Re: [Qemu-devel] [RFC] icount: warp in the main_loop.

[Frederic Konrad <fred.konrad@greensocs.com>]

On 04/07/2014 09:57, Paolo Bonzini wrote:
> Il 04/07/2014 09:30, Frederic Konrad ha scritto:
>>>   +    /*
>>> +     * In icount mode, sometimes the VCPU is blocked and an event is
>>> needed to
>>> +     * continue.
>>> +     * Just warp to make the time grows and have a chance to run the
>>> CPU.
>>> +     */
>>> +    qemu_clock_warp(QEMU_CLOCK_VIRTUAL);
>>>       return ret;
>>>   }
>>>
>> Paolo,
>> You mentioned some icount patches (I can't find where) can you point me
>> to them?
>> Did you already had this bug?
>
> Why is this needed?  It's possible that a qemu_clock_warp code is 
> missing somewhere, but for timers it should be handled here:
>
> static void timerlist_rearm(QEMUTimerList *timer_list)
> {
>     /* Interrupt execution to force deadline recalculation.  */
>     qemu_clock_warp(timer_list->clock->type);
>     timerlist_notify(timer_list);
> }
>
> If the VCPU is blocked, it will set vm_clock_warp_start to the 
> realtime clock value ("clock") a QEMU_CLOCK_REALTIME timer to the next 
> deadline ("clock + deadline").  At the next deadline, icount_warp_rt 
> will increase QEMU_CLOCK_VIRTUAL by "clock - vm_clock_warp_state" 
> which should trigger the clock event.

Right, but when I put a timer eg on QEMU_VIRTUAL_CLOCK the guest is stuck.
icount_warp_rt is not called neither qemu_clock_warp(..)..

So yes as you said seems a qemu_clock_warp is missing somewhere.

Shouldn't icount_warp_rt called regularly to advance the time when the 
VCPU is not
executing?

Thanks,
Fred
>
> Paolo