[PATCH v2] net/virtio-user: fix multiple queues fail in server mode

[zhiyong.yang@intel.com]

This patch fixes multiple queues failure when virtio-user works in
server mode.

This patch adds feature negotiation in the processing of virtio-user
reccnnection.

Fixes: bd8f50a45d0f ("net/virtio-user: support server mode")

Signed-off-by: Zhiyong Yang <zhiyong.yang@intel.com>
---

Changes in V2:
1. fix a comment typo.
2. add feature negotiation in the processing of reconnection.

 drivers/net/virtio/virtio_user/vhost_user.c      |  3 +++
 drivers/net/virtio/virtio_user/virtio_user_dev.c | 14 ++++++++++----
 drivers/net/virtio/virtio_user_ethdev.c          | 20 ++++++++++++++++++++
 3 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/drivers/net/virtio/virtio_user/vhost_user.c b/drivers/net/virtio/virtio_user/vhost_user.c
index a6df97a..93e4d92 100644
--- a/drivers/net/virtio/virtio_user/vhost_user.c
+++ b/drivers/net/virtio/virtio_user/vhost_user.c
@@ -263,6 +263,9 @@ struct hugepage_file_info {
 
 	PMD_DRV_LOG(INFO, "%s", vhost_msg_strings[req]);
 
+	if (dev->is_server && vhostfd < 0)
+		return -1;
+
 	msg.request = req;
 	msg.flags = VHOST_USER_VERSION;
 	msg.size = 0;
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index 38b8bc9..b7e1915 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -447,10 +447,16 @@ int virtio_user_stop_device(struct virtio_user_dev *dev)
 		return -1;
 	}
 
-	for (i = 0; i < q_pairs; ++i)
-		ret |= dev->ops->enable_qp(dev, i, 1);
-	for (i = q_pairs; i < dev->max_queue_pairs; ++i)
-		ret |= dev->ops->enable_qp(dev, i, 0);
+	/* Server mode can't enable queue pairs if vhostfd is invalid,
+	 * always return 0 in this case.
+	 */
+	if (dev->vhostfd >= 0)  {
+		for (i = 0; i < q_pairs; ++i)
+			ret |= dev->ops->enable_qp(dev, i, 1);
+		for (i = q_pairs; i < dev->max_queue_pairs; ++i)
+			ret |= dev->ops->enable_qp(dev, i, 0);
+	} else if (!dev->is_server)
+		ret = ~0;
 
 	dev->queue_pairs = q_pairs;
 
diff --git a/drivers/net/virtio/virtio_user_ethdev.c b/drivers/net/virtio/virtio_user_ethdev.c
index 4e7b3c3..91a0c44 100644
--- a/drivers/net/virtio/virtio_user_ethdev.c
+++ b/drivers/net/virtio/virtio_user_ethdev.c
@@ -30,6 +30,7 @@
 	int ret;
 	int flag;
 	int connectfd;
+	uint64_t features = dev->device_features, status;
 	struct rte_eth_dev *eth_dev = &rte_eth_devices[dev->port_id];
 
 	connectfd = accept(dev->listenfd, NULL, NULL);
@@ -37,6 +38,25 @@
 		return -1;
 
 	dev->vhostfd = connectfd;
+	if (dev->ops->send_request(dev, VHOST_USER_GET_FEATURES,
+				   &dev->device_features) < 0) {
+		PMD_INIT_LOG(ERR, "get_features failed: %s",
+			     strerror(errno));
+		return -1;
+	}
+
+	status = features & ~dev->device_features;
+	/* For following bits, vhost-user doesn't really need to know */
+	status &= ~(1ull << VIRTIO_NET_F_MAC);
+	status &= ~(1ull << VIRTIO_NET_F_CTRL_VLAN);
+	status &= ~(1ull << VIRTIO_NET_F_CTRL_MAC_ADDR);
+	status &= ~(1ull << VIRTIO_NET_F_STATUS);
+	if (status)
+		PMD_INIT_LOG(ERR, "WARNING: Some features (0x%lx) are not supported by vhost-user!",
+			     status);
+
+	dev->features &= dev->device_features;
+
 	flag = fcntl(connectfd, F_GETFD);
 	fcntl(connectfd, F_SETFL, flag | O_NONBLOCK);
 
-- 
1.8.3.1