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Date: Fri, 04 Jul 2014 09:57:42 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [RFC] icount: warp in the main_loop.
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To: Frederic Konrad <fred.konrad@greensocs.com>, qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, mark.burton@greensocs.com

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.

Paolo