diff --git a/sim/hei_sim_main.cpp b/sim/hei_sim_main.cpp
index b3f26d2..035d003 100644
--- a/sim/hei_sim_main.cpp
+++ b/sim/hei_sim_main.cpp
@@ -1,5 +1,5 @@
 
-#include "../hei_isolator.hpp"
+#include "../src/hei_isolator.hpp"
 
 int main()
 {
diff --git a/sim/hei_user_defines.hpp b/sim/hei_trace.hpp
similarity index 100%
rename from sim/hei_user_defines.hpp
rename to sim/hei_trace.hpp
diff --git a/sim/meson.build b/sim/meson.build
index 3693e81..fe3fa32 100644
--- a/sim/meson.build
+++ b/sim/meson.build
@@ -1,7 +1,7 @@
 tests = ['openpower-libhei-sim']
 
 sim_sources = ['hei_sim_main.cpp',
-                '../hei_isolator.cpp']
+                '../src/hei_isolator.cpp']
 
 foreach t : tests
   test(t, executable(t.underscorify(), sim_sources, include_directories : incdir))
diff --git a/hei_isolator.cpp b/src/hei_isolator.cpp
similarity index 100%
rename from hei_isolator.cpp
rename to src/hei_isolator.cpp
diff --git a/hei_isolator.hpp b/src/hei_isolator.hpp
similarity index 100%
rename from hei_isolator.hpp
rename to src/hei_isolator.hpp
diff --git a/hei_user_interface.hpp b/src/hei_user_interface.hpp
similarity index 85%
rename from hei_user_interface.hpp
rename to src/hei_user_interface.hpp
index a853837..b7dd092 100644
--- a/hei_user_interface.hpp
+++ b/src/hei_user_interface.hpp
@@ -3,7 +3,7 @@
 
 // This header provides access to headers and macros defined by the user
 // application.
-#include <hei_user_defines.hpp>
+#include <hei_trace.hpp>
 
 // The rest of this header contains interfaces that the user application must
 // define.