Hi Luwei, Thank you for the patch! Yet something to improve: [auto build test ERROR on kvm/linux-next] [also build test ERROR on tip/perf/core tip/auto-latest v5.6-rc4 next-20200306] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Luwei-Kang/PEBS-virtualization-enabling-via-DS/20200306-013049 base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next config: x86_64-randconfig-h003-20200305 (attached as .config) compiler: gcc-7 (Debian 7.5.0-5) 7.5.0 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 If you fix the issue, kindly add following tag Reported-by: kbuild test robot <lkp@xxxxxxxxx> All errors (new ones prefixed by >>): ld: arch/x86/kvm/pmu.o: in function `pmc_reprogram_counter': >> arch/x86/kvm/pmu.c:199: undefined reference to `perf_x86_pmu_unset_auto_reload' vim +199 arch/x86/kvm/pmu.c 101 102 static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type, 103 unsigned config, bool exclude_user, 104 bool exclude_kernel, bool intr, 105 bool in_tx, bool in_tx_cp) 106 { 107 struct kvm_pmu *pmu = vcpu_to_pmu(pmc->vcpu); 108 struct perf_event *event; 109 struct perf_event_attr attr = { 110 .type = type, 111 .size = sizeof(attr), 112 .pinned = true, 113 .exclude_idle = true, 114 .exclude_host = 1, 115 .exclude_user = exclude_user, 116 .exclude_kernel = exclude_kernel, 117 .config = config, 118 .disabled = 1, 119 }; 120 bool pebs = test_bit(pmc->idx, (unsigned long *)&pmu->pebs_enable); 121 122 attr.sample_period = (-pmc->counter) & pmc_bitmask(pmc); 123 124 if (in_tx) 125 attr.config |= HSW_IN_TX; 126 if (in_tx_cp) { 127 /* 128 * HSW_IN_TX_CHECKPOINTED is not supported with nonzero 129 * period. Just clear the sample period so at least 130 * allocating the counter doesn't fail. 131 */ 132 attr.sample_period = 0; 133 attr.config |= HSW_IN_TX_CHECKPOINTED; 134 } 135 136 if (pebs) { 137 /* 138 * Host never knows the precision level set by guest. 139 * Force Host's PEBS event to precision level 1, which will 140 * not impact the accuracy of the results for guest PEBS events. 141 * Because, 142 * - For most cases, there is no difference among precision 143 * level 1 to 3 for PEBS events. 144 * - The functions as below checks the precision level in host. 145 * But the results from these functions in host are replaced 146 * by guest when sampling the guest. 147 * The accuracy for guest PEBS events will not be impacted. 148 * -- event_constraints() impacts the index of counter. 149 * The index for host event is exactly the same as guest. 150 * It's decided by guest. 151 * -- pebs_update_adaptive_cfg() impacts the value of 152 * MSR_PEBS_DATA_CFG. When guest is switched in, 153 * the MSR value will be replaced by the value from guest. 154 * -- setup_sample () impacts the output of a PEBS record. 155 * Guest handles the PEBS records. 156 */ 157 attr.precise_ip = 1; 158 /* 159 * When the host's PMI handler completes, it's going to 160 * enter the guest and trigger the guest's PMI handler. 161 * 162 * At this moment, this function may be called by 163 * kvm_pmu_handle_event(). However the next sample_period 164 * hasn't been determined by guest yet and the left period, 165 * which probably be 0, is used for current sample_period. 166 * 167 * In this case, perf will mistakenly treat it as non 168 * sampling events. The PEBS event will error out. 169 * 170 * Fill it with maximum period to prevent the error out. 171 * The guest PMI handler will soon reprogram the counter. 172 */ 173 if (!attr.sample_period) 174 attr.sample_period = (-1ULL) & pmc_bitmask(pmc); 175 } 176 177 event = perf_event_create_kernel_counter(&attr, -1, current, 178 (intr || pebs) ? 179 kvm_perf_overflow_intr : 180 kvm_perf_overflow, pmc); 181 if (IS_ERR(event)) { 182 pr_debug_ratelimited("kvm_pmu: event creation failed %ld for pmc->idx = %d\n", 183 PTR_ERR(event), pmc->idx); 184 return; 185 } 186 187 if (pebs) { 188 event->guest_dedicated_idx = pmc->idx; 189 /* 190 * For guest PEBS events, guest takes the responsibility to 191 * drain PEBS buffers, and load proper values to reset counters. 192 * 193 * Host will unconditionally set auto-reload flag for PEBS 194 * events with fixed period which is not necessary. Host should 195 * do nothing in drain_pebs() but inject the PMI into the guest. 196 * 197 * Unset the auto-reload flag for guest PEBS events. 198 */ > 199 perf_x86_pmu_unset_auto_reload(event); 200 } 201 pmc->perf_event = event; 202 pmc_to_pmu(pmc)->event_count++; 203 perf_event_enable(event); 204 clear_bit(pmc->idx, pmc_to_pmu(pmc)->reprogram_pmi); 205 } 206 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
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