diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 77b75bc..2c9c6fb 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -718,8 +718,11 @@ static int virtio_serial_init_pci(PCIDevice *pci_dev)
         return -1;
     }
     vdev->nvectors = proxy->nvectors == DEV_NVECTORS_UNSPECIFIED
-                                        ? proxy->serial.max_virtserial_ports + 1
+                                        ? (proxy->serial.max_virtserial_ports + 1) * 2
                                         : proxy->nvectors;
+    /*msix.c: #define MSIX_MAX_ENTRIES 32*/
+    if (vdev->nvectors > 32)
+        vdev->nvectors = 32;
     virtio_init_pci(proxy, vdev);
     proxy->nvectors = vdev->nvectors;
     return 0;