net/virtio: support MTU feature

[dpdk.git] / drivers / net / virtio / virtio_ethdev.c

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 66770fc..d9986ab 100644 (file)
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -721,10 +721,13 @@ virtio_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
        uint32_t ether_hdr_len = ETHER_HDR_LEN + VLAN_TAG_LEN +
                                 hw->vtnet_hdr_size;
        uint32_t frame_size = mtu + ether_hdr_len;
+       uint32_t max_frame_size = hw->max_mtu + ether_hdr_len;
 
-       if (mtu < ETHER_MIN_MTU || frame_size > VIRTIO_MAX_RX_PKTLEN) {
+       max_frame_size = RTE_MIN(max_frame_size, VIRTIO_MAX_RX_PKTLEN);
+
+       if (mtu < ETHER_MIN_MTU || frame_size > max_frame_size) {
                PMD_INIT_LOG(ERR, "MTU should be between %d and %d",
-                       ETHER_MIN_MTU, VIRTIO_MAX_RX_PKTLEN - ether_hdr_len);
+                       ETHER_MIN_MTU, max_frame_size - ether_hdr_len);
                return -EINVAL;
        }
        return 0;
@@ -1158,6 +1161,18 @@ virtio_negotiate_features(struct virtio_hw *hw, uint64_t req_features)
        PMD_INIT_LOG(DEBUG, "host_features before negotiate = %" PRIx64,
                host_features);
 
+       /* If supported, ensure MTU value is valid before acknowledging it. */
+       if (host_features & req_features & (1ULL << VIRTIO_NET_F_MTU)) {
+               struct virtio_net_config config;
+
+               vtpci_read_dev_config(hw,
+                       offsetof(struct virtio_net_config, mtu),
+                       &config.mtu, sizeof(config.mtu));
+
+               if (config.mtu < ETHER_MIN_MTU)
+                       req_features &= ~(1ULL << VIRTIO_NET_F_MTU);
+       }
+
        /*
         * Negotiate features: Subset of device feature bits are written back
         * guest feature bits.
@@ -1392,6 +1407,32 @@ virtio_init_device(struct rte_eth_dev *eth_dev, uint64_t req_features)
 
                hw->max_queue_pairs = config->max_virtqueue_pairs;
 
+               if (vtpci_with_feature(hw, VIRTIO_NET_F_MTU)) {
+                       vtpci_read_dev_config(hw,
+                               offsetof(struct virtio_net_config, mtu),
+                               &config->mtu,
+                               sizeof(config->mtu));
+
+                       /*
+                        * MTU value has already been checked at negotiation
+                        * time, but check again in case it has changed since
+                        * then, which should not happen.
+                        */
+                       if (config->mtu < ETHER_MIN_MTU) {
+                               PMD_INIT_LOG(ERR, "invalid max MTU value (%u)",
+                                               config->mtu);
+                               return -1;
+                       }
+
+                       hw->max_mtu = config->mtu;
+                       /* Set initial MTU to maximum one supported by vhost */
+                       eth_dev->data->mtu = config->mtu;
+
+               } else {
+                       hw->max_mtu = VIRTIO_MAX_RX_PKTLEN - ETHER_HDR_LEN -
+                               VLAN_TAG_LEN - hw->vtnet_hdr_size;
+               }
+
                PMD_INIT_LOG(DEBUG, "config->max_virtqueue_pairs=%d",
                                config->max_virtqueue_pairs);
                PMD_INIT_LOG(DEBUG, "config->status=%d", config->status);