Re: [PATCH v3 00/12] [PATCH v3 00/12] x86/resctrl: Add kernel-mode (e.g., PLZA) support to the resctrl subsystem

[Moger, Babu]

Hi Tony,

On 6/26/2026 10:55 AM, Luck, Tony wrote:
> On Thu, Apr 30, 2026 at 06:24:45PM -0500, Babu Moger wrote:
> > Hi,
> >
> > This series adds support for AMD's Privilege-Level Zero Association
> > (PLZA) so kernel work can be assigned to a resctrl group, and wires it
> > up through a small generic "kernel mode" (kmode) layer in fs/resctrl
> > so future architectures can plug in without touching core resctrl.
> >
> > The features are documented in:
> >   
> >     AMD64 Zen6 Platform Quality of Service (PQOS) Extensions,
> >     Publication # 69193 Revision 1.00, Issue Date March 2026
> >   
> > available at https://bugzilla.kernel.org/show_bug.cgi?id=206537
> >
> > The patches are based on top of commit (7.1.0-rc1)
> > Commit 3382329a309d Merge branch into tip/master: 'timers/clocksource'.
>
> Hi Babu,
>
> Have you had any thoughts about a resctrl selftest for PLZA?
>
> I'm not sure there are any easy ways to show that PLZA is effective for
> MBA control (as most normal system calls don't do enough to easily detect
> whether the kernel CLOSID is applied). But perhaps you have some ideas for this?
>
> A test that sets global_assign_ctrl_assign_mon_per_cpu mode with a dedicated
> RMID to track kernel memory traffic would easily show MBM and llc_occupancy
> numbers for kernel activity.

The AMD selftests are already somewhat broken—or at least incomplete. We 
should get back to the earlier patch series:
https://lore.kernel.org/lkml/cover.1717626661.git.babu.moger@xxxxxxx/

I’ll start by looking into that. Afterward, I’ll consider what can be 
done for PLZA.

At the moment, I don’t have a clear idea for PLZA selftests. Thanks for 
the reminder—I’ll give it some thought.
Thanks
Babu