Merge tag 'stable/for-linus-3.20-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen features and fixes from David Vrabel:

 - Reworked handling for foreign (grant mapped) pages to simplify the
   code, enable a number of additional use cases and fix a number of
   long-standing bugs.

 - Prefer the TSC over the Xen PV clock when dom0 (and the TSC is
   stable).

 - Assorted other cleanup and minor bug fixes.

* tag 'stable/for-linus-3.20-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (25 commits)
  xen/manage: Fix USB interaction issues when resuming
  xenbus: Add proper handling of XS_ERROR from Xenbus for transactions.
  xen/gntdev: provide find_special_page VMA operation
  xen/gntdev: mark userspace PTEs as special on x86 PV guests
  xen-blkback: safely unmap grants in case they are still in use
  xen/gntdev: safely unmap grants in case they are still in use
  xen/gntdev: convert priv->lock to a mutex
  xen/grant-table: add a mechanism to safely unmap pages that are in use
  xen-netback: use foreign page information from the pages themselves
  xen: mark grant mapped pages as foreign
  xen/grant-table: add helpers for allocating pages
  x86/xen: require ballooned pages for grant maps
  xen: remove scratch frames for ballooned pages and m2p override
  xen/grant-table: pre-populate kernel unmap ops for xen_gnttab_unmap_refs()
  mm: add 'foreign' alias for the 'pinned' page flag
  mm: provide a find_special_page vma operation
  x86/xen: cleanup arch/x86/xen/mmu.c
  x86/xen: add some __init annotations in arch/x86/xen/mmu.c
  x86/xen: add some __init and static annotations in arch/x86/xen/setup.c
  x86/xen: use correct types for addresses in arch/x86/xen/setup.c
  ...

2 files changed, 13 insertions, 0 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index dd5ea3016fc4..237b3ba29225 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -290,6 +290,14 @@ struct vm_operations_struct {
         /* called by sys_remap_file_pages() to populate non-linear mapping */
         int (*remap_pages)(struct vm_area_struct *vma, unsigned long addr,
                            unsigned long size, pgoff_t pgoff);
+
+        /*
+         * Called by vm_normal_page() for special PTEs to find the
+         * page for @addr.  This is useful if the default behavior
+         * (using pte_page()) would not find the correct page.
+         */
+        struct page *(*find_special_page)(struct vm_area_struct *vma,
+                                          unsigned long addr);
 };
 
 struct mmu_gather;
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index e1f5fcd79792..5ed7bdaf22d5 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -121,8 +121,12 @@ enum pageflags {
         PG_fscache = PG_private_2,      /* page backed by cache */
 
         /* XEN */
+        /* Pinned in Xen as a read-only pagetable page. */
         PG_pinned = PG_owner_priv_1,
+        /* Pinned as part of domain save (see xen_mm_pin_all()). */
         PG_savepinned = PG_dirty,
+        /* Has a grant mapping of another (foreign) domain's page. */
+        PG_foreign = PG_owner_priv_1,
 
         /* SLOB */
         PG_slob_free = PG_private,
@@ -215,6 +219,7 @@ __PAGEFLAG(Slab, slab)
 PAGEFLAG(Checked, checked)              /* Used by some filesystems */
 PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned)     /* Xen */
 PAGEFLAG(SavePinned, savepinned);                       /* Xen */
+PAGEFLAG(Foreign, foreign);                             /* Xen */
 PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
 PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
         __SETPAGEFLAG(SwapBacked, swapbacked)