Re: Keystone Issue

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

Hi

> On 9 Jun 2020, at 16:47, Julien Grall <julien@xxxxxxx> wrote:
> 
> 
> 
> On 09/06/2020 16:28, Bertrand Marquis wrote:
>> Hi,
>>> On 9 Jun 2020, at 15:33, CodeWiz2280 <codewiz2280@xxxxxxxxx> wrote:
>>> 
>>> There does appear to be a secondary (CIC) controller that can forward
>>> events to the GIC-400 and EDMA controllers for the keystone 2 family.
>>> Admittedly, i'm not sure how it is being used with regards to the
>>> peripherals.  I only see mention of the GIC-400 parent for the devices
>>> in the device tree.  Maybe Bertrand has a better idea on whether any
>>> peripherals go through the CIC first?  I see that gic_interrupt ()
>>> fires once in Xen, which calls doIRQ to push out the virtual interrupt
>>> to the dom0 kernel.  The dom0 kernel then handles the interrupt and
>>> returns, but gic_interrupt() never fires again in Xen.
>> I do not remember of any CIC but the behaviour definitely look like an 
>> interrupt acknowledge problem.
>> Could you try the following:
>> --- a/xen/arch/arm/gic-v2.c
>> +++ b/xen/arch/arm/gic-v2.c
>> @@ -667,6 +667,9 @@ static void gicv2_guest_irq_end(struct irq_desc *desc)
>>      /* Lower the priority of the IRQ */
>>      gicv2_eoi_irq(desc);
>>      /* Deactivation happens in maintenance interrupt / via GICV */
>> +
>> +    /* Test for Keystone2 */
>> +    gicv2_dir_irq(desc);
>>  }
>> I think the problem I had was related to the vgic not deactivating properly 
>> the interrupt.
> 
> Are you suggesting the guest EOI is not properly forwarded to the hardware 
> when LR.HW is set? If so, this could possibly be workaround in Xen by raising 
> a maintenance interrupt every time a guest EOI an interrupt.

Agree the maintenance interrupt would definitely be the right solution.
This was an easy ack to check if that was the source of the problem.

> 
>> This might make the interrupt fire indefinitely !!
> 
> Most likely with level interrupt ;).

Yes but this is just to confirm ;-)

> 
> Cheers,
> 
> -- 
> Julien Grall