linux-kernel - Re: [PATCH 2/6] x86/microcode: Merge early loader

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Message-ID: <20151109101159.GA14962@pd.tnic>
Date:	Mon, 9 Nov 2015 11:11:59 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Harald Hoyer <harald@...hat.com>
Cc:	Josh Boyer <jwboyer@...oraproject.org>,
	Laura Abbott <labbott@...hat.com>, X86 ML <x86@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/6] x86/microcode: Merge early loader

On Mon, Nov 09, 2015 at 10:42:13AM +0100, Harald Hoyer wrote:
> Will this work with kernels not supporting the microcode loading?
> Theoretically the old kernels would just unpack all cpios one after
> the other, right?

Well, what we should be doing is adding two paths to the initrd:

for AMD:	kernel/x86/microcode/AuthenticAMD.bin
for Intel:	kernel/x86/microcode/GenuineIntel.bin

I.e., the microcode blobs become part of the initrd, see
Documentation/x86/early-microcode.txt. The loader goes and opens the one
it needs at boot time.

You could also add a switch for convenience, something like
--no-microcode or so, so that dracut doesn't add it but if one wants to
not add microcode, one could also move it away from, say, /lib/firmware/
so that dracut simply doesn't find it. The --no-microcode might be more
convenient though.

Kernels which don't support microcode loading would simply not look for
that path.

Let me know if this doesn't make sense and if I need to test/look at
patches.

Thanks.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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