linux-kernel - Re: [PATCH] x86, microcode: Make reload interface per system

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Date:	Tue, 19 Jun 2012 07:03:25 +0200
From:	Borislav Petkov <bp@...64.org>
To:	Henrique de Moraes Holschuh <hmh@....eng.br>
Cc:	Borislav Petkov <bp@...64.org>,
	LKML <linux-kernel@...r.kernel.org>, x86 <x86@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...nel.org>,
	Andreas Herrmann <andreas.herrmann3@....com>,
	Dimitri Sivanich <sivanich@....com>,
	Dmitry Adamushko <dmitry.adamushko@...il.com>,
	Greg Kroah-Hartman <greg@...ah.com>
Subject: Re: [PATCH] x86, microcode: Make reload interface per system

On Mon, Jun 18, 2012 at 11:46:39PM -0300, Henrique de Moraes Holschuh wrote:
> On Fri, 15 Jun 2012, Borislav Petkov wrote:
> > From: Borislav Petkov <borislav.petkov@....com>
> > Date: Fri, 15 Jun 2012 18:46:05 +0200
> > Subject: [PATCH] x86, microcode: Make reload interface per system
> > 
> > The reload interface should be per-system so that a full system ucode
> > reload happens (on each core) when doing
> > 
> > echo 1 > /sys/devices/system/cpu/microcode/reload
> > 
> > Move it to the cpu subsys directory instead of it being per-cpu.
> > 
> > Signed-off-by: Borislav Petkov <borislav.petkov@....com>
> 
> It is a pity this one is much harder to backport to 3.2 and 3.0.

Yeah, not harder. It changes the sysfs interface and we can't do that
for already released kernels.

But I think you meant that.

> I'd really like to have the new interface there. But it looks good,
> and we will support the new /sys/devices/system/cpu/microcode/reload
> sysfs node in Debian for the benefit of anyone using a newer kernel
> than the distro's (which will be based on 3.2).

Right, hopefully the next Debian release will have that nice shiny new
interface :-)

> So, fwiw, you have my:
> Acked-by-unimportant-person: Henrique de Moraes Holschuh <hmh@....eng.br>

No, don't underestimate yourself. I think it helps a lot to have someone
look at the patch and even better: give comments whether what we're
doing is sane for userspace. So, I appreciate your comments a lot, keep
'em coming :-)

Thanks for review and testing, I'll send out the patches soon.

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
GM: Alberto Bozzo
Reg: Dornach, Landkreis Muenchen
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