On 5/12/07 17:17, "Derek Murray" <Derek.Murray@xxxxxxxxxxxx> 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. Need to bite the bullet and fix this properly by setting a software flag in ptes that are not subject to reference counting. Unfortunately that also needs a hypervisor interface change, to allow setting of those pte flags. Easily done though, and we should definitely get that piece in for 3.2.0. Setting VM_PFNMAP is bogus. We used to do that for privcmd mappings too, but we stopped because IIRC it had other unwanted side effects. -- Keir _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
