diff --git a/tests/tcg/s390x/Makefile.softmmu-target b/tests/tcg/s390x/Makefile.softmmu-target
index f60f94b090..be242ba8f1 100644
--- a/tests/tcg/s390x/Makefile.softmmu-target
+++ b/tests/tcg/s390x/Makefile.softmmu-target
@@ -1,6 +1,7 @@
 S390X_SRC=$(SRC_PATH)/tests/tcg/s390x
 VPATH+=$(S390X_SRC)
-QEMU_OPTS+=-action panic=exit-failure -nographic $(EXTFLAGS) -kernel
+# EXTFLAGS can be passed by the user, e.g. to override the --accel
+QEMU_OPTS+=-action panic=exit-failure -nographic -serial chardev:output $(EXTFLAGS) -kernel
 LINK_SCRIPT=$(S390X_SRC)/softmmu.ld
 CFLAGS+=-ggdb -O0
 LDFLAGS=-nostdlib -static