diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
index 8b322b51c0..012a74455b 100644
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -2341,7 +2341,8 @@ gnttab_transfer(
          * pages when it is dying.
          */
         if ( unlikely(e->is_dying) ||
-             unlikely(domain_tot_pages(e) >= e->max_pages) )
+             unlikely(domain_tot_pages(e) >= e->max_pages) ||
+             unlikely(!(e->tot_pages + 1)) )
         {
             spin_unlock(&e->page_alloc_lock);
 
@@ -2350,8 +2351,8 @@ gnttab_transfer(
                          e->domain_id);
             else
                 gdprintk(XENLOG_INFO,
-                         "Transferee d%d has no headroom (tot %u, max %u)\n",
-                         e->domain_id, domain_tot_pages(e), e->max_pages);
+                         "Transferee %pd has no headroom (tot %u, max %u, ex %u)\n",
+                         e, domain_tot_pages(e), e->max_pages, e->extra_pages);
 
             gop.status = GNTST_general_error;
             goto unlock_and_copyback;
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 5801358b4b..d0baaa2ecd 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -2310,20 +2310,41 @@ int assign_pages(
     }
     else if ( !(memflags & MEMF_no_refcount) )
     {
-        unsigned int tot_pages = domain_tot_pages(d) + nr;
+        unsigned int tot_pages = domain_tot_pages(d);
 
         if ( unlikely(tot_pages > d->max_pages) )
         {
-            gprintk(XENLOG_INFO, "Over-allocation for domain %u: "
-                    "%u > %u\n", d->domain_id, tot_pages, d->max_pages);
+            gprintk(XENLOG_INFO, "Inconsistent allocation for %pd: %u > %u\n",
+                    d, tot_pages, d->max_pages);
+            rc = -EPERM;
+            goto out;
+        }
+
+        if ( unlikely(nr > d->max_pages - tot_pages) )
+        {
+            gprintk(XENLOG_INFO, "Over-allocation for %pd: %Lu > %u\n",
+                    d, tot_pages + 0ull + nr, d->max_pages);
             rc = -E2BIG;
             goto out;
         }
     }
 
-    if ( !(memflags & MEMF_no_refcount) &&
-         unlikely(domain_adjust_tot_pages(d, nr) == nr) )
-        get_knownalive_domain(d);
+    if ( !(memflags & MEMF_no_refcount) )
+    {
+        if ( unlikely(d->tot_pages + nr < nr) )
+        {
+            gprintk(XENLOG_INFO,
+                    "Excess allocation for %pd: %Lu (%u extra)\n",
+                    d, d->tot_pages + 0ull + nr, d->extra_pages);
+            if ( pg[0].count_info & PGC_extra )
+                d->extra_pages -= nr;
+            rc = -E2BIG;
+            goto out;
+        }
+
+        if ( unlikely(domain_adjust_tot_pages(d, nr) == nr) )
+            get_knownalive_domain(d);
+    }
 
     for ( i = 0; i < nr; i++ )
     {