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Re: [Xen-devel] [Q] Allow rdpmc access from DOM-0

To: "Mohapatra, Hemant" <Hemant.Mohapatra@xxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [Q] Allow rdpmc access from DOM-0
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Thu, 06 Sep 2007 15:59:10 +0100
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On 6/9/07 14:44, "Mohapatra, Hemant" <Hemant.Mohapatra@xxxxxxx> wrote:

> I boot into the new kernel but am still unable to trap rdpmc
> instructions from DOM0. Is there any step I am missing in my attempt to
> trap+emulate rdpmc?

RDPMC is not much use unless you can also set up the performance-counting
MSRs in advance to count appropriate things. Since we do not virtualise
these MSRs, providing access to RDPMC is pointless. You should look at
xenoprof for example usage of performance counter infrastructure in Xen.

 -- Keir

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