1 files changed, 15 insertions, 2 deletions

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 8009acbe41e4..696c694986d0 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -899,6 +899,13 @@ int m2p_add_override(unsigned long mfn, struct page *page,
                                         "m2p_add_override: pfn %lx not mapped", pfn))
                         return -EINVAL;
         }
+        WARN_ON(PagePrivate(page));
+        SetPagePrivate(page);
+        set_page_private(page, mfn);
+        page->index = pfn_to_mfn(pfn);
+
+        if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
+                return -ENOMEM;
 
         if (kmap_op != NULL) {
                 if (!PageHighMem(page)) {
@@ -937,16 +944,19 @@ int m2p_add_override(unsigned long mfn, struct page *page,
 }
 EXPORT_SYMBOL_GPL(m2p_add_override);
 int m2p_remove_override(struct page *page,
-                        struct gnttab_map_grant_ref *kmap_op,
-                        unsigned long mfn)
+                struct gnttab_map_grant_ref *kmap_op)
 {
         unsigned long flags;
+        unsigned long mfn;
         unsigned long pfn;
         unsigned long uninitialized_var(address);
         unsigned level;
         pte_t *ptep = NULL;
 
         pfn = page_to_pfn(page);
+        mfn = get_phys_to_machine(pfn);
+        if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))
+                return -EINVAL;
 
         if (!PageHighMem(page)) {
                 address = (unsigned long)__va(pfn << PAGE_SHIFT);
@@ -960,7 +970,10 @@ int m2p_remove_override(struct page *page,
         spin_lock_irqsave(&m2p_override_lock, flags);
         list_del(&page->lru);
         spin_unlock_irqrestore(&m2p_override_lock, flags);
+        WARN_ON(!PagePrivate(page));
+        ClearPagePrivate(page);
 
+        set_phys_to_machine(pfn, page->index);
         if (kmap_op != NULL) {
                 if (!PageHighMem(page)) {
                         struct multicall_space mcs;