diff --git a/hmp-commands.hx b/hmp-commands.hx
index 67569eff4a..0934b9b915 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1521,7 +1521,8 @@ ETEXI
         .args_type  = "item:s?",
         .params     = "[subcommand]",
         .help       = "show various information about the system state",
-        .mhandler.cmd = do_info,
+        .mhandler.cmd = do_info_help,
+        .sub_table = info_cmds,
     },
 
 STEXI
diff --git a/hmp.c b/hmp.c
index 68929b4acf..c7b6ba02fc 100644
--- a/hmp.c
+++ b/hmp.c
@@ -31,7 +31,7 @@ static void hmp_handle_error(Monitor *mon, Error **errp)
     }
 }
 
-void hmp_info_name(Monitor *mon)
+void hmp_info_name(Monitor *mon, const QDict *qdict)
 {
     NameInfo *info;
 
@@ -42,7 +42,7 @@ void hmp_info_name(Monitor *mon)
     qapi_free_NameInfo(info);
 }
 
-void hmp_info_version(Monitor *mon)
+void hmp_info_version(Monitor *mon, const QDict *qdict)
 {
     VersionInfo *info;
 
@@ -55,7 +55,7 @@ void hmp_info_version(Monitor *mon)
     qapi_free_VersionInfo(info);
 }
 
-void hmp_info_kvm(Monitor *mon)
+void hmp_info_kvm(Monitor *mon, const QDict *qdict)
 {
     KvmInfo *info;
 
@@ -70,7 +70,7 @@ void hmp_info_kvm(Monitor *mon)
     qapi_free_KvmInfo(info);
 }
 
-void hmp_info_status(Monitor *mon)
+void hmp_info_status(Monitor *mon, const QDict *qdict)
 {
     StatusInfo *info;
 
@@ -89,7 +89,7 @@ void hmp_info_status(Monitor *mon)
     qapi_free_StatusInfo(info);
 }
 
-void hmp_info_uuid(Monitor *mon)
+void hmp_info_uuid(Monitor *mon, const QDict *qdict)
 {
     UuidInfo *info;
 
@@ -98,7 +98,7 @@ void hmp_info_uuid(Monitor *mon)
     qapi_free_UuidInfo(info);
 }
 
-void hmp_info_chardev(Monitor *mon)
+void hmp_info_chardev(Monitor *mon, const QDict *qdict)
 {
     ChardevInfoList *char_info, *info;
 
@@ -111,7 +111,7 @@ void hmp_info_chardev(Monitor *mon)
     qapi_free_ChardevInfoList(char_info);
 }
 
-void hmp_info_mice(Monitor *mon)
+void hmp_info_mice(Monitor *mon, const QDict *qdict)
 {
     MouseInfoList *mice_list, *mouse;
 
@@ -131,7 +131,7 @@ void hmp_info_mice(Monitor *mon)
     qapi_free_MouseInfoList(mice_list);
 }
 
-void hmp_info_migrate(Monitor *mon)
+void hmp_info_migrate(Monitor *mon, const QDict *qdict)
 {
     MigrationInfo *info;
     MigrationCapabilityStatusList *caps, *cap;
@@ -209,7 +209,7 @@ void hmp_info_migrate(Monitor *mon)
     qapi_free_MigrationCapabilityStatusList(caps);
 }
 
-void hmp_info_migrate_capabilities(Monitor *mon)
+void hmp_info_migrate_capabilities(Monitor *mon, const QDict *qdict)
 {
     MigrationCapabilityStatusList *caps, *cap;
 
@@ -228,13 +228,13 @@ void hmp_info_migrate_capabilities(Monitor *mon)
     qapi_free_MigrationCapabilityStatusList(caps);
 }
 
-void hmp_info_migrate_cache_size(Monitor *mon)
+void hmp_info_migrate_cache_size(Monitor *mon, const QDict *qdict)
 {
     monitor_printf(mon, "xbzrel cache size: %" PRId64 " kbytes\n",
                    qmp_query_migrate_cache_size(NULL) >> 10);
 }
 
-void hmp_info_cpus(Monitor *mon)
+void hmp_info_cpus(Monitor *mon, const QDict *qdict)
 {
     CpuInfoList *cpu_list, *cpu;
 
@@ -272,7 +272,7 @@ void hmp_info_cpus(Monitor *mon)
     qapi_free_CpuInfoList(cpu_list);
 }
 
-void hmp_info_block(Monitor *mon)
+void hmp_info_block(Monitor *mon, const QDict *qdict)
 {
     BlockInfoList *block_list, *info;
 
@@ -326,7 +326,7 @@ void hmp_info_block(Monitor *mon)
     qapi_free_BlockInfoList(block_list);
 }
 
-void hmp_info_blockstats(Monitor *mon)
+void hmp_info_blockstats(Monitor *mon, const QDict *qdict)
 {
     BlockStatsList *stats_list, *stats;
 
@@ -360,7 +360,7 @@ void hmp_info_blockstats(Monitor *mon)
     qapi_free_BlockStatsList(stats_list);
 }
 
-void hmp_info_vnc(Monitor *mon)
+void hmp_info_vnc(Monitor *mon, const QDict *qdict)
 {
     VncInfo *info;
     Error *err = NULL;
@@ -406,7 +406,7 @@ out:
     qapi_free_VncInfo(info);
 }
 
-void hmp_info_spice(Monitor *mon)
+void hmp_info_spice(Monitor *mon, const QDict *qdict)
 {
     SpiceChannelList *chan;
     SpiceInfo *info;
@@ -453,7 +453,7 @@ out:
     qapi_free_SpiceInfo(info);
 }
 
-void hmp_info_balloon(Monitor *mon)
+void hmp_info_balloon(Monitor *mon, const QDict *qdict)
 {
     BalloonInfo *info;
     Error *err = NULL;
@@ -570,7 +570,7 @@ static void hmp_info_pci_device(Monitor *mon, const PciDeviceInfo *dev)
     }
 }
 
-void hmp_info_pci(Monitor *mon)
+void hmp_info_pci(Monitor *mon, const QDict *qdict)
 {
     PciInfoList *info_list, *info;
     Error *err = NULL;
@@ -593,7 +593,7 @@ void hmp_info_pci(Monitor *mon)
     qapi_free_PciInfoList(info_list);
 }
 
-void hmp_info_block_jobs(Monitor *mon)
+void hmp_info_block_jobs(Monitor *mon, const QDict *qdict)
 {
     BlockJobInfoList *list;
     Error *err = NULL;
diff --git a/hmp.h b/hmp.h
index 700fbdc777..44be683fcc 100644
--- a/hmp.h
+++ b/hmp.h
@@ -18,24 +18,24 @@
 #include "qapi-types.h"
 #include "qapi/qmp/qdict.h"
 
-void hmp_info_name(Monitor *mon);
-void hmp_info_version(Monitor *mon);
-void hmp_info_kvm(Monitor *mon);
-void hmp_info_status(Monitor *mon);
-void hmp_info_uuid(Monitor *mon);
-void hmp_info_chardev(Monitor *mon);
-void hmp_info_mice(Monitor *mon);
-void hmp_info_migrate(Monitor *mon);
-void hmp_info_migrate_capabilities(Monitor *mon);
-void hmp_info_migrate_cache_size(Monitor *mon);
-void hmp_info_cpus(Monitor *mon);
-void hmp_info_block(Monitor *mon);
-void hmp_info_blockstats(Monitor *mon);
-void hmp_info_vnc(Monitor *mon);
-void hmp_info_spice(Monitor *mon);
-void hmp_info_balloon(Monitor *mon);
-void hmp_info_pci(Monitor *mon);
-void hmp_info_block_jobs(Monitor *mon);
+void hmp_info_name(Monitor *mon, const QDict *qdict);
+void hmp_info_version(Monitor *mon, const QDict *qdict);
+void hmp_info_kvm(Monitor *mon, const QDict *qdict);
+void hmp_info_status(Monitor *mon, const QDict *qdict);
+void hmp_info_uuid(Monitor *mon, const QDict *qdict);
+void hmp_info_chardev(Monitor *mon, const QDict *qdict);
+void hmp_info_mice(Monitor *mon, const QDict *qdict);
+void hmp_info_migrate(Monitor *mon, const QDict *qdict);
+void hmp_info_migrate_capabilities(Monitor *mon, const QDict *qdict);
+void hmp_info_migrate_cache_size(Monitor *mon, const QDict *qdict);
+void hmp_info_cpus(Monitor *mon, const QDict *qdict);
+void hmp_info_block(Monitor *mon, const QDict *qdict);
+void hmp_info_blockstats(Monitor *mon, const QDict *qdict);
+void hmp_info_vnc(Monitor *mon, const QDict *qdict);
+void hmp_info_spice(Monitor *mon, const QDict *qdict);
+void hmp_info_balloon(Monitor *mon, const QDict *qdict);
+void hmp_info_pci(Monitor *mon, const QDict *qdict);
+void hmp_info_block_jobs(Monitor *mon, const QDict *qdict);
 void hmp_quit(Monitor *mon, const QDict *qdict);
 void hmp_stop(Monitor *mon, const QDict *qdict);
 void hmp_system_reset(Monitor *mon, const QDict *qdict);
diff --git a/hw/i8259.c b/hw/i8259.c
index 264879e097..54fe14447b 100644
--- a/hw/i8259.c
+++ b/hw/i8259.c
@@ -407,7 +407,7 @@ static void pic_init(PICCommonState *s)
     qdev_init_gpio_in(&s->dev.qdev, pic_set_irq, 8);
 }
 
-void pic_info(Monitor *mon)
+void pic_info(Monitor *mon, const QDict *qdict)
 {
     int i;
     PICCommonState *s;
@@ -425,7 +425,7 @@ void pic_info(Monitor *mon)
     }
 }
 
-void irq_info(Monitor *mon)
+void irq_info(Monitor *mon, const QDict *qdict)
 {
 #ifndef DEBUG_IRQ_COUNT
     monitor_printf(mon, "irq statistic code not compiled.\n");
diff --git a/hw/lm32_pic.c b/hw/lm32_pic.c
index 8f13355821..42f298ad51 100644
--- a/hw/lm32_pic.c
+++ b/hw/lm32_pic.c
@@ -39,7 +39,7 @@ struct LM32PicState {
 typedef struct LM32PicState LM32PicState;
 
 static LM32PicState *pic;
-void lm32_do_pic_info(Monitor *mon)
+void lm32_do_pic_info(Monitor *mon, const QDict *qdict)
 {
     if (pic == NULL) {
         return;
@@ -49,7 +49,7 @@ void lm32_do_pic_info(Monitor *mon)
             pic->im, pic->ip, pic->irq_state);
 }
 
-void lm32_irq_info(Monitor *mon)
+void lm32_irq_info(Monitor *mon, const QDict *qdict)
 {
     int i;
     uint32_t count;
diff --git a/hw/lm32_pic.h b/hw/lm32_pic.h
index 14456f37cb..555680304e 100644
--- a/hw/lm32_pic.h
+++ b/hw/lm32_pic.h
@@ -8,7 +8,7 @@ uint32_t lm32_pic_get_im(DeviceState *d);
 void lm32_pic_set_ip(DeviceState *d, uint32_t ip);
 void lm32_pic_set_im(DeviceState *d, uint32_t im);
 
-void lm32_do_pic_info(Monitor *mon);
-void lm32_irq_info(Monitor *mon);
+void lm32_do_pic_info(Monitor *mon, const QDict *qdict);
+void lm32_irq_info(Monitor *mon, const QDict *qdict);
 
 #endif /* QEMU_HW_LM32_PIC_H */
diff --git a/hw/loader.c b/hw/loader.c
index 3f59fcd14a..995edc3f98 100644
--- a/hw/loader.c
+++ b/hw/loader.c
@@ -778,7 +778,7 @@ void *rom_ptr(hwaddr addr)
     return rom->data + (addr - rom->addr);
 }
 
-void do_info_roms(Monitor *mon)
+void do_info_roms(Monitor *mon, const QDict *qdict)
 {
     Rom *rom;
 
diff --git a/hw/loader.h b/hw/loader.h
index 26480ad8dd..5e61c95b84 100644
--- a/hw/loader.h
+++ b/hw/loader.h
@@ -1,5 +1,6 @@
 #ifndef LOADER_H
 #define LOADER_H
+#include "qapi/qmp/qdict.h"
 
 /* loader.c */
 int get_image_size(const char *filename);
@@ -30,7 +31,7 @@ int rom_load_all(void);
 void rom_set_fw(void *f);
 int rom_copy(uint8_t *dest, hwaddr addr, size_t size);
 void *rom_ptr(hwaddr addr);
-void do_info_roms(Monitor *mon);
+void do_info_roms(Monitor *mon, const QDict *qdict);
 
 #define rom_add_file_fixed(_f, _a, _i)          \
     rom_add_file(_f, NULL, _a, _i)
diff --git a/hw/pc.h b/hw/pc.h
index 4134aa94e5..fbcf43d717 100644
--- a/hw/pc.h
+++ b/hw/pc.h
@@ -40,8 +40,8 @@ qemu_irq *i8259_init(ISABus *bus, qemu_irq parent_irq);
 qemu_irq *kvm_i8259_init(ISABus *bus);
 int pic_read_irq(DeviceState *d);
 int pic_get_output(DeviceState *d);
-void pic_info(Monitor *mon);
-void irq_info(Monitor *mon);
+void pic_info(Monitor *mon, const QDict *qdict);
+void irq_info(Monitor *mon, const QDict *qdict);
 
 /* Global System Interrupts */
 
diff --git a/hw/pcmcia.h b/hw/pcmcia.h
index aac1d77cc7..f91669305e 100644
--- a/hw/pcmcia.h
+++ b/hw/pcmcia.h
@@ -14,7 +14,7 @@ typedef struct {
 
 void pcmcia_socket_register(PCMCIASocket *socket);
 void pcmcia_socket_unregister(PCMCIASocket *socket);
-void pcmcia_info(Monitor *mon);
+void pcmcia_info(Monitor *mon, const QDict *qdict);
 
 struct PCMCIACardState {
     void *state;
diff --git a/hw/qdev-monitor.c b/hw/qdev-monitor.c
index 93283ee57a..1db5ee0f18 100644
--- a/hw/qdev-monitor.c
+++ b/hw/qdev-monitor.c
@@ -564,13 +564,13 @@ static void qbus_print(Monitor *mon, BusState *bus, int indent)
 }
 #undef qdev_printf
 
-void do_info_qtree(Monitor *mon)
+void do_info_qtree(Monitor *mon, const QDict *qdict)
 {
     if (sysbus_get_default())
         qbus_print(mon, sysbus_get_default(), 0);
 }
 
-void do_info_qdm(Monitor *mon)
+void do_info_qdm(Monitor *mon, const QDict *qdict)
 {
     object_class_foreach(qdev_print_devinfo, TYPE_DEVICE, false, NULL);
 }
diff --git a/hw/qdev-monitor.h b/hw/qdev-monitor.h
index fae1b1ec84..9ec485028e 100644
--- a/hw/qdev-monitor.h
+++ b/hw/qdev-monitor.h
@@ -6,8 +6,8 @@
 
 /*** monitor commands ***/
 
-void do_info_qtree(Monitor *mon);
-void do_info_qdm(Monitor *mon);
+void do_info_qtree(Monitor *mon, const QDict *qdict);
+void do_info_qdm(Monitor *mon, const QDict *qdict);
 int do_device_add(Monitor *mon, const QDict *qdict, QObject **ret_data);
 int do_device_del(Monitor *mon, const QDict *qdict, QObject **ret_data);
 int qdev_device_help(QemuOpts *opts);
diff --git a/hw/sun4m.c b/hw/sun4m.c
index 6f5de44a89..95c505821b 100644
--- a/hw/sun4m.c
+++ b/hw/sun4m.c
@@ -216,13 +216,13 @@ static void nvram_init(M48t59State *nvram, uint8_t *macaddr,
 
 static DeviceState *slavio_intctl;
 
-void sun4m_pic_info(Monitor *mon)
+void sun4m_pic_info(Monitor *mon, const QDict *qdict)
 {
     if (slavio_intctl)
         slavio_pic_info(mon, slavio_intctl);
 }
 
-void sun4m_irq_info(Monitor *mon)
+void sun4m_irq_info(Monitor *mon, const QDict *qdict)
 {
     if (slavio_intctl)
         slavio_irq_info(mon, slavio_intctl);
diff --git a/hw/sun4m.h b/hw/sun4m.h
index 47eb945f07..0361eeed41 100644
--- a/hw/sun4m.h
+++ b/hw/sun4m.h
@@ -27,8 +27,8 @@ void slavio_pic_info(Monitor *mon, DeviceState *dev);
 void slavio_irq_info(Monitor *mon, DeviceState *dev);
 
 /* sun4m.c */
-void sun4m_pic_info(Monitor *mon);
-void sun4m_irq_info(Monitor *mon);
+void sun4m_pic_info(Monitor *mon, const QDict *qdict);
+void sun4m_irq_info(Monitor *mon, const QDict *qdict);
 
 /* sparc32_dma.c */
 #include "sparc32_dma.h"
diff --git a/hw/usb.h b/hw/usb.h
index 50c297f341..bc42639b16 100644
--- a/hw/usb.h
+++ b/hw/usb.h
@@ -435,7 +435,7 @@ int set_usb_string(uint8_t *buf, const char *str);
 /* usb-linux.c */
 USBDevice *usb_host_device_open(USBBus *bus, const char *devname);
 int usb_host_device_close(const char *devname);
-void usb_host_info(Monitor *mon);
+void usb_host_info(Monitor *mon, const QDict *qdict);
 
 /* usb-bt.c */
 USBDevice *usb_bt_init(USBBus *bus, HCIInfo *hci);
diff --git a/hw/usb/bus.c b/hw/usb/bus.c
index 2dc76756a0..e58cd9ade2 100644
--- a/hw/usb/bus.c
+++ b/hw/usb/bus.c
@@ -542,7 +542,7 @@ static char *usb_get_fw_dev_path(DeviceState *qdev)
     return fw_path;
 }
 
-void usb_info(Monitor *mon)
+void usb_info(Monitor *mon, const QDict *qdict)
 {
     USBBus *bus;
     USBDevice *dev;
diff --git a/hw/usb/host-bsd.c b/hw/usb/host-bsd.c
index 172aecbffd..07f0e01cc0 100644
--- a/hw/usb/host-bsd.c
+++ b/hw/usb/host-bsd.c
@@ -633,7 +633,7 @@ static int usb_host_info_device(void *opaque,
     return 0;
 }
 
-void usb_host_info(Monitor *mon)
+void usb_host_info(Monitor *mon, const QDict *qdict)
 {
     usb_host_scan(mon, usb_host_info_device);
 }
diff --git a/hw/usb/host-linux.c b/hw/usb/host-linux.c
index ad75ce0702..a2cff8a74d 100644
--- a/hw/usb/host-linux.c
+++ b/hw/usb/host-linux.c
@@ -1998,7 +1998,7 @@ static void hex2str(int val, char *str, size_t size)
     }
 }
 
-void usb_host_info(Monitor *mon)
+void usb_host_info(Monitor *mon, const QDict *qdict)
 {
     struct USBAutoFilter *f;
     struct USBHostDevice *s;
diff --git a/include/net/net.h b/include/net/net.h
index de42dd76da..4a92b6c3d2 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -112,7 +112,7 @@ ssize_t qemu_deliver_packet_iov(NetClientState *sender,
                             void *opaque);
 
 void print_net_client(Monitor *mon, NetClientState *nc);
-void do_info_network(Monitor *mon);
+void do_info_network(Monitor *mon, const QDict *qdict);
 
 /* NIC info */
 
diff --git a/include/net/slirp.h b/include/net/slirp.h
index 54b655c272..0502389c68 100644
--- a/include/net/slirp.h
+++ b/include/net/slirp.h
@@ -40,7 +40,7 @@ int net_slirp_parse_legacy(QemuOptsList *opts_list, const char *optarg, int *ret
 
 int net_slirp_smb(const char *exported_dir);
 
-void do_info_usernet(Monitor *mon);
+void do_info_usernet(Monitor *mon, const QDict *qdict);
 
 #endif
 
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index c07d4ee458..cd12f0931b 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -68,7 +68,7 @@ void qemu_add_machine_init_done_notifier(Notifier *notify);
 void do_savevm(Monitor *mon, const QDict *qdict);
 int load_vmstate(const char *name);
 void do_delvm(Monitor *mon, const QDict *qdict);
-void do_info_snapshots(Monitor *mon);
+void do_info_snapshots(Monitor *mon, const QDict *qdict);
 
 void qemu_announce_self(void);
 
@@ -171,7 +171,7 @@ extern CharDriverState *parallel_hds[MAX_PARALLEL_PORTS];
 
 void do_usb_add(Monitor *mon, const QDict *qdict);
 void do_usb_del(Monitor *mon, const QDict *qdict);
-void usb_info(Monitor *mon);
+void usb_info(Monitor *mon, const QDict *qdict);
 
 void rtc_change_mon_event(struct tm *tm);
 
diff --git a/monitor.c b/monitor.c
index 77ac451a23..20bd19b05f 100644
--- a/monitor.c
+++ b/monitor.c
@@ -123,13 +123,17 @@ typedef struct mon_cmd_t {
     const char *help;
     void (*user_print)(Monitor *mon, const QObject *data);
     union {
-        void (*info)(Monitor *mon);
         void (*cmd)(Monitor *mon, const QDict *qdict);
         int  (*cmd_new)(Monitor *mon, const QDict *params, QObject **ret_data);
         int  (*cmd_async)(Monitor *mon, const QDict *params,
                           MonitorCompletion *cb, void *opaque);
     } mhandler;
     int flags;
+    /* @sub_table is a list of 2nd level of commands. If it do not exist,
+     * mhandler should be used. If it exist, sub_table[?].mhandler should be
+     * used, and mhandler of 1st level plays the role of help function.
+     */
+    struct mon_cmd_t *sub_table;
 } mon_cmd_t;
 
 /* file descriptors passed via SCM_RIGHTS */
@@ -807,28 +811,8 @@ static void user_async_cmd_handler(Monitor *mon, const mon_cmd_t *cmd,
     }
 }
 
-static void do_info(Monitor *mon, const QDict *qdict)
+static void do_info_help(Monitor *mon, const QDict *qdict)
 {
-    const mon_cmd_t *cmd;
-    const char *item = qdict_get_try_str(qdict, "item");
-
-    if (!item) {
-        goto help;
-    }
-
-    for (cmd = info_cmds; cmd->name != NULL; cmd++) {
-        if (compare_cmd(item, cmd->name))
-            break;
-    }
-
-    if (cmd->name == NULL) {
-        goto help;
-    }
-
-    cmd->mhandler.info(mon);
-    return;
-
-help:
     help_cmd(mon, "info");
 }
 
@@ -899,19 +883,19 @@ int monitor_get_cpu_index(void)
     return cpu->cpu_index;
 }
 
-static void do_info_registers(Monitor *mon)
+static void do_info_registers(Monitor *mon, const QDict *qdict)
 {
     CPUArchState *env;
     env = mon_get_cpu();
     cpu_dump_state(env, (FILE *)mon, monitor_fprintf, CPU_DUMP_FPU);
 }
 
-static void do_info_jit(Monitor *mon)
+static void do_info_jit(Monitor *mon, const QDict *qdict)
 {
     dump_exec_info((FILE *)mon, monitor_fprintf);
 }
 
-static void do_info_history(Monitor *mon)
+static void do_info_history(Monitor *mon, const QDict *qdict)
 {
     int i;
     const char *str;
@@ -930,7 +914,7 @@ static void do_info_history(Monitor *mon)
 
 #if defined(TARGET_PPC)
 /* XXX: not implemented in other targets */
-static void do_info_cpu_stats(Monitor *mon)
+static void do_info_cpu_stats(Monitor *mon, const QDict *qdict)
 {
     CPUArchState *env;
 
@@ -939,7 +923,7 @@ static void do_info_cpu_stats(Monitor *mon)
 }
 #endif
 
-static void do_trace_print_events(Monitor *mon)
+static void do_trace_print_events(Monitor *mon, const QDict *qdict)
 {
     trace_print_events((FILE *)mon, &monitor_fprintf);
 }
@@ -1491,7 +1475,7 @@ static void tlb_info_64(Monitor *mon, CPUArchState *env)
 }
 #endif
 
-static void tlb_info(Monitor *mon)
+static void tlb_info(Monitor *mon, const QDict *qdict)
 {
     CPUArchState *env;
 
@@ -1714,7 +1698,7 @@ static void mem_info_64(Monitor *mon, CPUArchState *env)
 }
 #endif
 
-static void mem_info(Monitor *mon)
+static void mem_info(Monitor *mon, const QDict *qdict)
 {
     CPUArchState *env;
 
@@ -1753,7 +1737,7 @@ static void print_tlb(Monitor *mon, int idx, tlb_t *tlb)
                    tlb->d, tlb->wt);
 }
 
-static void tlb_info(Monitor *mon)
+static void tlb_info(Monitor *mon, const QDict *qdict)
 {
     CPUArchState *env = mon_get_cpu();
     int i;
@@ -1769,7 +1753,7 @@ static void tlb_info(Monitor *mon)
 #endif
 
 #if defined(TARGET_SPARC) || defined(TARGET_PPC) || defined(TARGET_XTENSA)
-static void tlb_info(Monitor *mon)
+static void tlb_info(Monitor *mon, const QDict *qdict)
 {
     CPUArchState *env1 = mon_get_cpu();
 
@@ -1777,12 +1761,12 @@ static void tlb_info(Monitor *mon)
 }
 #endif
 
-static void do_info_mtree(Monitor *mon)
+static void do_info_mtree(Monitor *mon, const QDict *qdict)
 {
     mtree_info((fprintf_function)monitor_printf, mon);
 }
 
-static void do_info_numa(Monitor *mon)
+static void do_info_numa(Monitor *mon, const QDict *qdict)
 {
     int i;
     CPUArchState *env;
@@ -1808,7 +1792,7 @@ static void do_info_numa(Monitor *mon)
 int64_t qemu_time;
 int64_t dev_time;
 
-static void do_info_profile(Monitor *mon)
+static void do_info_profile(Monitor *mon, const QDict *qdict)
 {
     int64_t total;
     total = qemu_time;
@@ -1822,7 +1806,7 @@ static void do_info_profile(Monitor *mon)
     dev_time = 0;
 }
 #else
-static void do_info_profile(Monitor *mon)
+static void do_info_profile(Monitor *mon, const QDict *qdict)
 {
     monitor_printf(mon, "Internal profiler not compiled\n");
 }
@@ -1831,7 +1815,7 @@ static void do_info_profile(Monitor *mon)
 /* Capture support */
 static QLIST_HEAD (capture_list_head, CaptureState) capture_head;
 
-static void do_info_capture(Monitor *mon)
+static void do_info_capture(Monitor *mon, const QDict *qdict)
 {
     int i;
     CaptureState *s;
@@ -2429,12 +2413,6 @@ int monitor_handle_fd_param(Monitor *mon, const char *fdname)
     return fd;
 }
 
-/* mon_cmds and info_cmds would be sorted at runtime */
-static mon_cmd_t mon_cmds[] = {
-#include "hmp-commands.h"
-    { NULL, NULL, },
-};
-
 /* Please update hmp-commands.hx when adding or changing commands */
 static mon_cmd_t info_cmds[] = {
     {
@@ -2442,63 +2420,63 @@ static mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show the version of QEMU",
-        .mhandler.info = hmp_info_version,
+        .mhandler.cmd = hmp_info_version,
     },
     {
         .name       = "network",
         .args_type  = "",
         .params     = "",
         .help       = "show the network state",
-        .mhandler.info = do_info_network,
+        .mhandler.cmd = do_info_network,
     },
     {
         .name       = "chardev",
         .args_type  = "",
         .params     = "",
         .help       = "show the character devices",
-        .mhandler.info = hmp_info_chardev,
+        .mhandler.cmd = hmp_info_chardev,
     },
     {
         .name       = "block",
         .args_type  = "",
         .params     = "",
         .help       = "show the block devices",
-        .mhandler.info = hmp_info_block,
+        .mhandler.cmd = hmp_info_block,
     },
     {
         .name       = "blockstats",
         .args_type  = "",
         .params     = "",
         .help       = "show block device statistics",
-        .mhandler.info = hmp_info_blockstats,
+        .mhandler.cmd = hmp_info_blockstats,
     },
     {
         .name       = "block-jobs",
         .args_type  = "",
         .params     = "",
         .help       = "show progress of ongoing block device operations",
-        .mhandler.info = hmp_info_block_jobs,
+        .mhandler.cmd = hmp_info_block_jobs,
     },
     {
         .name       = "registers",
         .args_type  = "",
         .params     = "",
         .help       = "show the cpu registers",
-        .mhandler.info = do_info_registers,
+        .mhandler.cmd = do_info_registers,
     },
     {
         .name       = "cpus",
         .args_type  = "",
         .params     = "",
         .help       = "show infos for each CPU",
-        .mhandler.info = hmp_info_cpus,
+        .mhandler.cmd = hmp_info_cpus,
     },
     {
         .name       = "history",
         .args_type  = "",
         .params     = "",
         .help       = "show the command line history",
-        .mhandler.info = do_info_history,
+        .mhandler.cmd = do_info_history,
     },
 #if defined(TARGET_I386) || defined(TARGET_PPC) || defined(TARGET_MIPS) || \
     defined(TARGET_LM32) || (defined(TARGET_SPARC) && !defined(TARGET_SPARC64))
@@ -2508,11 +2486,11 @@ static mon_cmd_t info_cmds[] = {
         .params     = "",
         .help       = "show the interrupts statistics (if available)",
 #ifdef TARGET_SPARC
-        .mhandler.info = sun4m_irq_info,
+        .mhandler.cmd = sun4m_irq_info,
 #elif defined(TARGET_LM32)
-        .mhandler.info = lm32_irq_info,
+        .mhandler.cmd = lm32_irq_info,
 #else
-        .mhandler.info = irq_info,
+        .mhandler.cmd = irq_info,
 #endif
     },
     {
@@ -2521,11 +2499,11 @@ static mon_cmd_t info_cmds[] = {
         .params     = "",
         .help       = "show i8259 (PIC) state",
 #ifdef TARGET_SPARC
-        .mhandler.info = sun4m_pic_info,
+        .mhandler.cmd = sun4m_pic_info,
 #elif defined(TARGET_LM32)
-        .mhandler.info = lm32_do_pic_info,
+        .mhandler.cmd = lm32_do_pic_info,
 #else
-        .mhandler.info = pic_info,
+        .mhandler.cmd = pic_info,
 #endif
     },
 #endif
@@ -2534,7 +2512,7 @@ static mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show PCI info",
-        .mhandler.info = hmp_info_pci,
+        .mhandler.cmd = hmp_info_pci,
     },
 #if defined(TARGET_I386) || defined(TARGET_SH4) || defined(TARGET_SPARC) || \
     defined(TARGET_PPC) || defined(TARGET_XTENSA)
@@ -2543,7 +2521,7 @@ static mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show virtual to physical memory mappings",
-        .mhandler.info = tlb_info,
+        .mhandler.cmd = tlb_info,
     },
 #endif
 #if defined(TARGET_I386)
@@ -2552,7 +2530,7 @@ static mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show the active virtual memory mappings",
-        .mhandler.info = mem_info,
+        .mhandler.cmd = mem_info,
     },
 #endif
     {
@@ -2560,91 +2538,91 @@ static mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show memory tree",
-        .mhandler.info = do_info_mtree,
+        .mhandler.cmd = do_info_mtree,
     },
     {
         .name       = "jit",
         .args_type  = "",
         .params     = "",
         .help       = "show dynamic compiler info",
-        .mhandler.info = do_info_jit,
+        .mhandler.cmd = do_info_jit,
     },
     {
         .name       = "kvm",
         .args_type  = "",
         .params     = "",
         .help       = "show KVM information",
-        .mhandler.info = hmp_info_kvm,
+        .mhandler.cmd = hmp_info_kvm,
     },
     {
         .name       = "numa",
         .args_type  = "",
         .params     = "",
         .help       = "show NUMA information",
-        .mhandler.info = do_info_numa,
+        .mhandler.cmd = do_info_numa,
     },
     {
         .name       = "usb",
         .args_type  = "",
         .params     = "",
         .help       = "show guest USB devices",
-        .mhandler.info = usb_info,
+        .mhandler.cmd = usb_info,
     },
     {
         .name       = "usbhost",
         .args_type  = "",
         .params     = "",
         .help       = "show host USB devices",
-        .mhandler.info = usb_host_info,
+        .mhandler.cmd = usb_host_info,
     },
     {
         .name       = "profile",
         .args_type  = "",
         .params     = "",
         .help       = "show profiling information",
-        .mhandler.info = do_info_profile,
+        .mhandler.cmd = do_info_profile,
     },
     {
         .name       = "capture",
         .args_type  = "",
         .params     = "",
         .help       = "show capture information",
-        .mhandler.info = do_info_capture,
+        .mhandler.cmd = do_info_capture,
     },
     {
         .name       = "snapshots",
         .args_type  = "",
         .params     = "",
         .help       = "show the currently saved VM snapshots",
-        .mhandler.info = do_info_snapshots,
+        .mhandler.cmd = do_info_snapshots,
     },
     {
         .name       = "status",
         .args_type  = "",
         .params     = "",
         .help       = "show the current VM status (running|paused)",
-        .mhandler.info = hmp_info_status,
+        .mhandler.cmd = hmp_info_status,
     },
     {
         .name       = "pcmcia",
         .args_type  = "",
         .params     = "",
         .help       = "show guest PCMCIA status",
-        .mhandler.info = pcmcia_info,
+        .mhandler.cmd = pcmcia_info,
     },
     {
         .name       = "mice",
         .args_type  = "",
         .params     = "",
         .help       = "show which guest mouse is receiving events",
-        .mhandler.info = hmp_info_mice,
+        .mhandler.cmd = hmp_info_mice,
     },
     {
         .name       = "vnc",
         .args_type  = "",
         .params     = "",
         .help       = "show the vnc server status",
-        .mhandler.info = hmp_info_vnc,
+        .mhandler.cmd = hmp_info_vnc,
     },
 #if defined(CONFIG_SPICE)
     {
@@ -2652,7 +2630,7 @@ static mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show the spice server status",
-        .mhandler.info = hmp_info_spice,
+        .mhandler.cmd = hmp_info_spice,
     },
 #endif
     {
@@ -2660,14 +2638,14 @@ static mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show the current VM name",
-        .mhandler.info = hmp_info_name,
+        .mhandler.cmd = hmp_info_name,
     },
     {
         .name       = "uuid",
         .args_type  = "",
         .params     = "",
         .help       = "show the current VM UUID",
-        .mhandler.info = hmp_info_uuid,
+        .mhandler.cmd = hmp_info_uuid,
     },
 #if defined(TARGET_PPC)
     {
@@ -2675,7 +2653,7 @@ static mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show CPU statistics",
-        .mhandler.info = do_info_cpu_stats,
+        .mhandler.cmd = do_info_cpu_stats,
     },
 #endif
 #if defined(CONFIG_SLIRP)
@@ -2684,7 +2662,7 @@ static mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show user network stack connection states",
-        .mhandler.info = do_info_usernet,
+        .mhandler.cmd = do_info_usernet,
     },
 #endif
     {
@@ -2692,62 +2670,68 @@ static mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show migration status",
-        .mhandler.info = hmp_info_migrate,
+        .mhandler.cmd = hmp_info_migrate,
     },
     {
         .name       = "migrate_capabilities",
         .args_type  = "",
         .params     = "",
         .help       = "show current migration capabilities",
-        .mhandler.info = hmp_info_migrate_capabilities,
+        .mhandler.cmd = hmp_info_migrate_capabilities,
     },
     {
         .name       = "migrate_cache_size",
         .args_type  = "",
         .params     = "",
         .help       = "show current migration xbzrle cache size",
-        .mhandler.info = hmp_info_migrate_cache_size,
+        .mhandler.cmd = hmp_info_migrate_cache_size,
     },
     {
         .name       = "balloon",
         .args_type  = "",
         .params     = "",
         .help       = "show balloon information",
-        .mhandler.info = hmp_info_balloon,
+        .mhandler.cmd = hmp_info_balloon,
     },
     {
         .name       = "qtree",
         .args_type  = "",
         .params     = "",
         .help       = "show device tree",
-        .mhandler.info = do_info_qtree,
+        .mhandler.cmd = do_info_qtree,
     },
     {
         .name       = "qdm",
         .args_type  = "",
         .params     = "",
         .help       = "show qdev device model list",
-        .mhandler.info = do_info_qdm,
+        .mhandler.cmd = do_info_qdm,
     },
     {
         .name       = "roms",
         .args_type  = "",
         .params     = "",
         .help       = "show roms",
-        .mhandler.info = do_info_roms,
+        .mhandler.cmd = do_info_roms,
     },
     {
         .name       = "trace-events",
         .args_type  = "",
         .params     = "",
         .help       = "show available trace-events & their state",
-        .mhandler.info = do_trace_print_events,
+        .mhandler.cmd = do_trace_print_events,
     },
     {
         .name       = NULL,
     },
 };
 
+/* mon_cmds and info_cmds would be sorted at runtime */
+static mon_cmd_t mon_cmds[] = {
+#include "hmp-commands.h"
+    { NULL, NULL, },
+};
+
 static const mon_cmd_t qmp_cmds[] = {
 #include "qmp-commands-old.h"
     { /* NULL */ },
@@ -3542,18 +3526,27 @@ static const mon_cmd_t *search_dispatch_table(const mon_cmd_t *disp_table,
     return NULL;
 }
 
-static const mon_cmd_t *monitor_find_command(const char *cmdname)
-{
-    return search_dispatch_table(mon_cmds, cmdname);
-}
-
 static const mon_cmd_t *qmp_find_cmd(const char *cmdname)
 {
     return search_dispatch_table(qmp_cmds, cmdname);
 }
 
+/*
+ * Parse @cmdline according to command table @table.
+ * If @cmdline is blank, return NULL.
+ * If it can't be parsed, report to @mon, and return NULL.
+ * Else, insert command arguments into @qdict, and return the command.
+ * If sub-command table exist, and if @cmdline contains addtional string for
+ * sub-command, this function will try search sub-command table. if no
+ * addtional string for sub-command exist, this function will return the found
+ * one in @table.
+ * Do not assume the returned command points into @table!  It doesn't
+ * when the command is a sub-command.
+ */
 static const mon_cmd_t *monitor_parse_command(Monitor *mon,
                                               const char *cmdline,
+                                              int start,
+                                              mon_cmd_t *table,
                                               QDict *qdict)
 {
     const char *p, *typestr;
@@ -3564,20 +3557,35 @@ static const mon_cmd_t *monitor_parse_command(Monitor *mon,
     char *key;
 
 #ifdef DEBUG
-    monitor_printf(mon, "command='%s'\n", cmdline);
+    monitor_printf(mon, "command='%s', start='%d'\n", cmdline, start);
 #endif
 
     /* extract the command name */
-    p = get_command_name(cmdline, cmdname, sizeof(cmdname));
+    p = get_command_name(cmdline + start, cmdname, sizeof(cmdname));
     if (!p)
         return NULL;
 
-    cmd = monitor_find_command(cmdname);
+    cmd = search_dispatch_table(table, cmdname);
     if (!cmd) {
-        monitor_printf(mon, "unknown command: '%s'\n", cmdname);
+        monitor_printf(mon, "unknown command: '%.*s'\n",
+                       (int)(p - cmdline), cmdline);
         return NULL;
     }
 
+    /* filter out following useless space */
+    while (qemu_isspace(*p)) {
+        p++;
+    }
+    /* search sub command */
+    if (cmd->sub_table != NULL) {
+        /* check if user set additional command */
+        if (*p == '\0') {
+            return cmd;
+        }
+        return monitor_parse_command(mon, cmdline, p - cmdline,
+                                     cmd->sub_table, qdict);
+    }
+
     /* parse the parameters */
     typestr = cmd->args_type;
     for(;;) {
@@ -3933,7 +3941,7 @@ static void handle_user_command(Monitor *mon, const char *cmdline)
 
     qdict = qdict_new();
 
-    cmd = monitor_parse_command(mon, cmdline, qdict);
+    cmd = monitor_parse_command(mon, cmdline, 0, mon_cmds, qdict);
     if (!cmd)
         goto out;
 
diff --git a/net/net.c b/net/net.c
index 02b5458a1b..cdd9b04989 100644
--- a/net/net.c
+++ b/net/net.c
@@ -852,7 +852,7 @@ void print_net_client(Monitor *mon, NetClientState *nc)
                    NetClientOptionsKind_lookup[nc->info->type], nc->info_str);
 }
 
-void do_info_network(Monitor *mon)
+void do_info_network(Monitor *mon, const QDict *qdict)
 {
     NetClientState *nc, *peer;
     NetClientOptionsKind type;
diff --git a/net/slirp.c b/net/slirp.c
index c14259f004..4df550faf6 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -670,7 +670,7 @@ static int slirp_guestfwd(SlirpState *s, const char *config_str,
     return -1;
 }
 
-void do_info_usernet(Monitor *mon)
+void do_info_usernet(Monitor *mon, const QDict *qdict)
 {
     SlirpState *s;
 
diff --git a/savevm.c b/savevm.c
index 4e970ca0db..d9ff1d9b72 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2307,7 +2307,7 @@ void do_delvm(Monitor *mon, const QDict *qdict)
     }
 }
 
-void do_info_snapshots(Monitor *mon)
+void do_info_snapshots(Monitor *mon, const QDict *qdict)
 {
     BlockDriverState *bs, *bs1;
     QEMUSnapshotInfo *sn_tab, *sn, s, *sn_info = &s;
diff --git a/vl.c b/vl.c
index 8ce2b10541..f4cf7e8a85 100644
--- a/vl.c
+++ b/vl.c
@@ -1449,7 +1449,7 @@ void pcmcia_socket_unregister(PCMCIASocket *socket)
         }
 }
 
-void pcmcia_info(Monitor *mon)
+void pcmcia_info(Monitor *mon, const QDict *qdict)
 {
     struct pcmcia_socket_entry_s *iter;