[dpdk-dev] In DPDK 1.7.1, the link status of the interface using virtio driver is always down.

["Fu, Weiyi (NSN - CN/Hangzhou)" <weiyi.fu@nsn.com>]

Hi,
We are using the l2fwd based on DPDK 1.7.1  and found out that the link status of the interface using virtio driver is always down.
Is there any precondition to let the link up?

# ./pci_unbind.py --status

Network devices using IGB_UIO driver
====================================
0000:00:04.0 'Virtio network device' drv=igb_uio unused=
0000:00:05.0 'Virtio network device' drv=igb_uio unused=

Network devices using kernel driver
===================================
0000:00:03.0 'Virtio network device' if= drv=virtio-pci unused=igb_uio

Other network devices
=====================
<none>
[root@EIPU-0(KVMCluster) /root]
# /root/l2fwd -c 1 -n 1 -- -p 1
...
Port: 0 Link is DOWN
PMD: virtio_dev_start(): nb_queues=1
PMD: virtio_dev_start(): Notified backend at initialization
PMD: rte_eth_dev_config_restore: port 0: MAC address array not supported
PMD: rte_eth_promiscuous_disable: Function not supported
PMD: rte_eth_allmulticast_disable: Function not supported
done:
PMD: rte_eth_promiscuous_enable: Function not supported
Port 0, MAC address: FF:FF:00:00:00:00

Skipping disabled port 1

Checking link statusPMD: virtio_dev_link_update(): Get link status from hw
PMD: virtio_dev_link_update(): Port 0 is down
.PMD: virtio_dev_link_update(): Get link status from hw
PMD: virtio_dev_link_update(): Port 0 is down
.PMD: virtio_dev_link_update(): Get link status from hw
PMD: virtio_dev_link_update(): Port 0 is down
...

Brs,
Fu Weiyi