monitor: add handle_hmp_command trace event

It is often useful to correlate QEMU-internal events with monitor
commands that caused them.  Trace the full HMP command being executed.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 20170605104216.22429-2-stefanha@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

monitor.c

@@ -3088,6 +3088,8 @@ static void handle_hmp_command(Monitor *mon, const char *cmdline)
     QDict *qdict;
     const mon_cmd_t *cmd;
 
+    trace_handle_hmp_command(mon, cmdline);
+
     cmd = monitor_parse_command(mon, &cmdline, mon->cmd_table);
     if (!cmd) {
         return;

trace-events

@@ -45,6 +45,7 @@ qemu_system_powerdown_request(void) ""
 monitor_protocol_event_handler(uint32_t event, void *qdict) "event=%d data=%p"
 monitor_protocol_event_emit(uint32_t event, void *data) "event=%d data=%p"
 monitor_protocol_event_queue(uint32_t event, void *qdict, uint64_t rate) "event=%d data=%p rate=%" PRId64
+handle_hmp_command(void *mon, const char *cmdline) "mon %p cmdline: %s"
 
 # dma-helpers.c
 dma_blk_io(void *dbs, void *bs, int64_t offset, bool to_dev) "dbs=%p bs=%p offset=%" PRId64 " to_dev=%d"