1 files changed, 6 insertions, 3 deletions

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 736ed32a83c5..bb44990c8212 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2,8 +2,10 @@
 /*
  *  KVM guest address space mapping code
  *
- *    Copyright IBM Corp. 2007, 2016
+ *    Copyright IBM Corp. 2007, 2016, 2018
  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ *               David Hildenbrand <david@redhat.com>
+ *               Janosch Frank <frankja@linux.vnet.ibm.com>
  */
 
 #include <linux/kernel.h>
@@ -588,8 +590,8 @@ int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
                 return -EFAULT;
         pmd = pmd_offset(pud, vmaddr);
         VM_BUG_ON(pmd_none(*pmd));
-        /* large pmds cannot yet be handled */
-        if (pmd_large(*pmd))
+        /* Are we allowed to use huge pages? */
+        if (pmd_large(*pmd) && !gmap->mm->context.allow_gmap_hpage_1m)
                 return -EFAULT;
         /* Link gmap segment table entry location to page table. */
         rc = radix_tree_preload(GFP_KERNEL);
@@ -1632,6 +1634,7 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce,
         unsigned long limit;
         int rc;
 
+        BUG_ON(parent->mm->context.allow_gmap_hpage_1m);
         BUG_ON(gmap_is_shadow(parent));
         spin_lock(&parent->shadow_lock);
         sg = gmap_find_shadow(parent, asce, edat_level);