diff --git a/savevm.c b/savevm.c
index d874d08..ee27989 100644
--- a/savevm.c
+++ b/savevm.c
@@ -72,6 +72,7 @@
 
 #include "qemu-common.h"
 #include "hw/hw.h"
+#include "hw/qdev.h"
 #include "net.h"
 #include "monitor.h"
 #include "sysemu.h"
@@ -985,6 +986,11 @@
     .put  = put_unused_buffer,
 };
 
+typedef struct CompatEntry {
+    char idstr[256];
+    int instance_id;
+} CompatEntry;
+
 typedef struct SaveStateEntry {
     QTAILQ_ENTRY(SaveStateEntry) entry;
     char idstr[256];
@@ -998,6 +1004,7 @@
     LoadStateHandler *load_state;
     const VMStateDescription *vmsd;
     void *opaque;
+    CompatEntry *compat;
 } SaveStateEntry;
 
 
@@ -1019,6 +1026,23 @@
     return instance_id;
 }
 
+static int calculate_compat_instance_id(const char *idstr)
+{
+    SaveStateEntry *se;
+    int instance_id = 0;
+
+    QTAILQ_FOREACH(se, &savevm_handlers, entry) {
+        if (!se->compat)
+            continue;
+
+        if (strcmp(idstr, se->compat->idstr) == 0
+            && instance_id <= se->compat->instance_id) {
+            instance_id = se->compat->instance_id + 1;
+        }
+    }
+    return instance_id;
+}
+
 /* TODO: Individual devices generally have very little idea about the rest
    of the system, so instance_id should be removed/replaced.
    Meanwhile pass -1 as instance_id if you do not already have a clearly
@@ -1036,7 +1060,6 @@
     SaveStateEntry *se;
 
     se = qemu_mallocz(sizeof(SaveStateEntry));
-    pstrcpy(se->idstr, sizeof(se->idstr), idstr);
     se->version_id = version_id;
     se->section_id = global_section_id++;
     se->set_params = set_params;
@@ -1046,11 +1069,28 @@
     se->opaque = opaque;
     se->vmsd = NULL;
 
+    if (dev && dev->parent_bus && dev->parent_bus->info->get_dev_path) {
+        char *id = dev->parent_bus->info->get_dev_path(dev);
+        if (id) {
+            pstrcpy(se->idstr, sizeof(se->idstr), id);
+            pstrcat(se->idstr, sizeof(se->idstr), "/");
+            qemu_free(id);
+
+            se->compat = qemu_mallocz(sizeof(CompatEntry));
+            pstrcpy(se->compat->idstr, sizeof(se->compat->idstr), idstr);
+            se->compat->instance_id = instance_id == -1 ?
+                         calculate_compat_instance_id(idstr) : instance_id;
+            instance_id = -1;
+        }
+    }
+    pstrcat(se->idstr, sizeof(se->idstr), idstr);
+
     if (instance_id == -1) {
-        se->instance_id = calculate_new_instance_id(idstr);
+        se->instance_id = calculate_new_instance_id(se->idstr);
     } else {
         se->instance_id = instance_id;
     }
+    assert(!se->compat || se->instance_id == 0);
     /* add at the end of list */
     QTAILQ_INSERT_TAIL(&savevm_handlers, se, entry);
     return 0;
@@ -1071,9 +1111,20 @@
 void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque)
 {
     SaveStateEntry *se, *new_se;
+    char id[256] = "";
+
+    if (dev && dev->parent_bus && dev->parent_bus->info->get_dev_path) {
+        char *path = dev->parent_bus->info->get_dev_path(dev);
+        if (path) {
+            pstrcpy(id, sizeof(id), path);
+            pstrcat(id, sizeof(id), "/");
+            qemu_free(path);
+        }
+    }
+    pstrcat(id, sizeof(id), idstr);
 
     QTAILQ_FOREACH_SAFE(se, &savevm_handlers, entry, new_se) {
-        if (strcmp(se->idstr, idstr) == 0 && se->opaque == opaque) {
+        if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) {
             QTAILQ_REMOVE(&savevm_handlers, se, entry);
             qemu_free(se);
         }
@@ -1091,7 +1142,6 @@
     assert(alias_id == -1 || required_for_version >= vmsd->minimum_version_id);
 
     se = qemu_mallocz(sizeof(SaveStateEntry));
-    pstrcpy(se->idstr, sizeof(se->idstr), vmsd->name);
     se->version_id = vmsd->version_id;
     se->section_id = global_section_id++;
     se->save_live_state = NULL;
@@ -1101,11 +1151,28 @@
     se->vmsd = vmsd;
     se->alias_id = alias_id;
 
+    if (dev && dev->parent_bus && dev->parent_bus->info->get_dev_path) {
+        char *id = dev->parent_bus->info->get_dev_path(dev);
+        if (id) {
+            pstrcpy(se->idstr, sizeof(se->idstr), id);
+            pstrcat(se->idstr, sizeof(se->idstr), "/");
+            qemu_free(id);
+
+            se->compat = qemu_mallocz(sizeof(CompatEntry));
+            pstrcpy(se->compat->idstr, sizeof(se->compat->idstr), vmsd->name);
+            se->compat->instance_id = instance_id == -1 ?
+                         calculate_compat_instance_id(vmsd->name) : instance_id;
+            instance_id = -1;
+        }
+    }
+    pstrcat(se->idstr, sizeof(se->idstr), vmsd->name);
+
     if (instance_id == -1) {
-        se->instance_id = calculate_new_instance_id(vmsd->name);
+        se->instance_id = calculate_new_instance_id(se->idstr);
     } else {
         se->instance_id = instance_id;
     }
+    assert(!se->compat || se->instance_id == 0);
     /* add at the end of list */
     QTAILQ_INSERT_TAIL(&savevm_handlers, se, entry);
     return 0;
@@ -1451,6 +1518,13 @@
             (instance_id == se->instance_id ||
              instance_id == se->alias_id))
             return se;
+        /* Migrating from an older version? */
+        if (strstr(se->idstr, idstr) && se->compat) {
+            if (!strcmp(se->compat->idstr, idstr) &&
+                (instance_id == se->compat->instance_id ||
+                 instance_id == se->alias_id))
+                return se;
+        }
     }
     return NULL;
 }