Re: Re: Next steps with pv_ops for Xen

From: Keir Fraser <Keir.Fraser@cl.cam.ac.uk>
To: Derek Murray <Derek.Murray@cl.cam.ac.uk>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
	Eduardo Habkost <ehabkost@redhat.com>,
	Juan Quintela <quintela@redhat.com>,
	"Stephen C. Tweedie" <sct@redhat.com>,
	Jan Beulich <jbeulich@novell.com>,
	Glauber de Oliveira Costa <gcosta@redhat.com>,
	Chris Wright <chrisw@sous-sol.org>,
	"virtualization@lists.osdl.org" <virtualization@lists.osdl.org>,
	Gerd Hoffmann <kraxel@redhat.com>
Subject: Re: Re: Next steps with pv_ops for Xen
Date: Wed, 05 Dec 2007 16:58:51 +0000	[thread overview]
Message-ID: <C37C894B.1970F%Keir.Fraser@cl.cam.ac.uk> (raw)
In-Reply-To: <4756B60D.7030205@cl.cam.ac.uk>

On 5/12/07 14:30, "Derek Murray" <Derek.Murray@cl.cam.ac.uk> wrote:

> Keir Fraser wrote:
>> Is this patch to go into linux-2.6.18-xen.hg then?
> 
> Yes, even if it doesn't fix the exact bug we're seeing here, I think it
> should go in. I've attached a version with my signed-off-by and a better
> commit comment.

Actually I'm not so sure now. Presumably you add VM_PFNMAP to make
vm_normal_page() return NULL? But actually I would expect pte_pfn() to
return max_mapnr because the mapped page is not a local page. And that
should cause vm_normal_page() to return NULL always, regardless of whether
you assert VM_PFNMAP. Is gntdev being used to grant-and-map local pages in
the test that causes the crash?

 -- Keir