Re: [Xen-devel] Xen 4.5 random freeze question

[Andrii Tseglytskyi <andrii.tseglytskyi@xxxxxxxxxxxxxxx>]

Strange - looks like baseline code already does the same, that you
sent me yesterday. The only what is needed - is to set
PLATFORM_QUIRK_GUEST_PIRQ_NEED_EOI.
But baseline contains an issue. And in the same time changes on top of
5495a512b63bad868c147198f7f049c2617d468c work fine.

Regards,
Andrii

On Tue, Nov 18, 2014 at 12:41 PM, Andrii Tseglytskyi
<andrii.tseglytskyi@xxxxxxxxxxxxxxx> wrote:
> Hi Stefano,
>
> On Mon, Nov 17, 2014 at 8:02 PM, Stefano Stabellini
> <stefano.stabellini@xxxxxxxxxxxxx> wrote:
>> On Mon, 17 Nov 2014, Andrii Tseglytskyi wrote:
>>> Hi Stefano,
>>>
>>> Thank you for your answer.
>>>
>>> On Mon, Nov 17, 2014 at 6:39 PM, Stefano Stabellini
>>> <stefano.stabellini@xxxxxxxxxxxxx> wrote:
>>> > Although it is possible that that patch is the cause of your problem,
>>> > unfortunately it is part of a significant rework of the GIC driver in
>>> > Xen and I am afraid that testing with only a portion of that patch
>>> > series might introduce other subtle bugs.  For your reference the series
>>> > starts at commit 6f91502be64a05d0635454d629118b96ae38b50f and ends at
>>> > commit 72eaf29e8d70784aaf066ead79df1295a25ecfd0.
>>> >
>>>
>>> Yes, I tested with and without the whole series.
>>
>> And the result is that the series causes the problem?
>>
>
> Yes.
>
>>
>>> > If 5495a512b63bad868c147198f7f049c2617d468c is really the cause of your
>>> > problem, one idea that comes to mind is that GICH_LR_MAINTENANCE_IRQ
>>> > might not work correctly on your platform. It wouldn't be the first time
>>> > that we see hardware behaving that way, especially if you are using the
>>> > GIC secure registers instead of the non-secure register as GICH_LRn.HW
>>> > can only deactivate non-secure interrupts. This is usually due to a
>>> > configuration error in u-boot.
>>> >
>>> > Could you please try to set PLATFORM_QUIRK_GUEST_PIRQ_NEED_EOI for your
>>> > platform?
>>> >
>>>
>>> I tried this. Unfortunately it doesn't help.
>>
>> Could you try the following patch on top of
>> 5495a512b63bad868c147198f7f049c2617d468c ?
>>
>> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
>> index 302c031..a286376 100644
>> --- a/xen/arch/arm/gic.c
>> +++ b/xen/arch/arm/gic.c
>> @@ -557,10 +557,8 @@ static inline void gic_set_lr(int lr, struct 
>> pending_irq *p,
>>      BUG_ON(lr < 0);
>>      BUG_ON(state & ~(GICH_LR_STATE_MASK<<GICH_LR_STATE_SHIFT));
>>
>> -    lr_val = state | ((p->priority >> 3) << GICH_LR_PRIORITY_SHIFT) |
>> +    lr_val = state | GICH_LR_MAINTENANCE_IRQ | ((p->priority >> 3) << 
>> GICH_LR_PRIORITY_SHIFT) |
>>          ((p->irq & GICH_LR_VIRTUAL_MASK) << GICH_LR_VIRTUAL_SHIFT);
>> -    if ( p->desc != NULL )
>> -        lr_val |= GICH_LR_HW | (p->desc->irq << GICH_LR_PHYSICAL_SHIFT);
>>
>>      GICH[GICH_LR + lr] = lr_val;
>>
>> @@ -622,6 +620,12 @@ out:
>>      return;
>>  }
>>
>> +static void gic_irq_eoi(void *info)
>> +{
>> +    int virq = (uintptr_t) info;
>> +    GICC[GICC_DIR] = virq;
>> +}
>> +
>>  static void gic_update_one_lr(struct vcpu *v, int i)
>>  {
>>      struct pending_irq *p;
>> @@ -639,7 +643,10 @@ static void gic_update_one_lr(struct vcpu *v, int i)
>>          irq = (lr >> GICH_LR_VIRTUAL_SHIFT) & GICH_LR_VIRTUAL_MASK;
>>          p = irq_to_pending(v, irq);
>>          if ( p->desc != NULL )
>> +        {
>> +            gic_irq_eoi((void*)(uintptr_t)irq);
>>              p->desc->status &= ~IRQ_INPROGRESS;
>> +        }
>>          clear_bit(GIC_IRQ_GUEST_VISIBLE, &p->status);
>>          if ( test_bit(GIC_IRQ_GUEST_PENDING, &p->status) &&
>>                  test_bit(GIC_IRQ_GUEST_ENABLED, &p->status))
>
>
> It helps! Thank you a lot!
> I did about ~30 reboots and got no hangs. The only what is needed - is
> to rebase these changes on top of xen/master branch.
> Changes in patch can be applied only on top of
> 5495a512b63bad868c147198f7f049c2617d468c
> Will you do this change? Is it acceptable for baseline?
>
> Regards,
> Andrii
>
> --
>
> Andrii Tseglytskyi | Embedded Dev
> GlobalLogic
> www.globallogic.com



-- 

Andrii Tseglytskyi | Embedded Dev
GlobalLogic
www.globallogic.com

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