vmstate: add qom interface to get id

Add an interface to get the instance id, instead of depending on
Device and qdev_get_dev_path().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

3 files changed, 44 insertions, 0 deletions

diff --git a/include/hw/vmstate-if.h b/include/hw/vmstate-if.h
new file mode 100644
index 0000000000..8ff7f0f292
--- /dev/null
+++ b/include/hw/vmstate-if.h
@@ -0,0 +1,40 @@
+/*
+ * VMState interface
+ *
+ * Copyright (c) 2009-2019 Red Hat Inc
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef VMSTATE_IF_H
+#define VMSTATE_IF_H
+
+#include "qom/object.h"
+
+#define TYPE_VMSTATE_IF "vmstate-if"
+
+#define VMSTATE_IF_CLASS(klass)                                     \
+    OBJECT_CLASS_CHECK(VMStateIfClass, (klass), TYPE_VMSTATE_IF)
+#define VMSTATE_IF_GET_CLASS(obj)                           \
+    OBJECT_GET_CLASS(VMStateIfClass, (obj), TYPE_VMSTATE_IF)
+#define VMSTATE_IF(obj)                             \
+    INTERFACE_CHECK(VMStateIf, (obj), TYPE_VMSTATE_IF)
+
+typedef struct VMStateIf VMStateIf;
+
+typedef struct VMStateIfClass {
+    InterfaceClass parent_class;
+
+    char * (*get_id)(VMStateIf *obj);
+} VMStateIfClass;
+
+static inline char *vmstate_if_get_id(VMStateIf *vmif)
+{
+    if (!vmif) {
+        return NULL;
+    }
+
+    return VMSTATE_IF_GET_CLASS(vmif)->get_id(vmif);
+}
+
+#endif /* VMSTATE_IF_H */
diff --git a/include/migration/register.h b/include/migration/register.h
index a13359a08d..73149c9a01 100644
--- a/include/migration/register.h
+++ b/include/migration/register.h
@@ -14,6 +14,8 @@
 #ifndef MIGRATION_REGISTER_H
 #define MIGRATION_REGISTER_H
 
+#include "hw/vmstate-if.h"
+
 typedef struct SaveVMHandlers {
     /* This runs inside the iothread lock.  */
     SaveStateHandler *save_state;
diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index ac4f46a67d..f546f61c5e 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -27,6 +27,8 @@
 #ifndef QEMU_VMSTATE_H
 #define QEMU_VMSTATE_H
 
+#include "hw/vmstate-if.h"
+
 typedef struct VMStateInfo VMStateInfo;
 typedef struct VMStateField VMStateField;