sean-jc https://github.com/sean-jc/linux
        git fetch --no-tags sean-jc x86/cleanup_apic_set_base
        git checkout d9373d770b41ab420ff2c59d39cbbac60915a06e
        # 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/kvm/ drivers/ptp/