diff --git a/hw/ppc/mac_newworld.c b/hw/ppc/mac_newworld.c
index 2175962846..d88b38e925 100644
--- a/hw/ppc/mac_newworld.c
+++ b/hw/ppc/mac_newworld.c
@@ -157,6 +157,10 @@ static void ppc_core99_init(MachineState *machine)
     }
 
     /* allocate RAM */
+    if (machine->ram_size > 2 * GiB) {
+        error_report("RAM size more than 2 GiB is not supported");
+        exit(1);
+    }
     memory_region_add_subregion(get_system_memory(), 0, machine->ram);
 
     /* allocate and load firmware ROM */