From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime
Date: Mon, 28 Sep 2015 08:16:46 +0200
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Cc: Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>, "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>, Denys Vlasenko <dvlasenk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Leif Lindholm <leif.lindholm-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>, stable <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Brian Gerst <brgerst-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>, Matt Fleming <matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>, "Lee, Chun-Yi" <jlee-IBi9RG/b67k@public.gmane.org>, "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, James Bottomley <JBottomley-wo1vFcy6AUs@public.gmane.org>
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* Matthew Garrett <mjg59-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org> wrote:

> On Sun, Sep 27, 2015 at 09:30:48AM -0700, Andy Lutomirski wrote:
> > On Sep 26, 2015 1:19 PM, "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org> wrote:
> > >
> > > Sadly a lot of firmware is known to fail in that configuration :(  That was very much our guest choice.
> > >
> > 
> > Why can't we map everything completely 1:1 (VA = PA) and call the
> > setVA thing but pass it literally the identity.
> 
> Last time I tried this I found that some firmware makes assumptions 
> about having high addresses.

So the question is, what does Windows do?

PC firmware is a hostile environment for Linux, to be compatible the best we can 
do is to mimic the environment that the firmware is tested under - i.e. try to use 
the firmware in the way Windows uses it.

Thanks,

	Ingo