Re: Re: Next steps with pv_ops for Xen

[Derek Murray <Derek.Murray@cl.cam.ac.uk>]

Keir Fraser wrote:
> 
> 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?

That's right (gntdev is being used to map (but not grant) a local page). 
The test case creates a virtual block device in Dom0, and attempts to 
map its ring buffer in a user-space daemon in Dom0. Therefore pte_pfn 
succeeds.

Regards,

Derek.