Re: [PATCH v2 0/2] complete perf_allow_* trio and use in drm/xe

[Peter Zijlstra <peterz@infradead.org>]

On Fri, May 22, 2026 at 06:33:24PM -0700, John Hubbard wrote:
> perf_allow_cpu() and perf_allow_tracepoint() are static inline and
> reach into a non-exported sysctl, so modular drivers that want the
> same permission model as system-wide perf end up writing partial
> copies of this code. Let's instead export these properly so that modules
> can call them.
> 
> Commit 5e9629d0ae97 ("drivers/perf: arm_spe: Use perf_allow_kernel()
> for permissions") already moved perf_allow_kernel() out of line and
> exported it. Patch 1 does the same for the other two, and provides
> !CONFIG_PERF_EVENTS stubs so the helpers stay callable when perf is
> compiled out.
> 
> Patch 2 converts drm/xe's OA and EU stall paths to call
> perf_allow_cpu(), so xe observation now respects the system
> perf_event_paranoid policy and consults the LSM hook. Sites that have
> already configured an LSM perf policy or tuned the paranoid sysctl will
> now see those settings honored on xe as well.
> 
> Changes since v1:
> 
> * Patch 1: add !CONFIG_PERF_EVENTS stubs that fall back to
>   perfmon_capable() so the helpers remain callable when perf is
>   compiled out. The sashiko-bot AI review caught that the v1 code
>   would otherwise fail to build with PERF_EVENTS=n.
> 
> John Hubbard (2):
>   perf/core: out-of-line and export perf_allow_cpu/tracepoint()
>   drm/xe: gate observation streams with perf_allow_cpu()
> 
>  drivers/gpu/drm/xe/xe_eu_stall.c    |  5 +++--
>  drivers/gpu/drm/xe/xe_oa.c          | 25 +++++++++++++---------
>  drivers/gpu/drm/xe/xe_observation.c | 32 ++++++++++++++++++++++++-----
>  drivers/gpu/drm/xe/xe_observation.h |  3 +--
>  include/linux/perf_event.h          | 31 ++++++++++++++--------------
>  kernel/events/core.c                | 18 ++++++++++++++++
>  6 files changed, 79 insertions(+), 35 deletions(-)

Sure, works for me. How do you want to route these things, Xe tree or
-tip?