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[Xen-devel] RE: touching a missing page causes DomU to die

To: James Harper <james.harper@xxxxxxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] RE: touching a missing page causes DomU to die
From: Paul Durrant <Paul.Durrant@xxxxxxxxxx>
Date: Sat, 22 Jan 2011 16:04:57 +0000
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Thread-topic: touching a missing page causes DomU to die

  Then I guess I don't understand why the double buffering code is attempting 
to use the memory you have allocated and handed back to Xen. If your code 
allocated it then nothing else should be trying to use it, right?


> -----Original Message-----
> From: James Harper [mailto:james.harper@xxxxxxxxxxxxxxxx]
> Sent: 21 January 2011 21:52
> To: Paul Durrant; xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: RE: touching a missing page causes DomU to die
> > >
> > > My Windows PV drivers are crashing during hibernation, and I've
> > > finally
> > > figured out that it's because the windows hibernation mode
> driver
> > > double
> > > buffers memory before handing it to my block device driver, and
> in
> > > doing
> > > so 'touches' some pages of memory I have given back to xen (to
> work
> > > around a domu save crash).
> > >
> >
> > You've given memory belonging to the crash kernel back to Xen?
> >
> My driver allocates a few pages of memory and calls decrease
> reservation
> to give them back to xen. This is to work around a problem saving
> (or
> restoring?) a domu under xen where I need to give back an amount of
> pages equal to the pages xen has given me for setup (grant table I
> think).
> James

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