linux-kernel - Re: [PATCH v2] x86, msr: Document AMD "tweak MSRs", use MSR_FnnH

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Date:   Tue, 25 Apr 2017 18:15:23 +0200
From:   Denys Vlasenko <dvlasenk@...hat.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Ingo Molnar <mingo@...hat.com>, Andy Lutomirski <luto@...nel.org>,
        Brian Gerst <brgerst@...il.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "H. Peter Anvin" <hpa@...ux.intel.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] x86, msr: Document AMD "tweak MSRs", use MSR_FnnH_NAME
 scheme for them

On 04/25/2017 06:06 PM, Borislav Petkov wrote:
> Pls no. Not every MSR for every family. Only the 4 which are actually
> being used. We can't hold in here the full 32-bit MSR space.

The replacement of four define names is not the purpose
of the proposed patch.

The patch was prompted by the realization that these particular MSRs
are so badly and inconsistently documented that it takes many hours
of work and requires reading of literally a dozen PDFs to figure out
what are their names, which CPUs have them, and what bits are known.

Anyone who looks at only one document won't see the full picture.

Patch does not document bits, but at least documents all MSR names
and explains why documentation is so sparse.

If you think it's not useful, so be it.