4:55 a.m.
Hi David,
I love your patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v5.16-rc2]
[cannot apply to kvm/queue kvms390/next powerpc/topic/ppc-kvm kvmarm/next
mst-vhost/linux-next next-20211124]
[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/David-Woodhouse/KVM-Introduce-CO...
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
a90af8f15bdc9449ee2d24e1d73fa3f7e8633f81
config: i386-randconfig-a012-20211120
(https://download.01.org/0day-ci/archive/20211125/202111250122.hrwuy18G-lk...)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
#
https://github.com/0day-ci/linux/commit/cc99b12d3d722f77f611a364b7a359bb3...
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review
David-Woodhouse/KVM-Introduce-CONFIG_HAVE_KVM_DIRTY_RING/20211120-192837
git checkout cc99b12d3d722f77f611a364b7a359bb3105ad44
# save the config file to linux build tree
make W=1 ARCH=i386
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp(a)intel.com>
All errors (new ones prefixed by >>):
arch/x86/kvm/x86.c: In function 'vcpu_enter_guest':
> arch/x86/kvm/x86.c:9743:4: error: suggest braces around empty
body in an 'if' statement [-Werror=empty-body]
9743 | ; /* Nothing to
do. It just wanted to wake us */
| ^
cc1: all warnings being treated as errors
vim +/if +9743 arch/x86/kvm/x86.c
9593
9594 /*
9595 * Returns 1 to let vcpu_run() continue the guest execution loop without
9596 * exiting to the userspace. Otherwise, the value will be returned to the
9597 * userspace.
9598 */
9599 static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
9600 {
9601 int r;
9602 bool req_int_win =
9603 dm_request_for_irq_injection(vcpu) &&
9604 kvm_cpu_accept_dm_intr(vcpu);
9605 fastpath_t exit_fastpath;
9606
9607 bool req_immediate_exit = false;
9608
9609 /* Forbid vmenter if vcpu dirty ring is soft-full */
9610 if (unlikely(vcpu->kvm->dirty_ring_size &&
9611 kvm_dirty_ring_soft_full(&vcpu->dirty_ring))) {
9612 vcpu->run->exit_reason = KVM_EXIT_DIRTY_RING_FULL;
9613 trace_kvm_dirty_ring_exit(vcpu);
9614 r = 0;
9615 goto out;
9616 }
9617
9618 if (kvm_request_pending(vcpu)) {
9619 if (kvm_check_request(KVM_REQ_VM_DEAD, vcpu)) {
9620 r = -EIO;
9621 goto out;
9622 }
9623 if (kvm_check_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu)) {
9624 if (unlikely(!kvm_x86_ops.nested_ops->get_nested_state_pages(vcpu))) {
9625 r = 0;
9626 goto out;
9627 }
9628 }
9629 if (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu))
9630 kvm_mmu_unload(vcpu);
9631 if (kvm_check_request(KVM_REQ_MIGRATE_TIMER, vcpu))
9632 __kvm_migrate_timers(vcpu);
9633 if (kvm_check_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu))
9634 kvm_update_masterclock(vcpu->kvm);
9635 if (kvm_check_request(KVM_REQ_GLOBAL_CLOCK_UPDATE, vcpu))
9636 kvm_gen_kvmclock_update(vcpu);
9637 if (kvm_check_request(KVM_REQ_CLOCK_UPDATE, vcpu)) {
9638 r = kvm_guest_time_update(vcpu);
9639 if (unlikely(r))
9640 goto out;
9641 }
9642 if (kvm_check_request(KVM_REQ_MMU_SYNC, vcpu))
9643 kvm_mmu_sync_roots(vcpu);
9644 if (kvm_check_request(KVM_REQ_LOAD_MMU_PGD, vcpu))
9645 kvm_mmu_load_pgd(vcpu);
9646 if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu)) {
9647 kvm_vcpu_flush_tlb_all(vcpu);
9648
9649 /* Flushing all ASIDs flushes the current ASID... */
9650 kvm_clear_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu);
9651 }
9652 if (kvm_check_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu))
9653 kvm_vcpu_flush_tlb_current(vcpu);
9654 if (kvm_check_request(KVM_REQ_TLB_FLUSH_GUEST, vcpu))
9655 kvm_vcpu_flush_tlb_guest(vcpu);
9656
9657 if (kvm_check_request(KVM_REQ_REPORT_TPR_ACCESS, vcpu)) {
9658 vcpu->run->exit_reason = KVM_EXIT_TPR_ACCESS;
9659 r = 0;
9660 goto out;
9661 }
9662 if (kvm_check_request(KVM_REQ_TRIPLE_FAULT, vcpu)) {
9663 if (is_guest_mode(vcpu)) {
9664 kvm_x86_ops.nested_ops->triple_fault(vcpu);
9665 } else {
9666 vcpu->run->exit_reason = KVM_EXIT_SHUTDOWN;
9667 vcpu->mmio_needed = 0;
9668 r = 0;
9669 goto out;
9670 }
9671 }
9672 if (kvm_check_request(KVM_REQ_APF_HALT, vcpu)) {
9673 /* Page is swapped out. Do synthetic halt */
9674 vcpu->arch.apf.halted = true;
9675 r = 1;
9676 goto out;
9677 }
9678 if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu))
9679 record_steal_time(vcpu);
9680 if (kvm_check_request(KVM_REQ_SMI, vcpu))
9681 process_smi(vcpu);
9682 if (kvm_check_request(KVM_REQ_NMI, vcpu))
9683 process_nmi(vcpu);
9684 if (kvm_check_request(KVM_REQ_PMU, vcpu))
9685 kvm_pmu_handle_event(vcpu);
9686 if (kvm_check_request(KVM_REQ_PMI, vcpu))
9687 kvm_pmu_deliver_pmi(vcpu);
9688 if (kvm_check_request(KVM_REQ_IOAPIC_EOI_EXIT, vcpu)) {
9689 BUG_ON(vcpu->arch.pending_ioapic_eoi > 255);
9690 if (test_bit(vcpu->arch.pending_ioapic_eoi,
9691 vcpu->arch.ioapic_handled_vectors)) {
9692 vcpu->run->exit_reason = KVM_EXIT_IOAPIC_EOI;
9693 vcpu->run->eoi.vector =
9694 vcpu->arch.pending_ioapic_eoi;
9695 r = 0;
9696 goto out;
9697 }
9698 }
9699 if (kvm_check_request(KVM_REQ_SCAN_IOAPIC, vcpu))
9700 vcpu_scan_ioapic(vcpu);
9701 if (kvm_check_request(KVM_REQ_LOAD_EOI_EXITMAP, vcpu))
9702 vcpu_load_eoi_exitmap(vcpu);
9703 if (kvm_check_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu))
9704 kvm_vcpu_reload_apic_access_page(vcpu);
9705 if (kvm_check_request(KVM_REQ_HV_CRASH, vcpu)) {
9706 vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
9707 vcpu->run->system_event.type = KVM_SYSTEM_EVENT_CRASH;
9708 r = 0;
9709 goto out;
9710 }
9711 if (kvm_check_request(KVM_REQ_HV_RESET, vcpu)) {
9712 vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
9713 vcpu->run->system_event.type = KVM_SYSTEM_EVENT_RESET;
9714 r = 0;
9715 goto out;
9716 }
9717 if (kvm_check_request(KVM_REQ_HV_EXIT, vcpu)) {
9718 struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
9719
9720 vcpu->run->exit_reason = KVM_EXIT_HYPERV;
9721 vcpu->run->hyperv = hv_vcpu->exit;
9722 r = 0;
9723 goto out;
9724 }
9725
9726 /*
9727 * KVM_REQ_HV_STIMER has to be processed after
9728 * KVM_REQ_CLOCK_UPDATE, because Hyper-V SynIC timers
9729 * depend on the guest clock being up-to-date
9730 */
9731 if (kvm_check_request(KVM_REQ_HV_STIMER, vcpu))
9732 kvm_hv_process_stimers(vcpu);
9733 if (kvm_check_request(KVM_REQ_APICV_UPDATE, vcpu))
9734 kvm_vcpu_update_apicv(vcpu);
9735 if (kvm_check_request(KVM_REQ_APF_READY, vcpu))
9736 kvm_check_async_pf_completion(vcpu);
9737 if (kvm_check_request(KVM_REQ_MSR_FILTER_CHANGED, vcpu))
9738 static_call(kvm_x86_msr_filter_changed)(vcpu);
9739
9740 if (kvm_check_request(KVM_REQ_UPDATE_CPU_DIRTY_LOGGING, vcpu))
9741 static_call(kvm_x86_update_cpu_dirty_logging)(vcpu);
9742 if (kvm_check_request(KVM_REQ_GPC_INVALIDATE, vcpu))
9743 ; /* Nothing to do. It just wanted to wake us */
9744 }
9745
9746 if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win ||
9747 kvm_xen_has_interrupt(vcpu)) {
9748 ++vcpu->stat.req_event;
9749 r = kvm_apic_accept_events(vcpu);
9750 if (r < 0) {
9751 r = 0;
9752 goto out;
9753 }
9754 if (vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) {
9755 r = 1;
9756 goto out;
9757 }
9758
9759 r = inject_pending_event(vcpu, &req_immediate_exit);
9760 if (r < 0) {
9761 r = 0;
9762 goto out;
9763 }
9764 if (req_int_win)
9765 static_call(kvm_x86_enable_irq_window)(vcpu);
9766
9767 if (kvm_lapic_enabled(vcpu)) {
9768 update_cr8_intercept(vcpu);
9769 kvm_lapic_sync_to_vapic(vcpu);
9770 }
9771 }
9772
9773 r = kvm_mmu_reload(vcpu);
9774 if (unlikely(r)) {
9775 goto cancel_injection;
9776 }
9777
9778 preempt_disable();
9779
9780 static_call(kvm_x86_prepare_guest_switch)(vcpu);
9781
9782 /*
9783 * Disable IRQs before setting IN_GUEST_MODE. Posted interrupt
9784 * IPI are then delayed after guest entry, which ensures that they
9785 * result in virtual interrupt delivery.
9786 */
9787 local_irq_disable();
9788 vcpu->mode = IN_GUEST_MODE;
9789
9790 /*
9791 * If the guest requires direct access to mapped L1 pages, check
9792 * the caches are valid. Will raise KVM_REQ_GET_NESTED_STATE_PAGES
9793 * to go and revalidate them, if necessary.
9794 */
9795 if (is_guest_mode(vcpu) && kvm_x86_ops.nested_ops->check_guest_maps)
9796 kvm_x86_ops.nested_ops->check_guest_maps(vcpu);
9797
9798 srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
9799
9800 /*
9801 * 1) We should set ->mode before checking ->requests. Please see
9802 * the comment in kvm_vcpu_exiting_guest_mode().
9803 *
9804 * 2) For APICv, we should set ->mode before checking PID.ON. This
9805 * pairs with the memory barrier implicit in pi_test_and_set_on
9806 * (see vmx_deliver_posted_interrupt).
9807 *
9808 * 3) This also orders the write to mode from any reads to the page
9809 * tables done while the VCPU is running. Please see the comment
9810 * in kvm_flush_remote_tlbs.
9811 */
9812 smp_mb__after_srcu_read_unlock();
9813
9814 /*
9815 * This handles the case where a posted interrupt was
9816 * notified with kvm_vcpu_kick.
9817 */
9818 if (kvm_lapic_enabled(vcpu) && vcpu->arch.apicv_active)
9819 static_call(kvm_x86_sync_pir_to_irr)(vcpu);
9820
9821 if (kvm_vcpu_exit_request(vcpu)) {
9822 vcpu->mode = OUTSIDE_GUEST_MODE;
9823 smp_wmb();
9824 local_irq_enable();
9825 preempt_enable();
9826 vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
9827 r = 1;
9828 goto cancel_injection;
9829 }
9830
9831 if (req_immediate_exit) {
9832 kvm_make_request(KVM_REQ_EVENT, vcpu);
9833 static_call(kvm_x86_request_immediate_exit)(vcpu);
9834 }
9835
9836 fpregs_assert_state_consistent();
9837 if (test_thread_flag(TIF_NEED_FPU_LOAD))
9838 switch_fpu_return();
9839
9840 if (unlikely(vcpu->arch.switch_db_regs)) {
9841 set_debugreg(0, 7);
9842 set_debugreg(vcpu->arch.eff_db[0], 0);
9843 set_debugreg(vcpu->arch.eff_db[1], 1);
9844 set_debugreg(vcpu->arch.eff_db[2], 2);
9845 set_debugreg(vcpu->arch.eff_db[3], 3);
9846 } else if (unlikely(hw_breakpoint_active())) {
9847 set_debugreg(0, 7);
9848 }
9849
9850 for (;;) {
9851 /*
9852 * Assert that vCPU vs. VM APICv state is consistent. An APICv
9853 * update must kick and wait for all vCPUs before toggling the
9854 * per-VM state, and responsing vCPUs must wait for the update
9855 * to complete before servicing KVM_REQ_APICV_UPDATE.
9856 */
9857 WARN_ON_ONCE(kvm_apicv_activated(vcpu->kvm) != kvm_vcpu_apicv_active(vcpu));
9858
9859 exit_fastpath = static_call(kvm_x86_run)(vcpu);
9860 if (likely(exit_fastpath != EXIT_FASTPATH_REENTER_GUEST))
9861 break;
9862
9863 if (vcpu->arch.apicv_active)
9864 static_call(kvm_x86_sync_pir_to_irr)(vcpu);
9865
9866 if (unlikely(kvm_vcpu_exit_request(vcpu))) {
9867 exit_fastpath = EXIT_FASTPATH_EXIT_HANDLED;
9868 break;
9869 }
9870 }
9871
9872 /*
9873 * Do this here before restoring debug registers on the host. And
9874 * since we do this before handling the vmexit, a DR access vmexit
9875 * can (a) read the correct value of the debug registers, (b) set
9876 * KVM_DEBUGREG_WONT_EXIT again.
9877 */
9878 if (unlikely(vcpu->arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT)) {
9879 WARN_ON(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP);
9880 static_call(kvm_x86_sync_dirty_debug_regs)(vcpu);
9881 kvm_update_dr0123(vcpu);
9882 kvm_update_dr7(vcpu);
9883 }
9884
9885 /*
9886 * If the guest has used debug registers, at least dr7
9887 * will be disabled while returning to the host.
9888 * If we don't have active breakpoints in the host, we don't
9889 * care about the messed up debug address registers. But if
9890 * we have some of them active, restore the old state.
9891 */
9892 if (hw_breakpoint_active())
9893 hw_breakpoint_restore();
9894
9895 vcpu->arch.last_vmentry_cpu = vcpu->cpu;
9896 vcpu->arch.last_guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());
9897
9898 vcpu->mode = OUTSIDE_GUEST_MODE;
9899 smp_wmb();
9900
9901 static_call(kvm_x86_handle_exit_irqoff)(vcpu);
9902
9903 /*
9904 * Consume any pending interrupts, including the possible source of
9905 * VM-Exit on SVM and any ticks that occur between VM-Exit and now.
9906 * An instruction is required after local_irq_enable() to fully unblock
9907 * interrupts on processors that implement an interrupt shadow, the
9908 * stat.exits increment will do nicely.
9909 */
9910 kvm_before_interrupt(vcpu);
9911 local_irq_enable();
9912 ++vcpu->stat.exits;
9913 local_irq_disable();
9914 kvm_after_interrupt(vcpu);
9915
9916 /*
9917 * Wait until after servicing IRQs to account guest time so that any
9918 * ticks that occurred while running the guest are properly accounted
9919 * to the guest. Waiting until IRQs are enabled degrades the accuracy
9920 * of accounting via context tracking, but the loss of accuracy is
9921 * acceptable for all known use cases.
9922 */
9923 vtime_account_guest_exit();
9924
9925 if (lapic_in_kernel(vcpu)) {
9926 s64 delta = vcpu->arch.apic->lapic_timer.advance_expire_delta;
9927 if (delta != S64_MIN) {
9928 trace_kvm_wait_lapic_expire(vcpu->vcpu_id, delta);
9929 vcpu->arch.apic->lapic_timer.advance_expire_delta = S64_MIN;
9930 }
9931 }
9932
9933 local_irq_enable();
9934 preempt_enable();
9935
9936 vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
9937
9938 /*
9939 * Profile KVM exit RIPs:
9940 */
9941 if (unlikely(prof_on == KVM_PROFILING)) {
9942 unsigned long rip = kvm_rip_read(vcpu);
9943 profile_hit(KVM_PROFILING, (void *)rip);
9944 }
9945
9946 if (unlikely(vcpu->arch.tsc_always_catchup))
9947 kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
9948
9949 if (vcpu->arch.apic_attention)
9950 kvm_lapic_sync_from_vapic(vcpu);
9951
9952 r = static_call(kvm_x86_handle_exit)(vcpu, exit_fastpath);
9953 return r;
9954
9955 cancel_injection:
9956 if (req_immediate_exit)
9957 kvm_make_request(KVM_REQ_EVENT, vcpu);
9958 static_call(kvm_x86_cancel_injection)(vcpu);
9959 if (unlikely(vcpu->arch.apic_attention))
9960 kvm_lapic_sync_from_vapic(vcpu);
9961 out:
9962 return r;
9963 }
9964
---
0-DAY CI Kernel Test Service, Intel Corporation
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