[Xen-devel] Re: issues with movnti emulation

To:	Jan Beulich <jbeulich@xxxxxxxxxx>
Subject:	[Xen-devel] Re: issues with movnti emulation
From:	Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date:	Fri, 21 Nov 2008 11:19:38 +0000
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On 21/11/08 11:04, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:

>> Of course this data corruption ought only to happen in cases where we'd
>> previously have failed an mmio emulation (and hence probably killed the
>> guest kernel?).
> 
> Yes, we previously saw emulation failure messages. The guest wasn't
> killed because of that, however. I have to admit it's been a while since
> I last looked at mmio emulation - is it eagerly trying to emulate successive
> instructions, and return to native execution when emulation failed? If
> not, I could neither explain why only some data got corrupted here, nor
> why the guest didn't get killed.

TimD had the correct explanation -- page-table pages getting recycled via
Windows' page scrubber.

 -- Keir



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