iavf: Add ability to turn off CRC stripping for VF

Previously CRC stripping was always enabled for VF.

Now it is possible to turn off CRC stripping via ethtool:

    #ethtool -K <interface> rx-fcs on

To turn off CRC stripping, first VLAN stripping must be disabled:

    #ethtool -K <interface> rx-vlan-offload off

if any VLAN interfaces exists, otherwise VLAN stripping will be turned
off by the driver.

In iavf_configure_queues add check if CRC stripping is enabled for
VF, if it's enabled then set crc_disabled to false on every VF's
queue. In iavf_set_features add check if CRC stripping setting was
changed then schedule reset.

Signed-off-by: Norbert Zulinski <[email protected]>
Reviewed-by: Jesse Brandeburg <[email protected]>
Signed-off-by: Ahmed Zaki <[email protected]>
Tested-by: Rafal Romanowski <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>

Author: norbertx-zulinski

drivers/net/ethernet/intel/iavf/iavf.h

@@ -406,6 +406,8 @@ struct iavf_adapter {
 			  VIRTCHNL_VF_OFFLOAD_VLAN)
 #define VLAN_V2_ALLOWED(_a) ((_a)->vf_res->vf_cap_flags & \
 			     VIRTCHNL_VF_OFFLOAD_VLAN_V2)
+#define CRC_OFFLOAD_ALLOWED(_a) ((_a)->vf_res->vf_cap_flags & \
+				 VIRTCHNL_VF_OFFLOAD_CRC)
 #define VLAN_V2_FILTERING_ALLOWED(_a) \
 	(VLAN_V2_ALLOWED((_a)) && \
 	 ((_a)->vlan_v2_caps.filtering.filtering_support.outer || \

drivers/net/ethernet/intel/iavf/iavf_main.c

@@ -4401,6 +4401,9 @@ static int iavf_set_features(struct net_device *netdev,
 	    (features & NETIF_VLAN_OFFLOAD_FEATURES))
 		iavf_set_vlan_offload_features(adapter, netdev->features,
 					       features);
+	if (CRC_OFFLOAD_ALLOWED(adapter) &&
+	    ((netdev->features & NETIF_F_RXFCS) ^ (features & NETIF_F_RXFCS)))
+		iavf_schedule_reset(adapter, IAVF_FLAG_RESET_NEEDED);
 
 	return 0;
 }
@@ -4522,6 +4525,9 @@ iavf_get_netdev_vlan_hw_features(struct iavf_adapter *adapter)
 		}
 	}
 
+	if (CRC_OFFLOAD_ALLOWED(adapter))
+		hw_features |= NETIF_F_RXFCS;
+
 	return hw_features;
 }
 
@@ -4685,6 +4691,55 @@ iavf_fix_netdev_vlan_features(struct iavf_adapter *adapter,
 	return requested_features;
 }
 
+/**
+ * iavf_fix_strip_features - fix NETDEV CRC and VLAN strip features
+ * @adapter: board private structure
+ * @requested_features: stack requested NETDEV features
+ *
+ * Returns fixed-up features bits
+ **/
+static netdev_features_t
+iavf_fix_strip_features(struct iavf_adapter *adapter,
+			netdev_features_t requested_features)
+{
+	struct net_device *netdev = adapter->netdev;
+	bool crc_offload_req, is_vlan_strip;
+	netdev_features_t vlan_strip;
+	int num_non_zero_vlan;
+
+	crc_offload_req = CRC_OFFLOAD_ALLOWED(adapter) &&
+			  (requested_features & NETIF_F_RXFCS);
+	num_non_zero_vlan = iavf_get_num_vlans_added(adapter);
+	vlan_strip = (NETIF_F_HW_VLAN_CTAG_RX | NETIF_F_HW_VLAN_STAG_RX);
+	is_vlan_strip = requested_features & vlan_strip;
+
+	if (!crc_offload_req)
+		return requested_features;
+
+	if (!num_non_zero_vlan && (netdev->features & vlan_strip) &&
+	    !(netdev->features & NETIF_F_RXFCS) && is_vlan_strip) {
+		requested_features &= ~vlan_strip;
+		netdev_info(netdev, "Disabling VLAN stripping as FCS/CRC stripping is also disabled and there is no VLAN configured\n");
+		return requested_features;
+	}
+
+	if ((netdev->features & NETIF_F_RXFCS) && is_vlan_strip) {
+		requested_features &= ~vlan_strip;
+		if (!(netdev->features & vlan_strip))
+			netdev_info(netdev, "To enable VLAN stripping, first need to enable FCS/CRC stripping");
+
+		return requested_features;
+	}
+
+	if (num_non_zero_vlan && is_vlan_strip &&
+	    !(netdev->features & NETIF_F_RXFCS)) {
+		requested_features &= ~NETIF_F_RXFCS;
+		netdev_info(netdev, "To disable FCS/CRC stripping, first need to disable VLAN stripping");
+	}
+
+	return requested_features;
+}
+
 /**
  * iavf_fix_features - fix up the netdev feature bits
  * @netdev: our net device
@@ -4697,7 +4752,9 @@ static netdev_features_t iavf_fix_features(struct net_device *netdev,
 {
 	struct iavf_adapter *adapter = netdev_priv(netdev);
 
-	return iavf_fix_netdev_vlan_features(adapter, features);
+	features = iavf_fix_netdev_vlan_features(adapter, features);
+
+	return iavf_fix_strip_features(adapter, features);
 }
 
 static const struct net_device_ops iavf_netdev_ops = {

drivers/net/ethernet/intel/iavf/iavf_virtchnl.c

@@ -142,6 +142,7 @@ int iavf_send_vf_config_msg(struct iavf_adapter *adapter)
 	       VIRTCHNL_VF_OFFLOAD_RSS_PCTYPE_V2 |
 	       VIRTCHNL_VF_OFFLOAD_ENCAP |
 	       VIRTCHNL_VF_OFFLOAD_VLAN_V2 |
+	       VIRTCHNL_VF_OFFLOAD_CRC |
 	       VIRTCHNL_VF_OFFLOAD_ENCAP_CSUM |
 	       VIRTCHNL_VF_OFFLOAD_REQ_QUEUES |
 	       VIRTCHNL_VF_OFFLOAD_ADQ |
@@ -312,6 +313,9 @@ void iavf_configure_queues(struct iavf_adapter *adapter)
 		vqpi->rxq.databuffer_size =
 			ALIGN(adapter->rx_rings[i].rx_buf_len,
 			      BIT_ULL(IAVF_RXQ_CTX_DBUFF_SHIFT));
+		if (CRC_OFFLOAD_ALLOWED(adapter))
+			vqpi->rxq.crc_disable = !!(adapter->netdev->features &
+						   NETIF_F_RXFCS);
 		vqpi++;
 	}