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

From: Michal Kubecek
Date: Thu May 28 2020 - 01:50:36 EST


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 <doshir@xxxxxxxxxx>
> ---
[...]
> 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

> + 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
>