linux-kernel - Re: Bug (minor): microcode_intel.c applies updates to hyperthreaded cores

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Message-ID: <20091202202012.0c7b6768@infradead.org>
Date:	Wed, 2 Dec 2009 20:20:12 -0800
From:	Arjan van de Ven <arjan@...radead.org>
To:	Michael Breuer <mbreuer@...jas.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: Bug (minor): microcode_intel.c applies updates to hyperthreaded
 cores

On Wed, 02 Dec 2009 23:06:19 -0500
Michael Breuer <mbreuer@...jas.com> wrote:

> According to spec, microcode should only be applied to actual cores.
> As things are currently structured, looks like the fix would be in
> microcode_core.c. I don't think changing the loop to look for cores
> vs. cpu's would affect anything adversely, but honestly am not
> familiar enough with this code or other cpu types to be sure.
> 

isn't this

for each (logical) cpu
   check microcode version of the cpu
   if too old, apply microcode

the 2nd pair of a hyperthreading pair will never see the 'too old' case
happen...


-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
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