Andrew Melnichenko
2022-Feb-13 17:01 UTC
[PATCH v3 2/4] drivers/net/virtio_net: Added basic RSS support.
Hi all, On Tue, Feb 8, 2022 at 10:37 PM Willem de Bruijn <willemdebruijn.kernel at gmail.com> wrote:> > On Tue, Feb 8, 2022 at 1:19 PM Andrew Melnychenko <andrew at daynix.com> wrote: > > > > Added features for RSS. > > Added initialization, RXHASH feature and ethtool ops. > > By default RSS/RXHASH is disabled. > > Virtio RSS "IPv6 extensions" hashes disabled. > > Added ethtools ops to set key and indirection table. > > > > Signed-off-by: Andrew Melnychenko <andrew at daynix.com> > > --- > > drivers/net/virtio_net.c | 191 +++++++++++++++++++++++++++++++++++++-- > > 1 file changed, 185 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > index 1404e683a2fd..495aed524e33 100644 > > --- a/drivers/net/virtio_net.c > > +++ b/drivers/net/virtio_net.c > > @@ -169,6 +169,24 @@ struct receive_queue { > > struct xdp_rxq_info xdp_rxq; > > }; > > > > +/* This structure can contain rss message with maximum settings for indirection table and keysize > > + * Note, that default structure that describes RSS configuration virtio_net_rss_config > > + * contains same info but can't handle table values. > > + * In any case, structure would be passed to virtio hw through sg_buf split by parts > > + * because table sizes may be differ according to the device configuration. > > + */ > > +#define VIRTIO_NET_RSS_MAX_KEY_SIZE 40 > > Future proof, may want to support larger sizes. > > netdevice.h defines NETDEV_RSS_KEY_LEN at 52. > > tools/testing/selftests/net/toeplitz.c supports up to 60According to virtio specification, the length of the key is 40bytes(and an indirection table is 128 entries max). So for now, we support a maximum of the spec regardless of what the kernel is capable of.> > > +#define VIRTIO_NET_RSS_MAX_TABLE_LEN 128 > > +struct virtio_net_ctrl_rss { > > + u32 hash_types; > > conversely, u32 is a bit extreme?No, the structure virtio_net_ctrl_rss is specified by the specification.> > > + u16 indirection_table_mask; > > + u16 unclassified_queue; > > + u16 indirection_table[VIRTIO_NET_RSS_MAX_TABLE_LEN]; > > + u16 max_tx_vq; > > + u8 hash_key_length; > > + u8 key[VIRTIO_NET_RSS_MAX_KEY_SIZE]; > > +}; > > + > > /* Control VQ buffers: protected by the rtnl lock */ > > struct control_buf { > > struct virtio_net_ctrl_hdr hdr; > > @@ -178,6 +196,7 @@ struct control_buf { > > u8 allmulti; > > __virtio16 vid; > > __virtio64 offloads; > > + struct virtio_net_ctrl_rss rss; > > }; > > > > struct virtnet_info { > > @@ -206,6 +225,12 @@ struct virtnet_info { > > /* Host will merge rx buffers for big packets (shake it! shake it!) */ > > bool mergeable_rx_bufs; > > > > + /* Host supports rss and/or hash report */ > > + bool has_rss; > > + u8 rss_key_size; > > + u16 rss_indir_table_size; > > + u32 rss_hash_types_supported; > > + > > /* Has control virtqueue */ > > bool has_cvq; > > > > @@ -2184,6 +2209,56 @@ static void virtnet_get_ringparam(struct net_device *dev, > > ring->tx_pending = ring->tx_max_pending; > > } > > > > +static bool virtnet_commit_rss_command(struct virtnet_info *vi) > > +{ > > + struct net_device *dev = vi->dev; > > + struct scatterlist sgs[4]; > > + unsigned int sg_buf_size; > > + > > + /* prepare sgs */ > > + sg_init_table(sgs, 4); > > + > > + sg_buf_size = offsetof(struct virtio_net_ctrl_rss, indirection_table); > > + sg_set_buf(&sgs[0], &vi->ctrl->rss, sg_buf_size); > > + > > + sg_buf_size = sizeof(uint16_t) * vi->rss_indir_table_size; > > + sg_set_buf(&sgs[1], vi->ctrl->rss.indirection_table, sg_buf_size); > > + > > + sg_buf_size = offsetof(struct virtio_net_ctrl_rss, key) > > + - offsetof(struct virtio_net_ctrl_rss, max_tx_vq); > > + sg_set_buf(&sgs[2], &vi->ctrl->rss.max_tx_vq, sg_buf_size); > > + > > + sg_buf_size = vi->rss_key_size; > > + 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)) { > > + dev_warn(&dev->dev, "VIRTIONET issue with committing RSS sgs\n"); > > + return false; > > + } > > + return true; > > +} > > + > > +static void virtnet_init_default_rss(struct virtnet_info *vi) > > +{ > > + u32 indir_val = 0; > > + int i = 0; > > + > > + vi->ctrl->rss.hash_types = vi->rss_hash_types_supported; > > + vi->ctrl->rss.indirection_table_mask = vi->rss_indir_table_size - 1; > > Is table size always a power of two?Yes, it should be.> > > + vi->ctrl->rss.unclassified_queue = 0; > > + > > + for (; i < vi->rss_indir_table_size; ++i) { > > + indir_val = ethtool_rxfh_indir_default(i, vi->curr_queue_pairs); > > + vi->ctrl->rss.indirection_table[i] = indir_val; > > + } > > + > > + vi->ctrl->rss.max_tx_vq = vi->curr_queue_pairs; > > + vi->ctrl->rss.hash_key_length = vi->rss_key_size; > > + > > + netdev_rss_key_fill(vi->ctrl->rss.key, vi->rss_key_size); > > +} > > + > > > > static void virtnet_get_drvinfo(struct net_device *dev, > > struct ethtool_drvinfo *info) > > @@ -2412,6 +2487,71 @@ static void virtnet_update_settings(struct virtnet_info *vi) > > vi->duplex = duplex; > > } > > > > +static u32 virtnet_get_rxfh_key_size(struct net_device *dev) > > +{ > > + return ((struct virtnet_info *)netdev_priv(dev))->rss_key_size; > > +} > > + > > +static u32 virtnet_get_rxfh_indir_size(struct net_device *dev) > > +{ > > + return ((struct virtnet_info *)netdev_priv(dev))->rss_indir_table_size; > > +} > > + > > +static int virtnet_get_rxfh(struct net_device *dev, u32 *indir, u8 *key, u8 *hfunc) > > +{ > > + struct virtnet_info *vi = netdev_priv(dev); > > + int i; > > + > > + if (indir) { > > + for (i = 0; i < vi->rss_indir_table_size; ++i) > > + indir[i] = vi->ctrl->rss.indirection_table[i]; > > + } > > + > > + if (key) > > + memcpy(key, vi->ctrl->rss.key, vi->rss_key_size); > > + > > + if (hfunc) > > + *hfunc = ETH_RSS_HASH_TOP; > > + > > + return 0; > > +} > > + > > +static int virtnet_set_rxfh(struct net_device *dev, const u32 *indir, const u8 *key, const u8 hfunc) > > +{ > > + struct virtnet_info *vi = netdev_priv(dev); > > + int i; > > + > > + if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP) > > + return -EOPNOTSUPP; > > + > > + if (indir) { > > + for (i = 0; i < vi->rss_indir_table_size; ++i) > > + vi->ctrl->rss.indirection_table[i] = indir[i]; > > + } > > + if (key) > > + memcpy(vi->ctrl->rss.key, key, vi->rss_key_size); > > + > > + virtnet_commit_rss_command(vi); > > + > > + return 0; > > +} > > + > > +static int virtnet_get_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info, u32 *rule_locs) > > +{ > > + struct virtnet_info *vi = netdev_priv(dev); > > + int rc = 0; > > + > > + switch (info->cmd) { > > + case ETHTOOL_GRXRINGS: > > + info->data = vi->curr_queue_pairs; > > + break; > > + default: > > + rc = -EOPNOTSUPP; > > + } > > + > > + return rc; > > +} > > + > > static const struct ethtool_ops virtnet_ethtool_ops = { > > .supported_coalesce_params = ETHTOOL_COALESCE_MAX_FRAMES, > > .get_drvinfo = virtnet_get_drvinfo, > > @@ -2427,6 +2567,11 @@ static const struct ethtool_ops virtnet_ethtool_ops = { > > .set_link_ksettings = virtnet_set_link_ksettings, > > .set_coalesce = virtnet_set_coalesce, > > .get_coalesce = virtnet_get_coalesce, > > + .get_rxfh_key_size = virtnet_get_rxfh_key_size, > > + .get_rxfh_indir_size = virtnet_get_rxfh_indir_size, > > + .get_rxfh = virtnet_get_rxfh, > > + .set_rxfh = virtnet_set_rxfh, > > + .get_rxnfc = virtnet_get_rxnfc, > > }; > > > > static void virtnet_freeze_down(struct virtio_device *vdev) > > @@ -2679,6 +2824,16 @@ static int virtnet_set_features(struct net_device *dev, > > vi->guest_offloads = offloads; > > } > > > > + if ((dev->features ^ features) & NETIF_F_RXHASH) { > > + if (features & NETIF_F_RXHASH) > > + vi->ctrl->rss.hash_types = vi->rss_hash_types_supported; > > + else > > + vi->ctrl->rss.hash_types = VIRTIO_NET_HASH_REPORT_NONE; > > + > > + if (!virtnet_commit_rss_command(vi)) > > + return -EINVAL; > > + } > > + > > return 0; > > } > > > > @@ -3073,6 +3228,8 @@ static bool virtnet_validate_features(struct virtio_device *vdev) > > "VIRTIO_NET_F_CTRL_VQ") || > > VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") || > > 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"))) { > > return false; > > } > > @@ -3113,13 +3270,14 @@ static int virtnet_probe(struct virtio_device *vdev) > > u16 max_queue_pairs; > > int mtu; > > > > - /* Find if host supports multiqueue virtio_net device */ > > - err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ, > > - struct virtio_net_config, > > - max_virtqueue_pairs, &max_queue_pairs); > > + /* Find if host supports multiqueue/rss virtio_net device */ > > + max_queue_pairs = 1; > > + if (virtio_has_feature(vdev, VIRTIO_NET_F_MQ) || virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) > > + max_queue_pairs > > + virtio_cread16(vdev, offsetof(struct virtio_net_config, max_virtqueue_pairs)); > > Instead of testing either feature and treating them as somewhat equal, > shouldn't RSS be dependent on MQ?No, RSS is dependent on CTRL_VQ. Technically RSS and MQ are similar features.> > > > > /* We need at least 2 queue's */ > > - if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN || > > + if (max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN || > > max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX || > > !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) > > max_queue_pairs = 1; > > @@ -3207,6 +3365,23 @@ 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)) { > > + vi->has_rss = true; > > + vi->rss_indir_table_size > > + virtio_cread16(vdev, offsetof(struct virtio_net_config, > > + rss_max_indirection_table_length)); > > + vi->rss_key_size > > + virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size)); > > + > > + vi->rss_hash_types_supported > > + virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types)); > > + vi->rss_hash_types_supported &> > + ~(VIRTIO_NET_RSS_HASH_TYPE_IP_EX | > > + VIRTIO_NET_RSS_HASH_TYPE_TCP_EX | > > + VIRTIO_NET_RSS_HASH_TYPE_UDP_EX); > > + > > + dev->hw_features |= NETIF_F_RXHASH; > > Only make the feature visible when the hash is actually reported in > the skb, patch 3.VirtioNET has two features: RSS(steering only) and hash(hash report in vnet header) Both features may be enabled/disabled separately: 1. rss on and hash off - packets steered to the corresponding vqs 2. rss off and hash on - packets steered by tap(like mq) but headers have properly calculated hash. 3. rss on and hash on - packets steered to corresponding vqs and hash is present in the header. RXHASH feature allows the user to enable/disable the rss/hash(any combination). I think it's a good idea to leave RXHASH in patch 2/4 to give the user ability to manipulate the rss only feature. But, if you think that it requires to move it to the 3/4, I'll do it.> > Also, clearly separate the feature patches (2) rss, (3) rxhash, (4) > rxhash config.Currently: Patch 2/4 - adds VirtioNet rss feature. Patch 3/4 - adds VirtioNet hash report feature. Patch 4/4 - adds the ability to manipulate supported hash types. Can you provide more detailed suggestions on how to move hunks?
Willem de Bruijn
2022-Feb-13 22:09 UTC
[PATCH v3 2/4] drivers/net/virtio_net: Added basic RSS support.
> > > @@ -3113,13 +3270,14 @@ static int virtnet_probe(struct virtio_device *vdev) > > > u16 max_queue_pairs; > > > int mtu; > > > > > > - /* Find if host supports multiqueue virtio_net device */ > > > - err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ, > > > - struct virtio_net_config, > > > - max_virtqueue_pairs, &max_queue_pairs); > > > + /* Find if host supports multiqueue/rss virtio_net device */ > > > + max_queue_pairs = 1; > > > + if (virtio_has_feature(vdev, VIRTIO_NET_F_MQ) || virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) > > > + max_queue_pairs > > > + virtio_cread16(vdev, offsetof(struct virtio_net_config, max_virtqueue_pairs)); > > > > Instead of testing either feature and treating them as somewhat equal, > > shouldn't RSS be dependent on MQ? > > No, RSS is dependent on CTRL_VQ. Technically RSS and MQ are similar features.RSS depends on having multiple queues. What would enabling VIRTIO_NET_F_RSS without VIRTIO_NET_F_MQ do?> > > > > > > > /* We need at least 2 queue's */ > > > - if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN || > > > + if (max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN || > > > max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX || > > > !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) > > > max_queue_pairs = 1; > > > @@ -3207,6 +3365,23 @@ 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)) { > > > + vi->has_rss = true; > > > + vi->rss_indir_table_size > > > + virtio_cread16(vdev, offsetof(struct virtio_net_config, > > > + rss_max_indirection_table_length)); > > > + vi->rss_key_size > > > + virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size)); > > > + > > > + vi->rss_hash_types_supported > > > + virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types)); > > > + vi->rss_hash_types_supported &> > > + ~(VIRTIO_NET_RSS_HASH_TYPE_IP_EX | > > > + VIRTIO_NET_RSS_HASH_TYPE_TCP_EX | > > > + VIRTIO_NET_RSS_HASH_TYPE_UDP_EX); > > > + > > > + dev->hw_features |= NETIF_F_RXHASH; > > > > Only make the feature visible when the hash is actually reported in > > the skb, patch 3. > > VirtioNET has two features: RSS(steering only) and hash(hash report in > vnet header) > Both features may be enabled/disabled separately: > 1. rss on and hash off - packets steered to the corresponding vqs > 2. rss off and hash on - packets steered by tap(like mq) but headers > have properly calculated hash. > 3. rss on and hash on - packets steered to corresponding vqs and hash > is present in the header. > > RXHASH feature allows the user to enable/disable the rss/hash(any combination).I find that confusing, but.. I see that there is prior art where some drivers enable/disable entire RSS load balancing based on this flag. So ok.> I think it's a good idea to leave RXHASH in patch 2/4 to give the user > ability to manipulate the rss only feature. > But, if you think that it requires to move it to the 3/4, I'll do it. > > > > > Also, clearly separate the feature patches (2) rss, (3) rxhash, (4) > > rxhash config. > > Currently: > Patch 2/4 - adds VirtioNet rss feature. > Patch 3/4 - adds VirtioNet hash report feature. > Patch 4/4 - adds the ability to manipulate supported hash types. > > Can you provide more detailed suggestions on how to move hunks?I gave one in the follow-on patch, to which you responded. That's probably it.