vmstate: add VMS_MUST_EXIST

Can be used to verify a required field exists or validate
state in some other way.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
(cherry picked from commit 5bf81c8d63db0216a4d29dc87f9ce530bb791dd1)

Conflicts:
	vmstate.c

*removed dependency on b6fcfa59 (Move VMState code to vmstate.c)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/savevm.c b/savevm.c
index 2c87455aea..8a228070dc 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1762,6 +1762,10 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
                     return ret;
                 }
             }
+        } else if (field->flags & VMS_MUST_EXIST) {
+            fprintf(stderr, "Input validation failed: %s/%s\n",
+                    vmsd->name, field->name);
+            return -1;
         }
         field++;
     }
@@ -1802,6 +1806,12 @@ void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
                     field->info->put(f, addr, size);
                 }
             }
+        } else {
+            if (field->flags & VMS_MUST_EXIST) {
+                fprintf(stderr, "Output state validation failed: %s/%s\n",
+                        vmsd->name, field->name);
+                assert(!(field->flags & VMS_MUST_EXIST));
+            }
         }
         field++;
     }