[Qemu-devel] [PATCH 8/9] vmstate: Create optional sections

[Juan Quintela <quintela@redhat.com>]

To make sections optional, we need to do it at the beggining of the code.

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 include/migration/vmstate.h |  2 ++
 migration/vmstate.c         | 11 +++++++++++
 savevm.c                    |  4 ++++
 3 files changed, 17 insertions(+)

diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index fc5e643..a8b59eb 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -813,6 +813,8 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
 void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
                         void *opaque, QJSON *vmdesc);

+bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque);
+
 int vmstate_register_with_alias_id(DeviceState *dev, int instance_id,
                                    const VMStateDescription *vmsd,
                                    void *base, int alias_id,
diff --git a/migration/vmstate.c b/migration/vmstate.c
index 108995e..36dab84 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -276,6 +276,17 @@ static void vmsd_desc_field_end(const VMStateDescription *vmsd, QJSON *vmdesc,
     json_end_object(vmdesc);
 }

+
+bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque)
+{
+    if (vmsd->needed && !vmsd->needed(opaque)) {
+        /* optional section not needed */
+        return false;
+    }
+    return true;
+}
+
+
 void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
                         void *opaque, QJSON *vmdesc)
 {
diff --git a/savevm.c b/savevm.c
index 01770cd..2b4e554 100644
--- a/savevm.c
+++ b/savevm.c
@@ -763,6 +763,10 @@ void qemu_savevm_state_complete(QEMUFile *f)
         if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
             continue;
         }
+        if (se->vmsd && !vmstate_save_needed(se->vmsd, se->opaque)) {
+            continue;
+        }
+
         trace_savevm_section_start(se->idstr, se->section_id);

         json_start_object(vmdesc, NULL);
-- 
2.4.0