@samitouri / QOSamiQemu / commits / f96eac8a4f

monitor: minimal conversion of monitors to QOM

This introduces abstract QOM type "monitor", with concrete subtypes "monitor-hmp" and "monitor-qmp". This is the bare minimum conversion of just the type declarations and replacing g_new/g_free with object_new/object_unref. Command line option "-monitor" now creates a "monitor-hmp" object "/objects/compat_monitorNNN" in addition to the character device "/chardevs/compat_monitorNNN". NNN counts up from zero. Exception: "-monitor chardev:ID" creates a "monitor-hmp" object "/objects/ID", and does not create a character device. "-qmp" and "-qmp-pretty" work the same, except they create a "monitor-qmp" object. "-mon" now creates either a "monitor-hmp" or "monitor-qmp" object "/objects/ID" if the option argument provides an ID, else "/objects/compat_monitorNNN". "-gdbstub" and "-serial mon:..." now create a "monitor-hmp" object "/objects/compat_monitorNNN". Note that the object's name in "/objects/" matches the QemuOpts ID when it exists. The only cases where it doesn't exist are "-mon" without ID, "-gdbstub" and "-serial mon:". A future patch will make "monitor-hmp" and "monitor-qmp" work with "-object" and "object-add". Note: there is a slight change in the NNN values assigned. The old code would increment the counter for every monitor added (except for -mon, -serial mon:..., -gdbstub), regardless of whether it needed a "compat_monitorNNN" ID assignment. Now it is only incremented when an automatic ID assigned is needed (but even for -mon, -serial mon:..., -gdbstub). Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-ID: <20260706135824.2623960-6-berrange@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Commit message made slightly more precise] Signed-off-by: Markus Armbruster <armbru@redhat.com>

Daniel P. Berrangé committed Jul 6, 2026 at 14:57 UTC f96eac8a4fc48372eda26de396844be3b9f13d27

10 files changed +129 -29

chardev/char.c

+1 -1

@@ -805,7 +805,7 @@ static Chardev *qemu_chr_new_from_name(const char *label, const char *filename,

805

806 if (qemu_opt_get_bool(opts, "mux", 0)) {

807 assert(permit_mux_mon);

808 - monitor_new_hmp(chr, true, &err);

808 + monitor_new_hmp(NULL, chr, true, &err);

809 if (err) {

810 error_report_err(err);

811 object_unparent(OBJECT(chr));

gdbstub/system.c

+1 -1

@@ -390,7 +390,7 @@ bool gdbserver_start(const char *device, Error **errp)

390 /* Initialize a monitor terminal for gdb */

391 mon_chr = qemu_chardev_new(NULL, TYPE_CHARDEV_GDB,

392 NULL, NULL, &error_abort);

393 - monitor_new_hmp(mon_chr, false, &error_abort);

393 + monitor_new_hmp(NULL, mon_chr, false, &error_abort);

394 } else {

395 qemu_chr_fe_deinit(&gdbserver_system_state.chr, true);

396 mon_chr = gdbserver_system_state.mon_chr;

include/monitor/monitor.h

+15 -3

@@ -5,8 +5,17 @@

5 #include "qapi/qapi-types-misc.h"

6 #include "qemu/readline.h"

7 #include "exec/hwaddr.h"

8 +#include "qom/object.h"

9 +

10 +#define TYPE_MONITOR "monitor"

11 +OBJECT_DECLARE_TYPE(Monitor, MonitorClass, MONITOR);

12 +

13 +#define TYPE_MONITOR_HMP "monitor-hmp"

14 +OBJECT_DECLARE_TYPE(MonitorHMP, MonitorHMPClass, MONITOR_HMP);

15 +

16 +#define TYPE_MONITOR_QMP "monitor-qmp"

17 +OBJECT_DECLARE_TYPE(MonitorQMP, MonitorQMPClass, MONITOR_QMP);

9 -typedef struct MonitorHMP MonitorHMP;

19 typedef struct MonitorOptions MonitorOptions;

21 #define QMP_REQ_QUEUE_LEN_MAX 8

@@ -19,8 +28,11 @@ bool monitor_cur_is_qmp(void);

29 void monitor_init_globals(void);

30 void monitor_init_globals_core(void);

22 -void monitor_new_qmp(Chardev *chr, bool pretty, Error **errp);

23 -void monitor_new_hmp(Chardev *chr, bool use_readline, Error **errp);

31 +char *monitor_compat_id(void);

32 +void monitor_new_qmp(const char *id, Chardev *chr,

33 + bool pretty, Error **errp);

34 +void monitor_new_hmp(const char *id, Chardev *chr,

35 + bool use_readline, Error **errp);

36 int monitor_new(MonitorOptions *opts, bool allow_hmp, Error **errp);

37 int monitor_new_opts(QemuOpts *opts, Error **errp);

38 void monitor_cleanup(void);

monitor/hmp.c

+28 -3

@@ -43,6 +43,20 @@

43 #include "system/block-backend.h"

44 #include "trace.h"

46 +OBJECT_DEFINE_TYPE(MonitorHMP, monitor_hmp, MONITOR_HMP, MONITOR);

47 +

48 +static void monitor_hmp_finalize(Object *obj)

49 +{

50 +}

51 +

52 +static void monitor_hmp_class_init(ObjectClass *cls, const void *data)

53 +{

54 +}

55 +

56 +static void monitor_hmp_init(Object *obj)

57 +{

58 +}

59 +

60 static void monitor_command_cb(void *opaque, const char *cmdline,

61 void *readline_opaque)

62 {

@@ -1524,12 +1538,23 @@ static void monitor_readline_flush(void *opaque)

1538 monitor_flush(&mon->parent_obj);

1539 }

1540

1527 -void monitor_new_hmp(Chardev *chr, bool use_readline, Error **errp)

1541 +void monitor_new_hmp(const char *id, Chardev *chr,

1542 + bool use_readline, Error **errp)

1543 {

1529 - MonitorHMP *mon = g_new0(MonitorHMP, 1);

1544 + MonitorHMP *mon;

1545 + g_autofree char *autoid = id ? NULL : monitor_compat_id();

1546 + Object *obj = object_new_with_props(TYPE_MONITOR_HMP,

1547 + object_get_objects_root(),

1548 + id ? id : autoid,

1549 + errp,

1550 + NULL);

1551 + if (!obj) {

1552 + return;

1553 + }

1554 + mon = MONITOR_HMP(obj);

1555

1556 if (!qemu_chr_fe_init(&mon->parent_obj.chr, chr, errp)) {

1532 - g_free(mon);

1557 + object_unparent(OBJECT(mon));

1558 return;

1559 }

1560

monitor/monitor-internal.h

+16 -2

@@ -101,7 +101,13 @@ typedef struct HMPCommand {

101 bool coroutine;

102 } HMPCommand;

103

104 +

105 +struct MonitorClass {

106 + ObjectClass parent_class;

107 +};

108 +

109 struct Monitor {

110 + Object parent;

111 CharFrontend chr;

112 int suspend_cnt; /* Needs to be accessed atomically */

113 bool is_qmp;

@@ -127,6 +133,10 @@ struct Monitor {

133 int reset_seen;

134 };

135

136 +struct MonitorHMPClass {

137 + MonitorClass parent_class;

138 +};

139 +

140 struct MonitorHMP {

141 Monitor parent_obj;

142 bool use_readline;

@@ -140,7 +150,11 @@ struct MonitorHMP {

150 ReadLineState *rs;

151 };

152

143 -typedef struct {

153 +struct MonitorQMPClass {

154 + MonitorClass parent_class;

155 +};

156 +

157 +struct MonitorQMP {

158 Monitor parent_obj;

159 JSONMessageParser parser;

160 bool pretty;

@@ -160,7 +174,7 @@ typedef struct {

174 QemuMutex qmp_queue_lock;

175 /* Input queue that holds all the parsed QMP requests */

176 GQueue *qmp_requests;

163 -} MonitorQMP;

177 +};

178

179 /**

180 * Is @mon a QMP monitor?

monitor/monitor.c

+27 -4

@@ -73,6 +73,22 @@ static GHashTable *coroutine_mon; /* Maps Coroutine* to Monitor* */

73 MonitorList mon_list;

74 static bool monitor_destroyed;

76 +int monitor_device_index;

77 +

78 +OBJECT_DEFINE_ABSTRACT_TYPE(Monitor, monitor, MONITOR, OBJECT);

79 +

80 +static void monitor_finalize(Object *obj)

81 +{

82 +}

83 +

84 +static void monitor_class_init(ObjectClass *cls, const void *data)

85 +{

86 +}

87 +

88 +static void monitor_init(Object *obj)

89 +{

90 +}

91 +

92 Monitor *monitor_cur(void)

93 {

94 Monitor *mon;

@@ -598,7 +614,7 @@ void monitor_list_append(Monitor *mon)

614

615 if (mon) {

616 monitor_data_destroy(mon);

601 - g_free(mon);

617 + object_unparent(OBJECT(mon));

618 }

619 }

620

@@ -680,7 +696,7 @@ void monitor_cleanup(void)

696 monitor_flush(mon);

697 monitor_data_destroy(mon);

698 qemu_mutex_lock(&monitor_lock);

683 - g_free(mon);

699 + object_unparent(OBJECT(mon));

700 }

701 qemu_mutex_unlock(&monitor_lock);

702

@@ -715,6 +731,13 @@ void monitor_init_globals(void)

731 aio_co_schedule(iohandler_get_aio_context(), qmp_dispatcher_co);

732 }

733

734 +char *monitor_compat_id(void)

735 +{

736 + static int monitor_device_index;

737 +

738 + return g_strdup_printf("compat_monitor%d", monitor_device_index++);

739 +}

740 +

741 int monitor_new(MonitorOptions *opts, bool allow_hmp, Error **errp)

742 {

743 ERRP_GUARD();

@@ -732,7 +755,7 @@ int monitor_new(MonitorOptions *opts, bool allow_hmp, Error **errp)

755

756 switch (opts->mode) {

757 case MONITOR_MODE_CONTROL:

735 - monitor_new_qmp(chr, opts->pretty, errp);

758 + monitor_new_qmp(opts->id, chr, opts->pretty, errp);

759 break;

760 case MONITOR_MODE_READLINE:

761 if (!allow_hmp) {

@@ -743,7 +766,7 @@ int monitor_new(MonitorOptions *opts, bool allow_hmp, Error **errp)

766 error_setg(errp, "'pretty' is not compatible with HMP monitors");

767 return -1;

768 }

746 - monitor_new_hmp(chr, true, errp);

769 + monitor_new_hmp(opts->id, chr, true, errp);

770 break;

771 default:

772 g_assert_not_reached();

monitor/qmp-cmds.c

+8 -7

@@ -166,12 +166,12 @@ char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index,

166 int64_t cpu_index, Error **errp)

167 {

168 char *output = NULL;

169 - MonitorHMP hmp = {};

169 + MonitorHMP *hmp = MONITOR_HMP(object_new(TYPE_MONITOR_HMP));

170

171 - monitor_data_init(&hmp.parent_obj, false, true, false);

171 + monitor_data_init(&hmp->parent_obj, false, true, false);

172

173 if (has_cpu_index) {

174 - int ret = monitor_set_cpu(&hmp.parent_obj, cpu_index);

174 + int ret = monitor_set_cpu(&hmp->parent_obj, cpu_index);

175 if (ret < 0) {

176 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cpu-index",

177 "a CPU number");

@@ -179,14 +179,15 @@ char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index,

179 }

180 }

181

182 - handle_hmp_command(&hmp, command_line);

182 + handle_hmp_command(hmp, command_line);

183

184 - WITH_QEMU_LOCK_GUARD(&hmp.parent_obj.mon_lock) {

185 - output = g_strdup(hmp.parent_obj.outbuf->str);

184 + WITH_QEMU_LOCK_GUARD(&hmp->parent_obj.mon_lock) {

185 + output = g_strdup(hmp->parent_obj.outbuf->str);

186 }

187

188 out:

189 - monitor_data_destroy(&hmp.parent_obj);

189 + monitor_data_destroy(&hmp->parent_obj);

190 + object_unref(hmp);

191 return output;

192 }

193

monitor/qmp.c

+28 -3

@@ -71,6 +71,20 @@ typedef struct QMPRequest QMPRequest;

72 QmpCommandList qmp_commands, qmp_cap_negotiation_commands;

74 +OBJECT_DEFINE_TYPE(MonitorQMP, monitor_qmp, MONITOR_QMP, MONITOR);

75 +

76 +static void monitor_qmp_finalize(Object *obj)

77 +{

78 +}

79 +

80 +static void monitor_qmp_class_init(ObjectClass *cls, const void *data)

81 +{

82 +}

83 +

84 +static void monitor_qmp_init(Object *obj)

85 +{

86 +}

87 +

88 static bool qmp_oob_enabled(MonitorQMP *mon)

89 {

90 return mon->capab[QMP_CAPABILITY_OOB];

@@ -513,12 +527,23 @@ static void monitor_qmp_setup_handlers_bh(void *opaque)

527 monitor_list_append(&mon->parent_obj);

528 }

529

516 -void monitor_new_qmp(Chardev *chr, bool pretty, Error **errp)

530 +void monitor_new_qmp(const char *id, Chardev *chr,

531 + bool pretty, Error **errp)

532 {

518 - MonitorQMP *mon = g_new0(MonitorQMP, 1);

533 + MonitorQMP *mon;

534 + g_autofree char *autoid = id ? NULL : monitor_compat_id();

535 + Object *obj = object_new_with_props(TYPE_MONITOR_QMP,

536 + object_get_objects_root(),

537 + id ? id : autoid,

538 + errp,

539 + NULL);

540 + if (!obj) {

541 + return;

542 + }

543 + mon = MONITOR_QMP(obj);

544

545 if (!qemu_chr_fe_init(&mon->parent_obj.chr, chr, errp)) {

521 - g_free(mon);

546 + object_unparent(OBJECT(mon));

547 return;

548 }

549 qemu_chr_fe_set_echo(&mon->parent_obj.chr, true);

stubs/monitor-internal.c

+2 -1

@@ -8,6 +8,7 @@ int monitor_get_fd(Monitor *mon, const char *name, Error **errp)

8 return -1;

9 }

11 -void monitor_new_hmp(Chardev *chr, bool use_readline, Error **errp)

11 +void monitor_new_hmp(const char *id, Chardev *chr,

12 + bool use_readline, Error **errp)

13 {

14 }

system/vl.c

+3 -4

@@ -1252,7 +1252,6 @@ static int mon_init_func(void *opaque, QemuOpts *opts, Error **errp)

1252

1253 static void monitor_parse(const char *str, const char *mode, bool pretty)

1254 {

1255 - static int monitor_device_index = 0;

1255 QemuOpts *opts;

1256 const char *p;

1257 char label[32];

@@ -1260,8 +1259,9 @@ static void monitor_parse(const char *str, const char *mode, bool pretty)

1259 if (strstart(str, "chardev:", &p)) {

1260 snprintf(label, sizeof(label), "%s", p);

1261 } else {

1263 - snprintf(label, sizeof(label), "compat_monitor%d",

1264 - monitor_device_index);

1262 + g_autofree char *id = monitor_compat_id();

1263 + assert(strlen(id) < sizeof(label));

1264 + memcpy(label, id, strlen(id) + 1);

1265 opts = qemu_chr_parse_compat(label, str, true);

1266 if (!opts) {

1267 error_report("parse error: %s", str);

@@ -1277,7 +1277,6 @@ static void monitor_parse(const char *str, const char *mode, bool pretty)

1277 } else {

1278 assert(pretty == false);

1279 }

1280 - monitor_device_index++;

1280 }

1281

1282 struct device_config {