[PATCH V8 21/39] cpr: restart HMP interfaces

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

cpr-save <filename> <mode>
  mode may be "restart"

cpr-exec <command>
  Call qmp_cpr_exec().
  Arguments:
    command : command line to execute, with space-separated arguments

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 hmp-commands.hx       | 29 ++++++++++++++++++++++++++---
 include/monitor/hmp.h |  1 +
 monitor/hmp-cmds.c    | 11 +++++++++++
 3 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index d621968..da5dd60 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -357,7 +357,7 @@ ERST
     {
         .name       = "cpr-save",
         .args_type  = "filename:s,mode:s",
-        .params     = "filename 'reboot'",
+        .params     = "filename 'reboot'|'restart'",
         .help       = "create a checkpoint of the VM in file",
         .cmd        = hmp_cpr_save,
     },
@@ -377,13 +377,36 @@ SRST
   reboot, else it will be saved to the file.  To resume from the checkpoint,
   issue the quit command, reboot the system, start qemu using the same
   arguments plus -S, and issue the cpr-load command.
+
+  If *mode* is 'restart', the checkpoint remains valid after restarting
+  qemu using a subsequent cpr-exec.  Guest RAM must be backed by a
+  memory-backend-file with share=on.
+  To resume from the checkpoint, issue the cpr-load command.
+ERST
+
+    {
+        .name       = "cpr-exec",
+        .args_type  = "command:S",
+        .params     = "command",
+        .help       = "Restart qemu by directly exec'ing command",
+        .cmd        = hmp_cpr_exec,
+    },
+
+SRST
+``cpr-exec`` *command*
+  Restart qemu by directly exec'ing *command*, replacing the qemu process.
+  The PID remains the same.  Must be called after cpr-save restart.
+
+  *command*[0] should be the path of a new qemu binary, or a prefix command that
+  in turn exec's the new qemu binary.  The arguments must match those used
+  to initially start qemu, plus the -S option so new qemu starts in a paused
+  state.
 ERST
 
     {
         .name       = "cpr-load",
         .args_type  = "filename:s,mode:s",
-        .params     = "filename 'reboot'",
-
+        .params     = "filename 'reboot'|'restart'",
         .help       = "load VM checkpoint from file",
         .cmd        = hmp_cpr_load,
     },
diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index b44588e..ec4fa44 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -60,6 +60,7 @@ void hmp_loadvm(Monitor *mon, const QDict *qdict);
 void hmp_savevm(Monitor *mon, const QDict *qdict);
 void hmp_delvm(Monitor *mon, const QDict *qdict);
 void hmp_cpr_save(Monitor *mon, const QDict *qdict);
+void hmp_cpr_exec(Monitor *mon, const QDict *qdict);
 void hmp_cpr_load(Monitor *mon, const QDict *qdict);
 void hmp_migrate_cancel(Monitor *mon, const QDict *qdict);
 void hmp_migrate_continue(Monitor *mon, const QDict *qdict);
diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index 9f58b1f..b866c7f 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -1111,6 +1111,17 @@ void hmp_cpr_save(Monitor *mon, const QDict *qdict)
     hmp_handle_error(mon, err);
 }
 
+void hmp_cpr_exec(Monitor *mon, const QDict *qdict)
+{
+    Error *err = NULL;
+    const char *command = qdict_get_try_str(qdict, "command");
+    strList *args = strList_from_string(command, ' ');
+
+    qmp_cpr_exec(args, &err);
+    qapi_free_strList(args);
+    hmp_handle_error(mon, err);
+}
+
 void hmp_cpr_load(Monitor *mon, const QDict *qdict)
 {
     Error *err = NULL;
-- 
1.8.3.1