DPDK报错：Ethdev port_id=0 requested Rx offloads 0xe doesn‘t match Rx offloads capabilities 0x800

运行OpenNetVM的NF Manager时报错如下：Ethdev port_id=0 requested Rx offloads 0xe doesn't match Rx offloads capabilities 0x800 in rte_eth_dev_configure()

看错误描述应该是DPDK在初始化配置网卡的时候出了问题，我的网卡是NetXtreme II BCM57810 10 Gigabit Ethernet 168e，DPDK版本20.05（OpenNetVM自带）

百度得到的结果：DPDK在虚拟机上运行时，报错: Ethdev port_id=0 requested Rx offloads 0xe doesn't match Rx offloads capabilities 0x82a1d in rte_eth_dev_configure() - 代码笔记~ - 博客园这个错误是因为RX_OFFLOAD与TX_OFFLOAD可能不支持IPV4_CKSUM的检验解决办法： 1，在配置中注释掉 DEV_RX_OFFLOAD_CHECKSUM 2，在代码中关闭https://www.cnblogs.com/lyt-666/p/13410548.html

这个宏的位置在${RTE_SDK}/x86_64-native-linuxapp-gcc/include/rte_ethdev.h ，内容为：

#define DEV_RX_OFFLOAD_CHECKSUM (DEV_RX_OFFLOAD_IPV4_CKSUM | \DEV_RX_OFFLOAD_UDP_CKSUM | \DEV_RX_OFFLOAD_TCP_CKSUM)

其中

#define DEV_RX_OFFLOAD_IPV4_CKSUM  0x00000002
#define DEV_RX_OFFLOAD_UDP_CKSUM   0x00000004
#define DEV_RX_OFFLOAD_TCP_CKSUM   0x00000008

这个宏的主要作用就是使能网卡的硬件offload功能，具体说就是就是将报文的ip，tcp， udp的校验和计算交给网卡计算，节省cpu开销，从而提高吞吐量的手段

再进一步定位rte_eth_dev_configure里报错的这段代码，可以看到就是把dev_conf里的rx的offloads配置和dev_info里的网卡offloads能力做了一个比较，如果值不相等就报错

    /* Any requested offloading must be within its device capabilities */if ((dev_conf->rxmode.offloads & dev_info.rx_offload_capa) !=dev_conf->rxmode.offloads) {RTE_ETHDEV_LOG(ERR,"Ethdev port_id=%u requested Rx offloads 0x%"PRIx64" doesn't match Rx offloads ""capabilities 0x%"PRIx64" in %s()\n",port_id, dev_conf->rxmode.offloads,dev_info.rx_offload_capa,__func__);ret = -EINVAL;goto rollback;}

再看onvm_init.c里的实际配置

static const struct rte_eth_conf port_conf = {.rxmode = {.mq_mode = ETH_MQ_RX_RSS,.max_rx_pkt_len = RTE_ETHER_MAX_LEN,.split_hdr_size = 0,.offloads = DEV_RX_OFFLOAD_CHECKSUM,},.rx_adv_conf = {.rss_conf = {.rss_key = rss_symmetric_key, .rss_hf = ETH_RSS_IP | ETH_RSS_UDP | ETH_RSS_TCP | ETH_RSS_L2_PAYLOAD,},},.txmode = {.mq_mode = ETH_MQ_TX_NONE,.offloads = (DEV_TX_OFFLOAD_IPV4_CKSUM | DEV_TX_OFFLOAD_UDP_CKSUM | DEV_TX_OFFLOAD_TCP_CKSUM)},
};

onvm配置的rxmode.offloads就是宏定义的DEV_RX_OFFLOAD_CHECKSUM，值为0xe

而BCM57810网卡的参数为0x800，是一个关于支持巨型帧的宏

#define DEV_RX_OFFLOAD_JUMBO_FRAME      0x00000800

BCM57810网卡使用的驱动是bnx2x，在dpdk的bnx2x_ethdev.c文件里可以找到dev_info实际的设置

static int
bnx2x_dev_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
{struct bnx2x_softc *sc = dev->data->dev_private;dev_info->max_rx_queues  = sc->max_rx_queues;dev_info->max_tx_queues  = sc->max_tx_queues;dev_info->min_rx_bufsize = BNX2X_MIN_RX_BUF_SIZE;dev_info->max_rx_pktlen  = BNX2X_MAX_RX_PKT_LEN;dev_info->max_mac_addrs  = BNX2X_MAX_MAC_ADDRS;dev_info->speed_capa = ETH_LINK_SPEED_10G | ETH_LINK_SPEED_20G;dev_info->rx_offload_capa = DEV_RX_OFFLOAD_JUMBO_FRAME;dev_info->rx_desc_lim.nb_max = MAX_RX_AVAIL;dev_info->rx_desc_lim.nb_min = MIN_RX_SIZE_NONTPA;dev_info->rx_desc_lim.nb_mtu_seg_max = 1;dev_info->tx_desc_lim.nb_max = MAX_TX_AVAIL;return 0;
}

确实是只有一个dev_info->rx_offload_capa = DEV_RX_OFFLOAD_JUMBO_FRAME;

所以看起来是dpdk写的驱动里不支持onvm写的关于checksum的offloads功能，查下官方文档3. BNX2X Poll Mode Driver — dpdk 0.11 documentationhttps://dpdk-docs.readthedocs.io/en/latest/nics/bnx2x.html

3.1. Supported Features

BNX2X PMD has support for:

Base L2 features
Unicast/multicast filtering
Promiscuous mode
Port hardware statistics
SR-IOV VF

3.2. Non-supported Features

The features not yet supported include:

TSS (Transmit Side Scaling)
RSS (Receive Side Scaling)
LRO/TSO offload
Checksum offload
SR-IOV PF
Rx TX scatter gather

RSS、 Checksum offload这些都没支持

于是修改onvm_init.c里的网卡配置，使其与BNX2X驱动支持的功能匹配，修改代码如下

static const struct rte_eth_conf port_conf = {.rxmode = {.mq_mode = ETH_MQ_RX_RSS,.max_rx_pkt_len = RTE_ETHER_MAX_LEN,.split_hdr_size = 0,//.offloads = DEV_RX_OFFLOAD_CHECKSUM,.offloads = 0x800,},.rx_adv_conf = {.rss_conf = {.rss_key = rss_symmetric_key, .rss_hf = ETH_RSS_IP | ETH_RSS_UDP | ETH_RSS_TCP | ETH_RSS_L2_PAYLOAD,},},.txmode = {.mq_mode = ETH_MQ_TX_NONE,//.offloads = (DEV_TX_OFFLOAD_IPV4_CKSUM | DEV_TX_OFFLOAD_UDP_CKSUM | DEV_TX_OFFLOAD_TCP_CKSUM)},.offloads = 0x0},
};

重新编译onvm，这次可以跑起来了，但是RSS，checksum offloads这些功能显然都用不了了，所以结论是条件允许的话最好还是使用像i40e这些驱动支持的网卡运行onvm。。。