Subject: Re: [RFC PATCH 03/23] genirq: Introduce IRQF_DELIVER_AS_NMI

From: Julien Thierry <[email-masked]>
Date: Wed, 13 Jun 2018 11:25:18 +0100

On 13/06/18 10:57, Thomas Gleixner wrote:
> On Wed, 13 Jun 2018, Julien Thierry wrote:
>> On 13/06/18 10:20, Thomas Gleixner wrote:
>>> Adding NMI delivery support at low level architecture irq chip level is
>>> perfectly fine, but the exposure of that needs to be restricted very
>>> much. Adding it to the generic interrupt control interfaces is not going to
>>> happen. That's doomed to begin with and a complete abuse of the interface
>>> as the handler can not ever be used for that.
>>>
>>
>> Understood, however the need would be to provide a way for a driver to request
>> an interrupt to be delivered as an NMI (if irqchip supports it).
> 
> s/driver/specialized code written by people who know what they are doing/
> 
>> But from your response this would be out of the question (in the
>> interrupt/irq/irqchip definitions).
> 
> Adding some magic to the irq chip is fine, because that's where the low
> level integration needs to be done, but exposing it through the generic
> interrupt subsystem is a NONO for obvious reasons.
> 
>> Or somehow the concerned irqchip informs the arch it supports NMI delivery and
>> it is up to the interested drivers to query the arch whether NMI delivery is
>> supported by the system?
> 
> Yes, we need some infrastructure for that, but that needs to be separate
> and with very limited exposure.
> 

Right, makes sense. I'll check with Marc how such an infrastructure 
should be introduced.

Thanks,

-- 
Julien Thierry