From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mukesh Rathor <mukesh.rathor@oracle.com>
Subject: Re: [V6 PATCH 6.2/7] pvh dom0: Add and remove foreign
 pages
Date: Tue, 17 Dec 2013 18:34:26 -0800
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To: Tim Deegan <tim@xen.org>
Cc: jun.nakajima@intel.com, Xen-devel@lists.xensource.com, Ian Campbell <Ian.Campbell@citrix.com>, george.dunlap@eu.citrix.com, Julien Grall <julien.grall@linaro.org>, eddie.dong@intel.com, keir.xen@gmail.com, Jan Beulich <JBeulich@suse.com>
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On Tue, 17 Dec 2013 11:10:46 +0100
Tim Deegan <tim@xen.org> wrote:

> At 15:27 -0800 on 16 Dec (1387204042), Mukesh Rathor wrote:
> > On Mon, 16 Dec 2013 08:40:41 +0000
> > "Jan Beulich" <JBeulich@suse.com> wrote:
> > 
> > > >>> On 14.12.13 at 03:48, Mukesh Rathor <mukesh.rathor@oracle.com>
> > > >>> wrote:
> > > >> Also, Jan may have an opinion about whether a teardown
> > > >> operation that has to walk each p2m entry would have to be made
> > > >> preemptible.  I'm not sure where we draw the line on such
> > > >> things.
> > > > 
> > > > Since at present teardown cleanup of foreign is not really that
> > > > important as its only applicable to dom0, let me submit another
> > > > patch for it on Mon with few ideas. That would also keep this
> > > > patch size reasonable, and keep you from having to look at the
> > > > same code over and over. 
> > > > 
> > > > So, please take a look at the version below with above two
> > > > fixes. If you approve it, i can resubmit the entire series
> > > > rebased to latest with your ack on Monday, and the series can
> > > > go in while we resolve the p2m teardown.
> > > 
> > > Going through the patch again, I'm not seeing any loop being
> > > added. Am I missing something here?
> > 
> > Yes. Since the destruction of p2m leaking foreign pages only applies
> > to control domain being destroyed, i don't think it is that critical
> > that part get into 4.4.
> 
> Nak.  We can't let the tools break the refcounting.

BTW, it appears that currently this cleanup doesn't happen on PV. If on a 
PV control domain and the tool stack has mapped foreign pages, and the 
PV control domain dies, the refcnt will be messed up. Right?