linux-kernel - Re: [PATCH] x86/microcode: Check microcode revision before updating sibling threads

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Message-ID: <20180217200949.dktgcwhb7reopwnk@khazad-dum.debian.net>
Date:   Sat, 17 Feb 2018 18:09:49 -0200
From:   Henrique de Moraes Holschuh <hmh@....eng.br>
To:     Borislav Petkov <bp@...e.de>
Cc:     Ashok Raj <ashok.raj@...el.com>, X86 ML <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86/microcode: Check microcode revision before updating
 sibling threads

On Sat, 17 Feb 2018, Borislav Petkov wrote:
> On Sat, Feb 17, 2018 at 11:42:48AM -0200, Henrique de Moraes Holschuh wrote:
> > I wonder when this broke,
> 
> It didn't break - we're just printing the update only once.

It was before that change, when the microcode subsystem still printed a
message for every CPU that got updated or early-updated.

It was fixed to properly refresh the microcode revision in the percpu
area right before deciding whether it should update that cpu or not, and
thus it would skip the second thread on Intel cores because it would
notice it was already up-to-date.

Maybe it was just the late loader, though...  I'd need to do some git
log digging.

-- 
  Henrique Holschuh