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[Xen-devel] Re: c/s 19576 vs. AMD systems

To: Jan Beulich <jbeulich@xxxxxxxxxx>
Subject: [Xen-devel] Re: c/s 19576 vs. AMD systems
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Wed, 29 Apr 2009 10:43:32 +0100
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On 29/04/2009 09:53, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:

> I'm afraid this change is going to hurt on AMD systems where memory extends
> beyond the 4Gb boundary: Both such systems that I have direct access to
> have their Intel MTRRs only defined up to the 4Gb boundary, yet through
> the use of AMD specific MSRs (SYS_CFG.Tom2ForceMemTypeWB and TOM2)
> the default memory type for everything beyond the 4Gb boundary is WB.
> On these systems there shouldn't be any clipping. I certainly can put together
> a patch for this, but it'll take me a couple of days until I'd get to it.

What do you suggest? Make the clip Intel-specific? We've only seen problems
with (a very few) Intel boxes, so handling AMD at all may be quite

 -- Keir

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