diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c
index a1b1af26bc..e098585cda 100644
--- a/hw/mem/memory-device.c
+++ b/hw/mem/memory-device.c
@@ -374,6 +374,20 @@ void memory_device_pre_plug(MemoryDeviceState *md, MachineState *ms,
         goto out;
     }
 
+    /*
+     * We always want the memory region size to be multiples of the memory
+     * region alignment: for example, DIMMs with 1G+1byte size don't make
+     * any sense. Note that we don't check that the size is multiples
+     * of any additional alignment requirements the memory device might
+     * have when it comes to the address in physical address space.
+     */
+    if (!QEMU_IS_ALIGNED(memory_region_size(mr),
+                         memory_region_get_alignment(mr))) {
+        error_setg(errp, "backend memory size must be multiple of 0x%"
+                   PRIx64, memory_region_get_alignment(mr));
+        return;
+    }
+
     if (legacy_align) {
         align = *legacy_align;
     } else {