gnttab: bail from GFN-storing loops early in case of error

The contents of the output arrays are undefined anyway when the
operation itself gets marked as failed. There's no value in trying to
continue after a guest memory access failure.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/xen/common/compat/grant_table.c b/xen/common/compat/grant_table.c
index 4f6d0b05fbedd2f519f0ee57dff53614f68da344..744f9b6e3d2ba9ddd008beb59103249688e1bec6 100644 (file)
--- a/xen/common/compat/grant_table.c
+++ b/xen/common/compat/grant_table.c
@@ -179,7 +179,10 @@ int compat_grant_table_op(
                             unsigned int frame = (_s_)->frame_list.p[i]; \
                             if ( __copy_to_compat_offset((_d_)->frame_list, \
                                                          i, &frame, 1) ) \
+                            { \
                                 (_s_)->status = GNTST_bad_virt_addr; \
+                                break; \
+                            } \
                         } \
                     } \
                 } while (0)

diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
index 6326bae5aa725e58cd31d341d5cedf41dadafc0b..fa28c3cb7b7663083377db19acf0dd945b36b89a 100644 (file)
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -2101,7 +2101,10 @@ gnttab_setup_table(
         BUG_ON(SHARED_M2P(gmfn));
 
         if ( __copy_to_guest_offset(op.frame_list, i, &gmfn, 1) )
+        {
             op.status = GNTST_bad_virt_addr;
+            break;
+        }
     }
 
  unlock:
@@ -3311,7 +3314,10 @@ gnttab_get_status_frames(XEN_GUEST_HANDLE_PARAM(gnttab_get_status_frames_t) uop,
     {
         gmfn = gfn_x(gnttab_status_gfn(d, gt, i));
         if ( __copy_to_guest_offset(op.frame_list, i, &gmfn, 1) )
+        {
             op.status = GNTST_bad_virt_addr;
+            break;
+        }
     }
 
  unlock: