Re: [PATCH 0/3] irqchip/gic-v5: Tidy up LPI allocation

Lorenzo Pieralisi
2026-05-04T08:46:10Z

On Sat, May 02, 2026 at 11:40:10AM +0100, Marc Zyngier wrote:
> Hi Sascha,
>
> On Thu, 30 Apr 2026 16:33:58 +0100,
> Sascha Bischoff <Sascha.Bischoff@arm.com> wrote:
> >
> > LPIs are owned by the LPI domain, so allocating and freeing them from
> > the ITS MSI and IPI domains was always a bit backwards. Those domains
> > should only ask their parent for interrupts, and never need to
> > know how the parent picks or releases the underlying LPIs (or do it on
> > behalf of said parent, as was the case).
> >
> > This series moves LPI allocation into the LPI domain itself and
> > removes the exported wrappers that allowed LPI allocation from elsewhere.
> >
> > With that done, the LPI domain can also be slightly reworked to
> > support allocating and freeing more than one LPI at a time. This
> > rework is extended to the IPI allocation, too. The last patch makes
> > the ITS MSI domain request its parent interrupts as a single range,
> > matching the IPI cleanup from the previous patch.
> >
> > As a side effect of these changes, the IPI path now unwinds earlier
> > parent allocations correctly if a later allocation fails.
>
> Thanks for cleaning up this mess. It aligns the GICv5 host code with
> the expectations we have for hierarchical domains (don't mess with
> your parent's allocations), and will make the KVM management of
> doorbell LPIs less awkward. It also removes global helpers that always
> irked me, so:

Bah, sorry, it not only breaks the IRQ domains expectations but
the current allocation is really braindead - I was too fixated on
the IDA 1 by 1 allocation (that should really disappear asap) that
I could not see the wood for the trees.

Thank you Sascha for cleaning it up.

Reviewed-by: Lorenzo Pieralisi <lpieralisi@kernel.org>

> Reviewed-by: Marc Zyngier <maz@kernel.org>
>
> Thomas, could you please take th in at the earliest opportunity?
>
> Thanks,
>
> M.
>
> --
> Jazz isn't dead. It just smells funny.