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Message-ID: <202005070842.JFNeGs0v%lkp@intel.com>
Date: Thu, 7 May 2020 08:18:45 +0800
From: kbuild test robot <lkp@...el.com>
To: Li RongQing <lirongqing@...du.com>, linux-kernel@...r.kernel.org,
kvm@...r.kernel.org, x86@...nel.org, hpa@...or.com, bp@...en8.de,
mingo@...hat.com, tglx@...utronix.de, jmattson@...gle.com,
wanpengli@...cent.com, vkuznets@...hat.com,
sean.j.christopherson@...el.com, pbonzini@...hat.com,
xiaoyao.li@...el.com, wei.huang2@....com
Cc: kbuild-all@...ts.01.org
Subject: Re: [PATCH] [v4] KVM: X86: support APERF/MPERF registers
Hi Li,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on kvm/linux-next]
[also build test WARNING on next-20200505]
[cannot apply to tip/auto-latest linus/master linux/master v5.7-rc4]
[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/Li-RongQing/KVM-X86-support-APERF-MPERF-registers/20200507-023327
base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next
config: x86_64-allmodconfig (attached as .config)
compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 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 as appropriate
Reported-by: kbuild test robot <lkp@...el.com>
Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
All warnings (new ones prefixed by >>):
arch/x86/kvm/x86.c: In function 'vcpu_enter_guest':
>> arch/x86/kvm/x86.c:8219:13: warning: 'aperf' may be used uninitialized in this function [-Wmaybe-uninitialized]
u64 mperf, aperf;
^~~~~
>> arch/x86/kvm/x86.c:8219:6: warning: 'mperf' may be used uninitialized in this function [-Wmaybe-uninitialized]
u64 mperf, aperf;
^~~~~
vim +/aperf +8219 arch/x86/kvm/x86.c
8203
8204 /*
8205 * Returns 1 to let vcpu_run() continue the guest execution loop without
8206 * exiting to the userspace. Otherwise, the value will be returned to the
8207 * userspace.
8208 */
8209 static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
8210 {
8211 int r;
8212 bool req_int_win =
8213 dm_request_for_irq_injection(vcpu) &&
8214 kvm_cpu_accept_dm_intr(vcpu);
8215 enum exit_fastpath_completion exit_fastpath;
8216
8217 bool enable_aperfmperf = guest_aperfmperf_soft(vcpu->kvm);
8218 bool req_immediate_exit = false;
> 8219 u64 mperf, aperf;
8220
8221 if (kvm_request_pending(vcpu)) {
8222 if (kvm_check_request(KVM_REQ_GET_VMCS12_PAGES, vcpu)) {
8223 if (unlikely(!kvm_x86_ops.nested_ops->get_vmcs12_pages(vcpu))) {
8224 r = 0;
8225 goto out;
8226 }
8227 }
8228 if (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu))
8229 kvm_mmu_unload(vcpu);
8230 if (kvm_check_request(KVM_REQ_MIGRATE_TIMER, vcpu))
8231 __kvm_migrate_timers(vcpu);
8232 if (kvm_check_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu))
8233 kvm_gen_update_masterclock(vcpu->kvm);
8234 if (kvm_check_request(KVM_REQ_GLOBAL_CLOCK_UPDATE, vcpu))
8235 kvm_gen_kvmclock_update(vcpu);
8236 if (kvm_check_request(KVM_REQ_CLOCK_UPDATE, vcpu)) {
8237 r = kvm_guest_time_update(vcpu);
8238 if (unlikely(r))
8239 goto out;
8240 }
8241 if (kvm_check_request(KVM_REQ_MMU_SYNC, vcpu))
8242 kvm_mmu_sync_roots(vcpu);
8243 if (kvm_check_request(KVM_REQ_LOAD_MMU_PGD, vcpu))
8244 kvm_mmu_load_pgd(vcpu);
8245 if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu)) {
8246 kvm_vcpu_flush_tlb_all(vcpu);
8247
8248 /* Flushing all ASIDs flushes the current ASID... */
8249 kvm_clear_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu);
8250 }
8251 if (kvm_check_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu))
8252 kvm_vcpu_flush_tlb_current(vcpu);
8253 if (kvm_check_request(KVM_REQ_HV_TLB_FLUSH, vcpu))
8254 kvm_vcpu_flush_tlb_guest(vcpu);
8255
8256 if (kvm_check_request(KVM_REQ_REPORT_TPR_ACCESS, vcpu)) {
8257 vcpu->run->exit_reason = KVM_EXIT_TPR_ACCESS;
8258 r = 0;
8259 goto out;
8260 }
8261 if (kvm_check_request(KVM_REQ_TRIPLE_FAULT, vcpu)) {
8262 vcpu->run->exit_reason = KVM_EXIT_SHUTDOWN;
8263 vcpu->mmio_needed = 0;
8264 r = 0;
8265 goto out;
8266 }
8267 if (kvm_check_request(KVM_REQ_APF_HALT, vcpu)) {
8268 /* Page is swapped out. Do synthetic halt */
8269 vcpu->arch.apf.halted = true;
8270 r = 1;
8271 goto out;
8272 }
8273 if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu))
8274 record_steal_time(vcpu);
8275 if (kvm_check_request(KVM_REQ_SMI, vcpu))
8276 process_smi(vcpu);
8277 if (kvm_check_request(KVM_REQ_NMI, vcpu))
8278 process_nmi(vcpu);
8279 if (kvm_check_request(KVM_REQ_PMU, vcpu))
8280 kvm_pmu_handle_event(vcpu);
8281 if (kvm_check_request(KVM_REQ_PMI, vcpu))
8282 kvm_pmu_deliver_pmi(vcpu);
8283 if (kvm_check_request(KVM_REQ_IOAPIC_EOI_EXIT, vcpu)) {
8284 BUG_ON(vcpu->arch.pending_ioapic_eoi > 255);
8285 if (test_bit(vcpu->arch.pending_ioapic_eoi,
8286 vcpu->arch.ioapic_handled_vectors)) {
8287 vcpu->run->exit_reason = KVM_EXIT_IOAPIC_EOI;
8288 vcpu->run->eoi.vector =
8289 vcpu->arch.pending_ioapic_eoi;
8290 r = 0;
8291 goto out;
8292 }
8293 }
8294 if (kvm_check_request(KVM_REQ_SCAN_IOAPIC, vcpu))
8295 vcpu_scan_ioapic(vcpu);
8296 if (kvm_check_request(KVM_REQ_LOAD_EOI_EXITMAP, vcpu))
8297 vcpu_load_eoi_exitmap(vcpu);
8298 if (kvm_check_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu))
8299 kvm_vcpu_reload_apic_access_page(vcpu);
8300 if (kvm_check_request(KVM_REQ_HV_CRASH, vcpu)) {
8301 vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
8302 vcpu->run->system_event.type = KVM_SYSTEM_EVENT_CRASH;
8303 r = 0;
8304 goto out;
8305 }
8306 if (kvm_check_request(KVM_REQ_HV_RESET, vcpu)) {
8307 vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
8308 vcpu->run->system_event.type = KVM_SYSTEM_EVENT_RESET;
8309 r = 0;
8310 goto out;
8311 }
8312 if (kvm_check_request(KVM_REQ_HV_EXIT, vcpu)) {
8313 vcpu->run->exit_reason = KVM_EXIT_HYPERV;
8314 vcpu->run->hyperv = vcpu->arch.hyperv.exit;
8315 r = 0;
8316 goto out;
8317 }
8318
8319 /*
8320 * KVM_REQ_HV_STIMER has to be processed after
8321 * KVM_REQ_CLOCK_UPDATE, because Hyper-V SynIC timers
8322 * depend on the guest clock being up-to-date
8323 */
8324 if (kvm_check_request(KVM_REQ_HV_STIMER, vcpu))
8325 kvm_hv_process_stimers(vcpu);
8326 if (kvm_check_request(KVM_REQ_APICV_UPDATE, vcpu))
8327 kvm_vcpu_update_apicv(vcpu);
8328 }
8329
8330 if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) {
8331 ++vcpu->stat.req_event;
8332 kvm_apic_accept_events(vcpu);
8333 if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) {
8334 r = 1;
8335 goto out;
8336 }
8337
8338 if (inject_pending_event(vcpu) != 0)
8339 req_immediate_exit = true;
8340 else {
8341 /* Enable SMI/NMI/IRQ window open exits if needed.
8342 *
8343 * SMIs have three cases:
8344 * 1) They can be nested, and then there is nothing to
8345 * do here because RSM will cause a vmexit anyway.
8346 * 2) There is an ISA-specific reason why SMI cannot be
8347 * injected, and the moment when this changes can be
8348 * intercepted.
8349 * 3) Or the SMI can be pending because
8350 * inject_pending_event has completed the injection
8351 * of an IRQ or NMI from the previous vmexit, and
8352 * then we request an immediate exit to inject the
8353 * SMI.
8354 */
8355 if (vcpu->arch.smi_pending && !is_smm(vcpu))
8356 if (!kvm_x86_ops.enable_smi_window(vcpu))
8357 req_immediate_exit = true;
8358 if (vcpu->arch.nmi_pending)
8359 kvm_x86_ops.enable_nmi_window(vcpu);
8360 if (kvm_cpu_has_injectable_intr(vcpu) || req_int_win)
8361 kvm_x86_ops.enable_irq_window(vcpu);
8362 WARN_ON(vcpu->arch.exception.pending);
8363 }
8364
8365 if (kvm_lapic_enabled(vcpu)) {
8366 update_cr8_intercept(vcpu);
8367 kvm_lapic_sync_to_vapic(vcpu);
8368 }
8369 }
8370
8371 r = kvm_mmu_reload(vcpu);
8372 if (unlikely(r)) {
8373 goto cancel_injection;
8374 }
8375
8376 preempt_disable();
8377
8378 if (unlikely(enable_aperfmperf))
8379 guest_enter_aperfmperf(&mperf, &aperf);
8380
8381 kvm_x86_ops.prepare_guest_switch(vcpu);
8382
8383 /*
8384 * Disable IRQs before setting IN_GUEST_MODE. Posted interrupt
8385 * IPI are then delayed after guest entry, which ensures that they
8386 * result in virtual interrupt delivery.
8387 */
8388 local_irq_disable();
8389 vcpu->mode = IN_GUEST_MODE;
8390
8391 srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
8392
8393 /*
8394 * 1) We should set ->mode before checking ->requests. Please see
8395 * the comment in kvm_vcpu_exiting_guest_mode().
8396 *
8397 * 2) For APICv, we should set ->mode before checking PID.ON. This
8398 * pairs with the memory barrier implicit in pi_test_and_set_on
8399 * (see vmx_deliver_posted_interrupt).
8400 *
8401 * 3) This also orders the write to mode from any reads to the page
8402 * tables done while the VCPU is running. Please see the comment
8403 * in kvm_flush_remote_tlbs.
8404 */
8405 smp_mb__after_srcu_read_unlock();
8406
8407 /*
8408 * This handles the case where a posted interrupt was
8409 * notified with kvm_vcpu_kick.
8410 */
8411 if (kvm_lapic_enabled(vcpu) && vcpu->arch.apicv_active)
8412 kvm_x86_ops.sync_pir_to_irr(vcpu);
8413
8414 if (vcpu->mode == EXITING_GUEST_MODE || kvm_request_pending(vcpu)
8415 || need_resched() || signal_pending(current)) {
8416 vcpu->mode = OUTSIDE_GUEST_MODE;
8417 smp_wmb();
8418 local_irq_enable();
8419 preempt_enable();
8420 vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
8421 r = 1;
8422 goto cancel_injection;
8423 }
8424
8425 if (req_immediate_exit) {
8426 kvm_make_request(KVM_REQ_EVENT, vcpu);
8427 kvm_x86_ops.request_immediate_exit(vcpu);
8428 }
8429
8430 trace_kvm_entry(vcpu->vcpu_id);
8431 guest_enter_irqoff();
8432
8433 fpregs_assert_state_consistent();
8434 if (test_thread_flag(TIF_NEED_FPU_LOAD))
8435 switch_fpu_return();
8436
8437 if (unlikely(vcpu->arch.switch_db_regs)) {
8438 set_debugreg(0, 7);
8439 set_debugreg(vcpu->arch.eff_db[0], 0);
8440 set_debugreg(vcpu->arch.eff_db[1], 1);
8441 set_debugreg(vcpu->arch.eff_db[2], 2);
8442 set_debugreg(vcpu->arch.eff_db[3], 3);
8443 set_debugreg(vcpu->arch.dr6, 6);
8444 vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_RELOAD;
8445 }
8446
8447 exit_fastpath = kvm_x86_ops.run(vcpu);
8448
8449 /*
8450 * Do this here before restoring debug registers on the host. And
8451 * since we do this before handling the vmexit, a DR access vmexit
8452 * can (a) read the correct value of the debug registers, (b) set
8453 * KVM_DEBUGREG_WONT_EXIT again.
8454 */
8455 if (unlikely(vcpu->arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT)) {
8456 WARN_ON(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP);
8457 kvm_x86_ops.sync_dirty_debug_regs(vcpu);
8458 kvm_update_dr0123(vcpu);
8459 kvm_update_dr6(vcpu);
8460 kvm_update_dr7(vcpu);
8461 vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_RELOAD;
8462 }
8463
8464 /*
8465 * If the guest has used debug registers, at least dr7
8466 * will be disabled while returning to the host.
8467 * If we don't have active breakpoints in the host, we don't
8468 * care about the messed up debug address registers. But if
8469 * we have some of them active, restore the old state.
8470 */
8471 if (hw_breakpoint_active())
8472 hw_breakpoint_restore();
8473
8474 vcpu->arch.last_guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());
8475
8476 vcpu->mode = OUTSIDE_GUEST_MODE;
8477 smp_wmb();
8478
8479 kvm_x86_ops.handle_exit_irqoff(vcpu);
8480
8481 /*
8482 * Consume any pending interrupts, including the possible source of
8483 * VM-Exit on SVM and any ticks that occur between VM-Exit and now.
8484 * An instruction is required after local_irq_enable() to fully unblock
8485 * interrupts on processors that implement an interrupt shadow, the
8486 * stat.exits increment will do nicely.
8487 */
8488 kvm_before_interrupt(vcpu);
8489 local_irq_enable();
8490 ++vcpu->stat.exits;
8491 local_irq_disable();
8492 kvm_after_interrupt(vcpu);
8493
8494 guest_exit_irqoff();
8495 if (lapic_in_kernel(vcpu)) {
8496 s64 delta = vcpu->arch.apic->lapic_timer.advance_expire_delta;
8497 if (delta != S64_MIN) {
8498 trace_kvm_wait_lapic_expire(vcpu->vcpu_id, delta);
8499 vcpu->arch.apic->lapic_timer.advance_expire_delta = S64_MIN;
8500 }
8501 }
8502
8503 local_irq_enable();
8504
8505 if (unlikely(enable_aperfmperf))
8506 guest_exit_aperfmperf(vcpu, mperf, aperf);
8507
8508 preempt_enable();
8509
8510 vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
8511
8512 /*
8513 * Profile KVM exit RIPs:
8514 */
8515 if (unlikely(prof_on == KVM_PROFILING)) {
8516 unsigned long rip = kvm_rip_read(vcpu);
8517 profile_hit(KVM_PROFILING, (void *)rip);
8518 }
8519
8520 if (unlikely(vcpu->arch.tsc_always_catchup))
8521 kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
8522
8523 if (vcpu->arch.apic_attention)
8524 kvm_lapic_sync_from_vapic(vcpu);
8525
8526 r = kvm_x86_ops.handle_exit(vcpu, exit_fastpath);
8527 return r;
8528
8529 cancel_injection:
8530 kvm_x86_ops.cancel_injection(vcpu);
8531 if (unlikely(vcpu->arch.apic_attention))
8532 kvm_lapic_sync_from_vapic(vcpu);
8533 out:
8534 return r;
8535 }
8536
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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