linux-kernel - Re: [regression] microcode files missing in initramfs imgages from dracut (was Re: [PATCH] x86: Clean up remaining references to CONFIG_MICROCODE

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Message-ID: <20231122205135.GGZV5p157mBi6RYUNs@fat_crate.local>
Date:   Wed, 22 Nov 2023 21:51:35 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Linux regressions mailing list <regressions@...ts.linux.dev>,
        lukas.bulwahn@...il.com, dave.hansen@...ux.intel.com,
        hpa@...or.com, kernel-janitors@...r.kernel.org,
        linux-kernel@...r.kernel.org, mingo@...hat.com, tglx@...utronix.de,
        x86@...nel.org
Subject: Re: [regression] microcode files missing in initramfs imgages from
 dracut (was Re: [PATCH] x86: Clean up remaining references to
 CONFIG_MICROCODE_AMD)

On Wed, Nov 22, 2023 at 12:35:54PM -0800, Linus Torvalds wrote:
> IOW, the whole "users are the only thing that matters" pretty much
> means that it's a non-issue. Things continued to work, to the point
> that I'm actually surprised anybody even noticed.

Right, the patch which did the changes is in 6.6:

e6bcfdd75d53 ("x86/microcode: Hide the config knob")

I'm still waiting for the other shoe to drop when 6.6 gets used more but
we'll see...

> That said, I don't think some ELF note is the fix either. I think we
> might as well leave it at CONFIG_MICROCODE. Maybe add a note in the
> kernel Kconfig that this thing matters for dracut.
> 
> Dracut also checks for CONFIG_ACPI_INITRD_TABLE_OVERRIDE. It's a
> similar "normal users don't care".

Ok.

My only worry here is that we're making a precedent and basically saying
that it is ok for tools to grep .config to figure out what is supported
by the kernel. And then other tools might follow.

I have no clue how many tools are actually interested in stuff enabled
in the kernel .config though. If only dracut then sure, don't care, but
what if it starts proliferating...

I'm just talking with my devil's advocate hat on.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette