linux-kernel - Re: [PATCH] x86, microcode, Fix long microcode load time when firmware file is missing [v2]

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Date:	Mon, 28 Oct 2013 11:11:01 -0400
From:	Prarit Bhargava <prarit@...hat.com>
To:	Henrique de Moraes Holschuh <hmh@....eng.br>
CC:	Borislav Petkov <bp@...en8.de>, linux-kernel@...r.kernel.org,
	tigran@...azian.fsnet.co.uk, x86@...nel.org, andi@...stfloor.org
Subject: Re: [PATCH] x86, microcode, Fix long microcode load time when firmware
 file is missing [v2]



On 10/28/2013 11:06 AM, Henrique de Moraes Holschuh wrote:
> On Mon, 28 Oct 2013, Borislav Petkov wrote:
>> So Prarit, please split this patch into changes which *directly* address
>> the issue and other cleanups ontop. This will simplify review immensely
>> as having one single bulky patch is not easy on the eyes.
>>
>> Then, make sure to audit the lowlevel drivers whether they're already
>> issuing output on the error path before adding new printks arbitrarily.
> 
> Something else I couldn't check just from the description (and I apologise,
> but I did not look at your patch closely enough to check how you implemented
> the functionality on Intel): in the general case, it is NOT acceptable to
> bail out if you cannot find the firmware for the first processor.
> Mixed-stepping systems do exist, and you might need to update the microcode
> of, e.g, just the third processor.
> 
> AMD can get away with a half-done implementation of negative caching (or an
> "optimised one" depending on your PoV :) ) because they have per-family
> firmware files, so even mixed-stepping systems will require only the same
> file.  This is *not* true for Intel, which is really annoying.

Is that right? :(  I took Andi's comment to imply otherwise ...  If that's the
case then, yeah, back to the drawing board with this.

Andi (or anyone from Intel) -- care to offer a comment?

P.
> 
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