linux-kernel - Re: [PATCH v2 1/8] x86/CPU/AMD: Save NodeId on AMD-based systems

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Message-ID: <20200917103720.GG31960@zn.tnic>
Date:   Thu, 17 Sep 2020 12:37:20 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Yazen Ghannam <yazen.ghannam@....com>
Cc:     linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
        tony.luck@...el.com, x86@...nel.org,
        Smita.KoralahalliChannabasappa@....com
Subject: Re: [PATCH v2 1/8] x86/CPU/AMD: Save NodeId on AMD-based systems

On Wed, Sep 16, 2020 at 02:51:52PM -0500, Yazen Ghannam wrote:
> What do you think?

Yeah, forget logical_proc_id - the galactic senate of x86 maintainers
said that we're keeping that for when BIOS vendors f*ck up with the
phys_proc_id enumeration on AMD. Then we'll need that as a workaround.

Look instead at:

struct cpuinfo_x86 {

	...

        u16                     cpu_die_id;
        u16                     logical_die_id;

and

7745f03eb395 ("x86/topology: Add CPUID.1F multi-die/package support")

"Some new systems have multiple software-visible die within each
package."

and you could map the AMD packages to those dies. And if you guys
implement CPUID.1F to enumerate those packages the same way, then all
should just work (famous last words).

Because Intel dies is basically AMD packages consisting of a CCX, caches
and DF.

We would have to update the documentation in the end to denote that but
let's see if this should work for you too first. Because the concepts
sound very similar, if not identical...

Thx.

-- 
Regards/Gruss,
    Boris.

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