ACK: [SRU][J][PATCH 0/2] Add PPIN support for Intel EMR cpu

[Luke Nowakowski-Krijger]

Acked-by: Luke Nowakowski-Krijger <luke.nowakowskikrijger at canonical.com>

On Wed, May 10, 2023 at 5:58 PM Roxana Nicolescu <
roxana.nicolescu at canonical.com> wrote:

> BugLink: https://bugs.launchpad.net/bugs/2019131
>
> SRU Justification
>
> [Impact]
> Intel has introduced support for their new Emerald Rapids CPU.
> It was backported to Jammy in #lp2015372 and in #lp2015855.
>
> The remaining feature needed to fully support EMR is PPIN (the Protected
> Processor Inventory/Identification Number).
> This was recently pushed to upstream in 6.4 in commit
> 36168bc061b4368ad19e82b06a6463c95d3bb9a7.
> The change is very straightforward, it adds a new entry for
> EMERALDRAPIDS_X in the cpuids table where cpus that support ppin are
> listed. The table is then used in `ppin_init`.
>
> In Jammy, this implementation is missing. Both Amd and Intel have their
> own implementation which is doing pretty much the same. Instead of a
> list of cpus supported, a switch case is used instead in their init
> functions (amd_detect_ppin and intel_ppin_init).
> To reduce duplication of code and to help backport smoothly the new
> addition of EMR, commit 0dcab41d3487acadf64d0667398e032341bd9918
> “x86/cpu: Merge Intel and AMD ppin_init() functions” was backported too.
>
> Thus commits:
> - 0dcab41d3487acadf64d0667398e032341bd9918:
> "x86/cpu: Merge Intel and AMD ppin_init() functions"
> - 36168bc061b4368ad19e82b06a6463c95d3bb9a7:
> "x86/cpu: Add Xeon Emerald Rapids to list of CPUs that support PPIN"
> are needed to support PPIN for EMR.
>
> [Testing]
> Kernel was built on cbd and boot tested on a VM.
>
> [Regression potential]
> Very low, it is a small refactor that removes duplication and it
> should not affect the functionality.
>
> Tony Luck (2):
>   x86/cpu: Merge Intel and AMD ppin_init() functions
>   x86/cpu: Add Xeon Emerald Rapids to list of CPUs that support PPIN
>
>  arch/x86/kernel/cpu/amd.c       | 30 -------------
>  arch/x86/kernel/cpu/common.c    | 75 +++++++++++++++++++++++++++++++++
>  arch/x86/kernel/cpu/mce/intel.c | 42 ------------------
>  3 files changed, 75 insertions(+), 72 deletions(-)
>
> --
> 2.34.1
>
>
> --
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>
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