[dpdk-dev] [PATCH v2 09/12] virtio: add Rx checksum offload support

[Maxime Coquelin]

On 10/03/2016 11:00 AM, Olivier Matz wrote:
> Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
> ---
>  drivers/net/virtio/virtio_ethdev.c | 14 ++++----
>  drivers/net/virtio/virtio_ethdev.h |  2 +-
>  drivers/net/virtio/virtio_rxtx.c   | 69 ++++++++++++++++++++++++++++++++++++++
>  drivers/net/virtio/virtqueue.h     |  1 +
>  4 files changed, 78 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
> index fa56032..43cb096 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -1262,7 +1262,7 @@ eth_virtio_dev_init(struct rte_eth_dev *eth_dev)
>  	eth_dev->data->dev_flags = dev_flags;
>
>  	/* reset device and negotiate default features */
> -	ret = virtio_init_device(eth_dev, VIRTIO_PMD_GUEST_FEATURES);
> +	ret = virtio_init_device(eth_dev, VIRTIO_PMD_DEFAULT_GUEST_FEATURES);
>  	if (ret < 0)
>  		return ret;
>
> @@ -1351,13 +1351,10 @@ virtio_dev_configure(struct rte_eth_dev *dev)
>  	int ret;
>
>  	PMD_INIT_LOG(DEBUG, "configure");
> +	req_features = VIRTIO_PMD_DEFAULT_GUEST_FEATURES;
> +	if (rxmode->hw_ip_checksum)
> +		req_features |= (1ULL << VIRTIO_NET_F_GUEST_CSUM);
>
> -	if (rxmode->hw_ip_checksum) {
> -		PMD_DRV_LOG(ERR, "HW IP checksum not supported");
> -		return -EINVAL;
> -	}
> -
> -	req_features = VIRTIO_PMD_GUEST_FEATURES;
>  	/* if request features changed, reinit the device */
>  	if (req_features != hw->req_guest_features) {
>  		ret = virtio_init_device(dev, req_features);
> @@ -1578,6 +1575,9 @@ virtio_dev_info_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
>  	dev_info->default_txconf = (struct rte_eth_txconf) {
>  		.txq_flags = ETH_TXQ_FLAGS_NOOFFLOADS
>  	};
> +	dev_info->rx_offload_capa =
> +		DEV_RX_OFFLOAD_TCP_CKSUM |
> +		DEV_RX_OFFLOAD_UDP_CKSUM;
>  }
>
>  /*
> diff --git a/drivers/net/virtio/virtio_ethdev.h b/drivers/net/virtio/virtio_ethdev.h
> index 5d5e788..2fc9218 100644
> --- a/drivers/net/virtio/virtio_ethdev.h
> +++ b/drivers/net/virtio/virtio_ethdev.h
> @@ -54,7 +54,7 @@
>  #define VIRTIO_MAX_RX_PKTLEN  9728
>
>  /* Features desired/implemented by this driver. */
> -#define VIRTIO_PMD_GUEST_FEATURES		\
> +#define VIRTIO_PMD_DEFAULT_GUEST_FEATURES	\
>  	(1u << VIRTIO_NET_F_MAC		  |	\
>  	 1u << VIRTIO_NET_F_STATUS	  |	\
>  	 1u << VIRTIO_NET_F_MQ		  |	\
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index 724517e..eda678a 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -50,6 +50,7 @@
>  #include <rte_string_fns.h>
>  #include <rte_errno.h>
>  #include <rte_byteorder.h>
> +#include <rte_net.h>
>
>  #include "virtio_logs.h"
>  #include "virtio_ethdev.h"
> @@ -627,6 +628,56 @@ virtio_update_packet_stats(struct virtnet_stats *stats, struct rte_mbuf *mbuf)
>  	}
>  }
>
> +/* Optionally fill offload information in structure */
> +static int
> +virtio_rx_offload(struct rte_mbuf *m, struct virtio_net_hdr *hdr)
> +{
> +	struct rte_net_hdr_lens hdr_lens;
> +	uint32_t hdrlen, ptype;
> +	int l4_supported = 0;
> +
> +	/* nothing to do */
> +	if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
> +		return 0;
> +
> +	m->ol_flags |= PKT_RX_IP_CKSUM_UNKNOWN;
> +
> +	ptype = rte_net_get_ptype(m, &hdr_lens, RTE_PTYPE_ALL_MASK);
> +	m->packet_type = ptype;
> +	if ((ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_TCP ||
> +	    (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_UDP ||
> +	    (ptype & RTE_PTYPE_L4_MASK) == RTE_PTYPE_L4_SCTP)
> +		l4_supported = 1;
> +
> +	if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
> +		hdrlen = hdr_lens.l2_len + hdr_lens.l3_len + hdr_lens.l4_len;
> +		if (hdr->csum_start <= hdrlen && l4_supported) {
> +			m->ol_flags |= PKT_RX_L4_CKSUM_NONE;
> +		} else {
> +			/* Unknown proto or tunnel, do sw cksum. We can assume
> +			 * the cksum field is in the first segment since the
> +			 * buffers we provided to the host are large enough.
> +			 * In case of SCTP, this will be wrong since it's a CRC
> +			 * but there's nothing we can do.
> +			 */
> +			uint16_t csum, off;
> +
> +			csum = rte_raw_cksum_mbuf(m, hdr->csum_start,
> +				rte_pktmbuf_pkt_len(m) - hdr->csum_start);
> +			if (csum != 0xffff)
Why don't we do the 1-complement if 0xffff?
> +				csum = ~csum;
> +			off = hdr->csum_offset + hdr->csum_start;
> +			if (rte_pktmbuf_data_len(m) >= off + 1)
> +				*rte_pktmbuf_mtod_offset(m, uint16_t *,
> +					off) = csum;
> +		}
> +	} else if (hdr->flags & VIRTIO_NET_HDR_F_DATA_VALID && l4_supported) {
> +		m->ol_flags |= PKT_RX_L4_CKSUM_GOOD;
> +	}
> +
> +	return 0;
> +}
> +