[dpdk-dev] [PATCH] net/virtio: fix link status always being up

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

The virtio port link status will always be UP, even the port is stopped:

    testpmd> port stop 0
    Stopping ports...
    Checking link statuses...
    Port 0 Link Up - speed 10000 Mbps - full-duplex
    Done

The link status is queried by link_update callback when LSC is disabled.
Which in turn queries the "status" field.  However, the "status" is
read-only. I couldn't think of some proper ways to change the status
without doing device reset.

Instead of doing (the heavy) reset at stop, this patch introduced a flag,
which is set to 1 and 0 on start and stop, respectively. When it's set to
0, the link status is set to DOWN unconditionally.

Fixes: a85786dc816f ("virtio: fix states handling during initialization")

Cc: stable@dpdk.org
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
---
 drivers/net/virtio/virtio_ethdev.c | 7 ++++++-
 drivers/net/virtio/virtio_pci.h    | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 78cb3e8..b2f9570 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1768,6 +1768,7 @@ static int virtio_dev_xstats_get_names(struct rte_eth_dev *dev,
 		txvq = dev->data->tx_queues[i];
 		VIRTQUEUE_DUMP(txvq->vq);
 	}
+	hw->started = 1;
 
 	return 0;
 }
@@ -1823,6 +1824,7 @@ static void virtio_dev_free_mbufs(struct rte_eth_dev *dev)
 static void
 virtio_dev_stop(struct rte_eth_dev *dev)
 {
+	struct virtio_hw *hw = dev->data->dev_private;
 	struct rte_eth_link link;
 	struct rte_intr_conf *intr_conf = &dev->data->dev_conf.intr_conf;
 
@@ -1831,6 +1833,7 @@ static void virtio_dev_free_mbufs(struct rte_eth_dev *dev)
 	if (intr_conf->lsc || intr_conf->rxq)
 		rte_intr_disable(dev->intr_handle);
 
+	hw->started = 0;
 	memset(&link, 0, sizeof(link));
 	virtio_dev_atomic_write_link_status(dev, &link);
 }
@@ -1847,7 +1850,9 @@ static void virtio_dev_free_mbufs(struct rte_eth_dev *dev)
 	link.link_duplex = ETH_LINK_FULL_DUPLEX;
 	link.link_speed  = SPEED_10G;
 
-	if (vtpci_with_feature(hw, VIRTIO_NET_F_STATUS)) {
+	if (hw->started == 0) {
+		link.link_status = ETH_LINK_DOWN;
+	} else if (vtpci_with_feature(hw, VIRTIO_NET_F_STATUS)) {
 		PMD_INIT_LOG(DEBUG, "Get link status from hw");
 		vtpci_read_dev_config(hw,
 				offsetof(struct virtio_net_config, status),
diff --git a/drivers/net/virtio/virtio_pci.h b/drivers/net/virtio/virtio_pci.h
index 0362acd..e7290d7 100644
--- a/drivers/net/virtio/virtio_pci.h
+++ b/drivers/net/virtio/virtio_pci.h
@@ -253,6 +253,7 @@ struct virtio_hw {
 	uint64_t    req_guest_features;
 	uint64_t    guest_features;
 	uint32_t    max_queue_pairs;
+	uint16_t    started;
 	uint16_t	max_mtu;
 	uint16_t    vtnet_hdr_size;
 	uint8_t	    vlan_strip;
-- 
1.9.0