diff --git a/Makefile b/Makefile
index bb10dd3..d06942a 100644
--- a/Makefile
+++ b/Makefile
@@ -305,15 +305,16 @@ $(CONVERSION_GEN): $(LOCALBIN) # Build conversion-gen from tools folder.
 	GOBIN=$(LOCALBIN) $(GO_INSTALL) $(CONVERSION_GEN_PKG) $(CONVERSION_GEN_BIN) $(CONVERSION_GEN_VER)
 
 .PHONY: generate-go-conversions
-# The SRC_DIRS value is a comma-separated list of paths to old versions.
+# The SRC_DIRS value is a space-separated list of paths to old versions.
 # The --input-dirs value is a single path item; specify multiple --input-dirs
 # parameters if you have multiple old versions.
+SRC_DIRS=./api/v1alpha1
 generate-go-conversions: $(CONVERSION_GEN) ## Generate conversions go code
-	$(MAKE) clean-generated-conversions SRC_DIRS="./api/v1alpha1"
+	$(MAKE) clean-generated-conversions SRC_DIRS="$(SRC_DIRS)"
 	$(CONVERSION_GEN) \
 		--output-file=zz_generated.conversion.go \
 		--go-header-file=./hack/boilerplate.go.txt \
-		./api/v1alpha1
+		$(SRC_DIRS)
 
 .PHONY: clean-generated-conversions
 clean-generated-conversions: ## Remove files generated by conversion-gen from the mentioned dirs