Hi Wanpeng, I love your patch! Perhaps something to improve: [auto build test WARNING on kvm/linux-next] [also build test WARNING on linux/master vhost/linux-next next-20210125] [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/Wanpeng-Li/KVM-kvmclock-Fix-vCPUs-64-can-t-be-online-hotpluged/20210201-163927 base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next config: x86_64-allyesconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/132ae1cea476666dff619b5a7c5675011edd7fe7 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Wanpeng-Li/KVM-kvmclock-Fix-vCPUs-64-can-t-be-online-hotpluged/20210201-163927 git checkout 132ae1cea476666dff619b5a7c5675011edd7fe7 # save the attached .config to linux build tree make W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): arch/x86/kernel/kvmclock.c: In function 'kvm_setup_vsyscall_timeinfo': >> arch/x86/kernel/kvmclock.c:274:2: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] 274 | u8 flags; | ^~ vim +274 arch/x86/kernel/kvmclock.c 6a1cac56f41f9e Brijesh Singh 2018-09-14 268 e499a9b6dc488a Thomas Gleixner 2018-07-19 269 static int __init kvm_setup_vsyscall_timeinfo(void) e499a9b6dc488a Thomas Gleixner 2018-07-19 270 { 132ae1cea47666 Wanpeng Li 2021-02-01 271 kvmclock_init_mem(); 132ae1cea47666 Wanpeng Li 2021-02-01 272 e499a9b6dc488a Thomas Gleixner 2018-07-19 273 #ifdef CONFIG_X86_64 e499a9b6dc488a Thomas Gleixner 2018-07-19 @274 u8 flags; e499a9b6dc488a Thomas Gleixner 2018-07-19 275 95a3d4454bb1cf Thomas Gleixner 2018-07-19 276 if (!per_cpu(hv_clock_per_cpu, 0) || !kvmclock_vsyscall) e499a9b6dc488a Thomas Gleixner 2018-07-19 277 return 0; e499a9b6dc488a Thomas Gleixner 2018-07-19 278 95a3d4454bb1cf Thomas Gleixner 2018-07-19 279 flags = pvclock_read_flags(&hv_clock_boot[0].pvti); e499a9b6dc488a Thomas Gleixner 2018-07-19 280 if (!(flags & PVCLOCK_TSC_STABLE_BIT)) 95a3d4454bb1cf Thomas Gleixner 2018-07-19 281 return 0; e499a9b6dc488a Thomas Gleixner 2018-07-19 282 b95a8a27c300d1 Thomas Gleixner 2020-02-07 283 kvm_clock.vdso_clock_mode = VDSO_CLOCKMODE_PVCLOCK; e499a9b6dc488a Thomas Gleixner 2018-07-19 284 #endif 6a1cac56f41f9e Brijesh Singh 2018-09-14 285 e499a9b6dc488a Thomas Gleixner 2018-07-19 286 return 0; e499a9b6dc488a Thomas Gleixner 2018-07-19 287 } e499a9b6dc488a Thomas Gleixner 2018-07-19 288 early_initcall(kvm_setup_vsyscall_timeinfo); e499a9b6dc488a Thomas Gleixner 2018-07-19 289 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org