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Re: [Xen-devel] [PATCH 2/2] hvm: allow pass-through of new CPUID feature

To: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH 2/2] hvm: allow pass-through of new CPUID features
From: Andre Przywara <andre.przywara@xxxxxxx>
Date: Thu, 27 Jan 2011 13:05:19 +0100
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Keir Fraser <keir@xxxxxxx>
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Ian Jackson wrote:
Andre Przywara writes ("[Xen-devel] [PATCH 2/2] hvm: allow pass-through of new CPUID 
there are some new CPUID features that are safe for guests to see, as they don't require OS awareness (FPU/ALU related instructions only). Among features for new AMD CPUs there is also the PCLMULQDQ bit, which Intel CPU have already for quite a while.

This would seem to be a new feature.
I agree to some point, although (at least in respect to PCLMULQDQ) I'd consider this more as "forgotten enablement".

> We are currently in feature freeze.

Can you make a justification for a freeze exception ?
If you can make me believe that it does not take another year until this shows up in an official release, then I am totally fine with skipping 4.1.0. What is the policy regarding the 4.1.x releases? Have features like those a chance of being applied?


Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany

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