Merge branch 'stable/gntdev' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

* 'stable/gntdev' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/p2m: Fix module linking error.
  xen p2m: clear the old pte when adding a page to m2p_override
  xen gntdev: use gnttab_map_refs and gnttab_unmap_refs
  xen: introduce gnttab_map_refs and gnttab_unmap_refs
  xen p2m: transparently change the p2m mappings in the m2p override
  xen/gntdev: Fix circular locking dependency
  xen/gntdev: stop using "token" argument
  xen: gntdev: move use of GNTMAP_contains_pte next to the map_op
  xen: add m2p override mechanism
  xen: move p2m handling to separate file
  xen/gntdev: add VM_PFNMAP to vma
  xen/gntdev: allow usermode to map granted pages
  xen: define gnttab_set_map_op/unmap_op

Fix up trivial conflict in drivers/xen/Kconfig

1 files changed, 13 insertions, 3 deletions

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 8760cc60a21c..f25bdf238a33 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -42,6 +42,11 @@ extern unsigned int   machine_to_phys_order;
 extern unsigned long get_phys_to_machine(unsigned long pfn);
 extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
 
+extern int m2p_add_override(unsigned long mfn, struct page *page);
+extern int m2p_remove_override(struct page *page);
+extern struct page *m2p_find_override(unsigned long mfn);
+extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
+
 static inline unsigned long pfn_to_mfn(unsigned long pfn)
 {
         unsigned long mfn;
@@ -72,9 +77,6 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
         if (xen_feature(XENFEAT_auto_translated_physmap))
                 return mfn;
 
-        if (unlikely((mfn >> machine_to_phys_order) != 0))
-                return ~0;
-
         pfn = 0;
         /*
          * The array access can fail (e.g., device space beyond end of RAM).
@@ -83,6 +85,14 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
          */
         __get_user(pfn, &machine_to_phys_mapping[mfn]);
 
+        /*
+         * If this appears to be a foreign mfn (because the pfn
+         * doesn't map back to the mfn), then check the local override
+         * table to see if there's a better pfn to use.
+         */
+        if (get_phys_to_machine(pfn) != mfn)
+                pfn = m2p_find_override_pfn(mfn, pfn);
+
         return pfn;
 }