diff --git a/tests/qtest/cxl-test.c b/tests/qtest/cxl-test.c
index 5f0794e816..079011af6a 100644
--- a/tests/qtest/cxl-test.c
+++ b/tests/qtest/cxl-test.c
@@ -9,11 +9,13 @@
 #include "libqtest-single.h"
 
 #define QEMU_PXB_CMD "-machine q35,cxl=on " \
-                     "-device pxb-cxl,id=cxl.0,bus=pcie.0,bus_nr=52 "
+                     "-device pxb-cxl,id=cxl.0,bus=pcie.0,bus_nr=52 "  \
+                     "-cxl-fixed-memory-window targets.0=cxl.0,size=4G "
 
-#define QEMU_2PXB_CMD "-machine q35,cxl=on " \
+#define QEMU_2PXB_CMD "-machine q35,cxl=on "                            \
                       "-device pxb-cxl,id=cxl.0,bus=pcie.0,bus_nr=52 "  \
-                      "-device pxb-cxl,id=cxl.1,bus=pcie.0,bus_nr=53 "
+                      "-device pxb-cxl,id=cxl.1,bus=pcie.0,bus_nr=53 " \
+                      "-cxl-fixed-memory-window targets.0=cxl.0,targets.1=cxl.1,size=4G "
 
 #define QEMU_RP "-device cxl-rp,id=rp0,bus=cxl.0,chassis=0,slot=0 "