Virtualization - Aug 2021 - [RFC PATCH 0/3] drivers/net/virtio_net: Added RSS support.

This series of RFC patches for comments and additional proposals.

Virtio-net supports "hardware" RSS with toeplitz key.
Also, it allows receiving calculated hash in vheader
that may be used with RPS.
Added ethtools callbacks to manipulate RSS.

Technically hash calculation may be set only for
SRC+DST and SRC+DST+PORTSRC+PORTDST hashflows.
The completely disabling hash calculation for TCP or UDP
would disable hash calculation for IP.

RSS/RXHASH is disabled by default.

Andrew Melnychenko (3):
  drivers/net/virtio_net: Fixed vheader to use v1.
  drivers/net/virtio_net: Added basic RSS support.
  drivers/net/virtio_net: Added RSS hash report.

 drivers/net/virtio_net.c | 402 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 385 insertions(+), 17 deletions(-)

-- 
2.31.1

The header v1 provides additional info about RSS.
Added changes to computing proper header length.
In the next patches, the header may contain RSS hash info
for the hash population.

Signed-off-by: Andrew Melnychenko <andrew at daynix.com>
---
 drivers/net/virtio_net.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 56c3f8519093..85427b4f51bc 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -240,13 +240,13 @@ struct virtnet_info {
 };
 
 struct padded_vnet_hdr {
-	struct virtio_net_hdr_mrg_rxbuf hdr;
+	struct virtio_net_hdr_v1_hash hdr;
 	/*
 	 * hdr is in a separate sg buffer, and data sg buffer shares same page
 	 * with this header sg. This padding makes next sg 16 byte aligned
 	 * after the header.
 	 */
-	char padding[4];
+	char padding[12];
 };
 
 static bool is_xdp_frame(void *ptr)
@@ -1258,7 +1258,7 @@ static unsigned int get_mergeable_buf_len(struct
receive_queue *rq,
 					  struct ewma_pkt_len *avg_pkt_len,
 					  unsigned int room)
 {
-	const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+	const size_t hdr_len = ((struct virtnet_info
*)(rq->vq->vdev->priv))->hdr_len;
 	unsigned int len;
 
 	if (room)
@@ -1642,7 +1642,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff
*skb)
 	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
 	struct virtnet_info *vi = sq->vq->vdev->priv;
 	int num_sg;
-	unsigned hdr_len = vi->hdr_len;
+	unsigned int hdr_len = vi->hdr_len;
 	bool can_push;
 
 	pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
@@ -2819,7 +2819,7 @@ static void virtnet_del_vqs(struct virtnet_info *vi)
  */
 static unsigned int mergeable_min_buf_len(struct virtnet_info *vi, struct
virtqueue *vq)
 {
-	const unsigned int hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+	const unsigned int hdr_len = vi->hdr_len;
 	unsigned int rq_size = virtqueue_get_vring_size(vq);
 	unsigned int packet_len = vi->big_packets ? IP_MAX_MTU :
vi->dev->max_mtu;
 	unsigned int buf_len = hdr_len + ETH_HLEN + VLAN_HLEN + packet_len;
-- 
2.31.1

Added features for RSS and RSS hash report.
Added initialization, RXHASH feature and ethtool ops.
By default RSS/RXHASH is disabled.
Added ethtools ops to set key and indirection table.

Signed-off-by: Andrew Melnychenko <andrew at daynix.com>
---
 drivers/net/virtio_net.c | 215 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 203 insertions(+), 12 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 85427b4f51bc..d87bde246305 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -167,6 +167,23 @@ struct receive_queue {
 	struct xdp_rxq_info xdp_rxq;
 };
 
+/* This structure can contain rss message with maximum settings for indirection
table and keysize */
+#define VIRTIO_NET_RSS_MAX_KEY_SIZE     40
+#define VIRTIO_NET_RSS_MAX_TABLE_LEN    128
+struct virtio_net_ctrl_rss {
+	struct {
+		__le32 hash_types;
+		__le16 indirection_table_mask;
+		__le16 unclassified_queue;
+	} __packed table_info;
+	u16 indirection_table[VIRTIO_NET_RSS_MAX_TABLE_LEN];
+	struct {
+		u16 max_tx_vq; /* queues */
+		u8 hash_key_length;
+	} __packed key_info;
+	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;
@@ -176,6 +193,7 @@ struct control_buf {
 	u8 allmulti;
 	__virtio16 vid;
 	__virtio64 offloads;
+	struct virtio_net_ctrl_rss rss;
 };
 
 struct virtnet_info {
@@ -204,6 +222,14 @@ 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;
+	bool has_rss_hash_report;
+	u8 rss_key_size;
+	u16 rss_indir_table_size;
+	u32 rss_hash_types_supported;
+	u32 rss_hash_types_saved;
+
 	/* Has control virtqueue */
 	bool has_cvq;
 
@@ -393,7 +419,9 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 	hdr_p = p;
 
 	hdr_len = vi->hdr_len;
-	if (vi->mergeable_rx_bufs)
+	if (vi->has_rss_hash_report)
+		hdr_padded_len = sizeof(struct virtio_net_hdr_v1_hash);
+	else if (vi->mergeable_rx_bufs)
 		hdr_padded_len = sizeof(*hdr);
 	else
 		hdr_padded_len = sizeof(struct padded_vnet_hdr);
@@ -2171,6 +2199,56 @@ 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 = sizeof(vi->ctrl->rss.table_info);
+	sg_set_buf(&sgs[0], &vi->ctrl->rss.table_info, 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 = sizeof(vi->ctrl->rss.key_info);
+	sg_set_buf(&sgs[2], &vi->ctrl->rss.key_info, 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,
+				  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;
+	}
+	return true;
+}
+
+static void virtnet_init_default_rss(struct virtnet_info *vi)
+{
+	u32 indir_val = 0;
+	int i = 0;
+
+	vi->ctrl->rss.table_info.hash_types = vi->rss_hash_types_supported;
+	vi->rss_hash_types_saved = vi->rss_hash_types_supported;
+	vi->ctrl->rss.table_info.indirection_table_mask =
vi->rss_indir_table_size - 1;
+	vi->ctrl->rss.table_info.unclassified_queue = 0;
+
+	for (; i < vi->rss_indir_table_size; ++i) {
+		indir_val = ethtool_rxfh_indir_default(i, vi->max_queue_pairs);
+		vi->ctrl->rss.indirection_table[i] = indir_val;
+	}
+
+	vi->ctrl->rss.key_info.max_tx_vq = vi->curr_queue_pairs;
+	vi->ctrl->rss.key_info.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)
@@ -2395,6 +2473,72 @@ static void virtnet_update_settings(struct virtnet_info
*vi)
 		vi->duplex = duplex;
 }
 
+u32 virtnet_get_rxfh_key_size(struct net_device *dev)
+{
+	return ((struct virtnet_info *)netdev_priv(dev))->rss_key_size;
+}
+
+u32 virtnet_get_rxfh_indir_size(struct net_device *dev)
+{
+	return ((struct virtnet_info *)netdev_priv(dev))->rss_indir_table_size;
+}
+
+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;
+}
+
+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;
+}
+
+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;
+		rc = -EOPNOTSUPP;
+	}
+	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,
@@ -2410,6 +2554,11 @@ 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)
@@ -2662,6 +2811,16 @@ 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.table_info.hash_types = vi->rss_hash_types_saved;
+		else
+			vi->ctrl->rss.table_info.hash_types = 0;
+
+		if (!virtnet_commit_rss_command(vi))
+			return -EINVAL;
+	}
+
 	return 0;
 }
 
@@ -3080,13 +3239,14 @@ 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 = 0;
+	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));
 
 	/* 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;
@@ -3160,6 +3320,9 @@ static int virtnet_probe(struct virtio_device *vdev)
 
 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
 
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
+		vi->has_cvq = true;
+
 	/* If we can receive ANY GSO packets, we must allocate large ones. */
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
@@ -3170,8 +3333,32 @@ 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_MRG_RXBUF) ||
-	    virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
+	if (vi->has_cvq && virtio_has_feature(vdev,
VIRTIO_NET_F_HASH_REPORT)) {
+		vi->has_rss_hash_report = true;
+		vi->rss_indir_table_size = 1;
+		vi->rss_key_size = VIRTIO_NET_RSS_MAX_KEY_SIZE;
+	}
+
+	if (vi->has_cvq && 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));
+	}
+
+	if (vi->has_rss || vi->has_rss_hash_report) {
+		vi->rss_hash_types_supported +		    virtio_cread32(vdev, offsetof(struct
virtio_net_config, supported_hash_types));
+
+		dev->hw_features |= NETIF_F_RXHASH;
+	}
+
+	if (vi->has_cvq && 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);
@@ -3180,9 +3367,6 @@ static int virtnet_probe(struct virtio_device *vdev)
 	    virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
 		vi->any_header_sg = true;
 
-	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
-		vi->has_cvq = true;
-
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) {
 		mtu = virtio_cread16(vdev,
 				     offsetof(struct virtio_net_config,
@@ -3254,6 +3438,12 @@ static int virtnet_probe(struct virtio_device *vdev)
 
 	virtnet_set_queues(vi, vi->curr_queue_pairs);
 
+	if (vi->has_rss || vi->has_rss_hash_report) {
+		rtnl_lock();
+		virtnet_init_default_rss(vi);
+		rtnl_unlock();
+	}
+
 	/* Assume link up if device can't report link status,
 	   otherwise get link status from config. */
 	netif_carrier_off(dev);
@@ -3369,7 +3559,8 @@ static struct virtio_device_id id_table[] = {
 	VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, \
 	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_SPEED_DUPLEX, VIRTIO_NET_F_STANDBY, \
+	VIRTIO_NET_F_RSS, VIRTIO_NET_F_HASH_REPORT
 
 static unsigned int features[] = {
 	VIRTNET_FEATURES,
-- 
2.31.1

Added set_hash for skb.
Also added hashflow set/get callbacks.
Virtio RSS "IPv6 extensions" hashes disabled.
Also, disabling RXH_IP_SRC/DST for TCP would disable them for UDP.
TCP and UDP supports only:
ethtool -U eth0 rx-flow-hash tcp4 sd
    RXH_IP_SRC + RXH_IP_DST
ethtool -U eth0 rx-flow-hash tcp4 sdfn
    RXH_IP_SRC + RXH_IP_DST + RXH_L4_B_0_1 + RXH_L4_B_2_3

Signed-off-by: Andrew Melnychenko <andrew at daynix.com>
---
 drivers/net/virtio_net.c | 177 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 177 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d87bde246305..6a52eeaf9292 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1151,6 +1151,8 @@ 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);
@@ -1177,6 +1179,29 @@ static void receive_buf(struct virtnet_info *vi, struct
receive_queue *rq,
 		return;
 
 	hdr = skb_vnet_hdr(skb);
+	if (vi->has_rss_hash_report && (dev->features &
NETIF_F_RXHASH)) {
+		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);
+	}
 
 	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID)
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
@@ -2250,6 +2275,132 @@ static void virtnet_init_default_rss(struct virtnet_info
*vi)
 	netdev_rss_key_fill(vi->ctrl->rss.key, vi->rss_key_size);
 }
 
+void virtnet_get_hashflow(const struct virtnet_info *vi, struct ethtool_rxnfc
*info)
+{
+	info->data = 0;
+	switch (info->flow_type) {
+	case TCP_V4_FLOW:
+		if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_TCPv4) {
+			info->data = RXH_IP_SRC | RXH_IP_DST |
+						 RXH_L4_B_0_1 | RXH_L4_B_2_3;
+		} else if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv4) {
+			info->data = RXH_IP_SRC | RXH_IP_DST;
+		}
+		break;
+	case TCP_V6_FLOW:
+		if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_TCPv6) {
+			info->data = RXH_IP_SRC | RXH_IP_DST |
+						 RXH_L4_B_0_1 | RXH_L4_B_2_3;
+		} else if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv6) {
+			info->data = RXH_IP_SRC | RXH_IP_DST;
+		}
+		break;
+	case UDP_V4_FLOW:
+		if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_UDPv4) {
+			info->data = RXH_IP_SRC | RXH_IP_DST |
+						 RXH_L4_B_0_1 | RXH_L4_B_2_3;
+		} else if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv4) {
+			info->data = RXH_IP_SRC | RXH_IP_DST;
+		}
+		break;
+	case UDP_V6_FLOW:
+		if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_UDPv6) {
+			info->data = RXH_IP_SRC | RXH_IP_DST |
+						 RXH_L4_B_0_1 | RXH_L4_B_2_3;
+		} else if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv6) {
+			info->data = RXH_IP_SRC | RXH_IP_DST;
+		}
+		break;
+	case IPV4_FLOW:
+		if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv4)
+			info->data = RXH_IP_SRC | RXH_IP_DST;
+
+		break;
+	case IPV6_FLOW:
+		if (vi->rss_hash_types_saved & VIRTIO_NET_RSS_HASH_TYPE_IPv4)
+			info->data = RXH_IP_SRC | RXH_IP_DST;
+
+		break;
+	default:
+		info->data = 0;
+		break;
+	}
+}
+
+bool virtnet_set_hashflow(struct virtnet_info *vi, struct ethtool_rxnfc *info)
+{
+	u64 is_iphash = info->data & (RXH_IP_SRC | RXH_IP_DST);
+	u64 is_porthash = info->data & (RXH_L4_B_0_1 | RXH_L4_B_2_3);
+	u32 new_hashtypes = vi->rss_hash_types_saved;
+
+	if ((is_iphash && (is_iphash != (RXH_IP_SRC | RXH_IP_DST))) ||
+	    (is_porthash && (is_porthash != (RXH_L4_B_0_1 | RXH_L4_B_2_3)))) {
+		return false;
+	}
+
+	if (!is_iphash && is_porthash)
+		return false;
+
+	switch (info->flow_type) {
+	case TCP_V4_FLOW:
+	case UDP_V4_FLOW:
+	case IPV4_FLOW:
+		new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_IPv4;
+		if (is_iphash)
+			new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_IPv4;
+
+		break;
+	case TCP_V6_FLOW:
+	case UDP_V6_FLOW:
+	case IPV6_FLOW:
+		new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_IPv6;
+		if (is_iphash)
+			new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_IPv6;
+
+		break;
+	default:
+		break;
+	}
+
+	switch (info->flow_type) {
+	case TCP_V4_FLOW:
+		new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_TCPv4;
+		if (is_porthash)
+			new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_TCPv4;
+
+		break;
+	case UDP_V4_FLOW:
+		new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_UDPv4;
+		if (is_porthash)
+			new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_UDPv4;
+
+		break;
+	case TCP_V6_FLOW:
+		new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_TCPv6;
+		if (is_porthash)
+			new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_TCPv6;
+
+		break;
+	case UDP_V6_FLOW:
+		new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_UDPv6;
+		if (is_porthash)
+			new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_UDPv6;
+
+		break;
+	default:
+		break;
+	}
+
+	if (new_hashtypes != vi->rss_hash_types_saved) {
+		vi->rss_hash_types_saved = new_hashtypes;
+		vi->ctrl->rss.table_info.hash_types = vi->rss_hash_types_saved;
+		if (vi->dev->features & NETIF_F_RXHASH)
+			return virtnet_commit_rss_command(vi);
+	}
+
+	return true;
+}
+
 static void virtnet_get_drvinfo(struct net_device *dev,
 				struct ethtool_drvinfo *info)
 {
@@ -2530,8 +2681,28 @@ int virtnet_get_rxnfc(struct net_device *dev, struct
ethtool_rxnfc *info, u32 *r
 	switch (info->cmd) {
 	case ETHTOOL_GRXRINGS:
 		info->data = vi->curr_queue_pairs;
+		break;
+	case ETHTOOL_GRXFH:
+		virtnet_get_hashflow(vi, info);
+		break;
+	default:
 		rc = -EOPNOTSUPP;
 	}
+
+	return rc;
+}
+
+static int virtnet_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc
*info)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	int rc = 0;
+
+	switch (info->cmd) {
+	case ETHTOOL_SRXFH:
+		if (!virtnet_set_hashflow(vi, info))
+			rc = -EINVAL;
+
+		break;
 	default:
 		rc = -EOPNOTSUPP;
 	}
@@ -2559,6 +2730,7 @@ static const struct ethtool_ops virtnet_ethtool_ops = {
 	.get_rxfh = virtnet_get_rxfh,
 	.set_rxfh = virtnet_set_rxfh,
 	.get_rxnfc = virtnet_get_rxnfc,
+	.set_rxnfc = virtnet_set_rxnfc,
 };
 
 static void virtnet_freeze_down(struct virtio_device *vdev)
@@ -3351,8 +3523,13 @@ static int virtnet_probe(struct virtio_device *vdev)
 	if (vi->has_rss || vi->has_rss_hash_report) {
 		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;
+		dev->features |= NETIF_F_NTUPLE;
 	}
 
 	if (vi->has_cvq && vi->has_rss_hash_report)
-- 
2.31.1

Hi guys,
Can you please review possible virtio-net driver RSS support?
Do you have any comments or proposals?

On Wed, Aug 18, 2021 at 8:55 PM Andrew Melnychenko <andrew at daynix.com>
wrote:
> This series of RFC patches for comments and additional proposals.
>
> Virtio-net supports "hardware" RSS with toeplitz key.
> Also, it allows receiving calculated hash in vheader
> that may be used with RPS.
> Added ethtools callbacks to manipulate RSS.
>
> Technically hash calculation may be set only for
> SRC+DST and SRC+DST+PORTSRC+PORTDST hashflows.
> The completely disabling hash calculation for TCP or UDP
> would disable hash calculation for IP.
>
> RSS/RXHASH is disabled by default.
>
> Andrew Melnychenko (3):
>   drivers/net/virtio_net: Fixed vheader to use v1.
>   drivers/net/virtio_net: Added basic RSS support.
>   drivers/net/virtio_net: Added RSS hash report.
>
>  drivers/net/virtio_net.c | 402 +++++++++++++++++++++++++++++++++++++--
>  1 file changed, 385 insertions(+), 17 deletions(-)
>
> --
> 2.31.1
>
>
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? 2021/8/19 ??1:54, Andrew Melnychenko ??:
> The header v1 provides additional info about RSS.
> Added changes to computing proper header length.
> In the next patches, the header may contain RSS hash info
> for the hash population.
>
> Signed-off-by: Andrew Melnychenko <andrew at daynix.com>
> ---
>   drivers/net/virtio_net.c | 10 +++++-----
>   1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 56c3f8519093..85427b4f51bc 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -240,13 +240,13 @@ struct virtnet_info {
>   };
>   
>   struct padded_vnet_hdr {
> -	struct virtio_net_hdr_mrg_rxbuf hdr;
> +	struct virtio_net_hdr_v1_hash hdr;
>   	/*
>   	 * hdr is in a separate sg buffer, and data sg buffer shares same page
>   	 * with this header sg. This padding makes next sg 16 byte aligned
>   	 * after the header.
>   	 */
> -	char padding[4];
> +	char padding[12];
>   };

So we had:

 ??????? if (vi->mergeable_rx_bufs)
 ??????????????? hdr_padded_len = sizeof(*hdr);
 ??????? else
 ??????????????? hdr_padded_len = sizeof(struct padded_vnet_hdr);

I wonder if it's better to add one ore condition for the hash header 
instead of enforcing it even if it was not negotiated.

>   
>   static bool is_xdp_frame(void *ptr)
> @@ -1258,7 +1258,7 @@ static unsigned int get_mergeable_buf_len(struct
receive_queue *rq,
>   					  struct ewma_pkt_len *avg_pkt_len,
>   					  unsigned int room)
>   {
> -	const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
> +	const size_t hdr_len = ((struct virtnet_info
*)(rq->vq->vdev->priv))->hdr_len;
>   	unsigned int len;
>   
>   	if (room)
> @@ -1642,7 +1642,7 @@ static int xmit_skb(struct send_queue *sq, struct
sk_buff *skb)
>   	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
>   	struct virtnet_info *vi = sq->vq->vdev->priv;
>   	int num_sg;
> -	unsigned hdr_len = vi->hdr_len;
> +	unsigned int hdr_len = vi->hdr_len;

Looks like an unnecessary change.

>   	bool can_push;
>   
>   	pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
> @@ -2819,7 +2819,7 @@ static void virtnet_del_vqs(struct virtnet_info *vi)
>    */
>   static unsigned int mergeable_min_buf_len(struct virtnet_info *vi, struct
virtqueue *vq)
>   {
> -	const unsigned int hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
> +	const unsigned int hdr_len = vi->hdr_len;

I think the change here and get_mergeable_buf_len() should be a separate 
patch.

Thanks

>   	unsigned int rq_size = virtqueue_get_vring_size(vq);
>   	unsigned int packet_len = vi->big_packets ? IP_MAX_MTU :
vi->dev->max_mtu;
>   	unsigned int buf_len = hdr_len + ETH_HLEN + VLAN_HLEN + packet_len;

On Thu, Aug 19, 2021 at 1:55 AM Andrew Melnychenko <andrew at daynix.com>
wrote:
>
> Added features for RSS and RSS hash report.
> Added initialization, RXHASH feature and ethtool ops.
> By default RSS/RXHASH is disabled.
> Added ethtools ops to set key and indirection table.
>
> Signed-off-by: Andrew Melnychenko <andrew at daynix.com>
> ---
>  drivers/net/virtio_net.c | 215 ++++++++++++++++++++++++++++++++++++---
>  1 file changed, 203 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 85427b4f51bc..d87bde246305 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -167,6 +167,23 @@ struct receive_queue {
>         struct xdp_rxq_info xdp_rxq;
>  };
>
> +/* This structure can contain rss message with maximum settings for
indirection table and keysize */
> +#define VIRTIO_NET_RSS_MAX_KEY_SIZE     40
> +#define VIRTIO_NET_RSS_MAX_TABLE_LEN    128
> +struct virtio_net_ctrl_rss {
> +       struct {
> +               __le32 hash_types;
> +               __le16 indirection_table_mask;
> +               __le16 unclassified_queue;
> +       } __packed table_info;
> +       u16 indirection_table[VIRTIO_NET_RSS_MAX_TABLE_LEN];
> +       struct {
> +               u16 max_tx_vq; /* queues */
> +               u8 hash_key_length;
> +       } __packed key_info;
> +       u8 key[VIRTIO_NET_RSS_MAX_KEY_SIZE];
> +};

Any reason that those doesn't belong to uAPI?

And spec said:

"

The device MUST set rss_max_key_size to at least 40, if it offers
VIRTIO_NET_F_RSS or VIRTIO_NET_F_HASH_REPORT.

The device MUST set rss_max_indirection_table_length to at least 128,
if it offers VIRTIO_NET_F_RSS.

"

But it looks to me that you define those as maximum size instead of
minimum size?
> +
>  /* Control VQ buffers: protected by the rtnl lock */
>  struct control_buf {
>         struct virtio_net_ctrl_hdr hdr;
> @@ -176,6 +193,7 @@ struct control_buf {
>         u8 allmulti;
>         __virtio16 vid;
>         __virtio64 offloads;
> +       struct virtio_net_ctrl_rss rss;
>  };
>
>  struct virtnet_info {
> @@ -204,6 +222,14 @@ 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;
> +       bool has_rss_hash_report;
> +       u8 rss_key_size;
> +       u16 rss_indir_table_size;
> +       u32 rss_hash_types_supported;
> +       u32 rss_hash_types_saved;
> +
>         /* Has control virtqueue */
>         bool has_cvq;
>
> @@ -393,7 +419,9 @@ static struct sk_buff *page_to_skb(struct virtnet_info
*vi,
>         hdr_p = p;
>
>         hdr_len = vi->hdr_len;
> -       if (vi->mergeable_rx_bufs)
> +       if (vi->has_rss_hash_report)
> +               hdr_padded_len = sizeof(struct virtio_net_hdr_v1_hash);
> +       else if (vi->mergeable_rx_bufs)
>                 hdr_padded_len = sizeof(*hdr);
>         else
>                 hdr_padded_len = sizeof(struct padded_vnet_hdr);
I don't get here. You change the padder_vnet_hdr but here it was only
used for !non-mergeable ?

> @@ -2171,6 +2199,56 @@ 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 = sizeof(vi->ctrl->rss.table_info);
> +       sg_set_buf(&sgs[0], &vi->ctrl->rss.table_info,
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 = sizeof(vi->ctrl->rss.key_info);
> +       sg_set_buf(&sgs[2], &vi->ctrl->rss.key_info,
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,
> +                                 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;
> +       }
> +       return true;
> +}
> +
> +static void virtnet_init_default_rss(struct virtnet_info *vi)
> +{
> +       u32 indir_val = 0;
> +       int i = 0;
> +
> +       vi->ctrl->rss.table_info.hash_types =
vi->rss_hash_types_supported;
> +       vi->rss_hash_types_saved = vi->rss_hash_types_supported;
> +       vi->ctrl->rss.table_info.indirection_table_mask =
vi->rss_indir_table_size - 1;
> +       vi->ctrl->rss.table_info.unclassified_queue = 0;
> +
> +       for (; i < vi->rss_indir_table_size; ++i) {
> +               indir_val = ethtool_rxfh_indir_default(i,
vi->max_queue_pairs);
> +               vi->ctrl->rss.indirection_table[i] = indir_val;
> +       }
> +
> +       vi->ctrl->rss.key_info.max_tx_vq = vi->curr_queue_pairs;
> +       vi->ctrl->rss.key_info.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)
> @@ -2395,6 +2473,72 @@ static void virtnet_update_settings(struct
virtnet_info *vi)
>                 vi->duplex = duplex;
>  }
>
> +u32 virtnet_get_rxfh_key_size(struct net_device *dev)
> +{
> +       return ((struct virtnet_info *)netdev_priv(dev))->rss_key_size;
> +}
> +
> +u32 virtnet_get_rxfh_indir_size(struct net_device *dev)
> +{
> +       return ((struct virtnet_info
*)netdev_priv(dev))->rss_indir_table_size;
> +}
> +
> +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;
> +}
> +
> +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;
> +}
> +
> +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;
> +               rc = -EOPNOTSUPP;
> +       }
> +       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,
> @@ -2410,6 +2554,11 @@ 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)
> @@ -2662,6 +2811,16 @@ 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.table_info.hash_types =
vi->rss_hash_types_saved;
> +               else
> +                       vi->ctrl->rss.table_info.hash_types = 0;
> +
> +               if (!virtnet_commit_rss_command(vi))
> +                       return -EINVAL;
> +       }
> +
>         return 0;
>  }
>
> @@ -3080,13 +3239,14 @@ 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 = 0;
> +       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));
I think virtio_cread_features() can still work here, or am I missing anything?
>
>         /* 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;
> @@ -3160,6 +3320,9 @@ static int virtnet_probe(struct virtio_device *vdev)
>
>         INIT_WORK(&vi->config_work, virtnet_config_changed_work);
>
> +       if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
> +               vi->has_cvq = true;
> +
>         /* If we can receive ANY GSO packets, we must allocate large ones.
*/
>         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
>             virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
> @@ -3170,8 +3333,32 @@ 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_MRG_RXBUF) ||
> -           virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
> +       if (vi->has_cvq && virtio_has_feature(vdev,
VIRTIO_NET_F_HASH_REPORT)) {
Let's add a new validation in virtnet_validate_features(), then
there's no need for the check of cvq here (and the moving of the
has_cvq assignment).

> +               vi->has_rss_hash_report = true;
> +               vi->rss_indir_table_size = 1;
> +               vi->rss_key_size = VIRTIO_NET_RSS_MAX_KEY_SIZE;
> +       }
> +
> +       if (vi->has_cvq && 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));
> +       }
> +
> +       if (vi->has_rss || vi->has_rss_hash_report) {
> +               vi->rss_hash_types_supported > +                  
virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types));
> +
> +               dev->hw_features |= NETIF_F_RXHASH;
> +       }
> +
> +       if (vi->has_cvq && 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);
> @@ -3180,9 +3367,6 @@ static int virtnet_probe(struct virtio_device *vdev)
>             virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
>                 vi->any_header_sg = true;
>
> -       if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
> -               vi->has_cvq = true;
> -
>         if (virtio_has_feature(vdev, VIRTIO_NET_F_MTU)) {
>                 mtu = virtio_cread16(vdev,
>                                      offsetof(struct virtio_net_config,
> @@ -3254,6 +3438,12 @@ static int virtnet_probe(struct virtio_device *vdev)
>
>         virtnet_set_queues(vi, vi->curr_queue_pairs);
>
> +       if (vi->has_rss || vi->has_rss_hash_report) {
> +               rtnl_lock();
> +               virtnet_init_default_rss(vi);
> +               rtnl_unlock();
> +       }
I wonder what happens if the user sets a new RSS before this?

Thanks

> +
>         /* Assume link up if device can't report link status,
>            otherwise get link status from config. */
>         netif_carrier_off(dev);
> @@ -3369,7 +3559,8 @@ static struct virtio_device_id id_table[] = {
>         VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ, \
>         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_SPEED_DUPLEX, VIRTIO_NET_F_STANDBY, \
> +       VIRTIO_NET_F_RSS, VIRTIO_NET_F_HASH_REPORT
>
>  static unsigned int features[] = {
>         VIRTNET_FEATURES,
> --
> 2.31.1
>

On Thu, Aug 19, 2021 at 1:55 AM Andrew Melnychenko <andrew at daynix.com>
wrote:
>
> Added set_hash for skb.
> Also added hashflow set/get callbacks.
> Virtio RSS "IPv6 extensions" hashes disabled.
> Also, disabling RXH_IP_SRC/DST for TCP would disable them for UDP.
> TCP and UDP supports only:
> ethtool -U eth0 rx-flow-hash tcp4 sd
>     RXH_IP_SRC + RXH_IP_DST
> ethtool -U eth0 rx-flow-hash tcp4 sdfn
>     RXH_IP_SRC + RXH_IP_DST + RXH_L4_B_0_1 + RXH_L4_B_2_3
>
> Signed-off-by: Andrew Melnychenko <andrew at daynix.com>
> ---
>  drivers/net/virtio_net.c | 177 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 177 insertions(+)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index d87bde246305..6a52eeaf9292 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1151,6 +1151,8 @@ 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);
> @@ -1177,6 +1179,29 @@ static void receive_buf(struct virtnet_info *vi,
struct receive_queue *rq,
>                 return;
>
>         hdr = skb_vnet_hdr(skb);
> +       if (vi->has_rss_hash_report && (dev->features &
NETIF_F_RXHASH)) {
> +               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);
> +       }
>
>         if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID)
>                 skb->ip_summed = CHECKSUM_UNNECESSARY;
> @@ -2250,6 +2275,132 @@ static void virtnet_init_default_rss(struct
virtnet_info *vi)
>         netdev_rss_key_fill(vi->ctrl->rss.key, vi->rss_key_size);
>  }
>
> +void virtnet_get_hashflow(const struct virtnet_info *vi, struct
ethtool_rxnfc *info)
> +{
> +       info->data = 0;
> +       switch (info->flow_type) {
> +       case TCP_V4_FLOW:
> +               if (vi->rss_hash_types_saved &
VIRTIO_NET_RSS_HASH_TYPE_TCPv4) {
> +                       info->data = RXH_IP_SRC | RXH_IP_DST |
> +                                                RXH_L4_B_0_1 |
RXH_L4_B_2_3;
> +               } else if (vi->rss_hash_types_saved &
VIRTIO_NET_RSS_HASH_TYPE_IPv4) {
> +                       info->data = RXH_IP_SRC | RXH_IP_DST;
> +               }
> +               break;
> +       case TCP_V6_FLOW:
> +               if (vi->rss_hash_types_saved &
VIRTIO_NET_RSS_HASH_TYPE_TCPv6) {
> +                       info->data = RXH_IP_SRC | RXH_IP_DST |
> +                                                RXH_L4_B_0_1 |
RXH_L4_B_2_3;
> +               } else if (vi->rss_hash_types_saved &
VIRTIO_NET_RSS_HASH_TYPE_IPv6) {
> +                       info->data = RXH_IP_SRC | RXH_IP_DST;
> +               }
> +               break;
> +       case UDP_V4_FLOW:
> +               if (vi->rss_hash_types_saved &
VIRTIO_NET_RSS_HASH_TYPE_UDPv4) {
> +                       info->data = RXH_IP_SRC | RXH_IP_DST |
> +                                                RXH_L4_B_0_1 |
RXH_L4_B_2_3;
> +               } else if (vi->rss_hash_types_saved &
VIRTIO_NET_RSS_HASH_TYPE_IPv4) {
> +                       info->data = RXH_IP_SRC | RXH_IP_DST;
> +               }
> +               break;
> +       case UDP_V6_FLOW:
> +               if (vi->rss_hash_types_saved &
VIRTIO_NET_RSS_HASH_TYPE_UDPv6) {
> +                       info->data = RXH_IP_SRC | RXH_IP_DST |
> +                                                RXH_L4_B_0_1 |
RXH_L4_B_2_3;
> +               } else if (vi->rss_hash_types_saved &
VIRTIO_NET_RSS_HASH_TYPE_IPv6) {
> +                       info->data = RXH_IP_SRC | RXH_IP_DST;
> +               }
> +               break;
> +       case IPV4_FLOW:
> +               if (vi->rss_hash_types_saved &
VIRTIO_NET_RSS_HASH_TYPE_IPv4)
> +                       info->data = RXH_IP_SRC | RXH_IP_DST;
> +
> +               break;
> +       case IPV6_FLOW:
> +               if (vi->rss_hash_types_saved &
VIRTIO_NET_RSS_HASH_TYPE_IPv4)
> +                       info->data = RXH_IP_SRC | RXH_IP_DST;
> +
> +               break;
> +       default:
> +               info->data = 0;
> +               break;
> +       }
> +}
> +
> +bool virtnet_set_hashflow(struct virtnet_info *vi, struct ethtool_rxnfc
*info)
> +{
> +       u64 is_iphash = info->data & (RXH_IP_SRC | RXH_IP_DST);
> +       u64 is_porthash = info->data & (RXH_L4_B_0_1 |
RXH_L4_B_2_3);
> +       u32 new_hashtypes = vi->rss_hash_types_saved;
> +
> +       if ((is_iphash && (is_iphash != (RXH_IP_SRC | RXH_IP_DST)))
||
> +           (is_porthash && (is_porthash != (RXH_L4_B_0_1 |
RXH_L4_B_2_3)))) {
> +               return false;
> +       }
> +
> +       if (!is_iphash && is_porthash)
> +               return false;
> +
> +       switch (info->flow_type) {
> +       case TCP_V4_FLOW:
> +       case UDP_V4_FLOW:
> +       case IPV4_FLOW:
> +               new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_IPv4;
> +               if (is_iphash)
> +                       new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_IPv4;
> +
> +               break;
> +       case TCP_V6_FLOW:
> +       case UDP_V6_FLOW:
> +       case IPV6_FLOW:
> +               new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_IPv6;
> +               if (is_iphash)
> +                       new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_IPv6;
> +
> +               break;
> +       default:
> +               break;
> +       }
> +
> +       switch (info->flow_type) {
> +       case TCP_V4_FLOW:
> +               new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_TCPv4;
> +               if (is_porthash)
> +                       new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_TCPv4;
> +
> +               break;
> +       case UDP_V4_FLOW:
> +               new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_UDPv4;
> +               if (is_porthash)
> +                       new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_UDPv4;
> +
> +               break;
> +       case TCP_V6_FLOW:
> +               new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_TCPv6;
> +               if (is_porthash)
> +                       new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_TCPv6;
> +
> +               break;
> +       case UDP_V6_FLOW:
> +               new_hashtypes &= ~VIRTIO_NET_RSS_HASH_TYPE_UDPv6;
> +               if (is_porthash)
> +                       new_hashtypes |= VIRTIO_NET_RSS_HASH_TYPE_UDPv6;
> +
> +               break;
> +       default:
> +               break;
> +       }
> +
> +       if (new_hashtypes != vi->rss_hash_types_saved) {
> +               vi->rss_hash_types_saved = new_hashtypes;
> +               vi->ctrl->rss.table_info.hash_types =
vi->rss_hash_types_saved;
> +               if (vi->dev->features & NETIF_F_RXHASH)
> +                       return virtnet_commit_rss_command(vi);
> +       }
> +
> +       return true;
> +}
> +
>  static void virtnet_get_drvinfo(struct net_device *dev,
>                                 struct ethtool_drvinfo *info)
>  {
> @@ -2530,8 +2681,28 @@ int virtnet_get_rxnfc(struct net_device *dev, struct
ethtool_rxnfc *info, u32 *r
>         switch (info->cmd) {
>         case ETHTOOL_GRXRINGS:
>                 info->data = vi->curr_queue_pairs;
> +               break;
> +       case ETHTOOL_GRXFH:
> +               virtnet_get_hashflow(vi, info);
> +               break;
> +       default:
>                 rc = -EOPNOTSUPP;
>         }
> +
> +       return rc;
> +}
> +
> +static int virtnet_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc
*info)
> +{
> +       struct virtnet_info *vi = netdev_priv(dev);
> +       int rc = 0;
> +
> +       switch (info->cmd) {
> +       case ETHTOOL_SRXFH:
> +               if (!virtnet_set_hashflow(vi, info))
> +                       rc = -EINVAL;
> +
> +               break;
>         default:
>                 rc = -EOPNOTSUPP;
>         }
> @@ -2559,6 +2730,7 @@ static const struct ethtool_ops virtnet_ethtool_ops =
{
>         .get_rxfh = virtnet_get_rxfh,
>         .set_rxfh = virtnet_set_rxfh,
>         .get_rxnfc = virtnet_get_rxnfc,
> +       .set_rxnfc = virtnet_set_rxnfc,
>  };
>
>  static void virtnet_freeze_down(struct virtio_device *vdev)
> @@ -3351,8 +3523,13 @@ static int virtnet_probe(struct virtio_device *vdev)
>         if (vi->has_rss || vi->has_rss_hash_report) {
>                 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;
> +               dev->features |= NETIF_F_NTUPLE;
I think we don't support ntuple filters but hash filters?

Thanks
>         }
>
>         if (vi->has_cvq && vi->has_rss_hash_report)
> --
> 2.31.1
>