Re: [PATCH v2 for 6.2?] gicv3: fix ICH_MISR's LRENP computation

[Peter Maydell]

On Tue, 7 Dec 2021 at 15:49, Damien Hedde <damien.hedde@greensocs.com> wrote:
>
>
>
> On 12/7/21 16:45, Peter Maydell wrote:
> > On Tue, 7 Dec 2021 at 15:24, Peter Maydell <peter.maydell@linaro.org> wrote:
> >> The bug is a bug in any case and we'll fix it, it's just a
> >> question of whether it meets the bar to go into 6.2, which is
> >> hopefully going to have its final RC tagged today. If this
> >> patch had arrived a week ago then the bar would have been
> >> lower and it would definitely have gone in. As it is I have
> >> to weigh up the chances of this change causing a regression
> >> for eg KVM running on emulated QEMU.
> >
> > Looking at the KVM source it doesn't ever set the LRENPIE
> > bit (it doesn't even have a #define for it), which both
> > explains why we didn't notice this bug before and also
> > means we can be pretty certain we're not going to cause a
> > regression for KVM at least if we fix it...

> We are perfectly fine with this not going into 6.2.

I thought about it a bit more, and realized that we could
end up giving KVM spurious maintenance interrupts even though
it doesn't set the LRENPIE bit, because the incorrect OR
meant we'd send a maint irq whenever the EOIcount was nonzero.
So we've put this fix in for 6.2.

Thanks for the patch and the discussion.

-- PMM