On Tue, 28 Jun 2016 13:56:38 -0400 (EDT) Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > > > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > > > index fdc05ae..b15e32a 100644 > > > --- a/arch/x86/kvm/lapic.c > > > +++ b/arch/x86/kvm/lapic.c > > > @@ -1454,11 +1454,18 @@ static void start_apic_timer(struct > > > kvm_lapic *apic) /* lapic timer in tsc deadline mode */ > > > u64 tscdeadline = apic->lapic_timer.tscdeadline; > > > > > > - if (kvm_x86_ops->set_hv_timer && > > > - !kvm_x86_ops->set_hv_timer(apic->vcpu, > > > tscdeadline)) { > > > - apic->lapic_timer.hv_timer_in_use = true; > > > - > > > trace_kvm_hv_timer_state(apic->vcpu->vcpu_id, > > > + if (kvm_x86_ops->set_hv_timer) { > > > + if (kvm_x86_ops->set_hv_timer(apic->vcpu, > > > > Would it be better that if set_hv_timer fails, we clear the vmx > > timer (i.e. the VMCS field) before return the failure? I'm not sure > > if it make sense to clear the previous setup if a new setup fails, > > although it seems OK for me, since we have to cancel the hv_timer > > anyway. > > Good question. I think we should abstract a little the set_hv_timer > and cancel_hv_timer calls, for example with a new function > start_hv_tscdeadline. It's also simpler to avoid the race window by > disabling interrupts around the calls to set_hv_timer and > hrtimer_cancel. I'll see what I can come up with. Paolo, thanks for reply. Which race window you are talking about? Is it the kvm_lapic_switch_to_hv_timer()? If yes, hope we will not forgot it once the lapic timer is not pinned anymore in future. Thanks --jyh > > Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html