Hi Jianyong, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on linus/master] [also build test WARNING on v5.10-rc3 next-20201110] [cannot apply to tip/timers/core kvmarm/next kvm/linux-next] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Jianyong-Wu/Enable-ptp_kvm-for-a... base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git eccc876724927ff3b9ff91f36f7b6b159e948f0c config: arm64-randconfig-r016-20201111 (attached as .config) compiler: aarch64-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/0day-ci/linux/commit/94d44d1bc7bec0d91d4c4851dd935a752... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Jianyong-Wu/Enable-ptp_kvm-for-arm-arm64/20201111-142600 git checkout 94d44d1bc7bec0d91d4c4851dd935a752bffe07d # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): 1655 | int kvm_arch_ptp_get_crosststamp(u64 *cycle, struct timespec64 *ts, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- 19 | int kvm_arch_ptp_init(void) | ^~~~~~~~~~~~~~~~~ 30 | int kvm_arch_ptp_get_clock(struct timespec64 *ts) | ^~~~~~~~~~~~~~~~~~~~~~ vim +/kvm_arch_ptp_get_crosststamp +1655 drivers/clocksource/arm_arch_timer.c 1654 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org