diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index e1e4250e69..9dc3c61b5a 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -940,6 +940,12 @@ static void virtio_mem_prepare_memslots(VirtIOMEM *vmem)
         memory_region_init_alias(&vmem->memslots[idx], OBJECT(vmem), name,
                                  &vmem->memdev->mr, memslot_offset,
                                  memslot_size);
+        /*
+         * We want to be able to atomically and efficiently activate/deactivate
+         * individual memslots without affecting adjacent memslots in memory
+         * notifiers.
+         */
+        memory_region_set_unmergeable(&vmem->memslots[idx], true);
     }
 }