[PATCH V2 03/13] migration: save cpr mode

[Steve Sistare <steven.sistare@oracle.com>]

Save the mode in CPR state, so the user does not need to explicitly specify
it for the target.  Modify migrate_mode() so it returns the incoming mode on
the target.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 include/migration/cpr.h |  7 +++++++
 migration/cpr.c         | 23 ++++++++++++++++++++++-
 migration/migration.c   |  1 +
 migration/options.c     |  9 +++++++--
 4 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/include/migration/cpr.h b/include/migration/cpr.h
index e7b898b..ac7a63e 100644
--- a/include/migration/cpr.h
+++ b/include/migration/cpr.h
@@ -8,9 +8,16 @@
 #ifndef MIGRATION_CPR_H
 #define MIGRATION_CPR_H
 
+#include "qapi/qapi-types-migration.h"
+
+#define MIG_MODE_NONE           -1
+
 #define QEMU_CPR_FILE_MAGIC     0x51435052
 #define QEMU_CPR_FILE_VERSION   0x00000001
 
+MigMode cpr_get_incoming_mode(void);
+void cpr_set_incoming_mode(MigMode mode);
+
 typedef int (*cpr_walk_fd_cb)(int fd);
 void cpr_save_fd(const char *name, int id, int fd);
 void cpr_delete_fd(const char *name, int id);
diff --git a/migration/cpr.c b/migration/cpr.c
index e50fc75..7514c4e 100644
--- a/migration/cpr.c
+++ b/migration/cpr.c
@@ -21,10 +21,23 @@
 typedef QLIST_HEAD(CprFdList, CprFd) CprFdList;
 
 typedef struct CprState {
+    MigMode mode;
     CprFdList fds;
 } CprState;
 
-static CprState cpr_state;
+static CprState cpr_state = {
+    .mode = MIG_MODE_NONE,
+};
+
+MigMode cpr_get_incoming_mode(void)
+{
+    return cpr_state.mode;
+}
+
+void cpr_set_incoming_mode(MigMode mode)
+{
+    cpr_state.mode = mode;
+}
 
 /****************************************************************************/
 
@@ -124,11 +137,19 @@ void cpr_resave_fd(const char *name, int id, int fd)
 /*************************************************************************/
 #define CPR_STATE "CprState"
 
+static int cpr_state_presave(void *opaque)
+{
+    cpr_state.mode = migrate_mode();
+    return 0;
+}
+
 static const VMStateDescription vmstate_cpr_state = {
     .name = CPR_STATE,
     .version_id = 1,
     .minimum_version_id = 1,
+    .pre_save = cpr_state_presave,
     .fields = (VMStateField[]) {
+        VMSTATE_UINT32(mode, CprState),
         VMSTATE_QLIST_V(fds, CprState, 1, vmstate_cpr_fd, CprFd, next),
         VMSTATE_END_OF_LIST()
     }
diff --git a/migration/migration.c b/migration/migration.c
index 834b0a2..df00e5c 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -416,6 +416,7 @@ void migration_incoming_state_destroy(void)
         mis->postcopy_qemufile_dst = NULL;
     }
 
+    cpr_set_incoming_mode(MIG_MODE_NONE);
     yank_unregister_instance(MIGRATION_YANK_INSTANCE);
 }
 
diff --git a/migration/options.c b/migration/options.c
index 147cd2b..cc85a84 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -22,6 +22,7 @@
 #include "qapi/qmp/qnull.h"
 #include "sysemu/runstate.h"
 #include "migration/colo.h"
+#include "migration/cpr.h"
 #include "migration/misc.h"
 #include "migration.h"
 #include "migration-stats.h"
@@ -768,8 +769,12 @@ uint64_t migrate_max_postcopy_bandwidth(void)
 
 MigMode migrate_mode(void)
 {
-    MigrationState *s = migrate_get_current();
-    MigMode mode = s->parameters.mode;
+    MigMode mode = cpr_get_incoming_mode();
+
+    if (mode == MIG_MODE_NONE) {
+        MigrationState *s = migrate_get_current();
+        mode = s->parameters.mode;
+    }
 
     assert(mode >= 0 && mode < MIG_MODE__MAX);
     return mode;
-- 
1.8.3.1