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Re: Keystone Issue



(+ Marc)

On 09/06/2020 18:03, Bertrand Marquis wrote:
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
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



 


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