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

To: "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: RE: [Xen-devel] [Q] Allow rdpmc access from DOM-0
From: "Mohapatra, Hemant" <Hemant.Mohapatra@xxxxxxx>
Date: Thu, 6 Sep 2007 10:23:53 -0500
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Thread-topic: [Xen-devel] [Q] Allow rdpmc access from DOM-0
>  From: Keir Fraser [mailto:Keir.Fraser@xxxxxxxxxxxx]
>  Subject: Re: [Xen-devel] [Q] Allow rdpmc access from DOM-0
>  RDPMC is not much use unless you can also set up the
>  MSRs in advance to count appropriate things. Since we do not
>  these MSRs, providing access to RDPMC is pointless. You should look
>  xenoprof for example usage of performance counter infrastructure in

My bad; I should've mentioned this before: I already have allowed access
to the appropriate MSRs and can read/write to them using rdmsr/wrmsr on
DOM-0. It was easy to add them to the white-list since the opcode was
already being trapped and virtualized and it was only a matter of adding
access to the MSRs I needed specifically. 

I have worked with Xenoprof but I am essentially trying to port a few
applications to Xen here and trying to re-write them in conjunction with
Xenoprof seems like the round-about way of doing it. I am trying to
follow the route of how rdmsr/wrmsr were virtualized so that I can do
the same with rdpmc. I see no harm in this since RDMSR is already
allowed from Dom0.


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