Re: [PATCH 00/33] arm_mpam: Add basic mpam driver

Jonathan Cameron
2025-11-19T10:00:57Z

On Tue, 18 Nov 2025 14:55:07 -0800
Drew Fustini <fustini@kernel.org> wrote:

> On Tue, Nov 18, 2025 at 02:11:31PM +0000, Ben Horgan wrote:
> > Hi Drew,
> >
> > On 11/16/25 17:16, Drew Fustini wrote:
> > > On Fri, Nov 07, 2025 at 12:34:17PM +0000, Ben Horgan wrote:
> > >> Hi all,
> > > [snip]
> > >> The rest of the driver can be found here: (no updated version - based on v3)
> > >> https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git mpam/snapshot/v6.18-rc1
> > >
> > > Does anyone know of a hosting platform that offers ARM machines that
> > > have MPAM?
> >
> > As far as I know there aren't any.
> >
> > There is some MPAM support in the Orion Radxa board which is likely the
> > cheapest option. The MPAM acpi table isn't in the firmware though so
> > you'd need to load a custom table. James has this working.
>
> Thank you, I didn't realize that there was a dev board that supports
> MPAM. I didn't want to the expense or noise of a rackable server :)
>
> Drew
>
Hi Drew,

Obvious not functional as such, but I did spin qemu emulation with a bunch
of introspection so you could see what was configured. Aim was to poke
corner cases more easily than with real hardware. Did it's job at the time
and shook out some bugs.

I haven't rebased it recently though.
https://lore.kernel.org/qemu-devel/20230808115713.2613-1-Jonathan.Cameron@huawei.com/

https://gitlab.com/jic23/qemu/-/commits/mpam-2023-sept-01
Has what looks to be a slightly more recent rebase.

No monitor support though.

I might bring this back to poke the rest of this series as it moves forwards
(or if anyone else wants to they are welcome to do so)

FWIW we could in theory hook this up to the cache plugins to get some 'plausible'
numbers, but I never bothered as we have hardware (as seen by tested-by's on this
series).

Jonathan