Re: Multiple issues with event channel on Xen on ARM

[Julien Grall <julien.grall@linaro.org>]

On 02/05/2014 01:34 PM, David Vrabel wrote:

Hello David,

> I think the following patch should fix the 2-level problems.
> 
> You can force the use of 2-level events by using the xen.fifo_events=0
> Linux command line option.

Thanks for the patch, I'm now able to use 2-level events without issue
for a guest.
Now, I need to look at the fifo events when the domain is killed.

> 8<-------------------------------------------------
> xen/events: bind all new interdomain events to VCPU0
> 
> From: David Vrabel <david.vrabel@citrix.com>
> 
> Commit fc087e10734a4d3e40693fc099461ec1270b3fff (xen/events: remove
> unnecessary init_evtchn_cpu_bindings()) causes a regression.
> 
> The kernel-side VCPU binding was not being correctly set for newly
> allocated or bound interdomain events.  In ARM guests where 2-level
> events were used, this would result in no interdomain events being
> handled because the local VCPU masks would all be clear.
> 
> x86 guests would work because the irq affinity was set during irq
> setup and this would set the correct kernel-side VCPU binding.
> 
> Fix this by by properly initializing the kernel-side VCPU binding in
> bind_evtchn_to_irq().
> 
> Reported-by: Julian Grall <julien.grall@linaro.org>

s/Julian/Julien/

> Signed-off-by: David Vrabel <david.vrabel@citrix.com>

Tested-by: Julien Grall <julien.grall@linaro.org>

Regards,

> ---
>  drivers/xen/events/events_base.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
> index 4672e00..5cc1f78 100644
> --- a/drivers/xen/events/events_base.c
> +++ b/drivers/xen/events/events_base.c
> @@ -862,6 +862,9 @@ int bind_evtchn_to_irq(unsigned int evtchn)
>  			irq = ret;
>  			goto out;
>  		}
> +
> +		/* Newly bound event channels start off on VCPU0. */
> +		bind_evtchn_to_cpu(evtchn, 0);
>  	} else {
>  		struct irq_info *info = info_for_irq(irq);
>  		WARN_ON(info == NULL || info->type != IRQT_EVTCHN);
> 


-- 
Julien Grall