replay: introduce info hmp/qmp command

This patch introduces 'info replay' monitor command and
corresponding qmp request.
These commands request the current record/replay mode, replay log file
name, and the instruction count (number of recorded/replayed
instructions).  The instruction count can be used with the
replay_seek/replay_break commands added in the next two patches.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <160174520026.12451.13112161947433306561.stgit@pasha-ThinkPad-X280>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hmp-commands-info.hx

@@ -881,4 +881,15 @@ SRST
     Show SEV information.
 ERST
 
+    {
+        .name       = "replay",
+        .args_type  = "",
+        .params     = "",
+        .help       = "show record/replay information",
+        .cmd        = hmp_info_replay,
+    },
 
+SRST
+  ``info replay``
+    Display the record/replay information: mode and the current icount.
+ERST

include/monitor/hmp.h

@@ -129,5 +129,6 @@ void hmp_hotpluggable_cpus(Monitor *mon, const QDict *qdict);
 void hmp_info_vm_generation_id(Monitor *mon, const QDict *qdict);
 void hmp_info_memory_size_summary(Monitor *mon, const QDict *qdict);
 void hmp_info_sev(Monitor *mon, const QDict *qdict);
+void hmp_info_replay(Monitor *mon, const QDict *qdict);
 
 #endif

qapi/block-core.json

@@ -29,7 +29,8 @@
 #
 # @icount: Current instruction count. Appears when execution record/replay
 #          is enabled. Used for "time-traveling" to match the moment
-#          in the recorded execution with the snapshots. (since 5.2)
+#          in the recorded execution with the snapshots. This counter may
+#          be obtained through @query-replay command (since 5.2)
 #
 # Since: 1.3
 #

qapi/replay.json

@@ -24,3 +24,42 @@
 ##
 { 'enum': 'ReplayMode',
   'data': [ 'none', 'record', 'play' ] }
+
+##
+# @ReplayInfo:
+#
+# Record/replay information.
+#
+# @mode: current mode.
+#
+# @filename: name of the record/replay log file.
+#            It is present only in record or replay modes, when the log
+#            is recorded or replayed.
+#
+# @icount: current number of executed instructions.
+#
+# Since: 5.2
+#
+##
+{ 'struct': 'ReplayInfo',
+  'data': { 'mode': 'ReplayMode', '*filename': 'str', 'icount': 'int' } }
+
+##
+# @query-replay:
+#
+# Retrieve the record/replay information.
+# It includes current instruction count which may be used for
+# @replay-break and @replay-seek commands.
+#
+# Returns: record/replay information.
+#
+# Since: 5.2
+#
+# Example:
+#
+# -> { "execute": "query-replay" }
+# <- { "return": { "mode": "play", "filename": "log.rr", "icount": 220414 } }
+#
+##
+{ 'command': 'query-replay',
+  'returns': 'ReplayInfo' }

replay/meson.build

@@ -9,4 +9,5 @@ softmmu_ss.add(files(
   'replay-net.c',
   'replay-audio.c',
   'replay-random.c',
+  'replay-debugging.c',
 ))

replay/replay-debugging.c

@@ -0,0 +1,43 @@
+/*
+ * replay-debugging.c
+ *
+ * Copyright (c) 2010-2020 Institute for System Programming
+ *                         of the Russian Academy of Sciences.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "sysemu/replay.h"
+#include "replay-internal.h"
+#include "monitor/hmp.h"
+#include "monitor/monitor.h"
+#include "qapi/qapi-commands-replay.h"
+
+void hmp_info_replay(Monitor *mon, const QDict *qdict)
+{
+    if (replay_mode == REPLAY_MODE_NONE) {
+        monitor_printf(mon, "Record/replay is not active\n");
+    } else {
+        monitor_printf(mon,
+            "%s execution '%s': instruction count = %"PRId64"\n",
+            replay_mode == REPLAY_MODE_RECORD ? "Recording" : "Replaying",
+            replay_get_filename(), replay_get_current_icount());
+    }
+}
+
+ReplayInfo *qmp_query_replay(Error **errp)
+{
+    ReplayInfo *retval = g_new0(ReplayInfo, 1);
+
+    retval->mode = replay_mode;
+    if (replay_get_filename()) {
+        retval->filename = g_strdup(replay_get_filename());
+        retval->has_filename = true;
+    }
+    retval->icount = replay_get_current_icount();
+    return retval;
+}