| Message ID | 1643102220-35667-1-git-send-email-wanpengli@tencent.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: LAPIC: Also cancel preemption timer during SET_LAPIC | expand |
On 1/25/22 10:17, Wanpeng Li wrote: > From: Wanpeng Li <wanpengli@tencent.com> > > The below warning is splatting during guest reboot. > > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 1931 at arch/x86/kvm/x86.c:10322 kvm_arch_vcpu_ioctl_run+0x874/0x880 [kvm] > CPU: 0 PID: 1931 Comm: qemu-system-x86 Tainted: G I 5.17.0-rc1+ #5 > RIP: 0010:kvm_arch_vcpu_ioctl_run+0x874/0x880 [kvm] > Call Trace: > <TASK> > kvm_vcpu_ioctl+0x279/0x710 [kvm] > __x64_sys_ioctl+0x83/0xb0 > do_syscall_64+0x3b/0xc0 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x7fd39797350b > > This can be triggered by not exposing tsc-deadline mode and doing a reboot in > the guest. The lapic_shutdown() function which is called in sys_reboot path > will not disarm the flying timer, it just masks LVTT. lapic_shutdown() clears > APIC state w/ LVT_MASKED and timer-mode bit is 0, this can trigger timer-mode > switch between tsc-deadline and oneshot/periodic, which can result in preemption > timer be cancelled in apic_update_lvtt(). However, We can't depend on this when > not exposing tsc-deadline mode and oneshot/periodic modes emulated by preemption > timer. Qemu will synchronise states around reset, let's cancel preemption timer > under KVM_SET_LAPIC. > > Signed-off-by: Wanpeng Li <wanpengli@tencent.com> > --- > arch/x86/kvm/lapic.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index baca9fa37a91..4662469240bc 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -2629,7 +2629,7 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s) > kvm_apic_set_version(vcpu); > > apic_update_ppr(apic); > - hrtimer_cancel(&apic->lapic_timer.timer); > + cancel_apic_timer(apic); > apic->lapic_timer.expired_tscdeadline = 0; > apic_update_lvtt(apic); > apic_manage_nmi_watchdog(apic, kvm_lapic_get_reg(apic, APIC_LVT0)); Queued, with Cc to stable. Paolo
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index baca9fa37a91..4662469240bc 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2629,7 +2629,7 @@ int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s) kvm_apic_set_version(vcpu); apic_update_ppr(apic); - hrtimer_cancel(&apic->lapic_timer.timer); + cancel_apic_timer(apic); apic->lapic_timer.expired_tscdeadline = 0; apic_update_lvtt(apic); apic_manage_nmi_watchdog(apic, kvm_lapic_get_reg(apic, APIC_LVT0));