diff --git a/Makefile b/Makefile
index 93d8c76d1..e17b06726 100644
--- a/Makefile
+++ b/Makefile
@@ -453,6 +453,7 @@ scst-dkms-rpm:
 		<$${name}.spec.in >$${name}.spec &&			\
 	MAKE="$(MAKE)" rpmbuild --define="%_topdir $${rpmtopdir}"	\
 	    $(if $(KVER),--define="%kversion $(KVER)")			\
+	    $(if $(KDIR),--define="%kdir $(KDIR)")			\
 	    -ba $${name}.spec &&					\
 	rm -f $${name}-$(VERSION).tar.bz2
 
diff --git a/scst.spec.in b/scst.spec.in
index e1a21f0a4..a1435fd83 100644
--- a/scst.spec.in
+++ b/scst.spec.in
@@ -105,6 +105,7 @@ Authors:
 
 %build
 export KVER=%{kversion} PREFIX=%{_prefix}
+%{?kdir:%{expand:%%(export KDIR=%{kdir})}}
 export BUILD_2X_MODULE=y CONFIG_SCSI_QLA_FC=y CONFIG_SCSI_QLA2XXX_TARGET=y
 make 2release
 for d in scst fcst iscsi-scst qla2x00t/qla2x00-target scst_local srpt; do
@@ -113,6 +114,7 @@ done
 
 %install
 export KVER=%{kversion} PREFIX=%{_prefix} MANDIR=%{_mandir}
+%{?kdir:%{expand:%%(export KDIR=%{kdir})}}
 export BUILD_2X_MODULE=y CONFIG_SCSI_QLA_FC=y CONFIG_SCSI_QLA2XXX_TARGET=y
 for d in scst; do
     DESTDIR=%{buildroot} %{make} -C $d install