[dpdk-dev] [PATCH v4 1/5] net/e1000: fix max mtu size packets with vlan tag cannot be received by default

SteveX Yang stevex.yang at intel.com
Mon Sep 28 08:55:37 CEST 2020


testpmd will initialize default max packet length to 1518 which doesn't
include vlan tag size in ether overheader. Once, send the max mtu length
packet with vlan tag, the max packet length will exceed 1518 that will
cause packets dropped directly from NIC hw side.

e1000 can support single vlan tags that need more 4 bytes for max packet
size, so, configures the correct max packet size in dev_config ops.

Fixes: 35b2d13fd6fd ("net: add rte prefix to ether defines")

Signed-off-by: SteveX Yang <stevex.yang at intel.com>
---
 drivers/net/e1000/em_ethdev.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/e1000/em_ethdev.c b/drivers/net/e1000/em_ethdev.c
index 1dc360713..96ff99951 100644
--- a/drivers/net/e1000/em_ethdev.c
+++ b/drivers/net/e1000/em_ethdev.c
@@ -437,10 +437,22 @@ eth_em_configure(struct rte_eth_dev *dev)
 {
 	struct e1000_interrupt *intr =
 		E1000_DEV_PRIVATE_TO_INTR(dev->data->dev_private);
+	uint16_t frame_size = dev->data->mtu + E1000_ETH_OVERHEAD;
+	int rc = 0;
 
 	PMD_INIT_FUNC_TRACE();
 	intr->flags |= E1000_FLAG_NEED_LINK_UPDATE;
 
+	/**
+	 * Considering vlan tag packet, max frame size should be equal or
+	 * larger than total size of MTU and Ether overhead.
+	 */
+	if (frame_size > dev->data->dev_conf.rxmode.max_rx_pkt_len) {
+		rc = eth_em_mtu_set(dev, dev->data->mtu);
+		if (rc != 0)
+			return rc;
+	}
+
 	PMD_INIT_FUNC_TRACE();
 
 	return 0;
-- 
2.17.1



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