iavf: Add support for VIRTCHNL_VF_OFFLOAD_VLAN_V2 hotpath

The new VIRTCHNL_VF_OFFLOAD_VLAN_V2 capability added support that allows
the PF to set the location of the Tx and Rx VLAN tag for insertion and
stripping offloads. In order to support this functionality a few changes
are needed.

1. Add a new method to cache the VLAN tag location based on negotiated
   capabilities for the Tx and Rx ring flags. This needs to be called in
   the initialization and reset paths.

2. Refactor the transmit hotpath to account for the new Tx ring flags.
   When IAVF_TXR_FLAGS_VLAN_LOC_L2TAG2 is set, then the driver needs to
   insert the VLAN tag in the L2TAG2 field of the transmit descriptor.
   When the IAVF_TXRX_FLAGS_VLAN_LOC_L2TAG1 is set, then the driver needs
   to use the l2tag1 field of the data descriptor (same behavior as
   before).

3. Refactor the iavf_tx_prepare_vlan_flags() function to simplify
   transmit hardware VLAN offload functionality by only depending on the
   skb_vlan_tag_present() function. This can be done because the OS
   won't request transmit offload for a VLAN unless the driver told the
   OS it's supported and enabled.

4. Refactor the receive hotpath to account for the new Rx ring flags and
   VLAN ethertypes. This requires checking the Rx ring flags and
   descriptor status bits to determine the location of the VLAN tag.
   Also, since only a single ethertype can be supported at a time, check
   the enabled netdev features before specifying a VLAN ethertype in
   __vlan_hwaccel_put_tag().

Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 33 insertions, 38 deletions

diff --git a/drivers/net/ethernet/intel/iavf/iavf_txrx.c b/drivers/net/ethernet/intel/iavf/iavf_txrx.c
index 42c9f9dc235c..a0b1c18a3273 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_txrx.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_txrx.c
@@ -865,6 +865,9 @@ static void iavf_receive_skb(struct iavf_ring *rx_ring,
 	if ((rx_ring->netdev->features & NETIF_F_HW_VLAN_CTAG_RX) &&
 	    (vlan_tag & VLAN_VID_MASK))
 		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlan_tag);
+	else if ((rx_ring->netdev->features & NETIF_F_HW_VLAN_STAG_RX) &&
+		 vlan_tag & VLAN_VID_MASK)
+		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021AD), vlan_tag);
 
 	napi_gro_receive(&q_vector->napi, skb);
 }
@@ -1468,7 +1471,7 @@ static int iavf_clean_rx_irq(struct iavf_ring *rx_ring, int budget)
 		struct iavf_rx_buffer *rx_buffer;
 		union iavf_rx_desc *rx_desc;
 		unsigned int size;
-		u16 vlan_tag;
+		u16 vlan_tag = 0;
 		u8 rx_ptype;
 		u64 qword;
 
@@ -1551,9 +1554,13 @@ static int iavf_clean_rx_irq(struct iavf_ring *rx_ring, int budget)
 		/* populate checksum, VLAN, and protocol */
 		iavf_process_skb_fields(rx_ring, rx_desc, skb, rx_ptype);
 
-
-		vlan_tag = (qword & BIT(IAVF_RX_DESC_STATUS_L2TAG1P_SHIFT)) ?
-			   le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1) : 0;
+		if (qword & BIT(IAVF_RX_DESC_STATUS_L2TAG1P_SHIFT) &&
+		    rx_ring->flags & IAVF_TXRX_FLAGS_VLAN_TAG_LOC_L2TAG1)
+			vlan_tag = le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1);
+		if (rx_desc->wb.qword2.ext_status &
+		    cpu_to_le16(BIT(IAVF_RX_DESC_EXT_STATUS_L2TAG2P_SHIFT)) &&
+		    rx_ring->flags & IAVF_RXR_FLAGS_VLAN_TAG_LOC_L2TAG2_2)
+			vlan_tag = le16_to_cpu(rx_desc->wb.qword2.l2tag2_2);
 
 		iavf_trace(clean_rx_irq_rx, rx_ring, rx_desc, skb);
 		iavf_receive_skb(rx_ring, skb, vlan_tag);
@@ -1781,46 +1788,29 @@ tx_only:
  * Returns error code indicate the frame should be dropped upon error and the
  * otherwise  returns 0 to indicate the flags has been set properly.
  **/
-static inline int iavf_tx_prepare_vlan_flags(struct sk_buff *skb,
-					     struct iavf_ring *tx_ring,
-					     u32 *flags)
+static void iavf_tx_prepare_vlan_flags(struct sk_buff *skb,
+				       struct iavf_ring *tx_ring, u32 *flags)
 {
-	__be16 protocol = skb->protocol;
 	u32  tx_flags = 0;
 
-	if (protocol == htons(ETH_P_8021Q) &&
-	    !(tx_ring->netdev->features & NETIF_F_HW_VLAN_CTAG_TX)) {
-		/* When HW VLAN acceleration is turned off by the user the
-		 * stack sets the protocol to 8021q so that the driver
-		 * can take any steps required to support the SW only
-		 * VLAN handling.  In our case the driver doesn't need
-		 * to take any further steps so just set the protocol
-		 * to the encapsulated ethertype.
-		 */
-		skb->protocol = vlan_get_protocol(skb);
-		goto out;
-	}
 
-	/* if we have a HW VLAN tag being added, default to the HW one */
-	if (skb_vlan_tag_present(skb)) {
-		tx_flags |= skb_vlan_tag_get(skb) << IAVF_TX_FLAGS_VLAN_SHIFT;
-		tx_flags |= IAVF_TX_FLAGS_HW_VLAN;
-	/* else if it is a SW VLAN, check the next protocol and store the tag */
-	} else if (protocol == htons(ETH_P_8021Q)) {
-		struct vlan_hdr *vhdr, _vhdr;
-
-		vhdr = skb_header_pointer(skb, ETH_HLEN, sizeof(_vhdr), &_vhdr);
-		if (!vhdr)
-			return -EINVAL;
+	/* stack will only request hardware VLAN insertion offload for protocols
+	 * that the driver supports and has enabled
+	 */
+	if (!skb_vlan_tag_present(skb))
+		return;
 
-		protocol = vhdr->h_vlan_encapsulated_proto;
-		tx_flags |= ntohs(vhdr->h_vlan_TCI) << IAVF_TX_FLAGS_VLAN_SHIFT;
-		tx_flags |= IAVF_TX_FLAGS_SW_VLAN;
+	tx_flags |= skb_vlan_tag_get(skb) << IAVF_TX_FLAGS_VLAN_SHIFT;
+	if (tx_ring->flags & IAVF_TXR_FLAGS_VLAN_TAG_LOC_L2TAG2) {
+		tx_flags |= IAVF_TX_FLAGS_HW_OUTER_SINGLE_VLAN;
+	} else if (tx_ring->flags & IAVF_TXRX_FLAGS_VLAN_TAG_LOC_L2TAG1) {
+		tx_flags |= IAVF_TX_FLAGS_HW_VLAN;
+	} else {
+		dev_dbg(tx_ring->dev, "Unsupported Tx VLAN tag location requested\n");
+		return;
 	}
 
-out:
 	*flags = tx_flags;
-	return 0;
 }
 
 /**
@@ -2440,8 +2430,13 @@ static netdev_tx_t iavf_xmit_frame_ring(struct sk_buff *skb,
 	first->gso_segs = 1;
 
 	/* prepare the xmit flags */
-	if (iavf_tx_prepare_vlan_flags(skb, tx_ring, &tx_flags))
-		goto out_drop;
+	iavf_tx_prepare_vlan_flags(skb, tx_ring, &tx_flags);
+	if (tx_flags & IAVF_TX_FLAGS_HW_OUTER_SINGLE_VLAN) {
+		cd_type_cmd_tso_mss |= IAVF_TX_CTX_DESC_IL2TAG2 <<
+			IAVF_TXD_CTX_QW1_CMD_SHIFT;
+		cd_l2tag2 = (tx_flags & IAVF_TX_FLAGS_VLAN_MASK) >>
+			IAVF_TX_FLAGS_VLAN_SHIFT;
+	}
 
 	/* obtain protocol of skb */
 	protocol = vlan_get_protocol(skb);