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Date: Wed, 20 Jun 2012 16:49:22 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
CC: Peter Zijlstra <peterz@infradead.org>, Borislav Petkov <bp@amd64.org>,
        LKML <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Andreas Herrmann <andreas.herrmann3@amd.com>,
        Dimitri Sivanich <sivanich@sgi.com>,
        Dmitry Adamushko <dmitry.adamushko@gmail.com>,
        Greg Kroah-Hartman <greg@kroah.com>,
        "Yu, Fenghua" <fenghua.yu@intel.com>
Subject: Re: [PATCH] x86, microcode: Make reload interface per system
References: <20120615125240.GD6083@aftab.osrc.amd.com> <20120615165231.GA9169@aftab.osrc.amd.com> <20120619024639.GB6186@khazad-dum.debian.net> <4FDFF27C.5000205@zytor.com> <20120619051116.GB31591@aftab.osrc.amd.com> <1340093864.21745.6.camel@twins> <20120619102250.GA787@aftab.osrc.amd.com> <1340101568.21745.37.camel@twins> <20120619182228.GA18816@khazad-dum.debian.net> <4FE0DF9F.10401@zytor.com> <20120620234651.GD4223@khazad-dum.debian.net>
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On 06/20/2012 04:46 PM, Henrique de Moraes Holschuh wrote:
> 
> Well, it makes the kernel tell us what (amd/intel/whatever) firmware it
> wants, and requires (after patching) a simple echo 1 >foo to activate.  It
> is also harmless if activated without updated firmware in place.
> 
> /dev/cpu/microcode requires special software (or a dd with bs>=file size),
> since it borks if userspace breaks a microcode into two write() syscalls,
> and requires detection of the cpu vendor.  Very annoying.
> 

Yeah, because dd is such an exotic piece of software...

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.