Date: Mon, 26 Apr 2010 15:45:10 -0300
From: Glauber Costa <glommer@redhat.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, avi@redhat.com
Subject: Re: [PATCH 1/6] Enable pvclock flags in vcpu_time_info structure
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On Mon, Apr 26, 2010 at 11:11:57AM -0700, Jeremy Fitzhardinge wrote:
> On 04/26/2010 10:46 AM, Glauber Costa wrote:
> > This patch removes one padding byte and transform it into a flags
> > field. New versions of guests using pvclock will query these flags
> > upon each read.
> >   
> 
> Is this necessary?  Why not just make the pvclock driver maintain a
> local flag set, and have the HV backend call into it to update it.  Why
> does it need to be part of the pvclock structure?
Because it is already there, and we have plenty of space left?

There are obvious other ways, but I don't see any of them being simpler.
If we go by the method you suggested, we'd have, for instance, to register
the memory area where this flags lives. Which is a duplication of the
infrastructure already present in kvmclock.


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