Re: [RFC] x86/mm/KASLR: Remap GDTs at fixed location

[Andy Lutomirski]

On Fri, Jan 6, 2017 at 11:45 PM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
> * Andy Lutomirski <luto@xxxxxxxxxx> wrote:

>> P.S. Let's do the move to the fixmap, read/write as a separate patch. That will
>> make bisecting much easier.
>
> Absolutely, but this has to be within the same series, as the interim fixmap-only
> step is less secure in some circumstances: we are moving the writable GDT from a
> previously randomized location to a fixed location.

True, but despite being randomized its location was never even
remotely secret.  (Except on Kaby Lake or Foobar Lake or whatever CPU
that is.)

--Andy