Messages in this thread | | | Date | Sun, 01 Mar 2009 16:14:24 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] xen: core dom0 support |
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Jeremy Fitzhardinge wrote: > H. Peter Anvin wrote: >> In this particular case, this is actually false. "No PAT" in the >> processor is *not* the same thing as "no cacheability controls in the >> page tables". Every processor since the 386 has had UC, WT, and WB >> controls in the page tables; PAT only added the ability to do WC (and >> WP, which we don't use). Since the number of processors which can do >> WC at all but don't have PAT is a small set of increasingly obsolete >> processors, we may very well choose to simply ignore the WC >> capabilities of these particular processors. > > I'm not quite sure what you're referring to with "this is actually > false". Certainly we support cachability control in ptes under Xen. We > just don't support full PAT because Xen uses PAT for itself. >
What do you define as "full PAT"? If what you mean is that Xen lays claims to the PAT MSR and only allows a certain mapping that's hardly a problem... other than that it's not an exhaustible resource so I guess I really don't understand what you're trying to say here.
-hpa
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