linux-kernel - Re: commit bd9240a18edfbfa72e957fc2ba831cf1f13ea073 seems to break with intel-ucode 20180425

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Date:   Mon, 14 May 2018 14:58:56 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Gabriel C <nix.or.die@...il.com>
Cc:     kevin.b.stanton@...el.com, Thomas Gleixner <tglx@...utronix.de>,
        LKML <linux-kernel@...r.kernel.org>, X86 ML <x86@...nel.org>
Subject: Re: commit bd9240a18edfbfa72e957fc2ba831cf1f13ea073 seems to break
 with intel-ucode 20180425

On Mon, May 14, 2018 at 02:15:44PM +0200, Gabriel C wrote:
> http://ftp.frugalware.org/pub/other/people/crazy/ucode/cpuinfo-ucode-20180312
> http://ftp.frugalware.org/pub/other/people/crazy/ucode/cpuinfo-ucode-20180425

That's 0xc2 and 0x9e respectively, for the microcode revision.

For model 78 (INTEL_FAM6_SKYLAKE_MOBILE) we need at least 0xb2.

Now, obviously 0xc2 is in fact larger than 0xb2, however 0x9e is
smaller and it is rightfully complaining.

Now, I have (debian testing):

$ apt-cache show intel-microcode
Package: intel-microcode
Version: 3.20180425.1

$ hexdump /lib/firmware/intel-ucode/06-4e-03 | head
0000000 0001 0000 00c2 0000 2017 1116 06e3 0004
0000010 f699 c6c6 0001 0000 00c0 0000 83d0 0001
0000020 8400 0001 0000 0000 0000 0000 0000 0000

Which gives 0xc2 as version for your CPU.

If I download microcode-20180425.tgz from:

  https://downloadcenter.intel.com/download/27776/Linux-Processor-Microcode-Data-File

I again get 0xc2 for 06-4e-03.

So please double check your package...

> Loading microcode manually is working

IIRC late loading doesn't re-evaluate any of this. If you down-grade you
can 'wreck' your system.

> Also initramfs is made with dracut and his early microcode option.

Yes, early microcode should be the right thing.