Re: Re: [PATCH] supporting non-NX/XD capable processors on x86_64 xenlinux

[Jerone Young <jyoung5@us.ibm.com>]

On Thu, 2005-08-18 at 18:18 +0200, Andi Kleen wrote:
> On Thu, Aug 18, 2005 at 11:05:42AM -0500, Jerone Young wrote:
> > On Thu, 2005-08-18 at 17:51 +0200, Andi Kleen wrote:
> > > Keir Fraser <Keir.Fraser@cl.cam.ac.uk> writes:
> > > > 
> > > > By the way -- from what I've seen of this NX/XD discussion so far, it
> > > > sounds like even if CPUID says that NX/XD is supported, and you set
> > > > the EFER.NXE bit, the BIOS can still cause this to be ignored! Is this
> > > > true and, if so, what will happen if you try to use NX/XD anyway?
> > > > i.e., will the bit be ignored, or will its use cause a page fault?
> > > 
> > > I don't think that can happen. When NX is disabled or not there it
> > > doesn't appear in CPUID.
> > 
> > Ah but it does:

hehe... I didn't realize I left that statement in there...I just wanted
to post to the list to confirm with an example. Don't worry Andi ...
your still the x86-64 god in my book!

> 
> Your example confirms what I said.

> 
> -Andi
> 
-- 
Jerone Young
IBM Linux Technology Center
jyoung5@us.ibm.com
512-838-1157 (T/L: 678-1157)