diff --git a/dev/baddev.hh b/dev/baddev.hh
index c2a204c051..189f28331d 100644
--- a/dev/baddev.hh
+++ b/dev/baddev.hh
@@ -37,6 +37,8 @@
 #include "base/range.hh"
 #include "dev/io_device.hh"
 
+class MemoryController;
+
 /**
  * BadDevice
  * This device just panics when accessed. It is supposed to warn
diff --git a/dev/isa_fake.hh b/dev/isa_fake.hh
index 290b24b548..73e40c681e 100644
--- a/dev/isa_fake.hh
+++ b/dev/isa_fake.hh
@@ -37,6 +37,8 @@
 #include "base/range.hh"
 #include "dev/io_device.hh"
 
+class MemoryController;
+
 /**
  * IsaFake is a device that returns -1 on all reads and
  * accepts all writes. It is meant to be placed at an address range