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

[Julien Thierry]

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