> -----Original Message----- > From: kbuild test robot <lkp@xxxxxxxxx> > Sent: Saturday, March 7, 2020 12:28 AM > To: Luwei Kang <luwei.kang@xxxxxxxxx> > Cc: kbuild-all@xxxxxxxxxxxx; x86@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > kvm@xxxxxxxxxxxxxxx; peterz@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; > acme@xxxxxxxxxx; mark.rutland@xxxxxxx; > alexander.shishkin@xxxxxxxxxxxxxxx; jolsa@xxxxxxxxxx; > namhyung@xxxxxxxxxx; tglx@xxxxxxxxxxxxx; bp@xxxxxxxxx; hpa@xxxxxxxxx; > pbonzini@xxxxxxxxxx; sean.j.christopherson@xxxxxxxxx; > vkuznets@xxxxxxxxxx; wanpengli@xxxxxxxxxxx; jmattson@xxxxxxxxxx; > joro@xxxxxxxxxx; pawan.kumar.gupta@xxxxxxxxxxxxxxx; ak@xxxxxxxxxxxxxxx; > thomas.lendacky@xxxxxxx; fenghua.yu@xxxxxxxxx; > kan.liang@xxxxxxxxxxxxxxx; like.xu@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v1 05/11] KVM: x86/pmu: Add support to reprogram PEBS > event for guest counters > > 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-ena > bling-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' Since we may not lose PEBS functionality for other x86 vendors on KVM and we already have defined PERF_X86_EVENT_AUTO_RELOAD in the general arch/x86/events/perf_event.h, one of the ways to fix this issue is to move the definition of perf_x86_pmu_unset_auto_reload() to the end of arch/x86/events/core.c instead of making it Intel specific in previous patch "perf/x86: Expose a function to disable auto-reload." Thanks, Like Xu > > 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
