x86: check paging mode earlier in xenmem_add_to_physmap_one()

There's no point in deferring this until after some initial processing,
and it's actively wrong for the XENMAPSPACE_gmfn_foreign handling to not
have such a check at all.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: f38f3dccf1e1a8aabcf57364326fc8f44cddc41a
master date: 2017-11-28 13:14:43 +0100

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index d63fcf690facbb85eda7532c6b8ad3f585af919a..ada12c05c564d00a2c0386f29337d1b89fe6156f 100644 (file)
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5022,6 +5022,9 @@ int xenmem_add_to_physmap_one(
     int rc = 0;
     p2m_type_t p2mt;
 
+    if ( !paging_mode_translate(d) )
+        return -EACCES;
+
     switch ( space )
     {
         case XENMAPSPACE_shared_info:
@@ -5078,7 +5081,7 @@ int xenmem_add_to_physmap_one(
             break;
     }
 
-    if ( !paging_mode_translate(d) || (mfn == 0) )
+    if ( mfn == 0 )
     {
         if ( page )
             put_page(page);