diff --git a/hw/mips_malta.c b/hw/mips_malta.c
index 9a41cdf..ba67947 100644
--- a/hw/mips_malta.c
+++ b/hw/mips_malta.c
@@ -802,6 +802,12 @@
     qemu_register_reset(main_cpu_reset, env);
 
     /* allocate RAM */
+    if (ram_size > (256 << 20)) {
+        fprintf(stderr,
+                "qemu: Too much memory for this machine: %d MB, maximum 256 MB\n",
+                ((unsigned int)ram_size / (1 << 20)));
+        exit(1);
+    }
     cpu_register_physical_memory(0, ram_size, IO_MEM_RAM);
 
     /* Map the bios at two physical locations, as on the real board. */
diff --git a/hw/mips_r4k.c b/hw/mips_r4k.c
index 34b3853..1ed123e 100644
--- a/hw/mips_r4k.c
+++ b/hw/mips_r4k.c
@@ -178,6 +178,12 @@
     qemu_register_reset(main_cpu_reset, env);
 
     /* allocate RAM */
+    if (ram_size > (256 << 20)) {
+        fprintf(stderr,
+                "qemu: Too much memory for this machine: %d MB, maximum 256 MB\n",
+                ((unsigned int)ram_size / (1 << 20)));
+        exit(1);
+    }
     cpu_register_physical_memory(0, ram_size, IO_MEM_RAM);
 
     if (!mips_qemu_iomemtype) {