Re: [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver

Will Deacon
2026-04-23T08:57:12Z

On Wed, Apr 22, 2026 at 02:32:23PM +0100, Yeoreum Yun wrote:
> Hi All,
>
> > > On Tue, Apr 21, 2026 at 07:57:43AM +0100, Yeoreum Yun wrote:
> > >
> > > [...]
> > >
> > > >
> > > > Also, the FF-A initialization is not driven by a device probe, but rather
> > > > happens as part of the bus registration itself,
> > > > so it does not fit well with a device_link or probe deferral based approach.
> > > >
> > > > Instead, perhaps we could go with the idea I mentioned previously:
> > > > either introduce a notifier, or create a pseudo ffa_device
> > > > once pKVM initialization has completed, and
> > > > then let the ffa driver perform the additional initialization from there.
> > > >
> > > > Am I missing something?
> > > >
> > >
> > > In order to handle/cleanup some ugliness in interrupt management in the
> > > FF-A driver, we may introduce DT node eventually. But it will take sometime.
> >
> > Unfortunately, I think this DT node wouldn't be helpful to solve
> > this situation for dependency with the kvm misc device...
> >
> > IMHO, current situation, the notifier seems to good option. unless
> > we make the initcall to recongise this dependency.
> >
>
> I think the best approach for now is to introduce a notifier to handle this situation.
> If there are no further suggestions, I’ll send a v2 based on:
> - https://lore.kernel.org/all/aeS4rAeVQ0yJIPYw@e129823.arm.com/

I can't say that I'm a huge fan of that :/

The notifier will literally fire once, for a single listener. That's
called a function call.

Will