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Date: Sat, 7 Mar 2020 00:28:15 +0800
From: kbuild test robot <lkp@...el.com>
To: Luwei Kang <luwei.kang@...el.com>
Cc: kbuild-all@...ts.01.org, x86@...nel.org,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
mark.rutland@....com, alexander.shishkin@...ux.intel.com,
jolsa@...hat.com, namhyung@...nel.org, tglx@...utronix.de,
bp@...en8.de, hpa@...or.com, pbonzini@...hat.com,
sean.j.christopherson@...el.com, vkuznets@...hat.com,
wanpengli@...cent.com, jmattson@...gle.com, joro@...tes.org,
pawan.kumar.gupta@...ux.intel.com, ak@...ux.intel.com,
thomas.lendacky@....com, fenghua.yu@...el.com,
kan.liang@...ux.intel.com, like.xu@...ux.intel.com
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-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@...el.com>
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@lists.01.org
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