Re: [Qemu-devel] [PATCH] Change RTC time drift IRQ re-injection

[Anthony Liguori <aliguori@us.ibm.com>]

Gleb Natapov wrote:
> Currently IRQ are reinjected as soon as they are acknowledged to
> the RTC, but Windows sometimes do acknowledgement in a loop with
> global interrupt disabled waiting for interrupt to be cleared and
> it does not mask RTC vector in PIC/APIC while doing this. In such
> situation interrupt injection always fails and RTC interrupt is never
> cleared.
>
> Instead of reinjecting coalesced IRQs on acknowledgement the patch below
> reinjects them by accelerating RTC clock a bit. This way RTC interrupt
> is not constantly raced after coalesced interrupt.
>
> Signed-off-by: Gleb Natapov <gleb@redhat.com>
>              s->cmos_data[RTC_REG_C] = 0x00;
>              break;
>          default:
> @@ -512,6 +539,7 @@ static void rtc_save_td(QEMUFile *f, void *opaque)
>  
>      qemu_put_be32(f, s->irq_coalesced);
>      qemu_put_be32(f, s->period);
> +    qemu_put_timer(f, s->coalesced_timer);
>  }
>  
>  static int rtc_load_td(QEMUFile *f, void *opaque, int version_id)
> @@ -523,6 +551,7 @@ static int rtc_load_td(QEMUFile *f, void *opaque, int version_id)
>  
>      s->irq_coalesced = qemu_get_be32(f);
>      s->period = qemu_get_be32(f);
> +    qemu_get_timer(f, s->coalesced_timer);
>      return 0;
>   

If you're adding something to the savevm format, you have to increment 
the version_id and handle older versions correctly.


-- 
Regards,

Anthony Liguori