From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <jbeulich@novell.com>
Subject: Re: mapping of memory below 16Mb
Date: Thu, 24 Jan 2008 15:57:18 +0000
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	<C3BE5EAE.1B616%Keir.Fraser@cl.cam.ac.uk>
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To: Keir Fraser <Keir.Fraser@cl.cam.ac.uk>
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>> 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.

Hmm, I must have missed this going in. Is the indexing into PAT then
considered part of the ABI (as I can't see either a hypercall a guest
could use to learn what bit combination to use for certain attributes or
one to set a virtual PAT value)?

And regardless of that, SVM code has no sign of handling accesses to the
PAT MSR.

Jan