Hi Oliver, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on kvm/queue] [also build test WARNING on vhost/linux-next v5.14-rc1 next-20210716] [cannot apply to kvmarm/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/Oliver-Upton/KVM-Add-idempotent-... base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue config: x86_64-randconfig-a014-20210718 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 5d5b08761f944d5b9822d582378333cc4b36a0a7) 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 # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # https://github.com/0day-ci/linux/commit/72b6d584e6ac692038a7d70e8782f0dfa... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Oliver-Upton/KVM-Add-idempotent-controls-for-migrating-system-counter-state/20210718-103407 git checkout 72b6d584e6ac692038a7d70e8782f0dfa179e5fb # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 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 >>): * Returns true if realtime and TSC values were written back to the caller. vim +2784 arch/x86/kvm/x86.c 2782 2783 /** 2785 * Returns false if a clock triplet cannot be obtained, such as if the host's 2786 * realtime clock is not based on the TSC. 2787 */ 2788 static bool get_kvmclock_and_realtime(struct kvm *kvm, u64 *kvmclock_ns, 2789 u64 *realtime_ns, u64 *tsc) 2790 { 2791 struct kvm_arch *ka = &kvm->arch; 2792 struct pvclock_vcpu_time_info hv_clock; 2793 unsigned long flags; 2794 bool ret = false; 2795 2796 spin_lock_irqsave(&ka->pvclock_gtod_sync_lock, flags); 2797 if (!ka->use_master_clock) { 2798 spin_unlock_irqrestore(&ka->pvclock_gtod_sync_lock, flags); 2799 *kvmclock_ns = get_kvmclock_base_ns() + ka->kvmclock_offset; 2800 return false; 2801 } 2802 2803 hv_clock.tsc_timestamp = ka->master_cycle_now; 2804 hv_clock.system_time = ka->master_kernel_ns + ka->kvmclock_offset; 2805 spin_unlock_irqrestore(&ka->pvclock_gtod_sync_lock, flags); 2806 2807 /* both __this_cpu_read() and rdtsc() should be on the same cpu */ 2808 get_cpu(); 2809 2810 if (__this_cpu_read(cpu_tsc_khz)) { 2811 struct timespec64 ts; 2812 u64 tsc_val; 2813 2814 kvm_get_time_scale(NSEC_PER_SEC, __this_cpu_read(cpu_tsc_khz) * 1000LL, 2815 &hv_clock.tsc_shift, 2816 &hv_clock.tsc_to_system_mul); 2817 2818 if (kvm_get_walltime_and_clockread(&ts, &tsc_val)) { 2819 *realtime_ns = ts.tv_nsec + NSEC_PER_SEC * ts.tv_sec; 2820 *tsc = tsc_val; 2821 ret = true; 2822 } 2823 2824 *kvmclock_ns = __pvclock_read_cycles(&hv_clock, tsc_val); 2825 } else 2826 *kvmclock_ns = get_kvmclock_base_ns() + ka->kvmclock_offset; 2827 2828 put_cpu(); 2829 2830 return ret; 2831 } 2832 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org