[PATCH v3 1/7] net/virtio_user: fix wrongly set features

[Jianfeng Tan <jianfeng.tan@intel.com>]

Before the commit 86d59b21468a ("net/virtio: support LRO"), features
in virtio PMD, is decided and properly set at device initialization
and will not be changed. But afterward, features could be changed in
virtio_dev_configure(), and will be re-negotiated if it's changed.

In virtio_user, device features is obtained at driver probe phase
only once, but we did not store it. So the added feature bits in
re-negotiation will fail.

To fix it, we store it down, and will be used to feature negotiation
either at device initialization phase or device configure phase.

Fixes: e9efa4d93821 ("net/virtio-user: add new virtual PCI driver")

CC: stable@dpdk.org

Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
---
 drivers/net/virtio/virtio_user/virtio_user_dev.c | 34 +++++++++++-------------
 drivers/net/virtio/virtio_user/virtio_user_dev.h |  5 +++-
 drivers/net/virtio/virtio_user_ethdev.c          |  4 +--
 3 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index e239e0e..0d7e17b 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -148,12 +148,13 @@ virtio_user_start_device(struct virtio_user_dev *dev)
 
 	/* Step 1: set features
 	 * Make sure VHOST_USER_F_PROTOCOL_FEATURES is added if mq is enabled,
-	 * and VIRTIO_NET_F_MAC is stripped.
+	 * VIRTIO_NET_F_MAC and VIRTIO_NET_F_CTRL_VQ is stripped.
 	 */
 	features = dev->features;
 	if (dev->max_queue_pairs > 1)
 		features |= VHOST_USER_MQ;
 	features &= ~(1ull << VIRTIO_NET_F_MAC);
+	features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
 	ret = vhost_user_sock(dev->vhostfd, VHOST_USER_SET_FEATURES, &features);
 	if (ret < 0)
 		goto error;
@@ -228,29 +229,26 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
 	}
 
 	if (vhost_user_sock(dev->vhostfd, VHOST_USER_GET_FEATURES,
-			    &dev->features) < 0) {
+			    &dev->device_features) < 0) {
 		PMD_INIT_LOG(ERR, "get_features failed: %s", strerror(errno));
 		return -1;
 	}
 	if (dev->mac_specified)
-		dev->features |= (1ull << VIRTIO_NET_F_MAC);
+		dev->device_features |= (1ull << VIRTIO_NET_F_MAC);
 
-	if (!cq) {
-		dev->features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
-		/* Also disable features depends on VIRTIO_NET_F_CTRL_VQ */
-		dev->features &= ~(1ull << VIRTIO_NET_F_CTRL_RX);
-		dev->features &= ~(1ull << VIRTIO_NET_F_CTRL_VLAN);
-		dev->features &= ~(1ull << VIRTIO_NET_F_GUEST_ANNOUNCE);
-		dev->features &= ~(1ull << VIRTIO_NET_F_MQ);
-		dev->features &= ~(1ull << VIRTIO_NET_F_CTRL_MAC_ADDR);
-	} else {
-		/* vhost user backend does not need to know ctrl-q, so
-		 * actually we need add this bit into features. However,
-		 * DPDK vhost-user does send features with this bit, so we
-		 * check it instead of OR it for now.
+	if (cq) {
+		/* device does not really need to know anything about CQ,
+		 * so if necessary, we just claim to support CQ
 		 */
-		if (!(dev->features & (1ull << VIRTIO_NET_F_CTRL_VQ)))
-			PMD_INIT_LOG(INFO, "vhost does not support ctrl-q");
+		dev->device_features |= (1ull << VIRTIO_NET_F_CTRL_VQ);
+	} else {
+		dev->device_features &= ~(1ull << VIRTIO_NET_F_CTRL_VQ);
+		/* Also disable features depends on VIRTIO_NET_F_CTRL_VQ */
+		dev->device_features &= ~(1ull << VIRTIO_NET_F_CTRL_RX);
+		dev->device_features &= ~(1ull << VIRTIO_NET_F_CTRL_VLAN);
+		dev->device_features &= ~(1ull << VIRTIO_NET_F_GUEST_ANNOUNCE);
+		dev->device_features &= ~(1ull << VIRTIO_NET_F_MQ);
+		dev->device_features &= ~(1ull << VIRTIO_NET_F_CTRL_MAC_ADDR);
 	}
 
 	if (dev->max_queue_pairs > 1) {
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.h b/drivers/net/virtio/virtio_user/virtio_user_dev.h
index 33690b5..28fc788 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.h
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.h
@@ -46,7 +46,10 @@ struct virtio_user_dev {
 	uint32_t	max_queue_pairs;
 	uint32_t	queue_pairs;
 	uint32_t	queue_size;
-	uint64_t	features;
+	uint64_t	features; /* the negotiated features with driver,
+				   * and will be sync with device
+				   */
+	uint64_t	device_features; /* supported features by device */
 	uint8_t		status;
 	uint8_t		mac_addr[ETHER_ADDR_LEN];
 	char		path[PATH_MAX];
diff --git a/drivers/net/virtio/virtio_user_ethdev.c b/drivers/net/virtio/virtio_user_ethdev.c
index 8cb983c..4a5a227 100644
--- a/drivers/net/virtio/virtio_user_ethdev.c
+++ b/drivers/net/virtio/virtio_user_ethdev.c
@@ -117,7 +117,7 @@ virtio_user_get_features(struct virtio_hw *hw)
 {
 	struct virtio_user_dev *dev = virtio_user_get_dev(hw);
 
-	return dev->features;
+	return dev->device_features;
 }
 
 static void
@@ -125,7 +125,7 @@ virtio_user_set_features(struct virtio_hw *hw, uint64_t features)
 {
 	struct virtio_user_dev *dev = virtio_user_get_dev(hw);
 
-	dev->features = features;
+	dev->features = features & dev->device_features;
 }
 
 static uint8_t
-- 
2.7.4