linux-kernel - Re: [PATCH V2 0/8] x86/topology: Improve CPUID.1F handling

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Date:   Tue, 20 Sep 2022 09:57:05 +0800
From:   Zhang Rui <rui.zhang@...el.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org,
        linux-hwmon@...r.kernel.org
Cc:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, hpa@...or.com, corbet@....net,
        fenghua.yu@...el.com, jdelvare@...e.com, linux@...ck-us.net,
        len.brown@...el.com, Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH V2 0/8] x86/topology: Improve CPUID.1F handling

On Tue, 2022-08-16 at 13:16 +0800, Zhang Rui wrote:
> On Intel AlderLake-N platforms where there are Ecores only, the Ecore
> Module topology is enumerated via CPUID.1F Module level, which has
> not
> been supported by Linux kernel yet.
> 
> This exposes two issues in current CPUID.1F handling code.
> 1. Linux interprets the Module ID bits as package ID and erroneously
>    reports a multi module system as a multi-package system.
> 2. Linux excludes the unknown Module ID bits from the core ID, and
> results
>    in duplicate core ID’s shown in a package after the first issue
> solved.
> 
> Plus that, a third problem is observed on Intel Hybrid ADL-S/P
> platforms.
> The return value of CPUID.1F SMT level EBX (number of siblings)
> differs on
> Pcore CPUs and Ecore CPUs, and results in inconsistent
> smp_num_siblings
> value based on the Pcore/Ecore CPU enumeration order. This could
> bring
> some potential issues although we have not observed any
> functionalities
> issues so far.
> 
> This patch series fixes these three problems in CPUID.1F handling
> code,
> together with some related fixes and document updates.
> 
> 
Hi,

These patches are mainly bug fixes for ADL-N and Intel Hybrid
platforms.
May I know if there are any further changes needed?

thanks,
rui


> thanks,
> -rui
> 
> ---
> Changes since V1:
>  - fix/improve changelog/comment wording issues
>  - reorder the patches to eliminate bisection breakage window
>  - add a new patch for coretemp driver variable renaming
>  - update coretemp driver patch to fix a case of ida_free(&ida, -2)