Re: [PATCH v2 0/3] perf/x86/amd/uncore: Add common helpers and Hygon support

[Borislav Petkov]

+ AMD people who work on this code.

On Wed, Jul 01, 2026 at 09:34:14AM +0000, Qi Liu wrote:
> This series adds initial Hygon uncore PMU support.
> 
> Hygon uncore PMUs use a programming model close to the AMD uncore PMU,
> so this series factors out a small set of common helpers for perf event
> handling, counter assignment and per-CPU context management.
> 
> The Hygon-specific support is kept in the Hygon driver. This series
> supports the Hygon DF and DF IOD PMUs. No Hygon-specific logic is
> added to the AMD driver.
> 
> Changes since RFC:
>   - Address sashiko bot review.
> Changes since v1:
>   - Rename the helper namespace to amd_uncore_common_* to avoid
>     an generic uncore_common_* prefix, and to keep it distinct
>     from the existing amd_uncore_* names.
> 
> 
> Qi Liu (3):
>   perf/x86/amd/uncore: Add common PMU helper functions
>   perf/x86/amd/uncore: Convert AMD driver to common PMU helpers
>   perf/x86/amd/uncore: Add Hygon uncore PMU support
> 
>  arch/x86/events/Kconfig                 |  17 +
>  arch/x86/events/amd/Makefile            |   4 +
>  arch/x86/events/amd/amd_uncore_common.c | 403 +++++++++++++++++
>  arch/x86/events/amd/amd_uncore_common.h | 114 +++++
>  arch/x86/events/amd/hygon_uncore.c      | 556 +++++++++++++++++++++++
>  arch/x86/events/amd/uncore.c            | 578 +++---------------------
>  arch/x86/include/asm/msr-index.h        |   2 +
>  arch/x86/include/asm/perf_event.h       |  20 +
>  include/linux/cpuhotplug.h              |   3 +
>  9 files changed, 1192 insertions(+), 505 deletions(-)
>  create mode 100644 arch/x86/events/amd/amd_uncore_common.c
>  create mode 100644 arch/x86/events/amd/amd_uncore_common.h
>  create mode 100644 arch/x86/events/amd/hygon_uncore.c

I'm sure Ravi and Sandipan will give you more indepth comments but the general
direction with reusing AMD code on Hygon is to copy it first for your purposes
and, later, when it turns out the helpers do remain identical, then to merge
them.

Vs defining common helpers now and stifling your and AMD development by trying
to shoehorn common helpers with an architecture which is here and there a bit
different.

Also, I'm not sure about all those export symbols gunk - why would common
events helpers need exports to modules but meh, Peter will give his thoughts
here.

Also, Sashiko has comments:

https://lore.kernel.org/r/20260701094808.5C8BC1F000E9@xxxxxxxxxxxxxxx

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette