Messages in this thread | | | Date | Tue, 14 Feb 2023 10:32:22 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v2 2/8] x86/mtrr: support setting MTRR state for software defined MTRRs |
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On Tue, Feb 14, 2023 at 10:17:12AM +0100, Juergen Gross wrote: > I guess this largely depends on the functionality. I don't see why anyone > would try to use MTRR overwrite functionality without really needing it. > > But maybe I'm wrong here and I'm under-estimating the "creativity" of > kernel hackers.
This is exactly it - if it is there, it will get used eventually.
Think of it this way: this is a special, well, kinda hack, if you will, which *nothing* else would need. We can always relax the condition for using it if something else appears with a valid use case.
What we can't do nearly as easily is the reverse: remove it or tighten the check later.
So the general policy is: workarounds like this need to be as specialized as possible.
> Maybe I haven't seen enough crazy hacks yet. :-)
You're kidding, right? You hack on Xen for a long time... :-P
> No need to further discuss this topic from my side, as I have voiced my > opinion and you did so, too. I will add the tests you are asking for.
Thanks!
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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