pc-dimm: add a function to calculate VM's current RAM size

The global parameter 'ram_size' does not take into account
the hotplugged memory.

In some codes, we use 'ram_size' as current VM's real RAM size,
which is not correct.

Add function 'get_current_ram_size' to calculate VM's current RAM size,
it will enumerate present memory devices and also plus ram_size.

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

hw/mem/pc-dimm.c

@@ -100,6 +100,32 @@ int qmp_pc_dimm_device_list(Object *obj, void *opaque)
     return 0;
 }
 
+ram_addr_t get_current_ram_size(void)
+{
+    MemoryDeviceInfoList *info_list = NULL;
+    MemoryDeviceInfoList **prev = &info_list;
+    MemoryDeviceInfoList *info;
+    ram_addr_t size = ram_size;
+
+    qmp_pc_dimm_device_list(qdev_get_machine(), &prev);
+    for (info = info_list; info; info = info->next) {
+        MemoryDeviceInfo *value = info->value;
+
+        if (value) {
+            switch (value->kind) {
+            case MEMORY_DEVICE_INFO_KIND_DIMM:
+                size += value->dimm->size;
+                break;
+            default:
+                break;
+            }
+        }
+    }
+    qapi_free_MemoryDeviceInfoList(info_list);
+
+    return size;
+}
+
 static int pc_dimm_slot2bitmap(Object *obj, void *opaque)
 {
     unsigned long *bitmap = opaque;

include/exec/cpu-common.h

@@ -52,6 +52,7 @@ typedef uintptr_t ram_addr_t;
 #endif
 
 extern ram_addr_t ram_size;
+ram_addr_t get_current_ram_size(void);
 
 /* memory API */
 

stubs/qmp_pc_dimm_device_list.c

@@ -5,3 +5,8 @@ int qmp_pc_dimm_device_list(Object *obj, void *opaque)
 {
    return 0;
 }
+
+ram_addr_t get_current_ram_size(void)
+{
+    return ram_size;
+}