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Re: [Xen-devel] [PATCH] xen: fix MSR xentrace output

To: George Dunlap <dunlapg@xxxxxxxxx>, Christoph Egger <Christoph.Egger@xxxxxxx>
Subject: Re: [Xen-devel] [PATCH] xen: fix MSR xentrace output
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Tue, 3 Aug 2010 17:57:17 +0100
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Thread-topic: [Xen-devel] [PATCH] xen: fix MSR xentrace output
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Well, some of the various MSR_READ/WRITE traces are wrong one way or the
other. The vmx/svm-specific trace points have since the beginning of time
been ordered msr_index,msr_low,msr_high. It's the new trace points added by
you to hvm.c that are the 'novel' way round (msr_low,msr_high,msr_index).
Also the proliferation of trace points is stupid: the vmx/svm-specific ones
could easily be got rid of and be on a common exit path from the hvm-generic
intercept functions instead. The movement and duplication of the MSR_WRITE
trace points in Christoph's patch is especially egregious, as the
svm/vmx-specific trace points can simply be deleted.

 -- Keir

On 03/08/2010 17:39, "George Dunlap" <dunlapg@xxxxxxxxx> wrote:

> NACK for discussion.
> What do you mean they're "mixed up"?  Putting the 64-bit value first
> makes it easy to define a structure you can just point directly at the
> binary data.  If xentrace_format is different, wouldnt' it be easier
> to change it than the hypervisor?
>  -George
> On Tue, Aug 3, 2010 at 5:24 PM, Christoph Egger <Christoph.Egger@xxxxxxx>
> wrote:
>> Hi!
>> Attached patch corrects MSR read/write trace output.
>> Also avoid duplicate MSR read/write lines in xentrace output.
>> MSR and value are mixed up.
>> Signed-off-by: Christoph Egger <Christoph.Egger@xxxxxxx>
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