[v5,16/16] qmp: add query-memdev

diff --git a/numa.c b/numa.c
index 8ba5a38..ce9382d 100644
--- a/numa.c
+++ b/numa.c
@@ -31,9 +31,14 @@ 
 #include "qapi-visit.h"
 #include "qapi/opts-visitor.h"
 #include "qapi/dealloc-visitor.h"
+#include "qapi/qmp-output-visitor.h"
+#include "qapi/qmp-input-visitor.h"
+#include "qapi/string-output-visitor.h"
+#include "qapi/string-input-visitor.h"
 #include "qapi/qmp/qerror.h"
 #include "hw/boards.h"
 #include "sysemu/hostmem.h"
+#include "qmp-commands.h"
 
 QemuOptsList qemu_numa_opts = {
     .name = "numa",
@@ -280,3 +285,70 @@  void memory_region_allocate_system_memory(MemoryRegion *mr, Object *owner,
         addr += size;
     }
 }
+
+MemdevList *qmp_query_memdev(Error **errp)
+{
+    MemdevList *list = NULL, *m;
+    HostMemoryBackend *backend;
+    Error *err = NULL;
+    int i;
+
+    for (i = 0; i < nb_numa_nodes; i++) {
+        backend = numa_info[i].node_memdev;
+
+        m = g_malloc0(sizeof(*m));
+        m->value = g_malloc0(sizeof(*m->value));
+        m->value->size = object_property_get_int(OBJECT(backend), "size",
+                                                 &err);
+        if (err) {
+            goto error;
+        }
+
+        m->value->merge = object_property_get_bool(OBJECT(backend), "merge",
+                                                   &err);
+        if (err) {
+            goto error;
+        }
+
+        m->value->dump = object_property_get_bool(OBJECT(backend), "dump",
+                                                  &err);
+        if (err) {
+            goto error;
+        }
+
+        m->value->prealloc = object_property_get_bool(OBJECT(backend),
+                                                      "prealloc", &err);
+        if (err) {
+            goto error;
+        }
+
+        m->value->policy = object_property_get_enum(OBJECT(backend),
+                                                    "policy",
+                                                    HostMemPolicy_lookup,
+                                                    &err);
+        if (err) {
+            goto error;
+        }
+
+        object_property_get_uint16List(OBJECT(backend), "host-nodes",
+                                       &m->value->host_nodes, &err);
+        if (err) {
+            goto error;
+        }
+
+        m->next = list;
+        list = m;
+    }
+
+    return list;
+
+error:
+    while (list) {
+        m = list;
+        list = list->next;
+        g_free(m->value);
+        g_free(m);
+    }
+    qerror_report_err(err);
+    return NULL;
+}
diff --git a/qapi-schema.json b/qapi-schema.json
index 0898c00..c3eafcf 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -4779,3 +4779,43 @@ 
 ##
 { 'enum': 'HostMemPolicy',
   'data': [ 'default', 'preferred', 'bind', 'interleave' ] }
+
+##
+# @Memdev:
+#
+# Information of memory device
+#
+# @size: memory device size
+#
+# @merge: enables or disables memory merge support
+#
+# @dump: includes memory device's memory in a core dump or not
+#
+# @prealloc: enables or disables memory preallocation
+#
+# @host-nodes: host nodes for its memory policy
+#
+# @policy: memory policy of memory device
+#
+# Since: 2.1
+##
+
+{ 'type': 'Memdev',
+  'data': {
+    'size':       'size',
+    'merge':      'bool',
+    'dump':       'bool',
+    'prealloc':   'bool',
+    'host-nodes': ['uint16'],
+    'policy':     'HostMemPolicy' }}
+
+##
+# @query-memdev:
+#
+# Returns information for all memory devices.
+#
+# Returns: a list of @Memdev.
+#
+# Since: 2.1
+##
+{ 'command': 'query-memdev', 'returns': ['Memdev'] }
diff --git a/qmp-commands.hx b/qmp-commands.hx
index d8aa4ed..bb34cd8 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -3572,3 +3572,41 @@  Example:
                    } } ] }
 
 EQMP
+
+    {
+        .name       = "query-memdev",
+        .args_type  = "",
+        .mhandler.cmd_new = qmp_marshal_input_query_memdev,
+    },
+
+SQMP
+query-memdev
+------------
+
+Show memory devices information.
+
+
+Example (1):
+
+-> { "execute": "query-memdev" }
+<- { "return": [
+       {
+         "size": 536870912,
+         "merge": false,
+         "dump": true,
+         "prealloc": false,
+         "host-nodes": [0, 1],
+         "policy": "bind"
+       },
+       {
+         "size": 536870912,
+         "merge": false,
+         "dump": true,
+         "prealloc": true,
+         "host-nodes": [2, 3],
+         "policy": "preferred"
+       }
+     ]
+   }
+
+EQMP