Re: [PATCH net-next 2/4] vmxnet3: add support to get/set rx flow hash

From: Michal Kubecek <hidden>
Date: 2020-05-28 05:50:33
Also in: lkml

On Wed, May 27, 2020 at 07:07:04PM -0700, Ronak Doshi wrote:

With vmxnet3 version 4, the emulation supports multiqueue(RSS) for
UDP and ESP traffic. A guest can enable/disable RSS for UDP/ESP over
IPv4/IPv6 by issuing commands introduced in this patch. ESP ipv6 is
not yet supported in this patch.

This patch implements get_rss_hash_opts and set_rss_hash_opts
methods to allow querying and configuring different Rx flow hash
configurations.

Signed-off-by: Ronak Doshi <redacted>
---

[...]

quoted hunk ↗ jump to hunk

diff --git a/drivers/net/vmxnet3/vmxnet3_ethtool.c b/drivers/net/vmxnet3/vmxnet3_ethtool.c
index 1163eca7aba5..ceedf63020cb 100644
--- a/drivers/net/vmxnet3/vmxnet3_ethtool.c
+++ b/drivers/net/vmxnet3/vmxnet3_ethtool.c

@@ -665,18 +665,236 @@ vmxnet3_set_ringparam(struct net_device *netdev,
 	return err;
 }
 
+static int
+vmxnet3_get_rss_hash_opts(struct vmxnet3_adapter *adapter,
+			  struct ethtool_rxnfc *info)
+{
+	enum Vmxnet3_RSSField rss_fields;
+
+	if (netif_running(adapter->netdev)) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&adapter->cmd_lock, flags);
+
+		VMXNET3_WRITE_BAR1_REG(adapter, VMXNET3_REG_CMD,
+				       VMXNET3_CMD_GET_RSS_FIELDS);
+		rss_fields = VMXNET3_READ_BAR1_REG(adapter, VMXNET3_REG_CMD);
+		spin_unlock_irqrestore(&adapter->cmd_lock, flags);
+	} else {
+		rss_fields = adapter->rss_fields;
+	}
+
+	info->data = 0;
+
+	/* Report default options for RSS on vmxnet3 */
+	switch (info->flow_type) {
+	case TCP_V4_FLOW:
+		if (rss_fields & VMXNET3_RSS_FIELDS_TCPIP4)
+			info->data |= RXH_L4_B_0_1 | RXH_L4_B_2_3 |
+				      RXH_IP_SRC | RXH_IP_DST;
+		break;
+	case UDP_V4_FLOW:
+		if (rss_fields & VMXNET3_RSS_FIELDS_UDPIP4)
+			info->data |= RXH_L4_B_0_1 | RXH_L4_B_2_3 |
+				      RXH_IP_SRC | RXH_IP_DST;
+		break;

In both cases above (and also in the two for IPv6 below) you set
info->data to either 0 or all four bits, depending on the value of
corresponding flag in rss_fields. But in vmxnet3_set_rss_hash_opt()
you have different mapping:

  - for TCP, you only accept all four bits (no other value) and don't
    touch rss_fields at all
  - for UDP, you allow either all four bits (and set the flag) or the
    two IP related bits (and clear the flag)

The UDPv4/UDPv6 behaviour of vmxnet3_set_rss_hash_opt() seems to be the
correct one but you should be consistent between get and set handlers.

+	case AH_ESP_V4_FLOW:
+	case AH_V4_FLOW:
+	case ESP_V4_FLOW:
+		if (rss_fields & VMXNET3_RSS_FIELDS_ESPIP4)
+			info->data |= RXH_L4_B_0_1 | RXH_L4_B_2_3;

If this fallthrough is intentional (it seems to be), it should be
marked.

Michal

quoted hunk ↗ jump to hunk

+	case SCTP_V4_FLOW:
+	case IPV4_FLOW:
+		info->data |= RXH_IP_SRC | RXH_IP_DST;
+		break;
+	case TCP_V6_FLOW:
+		if (rss_fields & VMXNET3_RSS_FIELDS_TCPIP6)
+			info->data |= RXH_L4_B_0_1 | RXH_L4_B_2_3 |
+				      RXH_IP_SRC | RXH_IP_DST;
+		break;
+	case UDP_V6_FLOW:
+		if (rss_fields & VMXNET3_RSS_FIELDS_UDPIP6)
+			info->data |= RXH_L4_B_0_1 | RXH_L4_B_2_3 |
+				      RXH_IP_SRC | RXH_IP_DST;
+		break;
+	case AH_ESP_V6_FLOW:
+	case AH_V6_FLOW:
+	case ESP_V6_FLOW:
+	case SCTP_V6_FLOW:
+	case IPV6_FLOW:
+		info->data |= RXH_IP_SRC | RXH_IP_DST;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int
+vmxnet3_set_rss_hash_opt(struct net_device *netdev,
+			 struct vmxnet3_adapter *adapter,
+			 struct ethtool_rxnfc *nfc)
+{
+	enum Vmxnet3_RSSField rss_fields = adapter->rss_fields;
+
+	/* RSS does not support anything other than hashing
+	 * to queues on src and dst IPs and ports
+	 */
+	if (nfc->data & ~(RXH_IP_SRC | RXH_IP_DST |
+			  RXH_L4_B_0_1 | RXH_L4_B_2_3))
+		return -EINVAL;
+
+	switch (nfc->flow_type) {
+	case TCP_V4_FLOW:
+	case TCP_V6_FLOW:
+		if (!(nfc->data & RXH_IP_SRC) ||
+		    !(nfc->data & RXH_IP_DST) ||
+		    !(nfc->data & RXH_L4_B_0_1) ||
+		    !(nfc->data & RXH_L4_B_2_3))
+			return -EINVAL;
+		break;
+	case UDP_V4_FLOW:
+		if (!(nfc->data & RXH_IP_SRC) ||
+		    !(nfc->data & RXH_IP_DST))
+			return -EINVAL;
+		switch (nfc->data & (RXH_L4_B_0_1 | RXH_L4_B_2_3)) {
+		case 0:
+			rss_fields &= ~VMXNET3_RSS_FIELDS_UDPIP4;
+			break;
+		case (RXH_L4_B_0_1 | RXH_L4_B_2_3):
+			rss_fields |= VMXNET3_RSS_FIELDS_UDPIP4;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case UDP_V6_FLOW:
+		if (!(nfc->data & RXH_IP_SRC) ||
+		    !(nfc->data & RXH_IP_DST))
+			return -EINVAL;
+		switch (nfc->data & (RXH_L4_B_0_1 | RXH_L4_B_2_3)) {
+		case 0:
+			rss_fields &= ~VMXNET3_RSS_FIELDS_UDPIP6;
+			break;
+		case (RXH_L4_B_0_1 | RXH_L4_B_2_3):
+			rss_fields |= VMXNET3_RSS_FIELDS_UDPIP6;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case ESP_V4_FLOW:
+	case AH_V4_FLOW:
+	case AH_ESP_V4_FLOW:
+		if (!(nfc->data & RXH_IP_SRC) ||
+		    !(nfc->data & RXH_IP_DST))
+			return -EINVAL;
+		switch (nfc->data & (RXH_L4_B_0_1 | RXH_L4_B_2_3)) {
+		case 0:
+			rss_fields &= ~VMXNET3_RSS_FIELDS_ESPIP4;
+			break;
+		case (RXH_L4_B_0_1 | RXH_L4_B_2_3):
+			rss_fields |= VMXNET3_RSS_FIELDS_ESPIP4;
+		break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case ESP_V6_FLOW:
+	case AH_V6_FLOW:
+	case AH_ESP_V6_FLOW:
+	case SCTP_V4_FLOW:
+	case SCTP_V6_FLOW:
+		if (!(nfc->data & RXH_IP_SRC) ||
+		    !(nfc->data & RXH_IP_DST) ||
+		    (nfc->data & RXH_L4_B_0_1) ||
+		    (nfc->data & RXH_L4_B_2_3))
+			return -EINVAL;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* if we changed something we need to update flags */
+	if (rss_fields != adapter->rss_fields) {
+		adapter->default_rss_fields = false;
+		if (netif_running(netdev)) {
+			struct Vmxnet3_DriverShared *shared = adapter->shared;
+			union Vmxnet3_CmdInfo *cmdInfo = &shared->cu.cmdInfo;
+			unsigned long flags;
+
+			spin_lock_irqsave(&adapter->cmd_lock, flags);
+			cmdInfo->setRssFields = rss_fields;
+			VMXNET3_WRITE_BAR1_REG(adapter, VMXNET3_REG_CMD,
+					       VMXNET3_CMD_SET_RSS_FIELDS);
+
+			/* Not all requested RSS may get applied, so get and
+			 * cache what was actually applied.
+			 */
+			VMXNET3_WRITE_BAR1_REG(adapter, VMXNET3_REG_CMD,
+					       VMXNET3_CMD_GET_RSS_FIELDS);
+			adapter->rss_fields =
+				VMXNET3_READ_BAR1_REG(adapter, VMXNET3_REG_CMD);
+			spin_unlock_irqrestore(&adapter->cmd_lock, flags);
+		} else {
+			/* When the device is activated, we will try to apply
+			 * these rules and cache the applied value later.
+			 */
+			adapter->rss_fields = rss_fields;
+		}
+	}
+	return 0;
+}
 
 static int
 vmxnet3_get_rxnfc(struct net_device *netdev, struct ethtool_rxnfc *info,
 		  u32 *rules)
 {
 	struct vmxnet3_adapter *adapter = netdev_priv(netdev);
+	int err = 0;
+
 	switch (info->cmd) {
 	case ETHTOOL_GRXRINGS:
 		info->data = adapter->num_rx_queues;
-		return 0;
+		break;
+	case ETHTOOL_GRXFH:
+		if (!VMXNET3_VERSION_GE_4(adapter)) {
+			err = -EOPNOTSUPP;
+			break;
+		}
+		err = vmxnet3_get_rss_hash_opts(adapter, info);
+		break;
+	default:
+		err = -EOPNOTSUPP;
+		break;
 	}
-	return -EOPNOTSUPP;
+
+	return err;
+}
+
+static int
+vmxnet3_set_rxnfc(struct net_device *netdev, struct ethtool_rxnfc *info)
+{
+	struct vmxnet3_adapter *adapter = netdev_priv(netdev);
+	int err = 0;
+
+	if (!VMXNET3_VERSION_GE_4(adapter)) {
+		err = -EOPNOTSUPP;
+		goto done;
+	}
+
+	switch (info->cmd) {
+	case ETHTOOL_SRXFH:
+		err = vmxnet3_set_rss_hash_opt(netdev, adapter, info);
+		break;
+	default:
+		err = -EOPNOTSUPP;
+		break;
+	}
+
+done:
+	return err;
 }
 
 #ifdef VMXNET3_RSS

@@ -887,6 +1105,7 @@ static const struct ethtool_ops vmxnet3_ethtool_ops = {
 	.get_ringparam     = vmxnet3_get_ringparam,
 	.set_ringparam     = vmxnet3_set_ringparam,
 	.get_rxnfc         = vmxnet3_get_rxnfc,
+	.set_rxnfc         = vmxnet3_set_rxnfc,
 #ifdef VMXNET3_RSS
 	.get_rxfh_indir_size = vmxnet3_get_rss_indir_size,
 	.get_rxfh          = vmxnet3_get_rss,

diff --git a/drivers/net/vmxnet3/vmxnet3_int.h b/drivers/net/vmxnet3/vmxnet3_int.h
index e803ffad75d6..d52ccc3eeba2 100644
--- a/drivers/net/vmxnet3/vmxnet3_int.h
+++ b/drivers/net/vmxnet3/vmxnet3_int.h

@@ -377,6 +377,8 @@ struct vmxnet3_adapter {
 	u16 rxdata_desc_size;
 
 	bool rxdataring_enabled;
+	bool default_rss_fields;
+	enum Vmxnet3_RSSField rss_fields;
 
 	struct work_struct work;

@@ -438,6 +440,8 @@ struct vmxnet3_adapter {
 
 #define VMXNET3_COAL_RBC_RATE(usecs) (1000000 / usecs)
 #define VMXNET3_COAL_RBC_USECS(rbc_rate) (1000000 / rbc_rate)
+#define VMXNET3_RSS_FIELDS_DEFAULT (VMXNET3_RSS_FIELDS_TCPIP4 | \
+				    VMXNET3_RSS_FIELDS_TCPIP6)
 
 int
 vmxnet3_quiesce_dev(struct vmxnet3_adapter *adapter);

-- 
2.11.0

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