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Re: [Xen-devel] [PATCH] Allow dom0 to write MSR IA32_ENERGY_PERF_BIAS

To: Jan Beulich <JBeulich@xxxxxxxxxx>, Gang Wei <gang.wei@xxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Allow dom0 to write MSR IA32_ENERGY_PERF_BIAS
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Wed, 5 Jan 2011 08:13:16 +0000
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Thread-topic: [Xen-devel] [PATCH] Allow dom0 to write MSR IA32_ENERGY_PERF_BIAS
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On 05/01/2011 07:59, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

>>> Why would you allow this only if Dom0 has its vcpus pinned?
>> It is meaningless if dom0 can't control all pcpus exactly. Only in case of
>> dom0 vcpus pinned, it makes sense.
> Disagree. The user mode tool could set its own affinity (virtual and
> physical) and then issue the MSR write. Please don't enforce
> restrictions where not really needed (I actually suppose that the
> restriction should be removed for MSR_IA32_THERM_CONTROL too).

If so, it deserves a separate patch to strip out *all* the is_pinned checks
at the same time.

 -- Keir

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