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

From	Borislav Petkov <bp@alien8.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/6] x86/microcode: Merge early loader
Date	2015-11-09 11:20 +0100
Message-ID	<qsRIo-55g-57@gated-at.bofh.it> (permalink)
References	<qlBS2-8v7-1@gated-at.bofh.it> <qlBS2-8v7-13@gated-at.bofh.it> <qrURY-d0-11@gated-at.bofh.it> <qrV1F-gl-37@gated-at.bofh.it> <qsRfk-4E2-17@gated-at.bofh.it>
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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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Re: [PATCH 2/6] x86/microcode: Merge early loader Josh Boyer <jwboyer@fedoraproject.org> - 2015-11-06 20:30 +0100
  Re: [PATCH 2/6] x86/microcode: Merge early loader Borislav Petkov <bp@alien8.de> - 2015-11-06 20:40 +0100
    Re: [PATCH 2/6] x86/microcode: Merge early loader Harald Hoyer <harald@redhat.com> - 2015-11-09 10:50 +0100
      Re: [PATCH 2/6] x86/microcode: Merge early loader Borislav Petkov <bp@alien8.de> - 2015-11-09 11:20 +0100

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