diff --git a/README.adoc b/README.adoc
index 38346d1..ac013ba 100644
--- a/README.adoc
+++ b/README.adoc
@@ -3285,6 +3285,14 @@ Related:
 
 * https://serverfault.com/questions/769874/how-to-forward-a-port-from-guest-to-host-in-qemu-kvm
 
+==== Secondary disk
+
+A simpler and possibly less overhead alternative to <<9P>> would be to generate a secondary disk image with the bencmark you want to rebuild.
+
+Then you can `umount` and re-mount on guest without reboot.
+
+We don't support this yet, but it should not be too hard to hack it up, maybe by hooking into link:rootfs_post_build_script[].
+
 === QEMU user mode
 
 This has nothing to do with the Linux kernel, but it is cool: