virtio-crypto-pci: add check for cryptodev object

We must assure each virtio crypto pci device has
an vaild cryptodev backend object.

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/virtio/virtio-crypto-pci.c

@@ -31,6 +31,11 @@ static void virtio_crypto_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     VirtIOCryptoPCI *vcrypto = VIRTIO_CRYPTO_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&vcrypto->vdev);
 
+    if (vcrypto->vdev.conf.cryptodev == NULL) {
+        error_setg(errp, "'cryptodev' parameter expects a valid object");
+        return;
+    }
+
     qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
     virtio_pci_force_virtio_1(vpci_dev);
     object_property_set_bool(OBJECT(vdev), true, "realized", errp);