Re: [Xen-devel] mapping of memory below 16Mb

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 24/1/08 16:24, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:

>>> The WP attribute raises another question: Are there any plans to make
>>> Xen use PAT rather than (relying on) MTRRs? Linux folks seem to be
>>> finally getting closer to this, too, so even virtual PAT support may be
>>> needed in not too distant future...
>> 
>> We already support PAT for both PV guests and HVM guests.
> 
> Oh, and my understanding of PAT support goes beyond just setting the
> PAT MSR and adjusting page table flags. Specifically, if we have PAT we
> should never need to modify MTRRs, which would eliminate conflicts on
> updates of those that I'm seeing on various boxes, always just
> depending on how BIOS sets them up, and always related to overlaps
> of the video memory with existing MTRR ranges.

That's a dom0 issue. Xen itself does not proactively mess with the MTRRs.

 -- Keir



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel