diff --git a/include/hw/cpu/cortex_mpcore.h b/include/hw/cpu/cortex_mpcore.h
index 4084c6003a..1d94c8769d 100644
--- a/include/hw/cpu/cortex_mpcore.h
+++ b/include/hw/cpu/cortex_mpcore.h
@@ -30,14 +30,22 @@
 #define TYPE_CORTEX_MPCORE_PRIV "cortex_mpcore_priv"
 OBJECT_DECLARE_TYPE(CortexMPPrivState, CortexMPPrivClass, CORTEX_MPCORE_PRIV)
 
+/**
+ * CortexMPPrivClass:
+ * @container_size - size of the device's MMIO region
+ */
 struct CortexMPPrivClass {
     SysBusDeviceClass parent_class;
 
     DeviceRealize parent_realize;
+
+    uint64_t container_size;
 };
 
 struct CortexMPPrivState {
     SysBusDevice parent_obj;
+
+    MemoryRegion container;
 };
 
 #define TYPE_A9MPCORE_PRIV "a9mpcore_priv"
@@ -47,7 +55,6 @@ struct A9MPPrivState {
     CortexMPPrivState parent_obj;
 
     uint32_t num_cpu;
-    MemoryRegion container;
     uint32_t num_irq;
 
     A9SCUState scu;
@@ -65,7 +72,6 @@ struct A15MPPrivState {
 
     uint32_t num_cpu;
     uint32_t num_irq;
-    MemoryRegion container;
 
     GICState gic;
 };
diff --git a/hw/cpu/a15mpcore.c b/hw/cpu/a15mpcore.c
index 5a57145179..128941eb50 100644
--- a/hw/cpu/a15mpcore.c
+++ b/hw/cpu/a15mpcore.c
@@ -36,12 +36,8 @@ static void a15mp_priv_set_irq(void *opaque, int irq, int level)
 
 static void a15mp_priv_initfn(Object *obj)
 {
-    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
     A15MPPrivState *s = A15MPCORE_PRIV(obj);
 
-    memory_region_init(&s->container, obj, "a15mp-priv-container", 0x8000);
-    sysbus_init_mmio(sbd, &s->container);
-
     object_initialize_child(obj, "gic", &s->gic, gic_class_name());
     qdev_prop_set_uint32(DEVICE(&s->gic), "revision", 2);
 }
@@ -51,6 +47,7 @@ static void a15mp_priv_realize(DeviceState *dev, Error **errp)
     CortexMPPrivClass *cc = CORTEX_MPCORE_PRIV_GET_CLASS(dev);
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
     A15MPPrivState *s = A15MPCORE_PRIV(dev);
+    CortexMPPrivState *c = CORTEX_MPCORE_PRIV(dev);
     DeviceState *gicdev;
     SysBusDevice *gicsbd;
     Error *local_err = NULL;
@@ -133,20 +130,20 @@ static void a15mp_priv_realize(DeviceState *dev, Error **errp)
      *  0x5600-0x57ff -- GIC virtual interface control for CPU 3
      *  0x6000-0x7fff -- GIC virtual CPU interface
      */
-    memory_region_add_subregion(&s->container, 0x1000,
+    memory_region_add_subregion(&c->container, 0x1000,
                                 sysbus_mmio_get_region(gicsbd, 0));
-    memory_region_add_subregion(&s->container, 0x2000,
+    memory_region_add_subregion(&c->container, 0x2000,
                                 sysbus_mmio_get_region(gicsbd, 1));
     if (has_el2) {
-        memory_region_add_subregion(&s->container, 0x4000,
+        memory_region_add_subregion(&c->container, 0x4000,
                                     sysbus_mmio_get_region(gicsbd, 2));
-        memory_region_add_subregion(&s->container, 0x6000,
+        memory_region_add_subregion(&c->container, 0x6000,
                                     sysbus_mmio_get_region(gicsbd, 3));
         for (i = 0; i < s->num_cpu; i++) {
             hwaddr base = 0x5000 + i * 0x200;
             MemoryRegion *mr = sysbus_mmio_get_region(gicsbd,
                                                       4 + s->num_cpu + i);
-            memory_region_add_subregion(&s->container, base, mr);
+            memory_region_add_subregion(&c->container, base, mr);
         }
     }
 }
@@ -168,6 +165,8 @@ static void a15mp_priv_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
     CortexMPPrivClass *cc = CORTEX_MPCORE_PRIV_CLASS(klass);
 
+    cc->container_size = 0x8000;
+
     device_class_set_parent_realize(dc, a15mp_priv_realize,
                                     &cc->parent_realize);
     device_class_set_props(dc, a15mp_priv_properties);
diff --git a/hw/cpu/a9mpcore.c b/hw/cpu/a9mpcore.c
index d59e49126b..08346b0049 100644
--- a/hw/cpu/a9mpcore.c
+++ b/hw/cpu/a9mpcore.c
@@ -30,9 +30,6 @@ static void a9mp_priv_initfn(Object *obj)
 {
     A9MPPrivState *s = A9MPCORE_PRIV(obj);
 
-    memory_region_init(&s->container, obj, "a9mp-priv-container", 0x2000);
-    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->container);
-
     object_initialize_child(obj, "scu", &s->scu, TYPE_A9_SCU);
 
     object_initialize_child(obj, "gic", &s->gic, TYPE_ARM_GIC);
@@ -47,6 +44,7 @@ static void a9mp_priv_initfn(Object *obj)
 static void a9mp_priv_realize(DeviceState *dev, Error **errp)
 {
     CortexMPPrivClass *cc = CORTEX_MPCORE_PRIV_GET_CLASS(dev);
+    CortexMPPrivState *c = CORTEX_MPCORE_PRIV(dev);
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
     A9MPPrivState *s = A9MPCORE_PRIV(dev);
     DeviceState *scudev, *gicdev, *gtimerdev, *mptimerdev, *wdtdev;
@@ -134,21 +132,21 @@ static void a9mp_priv_realize(DeviceState *dev, Error **errp)
      *  0x0700-0x0fff -- nothing
      *  0x1000-0x1fff -- GIC Distributor
      */
-    memory_region_add_subregion(&s->container, 0,
+    memory_region_add_subregion(&c->container, 0,
                                 sysbus_mmio_get_region(scubusdev, 0));
     /* GIC CPU interface */
-    memory_region_add_subregion(&s->container, 0x100,
+    memory_region_add_subregion(&c->container, 0x100,
                                 sysbus_mmio_get_region(gicbusdev, 1));
-    memory_region_add_subregion(&s->container, 0x200,
+    memory_region_add_subregion(&c->container, 0x200,
                                 sysbus_mmio_get_region(gtimerbusdev, 0));
     /* Note that the A9 exposes only the "timer/watchdog for this core"
      * memory region, not the "timer/watchdog for core X" ones 11MPcore has.
      */
-    memory_region_add_subregion(&s->container, 0x600,
+    memory_region_add_subregion(&c->container, 0x600,
                                 sysbus_mmio_get_region(mptimerbusdev, 0));
-    memory_region_add_subregion(&s->container, 0x620,
+    memory_region_add_subregion(&c->container, 0x620,
                                 sysbus_mmio_get_region(wdtbusdev, 0));
-    memory_region_add_subregion(&s->container, 0x1000,
+    memory_region_add_subregion(&c->container, 0x1000,
                                 sysbus_mmio_get_region(gicbusdev, 0));
 
     /* Wire up the interrupt from each watchdog and timer.
@@ -183,6 +181,8 @@ static void a9mp_priv_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
     CortexMPPrivClass *cc = CORTEX_MPCORE_PRIV_CLASS(klass);
 
+    cc->container_size = 0x2000;
+
     device_class_set_parent_realize(dc, a9mp_priv_realize, &cc->parent_realize);
     device_class_set_props(dc, a9mp_priv_properties);
 }
diff --git a/hw/cpu/cortex_mpcore.c b/hw/cpu/cortex_mpcore.c
index 7d3796bd69..0c12f99610 100644
--- a/hw/cpu/cortex_mpcore.c
+++ b/hw/cpu/cortex_mpcore.c
@@ -7,13 +7,27 @@
  */
 
 #include "qemu/osdep.h"
+#include "qapi/error.h"
 #include "hw/cpu/cortex_mpcore.h"
 
+static void cortex_mpcore_priv_instance_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    CortexMPPrivState *s = CORTEX_MPCORE_PRIV(obj);
+    CortexMPPrivClass *k = CORTEX_MPCORE_PRIV_GET_CLASS(obj);
+
+    assert(k->container_size > 0);
+    memory_region_init(&s->container, obj,
+                       "mpcore-priv-container", k->container_size);
+    sysbus_init_mmio(sbd, &s->container);
+}
+
 static const TypeInfo cortex_mpcore_types[] = {
     {
         .name           = TYPE_CORTEX_MPCORE_PRIV,
         .parent         = TYPE_SYS_BUS_DEVICE,
         .instance_size  = sizeof(CortexMPPrivState),
+        .instance_init  = cortex_mpcore_priv_instance_init,
         .class_size     = sizeof(CortexMPPrivClass),
         .abstract       = true,
     },
