diff --git a/test/sim/tb_cxxrtl/Makefile b/test/sim/tb_cxxrtl/Makefile
index 1f0ff9c..03d3a47 100644
--- a/test/sim/tb_cxxrtl/Makefile
+++ b/test/sim/tb_cxxrtl/Makefile
@@ -12,6 +12,7 @@ EXTENSION_ZBS    := 1
 
 DEBUG_SUPPORT    := 1
 U_MODE           := 1
+PMP_REGIONS      := 4
 
 MULDIV_UNROLL    := 2
 MUL_FAST         := 1
@@ -36,6 +37,7 @@ SYNTH_CMD += chparam -set EXTENSION_ZBC $(EXTENSION_ZBC) $(TOP);
 SYNTH_CMD += chparam -set EXTENSION_ZBS $(EXTENSION_ZBS) $(TOP);
 SYNTH_CMD += chparam -set DEBUG_SUPPORT $(DEBUG_SUPPORT) $(TOP);
 SYNTH_CMD += chparam -set U_MODE $(U_MODE) $(TOP);
+SYNTH_CMD += chparam -set PMP_REGIONS $(PMP_REGIONS) $(TOP);
 SYNTH_CMD += chparam -set CSR_COUNTER 1 $(TOP);
 SYNTH_CMD += chparam -set RESET_VECTOR $(CPU_RESET_VECTOR) $(TOP);
 SYNTH_CMD += chparam -set REDUCED_BYPASS $(REDUCED_BYPASS) $(TOP);