[PATCH 1/2] migration: Boost SaveStateEntry.instance_id to 64 bits

[Peter Xu <peterx@redhat.com>]

It was "int" and used as 32bits fields (see save_section_header()).
It's unsafe already because sizeof(int) could be 2 on i386, I think.
So at least uint32_t would suite more.  While it also uses "-1" as a
placeholder of "we want to generate the instance ID automatically".
Hence a more proper value should be int64_t.

This will start to be useful after next patch in which we can start to
convert a real uint32_t value as instance ID.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/migration/register.h |  2 +-
 include/migration/vmstate.h  |  4 ++--
 migration/savevm.c           | 10 +++++-----
 stubs/vmstate.c              |  2 +-
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/include/migration/register.h b/include/migration/register.h
index a13359a08d..54f42c7413 100644
--- a/include/migration/register.h
+++ b/include/migration/register.h
@@ -69,7 +69,7 @@ typedef struct SaveVMHandlers {
 } SaveVMHandlers;
 
 int register_savevm_live(const char *idstr,
-                         int instance_id,
+                         int64_t instance_id,
                          int version_id,
                          const SaveVMHandlers *ops,
                          void *opaque);
diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index 1fbfd099dd..6a7498463c 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -1114,14 +1114,14 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
 bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque);
 
 /* Returns: 0 on success, -1 on failure */
-int vmstate_register_with_alias_id(DeviceState *dev, int instance_id,
+int vmstate_register_with_alias_id(DeviceState *dev, int64_t instance_id,
                                    const VMStateDescription *vmsd,
                                    void *base, int alias_id,
                                    int required_for_version,
                                    Error **errp);
 
 /* Returns: 0 on success, -1 on failure */
-static inline int vmstate_register(DeviceState *dev, int instance_id,
+static inline int vmstate_register(DeviceState *dev, int64_t instance_id,
                                    const VMStateDescription *vmsd,
                                    void *opaque)
 {
diff --git a/migration/savevm.c b/migration/savevm.c
index bb9462a54d..dc9281c897 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -233,7 +233,7 @@ typedef struct CompatEntry {
 typedef struct SaveStateEntry {
     QTAILQ_ENTRY(SaveStateEntry) entry;
     char idstr[256];
-    int instance_id;
+    int64_t instance_id;
     int alias_id;
     int version_id;
     /* version id read from the stream */
@@ -668,7 +668,7 @@ void dump_vmstate_json_to_file(FILE *out_file)
 static int calculate_new_instance_id(const char *idstr)
 {
     SaveStateEntry *se;
-    int instance_id = 0;
+    int64_t instance_id = 0;
 
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
         if (strcmp(idstr, se->idstr) == 0
@@ -730,7 +730,7 @@ static void savevm_state_handler_insert(SaveStateEntry *nse)
    Meanwhile pass -1 as instance_id if you do not already have a clearly
    distinguishing id for all instances of your device class. */
 int register_savevm_live(const char *idstr,
-                         int instance_id,
+                         int64_t instance_id,
                          int version_id,
                          const SaveVMHandlers *ops,
                          void *opaque)
@@ -784,7 +784,7 @@ void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque)
     }
 }
 
-int vmstate_register_with_alias_id(DeviceState *dev, int instance_id,
+int vmstate_register_with_alias_id(DeviceState *dev, int64_t instance_id,
                                    const VMStateDescription *vmsd,
                                    void *opaque, int alias_id,
                                    int required_for_version,
@@ -1566,7 +1566,7 @@ int qemu_save_device_state(QEMUFile *f)
     return qemu_file_get_error(f);
 }
 
-static SaveStateEntry *find_se(const char *idstr, int instance_id)
+static SaveStateEntry *find_se(const char *idstr, int64_t instance_id)
 {
     SaveStateEntry *se;
 
diff --git a/stubs/vmstate.c b/stubs/vmstate.c
index e1e89b87f0..699003f3b0 100644
--- a/stubs/vmstate.c
+++ b/stubs/vmstate.c
@@ -4,7 +4,7 @@
 const VMStateDescription vmstate_dummy = {};
 
 int vmstate_register_with_alias_id(DeviceState *dev,
-                                   int instance_id,
+                                   int64_t instance_id,
                                    const VMStateDescription *vmsd,
                                    void *base, int alias_id,
                                    int required_for_version,
-- 
2.21.0