2017-06-29 19:43 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>:
>
>
> On 29/06/2017 10:44, Wanpeng Li wrote:
>>>> You still need to enable the preemption timer even if you return 1, so
>>>> in lapic.c it becomes
>>>>
>>>> if (!apic_lvtt_period(apic)) {
>>>> if (r)
>>>> apic_timer_expired(apic);
>>>> if (atomic_read(&apic->lapic_timer.pending))
>>>> need_cancel = true;
>>>> }
>>> I think the codes are more clear but the same as above. We didn't
>>> program preemption timer vmcs field if delta == 0, so how to
>>> understand "need to enable the preemption timer even if return 1"?
>> I guess you mean start_hv_timer() should return true, right?
>
> vmx.c's set_hv_timer callback should set the preemption timer execution
> control. Otherwise, kvm_lapic_hv_timer_expired is again not called.
I see, this should be set for apic timer periodic mode.
Regards,
Wanpeng Li
