diff --git a/arch/sim/src/Makefile b/arch/sim/src/Makefile
index bd9a608fd4c..00aea45a544 100644
--- a/arch/sim/src/Makefile
+++ b/arch/sim/src/Makefile
@@ -82,6 +82,7 @@ endif
 
 ifeq ($(CONFIG_SMP),y)
   CSRCS += up_smpsignal.c up_smphook.c up_cpuidlestack.c
+  HOSTCFLAGS += -DCONFIG_SMP=1 -DCONFIG_SMP_NCPUS=$(CONFIG_SMP_NCPUS)
   HOSTSRCS += up_simsmp.c
 endif
 
@@ -158,10 +159,6 @@ endif # HOSTOS != Cygwin
 endif # CONFIG_NET_ETHERNET
 endif # CONFIG_SIM_NETDEV
 
-ifeq ($(CONFIG_SMP),y)
-  HOSTCFLAGS += -DCONFIG_SMP=1 -DCONFIG_SMP_NCPUS=$(CONFIG_SMP_NCPUS)
-endif
-
 ifeq ($(CONFIG_FS_HOSTFS),y)
   HOSTSRCS += up_hostfs.c