Btw we can excluisvely check this test on latest QEMU by given TESTPATH and setting QTEST_VHOST_USER_FIXME environment variable,
QTEST_VHOST_USER_FIXME=1 QTEST_QEMU_BINARY=x86_64-softmmu/qemu-system-x86_64 QTEST_QEMU_IMG=qemu-img tests/qos-test -p /x86_64/pc/i440FX-pcihost/pci-bus-pc/pci-bus/virtio-net-pci/virtio-net/virtio-net-tests/vhost-user/flags-mismatch