Re: [PATCH v3 3/4] drivers/net/virtio_net: Added RSS hash report.

From: Willem de Bruijn
Date: Tue Feb 08 2022 - 17:29:35 EST


On Tue, Feb 8, 2022 at 1:19 PM Andrew Melnychenko <andrew@xxxxxxxxxx> wrote:
>
> Added features for RSS hash report.
> If hash is provided - it sets to skb.
> Added checks if rss and/or hash are enabled together.
>
> Signed-off-by: Andrew Melnychenko <andrew@xxxxxxxxxx>
> ---
> drivers/net/virtio_net.c | 51 ++++++++++++++++++++++++++++++++++------
> 1 file changed, 44 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 495aed524e33..543da2fbdd2d 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -227,6 +227,7 @@ struct virtnet_info {
>
> /* Host supports rss and/or hash report */
> bool has_rss;
> + bool has_rss_hash_report;
> u8 rss_key_size;
> u16 rss_indir_table_size;
> u32 rss_hash_types_supported;
> @@ -421,7 +422,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
>
> hdr_len = vi->hdr_len;
> if (vi->mergeable_rx_bufs)
> - hdr_padded_len = sizeof(*hdr);
> + hdr_padded_len = hdr_len;

Belongs in patch 1?

> else
> hdr_padded_len = sizeof(struct padded_vnet_hdr);
>
> @@ -1156,6 +1157,8 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
> struct net_device *dev = vi->dev;
> struct sk_buff *skb;
> struct virtio_net_hdr_mrg_rxbuf *hdr;
> + struct virtio_net_hdr_v1_hash *hdr_hash;
> + enum pkt_hash_types rss_hash_type;
>
> if (unlikely(len < vi->hdr_len + ETH_HLEN)) {
> pr_debug("%s: short packet %i\n", dev->name, len);
> @@ -1182,6 +1185,29 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
> return;
>
> hdr = skb_vnet_hdr(skb);
> + if (dev->features & NETIF_F_RXHASH && vi->has_rss_hash_report) {

Can the first be true if the second is not?

> + hdr_hash = (struct virtio_net_hdr_v1_hash *)(hdr);
> +
> + switch (hdr_hash->hash_report) {
> + case VIRTIO_NET_HASH_REPORT_TCPv4:
> + case VIRTIO_NET_HASH_REPORT_UDPv4:
> + case VIRTIO_NET_HASH_REPORT_TCPv6:
> + case VIRTIO_NET_HASH_REPORT_UDPv6:
> + case VIRTIO_NET_HASH_REPORT_TCPv6_EX:
> + case VIRTIO_NET_HASH_REPORT_UDPv6_EX:
> + rss_hash_type = PKT_HASH_TYPE_L4;
> + break;
> + case VIRTIO_NET_HASH_REPORT_IPv4:
> + case VIRTIO_NET_HASH_REPORT_IPv6:
> + case VIRTIO_NET_HASH_REPORT_IPv6_EX:
> + rss_hash_type = PKT_HASH_TYPE_L3;
> + break;
> + case VIRTIO_NET_HASH_REPORT_NONE:
> + default:
> + rss_hash_type = PKT_HASH_TYPE_NONE;
> + }
> + skb_set_hash(skb, hdr_hash->hash_value, rss_hash_type);
> + }

so many lines, perhaps deserves a helper function

>
> if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID)
> skb->ip_summed = CHECKSUM_UNNECESSARY;
> @@ -2232,7 +2258,8 @@ static bool virtnet_commit_rss_command(struct virtnet_info *vi)
> sg_set_buf(&sgs[3], vi->ctrl->rss.key, sg_buf_size);
>
> if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
> - VIRTIO_NET_CTRL_MQ_RSS_CONFIG, sgs)) {
> + vi->has_rss ? VIRTIO_NET_CTRL_MQ_RSS_CONFIG
> + : VIRTIO_NET_CTRL_MQ_HASH_CONFIG, sgs)) {
> dev_warn(&dev->dev, "VIRTIONET issue with committing RSS sgs\n");
> return false;
> }
> @@ -3230,6 +3257,8 @@ static bool virtnet_validate_features(struct virtio_device *vdev)
> VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
> "VIRTIO_NET_F_CTRL_VQ") ||
> VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_RSS,
> + "VIRTIO_NET_F_CTRL_VQ") ||
> + VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_HASH_REPORT,
> "VIRTIO_NET_F_CTRL_VQ"))) {
> return false;
> }
> @@ -3365,8 +3394,13 @@ static int virtnet_probe(struct virtio_device *vdev)
> if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
> vi->mergeable_rx_bufs = true;
>
> - if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) {
> + if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT))
> + vi->has_rss_hash_report = true;
> +
> + if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS))
> vi->has_rss = true;
> +
> + if (vi->has_rss || vi->has_rss_hash_report) {
> vi->rss_indir_table_size =
> virtio_cread16(vdev, offsetof(struct virtio_net_config,

should indir table size be zero if only hash report is enabled?

> rss_max_indirection_table_length));
> @@ -3382,8 +3416,11 @@ static int virtnet_probe(struct virtio_device *vdev)
>
> dev->hw_features |= NETIF_F_RXHASH;
> }
> - if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF) ||
> - virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
> +
> + if (vi->has_rss_hash_report)
> + vi->hdr_len = sizeof(struct virtio_net_hdr_v1_hash);
> + else if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF) ||
> + virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
> vi->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
> else
> vi->hdr_len = sizeof(struct virtio_net_hdr);
> @@ -3450,7 +3487,7 @@ static int virtnet_probe(struct virtio_device *vdev)
> }
> }
>
> - if (vi->has_rss)
> + if (vi->has_rss || vi->has_rss_hash_report)
> virtnet_init_default_rss(vi);
>
> err = register_netdev(dev);
> @@ -3585,7 +3622,7 @@ static struct virtio_device_id id_table[] = {
> VIRTIO_NET_F_CTRL_MAC_ADDR, \
> VIRTIO_NET_F_MTU, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, \
> VIRTIO_NET_F_SPEED_DUPLEX, VIRTIO_NET_F_STANDBY, \
> - VIRTIO_NET_F_RSS
> + VIRTIO_NET_F_RSS, VIRTIO_NET_F_HASH_REPORT
>
> static unsigned int features[] = {
> VIRTNET_FEATURES,
> --
> 2.34.1
>