Re: [PATCH 1/4] genirq: Provide basic NMI management for interrupt lines

From: Marc Zyngier
Date: Thu Aug 02 2018 - 12:02:29 EST


On Thu, 02 Aug 2018 07:55:49 +0100,
Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> On Thu, 2 Aug 2018, Marc Zyngier wrote:
> >
> > If we need to distinguish between the two, then we need two flags. One
> > that indicates the generation capability, and one that indicates the
> > forwarding capability.
>
> There is absolutely no reason to expose this on x86, really.
>
> Why?
>
> Because NMI is an utter trainwreck on x86. It's a single entry point
> without the ability of differentiation from which source the NMI
> originated. So mapping it to anything generic is just not going to work.
>
> It has absolutely nothing to do with the normal way of vector based
> interrupt operation and I don't see at all how adding this just because
> would improve anything on x86. In fact it would create more problems than
> it solves.

Fair enough. Does it mean Julien can completely ignore the x86
requirements for this and focus on something that fit the need of
architectures where (pseudo-)NMIs can be managed similarly to normal
interrupts (arm, arm64, sparc...)?

Thanks,

M.

--
Jazz is not dead, it just smell funny.