[PATCH v10 01/30] arm64/sysreg: Update SMIDR_EL1 to DDI0601 2025-06

[Mark Rutland]

On Sat, May 09, 2026 at 09:43:11AM +0900, Mark Brown wrote:
> On Fri, May 08, 2026 at 06:12:01PM +0100, Mark Rutland wrote:
> > On Fri, Mar 06, 2026 at 05:00:53PM +0000, Mark Brown wrote:
> 
> > > Update the definition of SMIDR_EL1 in the sysreg definition to reflect the
> > > information in DD0601 2025-06. This includes somewhat more generic ways of
> > > describing the sharing of SMCUs, more information on supported priorities
> > > and provides additional resolution for describing affinity groups.
> 
> > FWIW, these are all in ARM DDI 0487 M.b:
> 
> >   https://developer.arm.com/documentation/ddi0487/mb/
> 
> > Is anything later in the series going to depend on these fields, or
> > would everything behave correctly with the existing RES0 field
> > definitions?
> 
> We're exposing the affinity fields so there's a build time issue.

What I'm asking is what is the rationale for updating these definitions?
e.g.

* Are we planning to use any of the fields in a specific way in the
  *host*?

* Are we planning to use any of the fields in a specific way in the
  *guest*?

* Is this updated just out of habit?

Knowing the rationale would help with review, even if that rationale is
just "it seemed nice to use the latest".

> > > +Field	55:52	HIP
> 
> > Reading the ARM ARM, HIP is arguably a backwards-incompatible change.
> 
> Yes, I belive people are aware.

Ok. Is that considered a problem, or accepted?

Which people are aware?

> > Do we expect to expose that to VMs, or just hide priorities entirely? I
> > suspect we probably want to require that the guest sees
> > SMIDR_EL1.SMPS==0, and not care about any of that.
> 
> Currently we're not exposing priority support to guests so we don't need
> to worry about it yet.

Do we plan to in future?

Mark.