diff --git a/hw/core/machine.c b/hw/core/machine.c
index c4a2ab2282..28a475ad97 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -52,6 +52,7 @@ GlobalProperty hw_compat_3_1[] = {
     { "virtio-blk-device", "discard", "false" },
     { "virtio-blk-device", "write-zeroes", "false" },
     { "virtio-balloon-device", "qemu-4-0-config-size", "false" },
+    { "pcie-root-port-base", "disable-acs", "true" }, /* Added in 4.1 */
 };
 const size_t hw_compat_3_1_len = G_N_ELEMENTS(hw_compat_3_1);