Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y

From	Måns Rullgård <mans@mansr.com>
Newsgroups	linux.kernel
Subject	Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y
Date	2016-01-19 14:00 +0100
Message-ID	<qSE37-7ZZ-3@gated-at.bofh.it> (permalink)
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Michal Marek <mmarek@suse.cz> writes:

> Dne 19.1.2016 v 13:29 Måns Rullgård napsal(a):
>> Force-enabling BLK_DEV_INITRD isn't going to make anyone change their
>> boot scripts.
>
> If you are on a regular distro, /sbin/installkernel should do the right
> thing: Run mkinitrd / dracut and if the tools are recent enough and
> there is a microcode update for your CPU, a cpio with the microcode blob
> will be prepended to the initrd. So this is more or less covered.

I'd be rather cross if something suddenly started building initrds on my
systems.  To me they're just a useless level of complexity to maintain.
(I'm not denying they can be useful to others.)

>> I'd also like to get a coherent answer to why microcode update is 
>> preferably done from an initrd as opposed to shortly after mounting
>> a regular disk.  My systems seem perfectly happy doing the latter.
>
> It's not even done *from* the initrd but way earlier. We learned the
> hard way when Intel released a microcode update for Haswell which
> disabled TSX: Userspace did not expect the feature flags to change and
> previously valid instructions to start trapping. This can in principle
> happen again and with any vendor.

OK, I can see how that might be a problem.

-- 
Måns Rullgård

Thread

[RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y (was: Re: [RFC PATCH]  x86/kconfig: Sanity-check config file during oldconfig) Ingo Molnar <mingo@kernel.org> - 2016-01-19 09:30 +0100
  Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y (was: Re: [RFC PATCH]  x86/kconfig: Sanity-check config file during oldconfig) Markus Trippelsdorf <markus@trippelsdorf.de> - 2016-01-19 09:50 +0100
    Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y (was: Re: [RFC PATCH]  x86/kconfig: Sanity-check config file during oldconfig) Ingo Molnar <mingo@kernel.org> - 2016-01-19 10:00 +0100
      Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y (was: Re: [RFC PATCH]  x86/kconfig: Sanity-check config file during oldconfig) Borislav Petkov <bp@suse.de> - 2016-01-19 10:50 +0100
  Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y (was: Re: [RFC PATCH]  x86/kconfig: Sanity-check config file during oldconfig) Peter Zijlstra <peterz@infradead.org> - 2016-01-19 10:10 +0100
    Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y (was: Re: [RFC PATCH]  x86/kconfig: Sanity-check config file during oldconfig) Ingo Molnar <mingo@kernel.org> - 2016-01-19 10:20 +0100
  Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y (was: Re: [RFC PATCH]  x86/kconfig: Sanity-check config file during oldconfig) Borislav Petkov <bp@suse.de> - 2016-01-19 10:50 +0100
  Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y Michal Marek <mmarek@suse.cz> - 2016-01-19 11:00 +0100
    Re: [RFC] CONFIG_GENERIC_BOOTABLE_CONFIG=y Ingo Molnar <mingo@kernel.org> - 2016-01-19 11:40 +0100
      Re: [RFC] CONFIG_GENERIC_BOOTABLE_CONFIG=y Linus Torvalds <torvalds@linux-foundation.org> - 2016-01-19 18:30 +0100
        Re: [RFC] CONFIG_GENERIC_BOOTABLE_CONFIG=y "Austin S. Hemmelgarn" <ahferroin7@gmail.com> - 2016-01-19 19:00 +0100
  Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y Måns Rullgård <mans@mansr.com> - 2016-01-19 13:30 +0100
    Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y Michal Marek <mmarek@suse.cz> - 2016-01-19 13:50 +0100
      Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y Måns Rullgård <mans@mansr.com> - 2016-01-19 14:00 +0100
  Re: [RFC] CONFIG_FORCE_MINIMALLY_SANE_CONFIG=y (was: Re: [RFC PATCH]  x86/kconfig: Sanity-check config file during oldconfig) "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-01-21 23:10 +0100

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