Hi Oliver, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on kvm/linux-next] [also build test WARNING on vhost/linux-next v5.8-rc6 next-20200721] [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_-GET-SET-_TSC_O... base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next config: x86_64-allmodconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-14) 9.3.0 reproduce (this is a W=1 build): # 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 <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): 2052 | void kvm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset, u64 tsc, u64 ns, | ^~~~~~~~~~~~~~~~~~~~ vim +/kvm_write_tsc_offset +2052 arch/x86/kvm/x86.c 2047 2048 /* 2049 * Sets the TSC offset for the vCPU and tracks the TSC matching generation. Must 2050 * hold the kvm->arch.tsc_write_lock to call this function. 2051 */ 2053 bool matched) 2054 { 2055 struct kvm *kvm = vcpu->kvm; 2056 bool already_matched; 2057 2058 already_matched = (vcpu->arch.this_tsc_generation == kvm->arch.cur_tsc_generation); 2059 /* 2060 * We also track the most recent recorded KHZ, write and time to 2061 * allow the matching interval to be extended at each write. 2062 */ 2063 kvm->arch.last_tsc_nsec = ns; 2064 kvm->arch.last_tsc_write = tsc; 2065 kvm->arch.last_tsc_khz = vcpu->arch.virtual_tsc_khz; 2066 2067 vcpu->arch.last_guest_tsc = tsc; 2068 2069 /* Keep track of which generation this VCPU has synchronized to */ 2070 vcpu->arch.this_tsc_generation = kvm->arch.cur_tsc_generation; 2071 vcpu->arch.this_tsc_nsec = kvm->arch.cur_tsc_nsec; 2072 vcpu->arch.this_tsc_write = kvm->arch.cur_tsc_write; 2073 2074 kvm_vcpu_write_tsc_offset(vcpu, offset); 2075 2076 spin_lock(&kvm->arch.pvclock_gtod_sync_lock); 2077 if (!matched) { 2078 /* 2079 * We split periods of matched TSC writes into generations. 2080 * For each generation, we track the original measured 2081 * nanosecond time, offset, and write, so if TSCs are in 2082 * sync, we can match exact offset, and if not, we can match 2083 * exact software computation in compute_guest_tsc() 2084 * 2085 * These values are tracked in kvm->arch.cur_xxx variables. 2086 */ 2087 kvm->arch.nr_vcpus_matched_tsc = 0; 2088 kvm->arch.cur_tsc_generation++; 2089 kvm->arch.cur_tsc_nsec = ns; 2090 kvm->arch.cur_tsc_write = tsc; 2091 kvm->arch.cur_tsc_offset = offset; 2092 } else if (!already_matched) { 2093 kvm->arch.nr_vcpus_matched_tsc++; 2094 } 2095 2096 kvm_track_tsc_matching(vcpu); 2097 spin_unlock(&kvm->arch.pvclock_gtod_sync_lock); 2098 } 2099 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org