net/vhost: support TSO disabling

TSO (TCP Segmentation Offload) is enabled by default on vhost.
Add the ability to disable TSO on vhost.
The user should also disable the feature on the virtual machine's xml.

Signed-off-by: Noa Ezra <noae@mellanox.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Matan Azrad <matan@mellanox.com>

doc/guides/nics/vhost.rst

@@ -76,6 +76,11 @@ The user can specify below arguments in `--vdev` option.
     It is used to enable postcopy live-migration support in vhost library.
     (Default: 0 (disabled))
 
+#.  ``tso``:
+
+    It is used to enable tso support in vhost library.
+    (Default: 0 (disabled))
+
 Vhost PMD event handling
 ------------------------
 

drivers/net/vhost/rte_eth_vhost.c

@@ -31,6 +31,7 @@ enum {VIRTIO_RXQ, VIRTIO_TXQ, VIRTIO_QNUM};
 #define ETH_VHOST_DEQUEUE_ZERO_COPY	"dequeue-zero-copy"
 #define ETH_VHOST_IOMMU_SUPPORT		"iommu-support"
 #define ETH_VHOST_POSTCOPY_SUPPORT	"postcopy-support"
+#define ETH_VHOST_VIRTIO_NET_F_HOST_TSO "tso"
 #define VHOST_MAX_PKT_BURST 32
 
 static const char *valid_arguments[] = {
@@ -40,6 +41,7 @@ static const char *valid_arguments[] = {
 	ETH_VHOST_DEQUEUE_ZERO_COPY,
 	ETH_VHOST_IOMMU_SUPPORT,
 	ETH_VHOST_POSTCOPY_SUPPORT,
+	ETH_VHOST_VIRTIO_NET_F_HOST_TSO,
 	NULL
 };
 
@@ -1209,7 +1211,8 @@ static const struct eth_dev_ops ops = {
 
 static int
 eth_dev_vhost_create(struct rte_vdev_device *dev, char *iface_name,
-	int16_t queues, const unsigned int numa_node, uint64_t flags)
+	int16_t queues, const unsigned int numa_node, uint64_t flags,
+	uint64_t disable_flags)
 {
 	const char *name = rte_vdev_device_name(dev);
 	struct rte_eth_dev_data *data;
@@ -1281,6 +1284,12 @@ eth_dev_vhost_create(struct rte_vdev_device *dev, char *iface_name,
 	if (rte_vhost_driver_register(iface_name, flags))
 		goto error;
 
+	if (disable_flags) {
+		if (rte_vhost_driver_disable_features(iface_name,
+					disable_flags))
+			goto error;
+	}
+
 	if (rte_vhost_driver_callback_register(iface_name, &vhost_ops) < 0) {
 		VHOST_LOG(ERR, "Can't register callbacks\n");
 		goto error;
@@ -1343,10 +1352,12 @@ rte_pmd_vhost_probe(struct rte_vdev_device *dev)
 	char *iface_name;
 	uint16_t queues;
 	uint64_t flags = 0;
+	uint64_t disable_flags = 0;
 	int client_mode = 0;
 	int dequeue_zero_copy = 0;
 	int iommu_support = 0;
 	int postcopy_support = 0;
+	int tso = 0;
 	struct rte_eth_dev *eth_dev;
 	const char *name = rte_vdev_device_name(dev);
 
@@ -1428,11 +1439,24 @@ rte_pmd_vhost_probe(struct rte_vdev_device *dev)
 			flags |= RTE_VHOST_USER_POSTCOPY_SUPPORT;
 	}
 
+	if (rte_kvargs_count(kvlist, ETH_VHOST_VIRTIO_NET_F_HOST_TSO) == 1) {
+		ret = rte_kvargs_process(kvlist,
+				ETH_VHOST_VIRTIO_NET_F_HOST_TSO,
+				&open_int, &tso);
+		if (ret < 0)
+			goto out_free;
+
+		if (tso == 0) {
+			disable_flags |= (1ULL << VIRTIO_NET_F_HOST_TSO4);
+			disable_flags |= (1ULL << VIRTIO_NET_F_HOST_TSO6);
+		}
+	}
+
 	if (dev->device.numa_node == SOCKET_ID_ANY)
 		dev->device.numa_node = rte_socket_id();
 
 	eth_dev_vhost_create(dev, iface_name, queues, dev->device.numa_node,
-		flags);
+		flags, disable_flags);
 
 out_free:
 	rte_kvargs_free(kvlist);
@@ -1476,7 +1500,8 @@ RTE_PMD_REGISTER_PARAM_STRING(net_vhost,
 	"client=<0|1> "
 	"dequeue-zero-copy=<0|1> "
 	"iommu-support=<0|1> "
-	"postcopy-support=<0|1>");
+	"postcopy-support=<0|1> "
+	"tso=<0|1>");
 
 RTE_INIT(vhost_init_log)
 {