Re: Keystone Issue

[Julien Grall <julien@xen.org>]

(+ Marc)

On 09/06/2020 18:03, Bertrand Marquis wrote:
> Hi
> 
>> On 9 Jun 2020, at 16:47, Julien Grall <julien@xen.org> wrote:
>>
>>
>>
>> On 09/06/2020 16:28, Bertrand Marquis wrote:
>>> Hi,
>>>> On 9 Jun 2020, at 15:33, CodeWiz2280 <codewiz2280@gmail.com> 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
I would like to make sure we aren't missing anything in Xen first. From 
what you said, you have encountered this issue in the past with a 
different hypervisor. So it doesn't look like to be Xen related.

Was there any official statement from TI? If not, can we try to get some 
input from them first?
	
@Marc, I know you dropped 32-bit support in KVM recently :). Although, I 
was wondering if you heard about any potential issue with guest EOI not 
forwarded to the host. This is on TI Keystone (Cortex A-15).

Cheers,

-- 
Julien Grall