vmstate: Add VMSTATE_BUFFER_UNUSED

It allows to have 'things' in savevm format not backed in the device state
Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/savevm.c b/savevm.c
index cbb60f3a2..70e8a7d36 100644
--- a/savevm.c
+++ b/savevm.c
@@ -944,6 +944,26 @@ const VMStateInfo vmstate_info_buffer = {
     .put  = put_buffer,
 };
 
+/* unused buffers: space that was used for some fields that are
+   not usefull anymore */
+
+static int get_unused_buffer(QEMUFile *f, void *pv, size_t size)
+{
+    qemu_fseek(f, size, SEEK_CUR);
+    return 0;
+}
+
+static void put_unused_buffer(QEMUFile *f, void *pv, size_t size)
+{
+    qemu_fseek(f, size, SEEK_CUR);
+}
+
+const VMStateInfo vmstate_info_unused_buffer = {
+    .name = "unused_buffer",
+    .get  = get_unused_buffer,
+    .put  = put_unused_buffer,
+};
+
 typedef struct SaveStateEntry {
     QTAILQ_ENTRY(SaveStateEntry) entry;
     char idstr[256];