[dpdk-dev] [PATCH] net/i40e: issue with ADD VLAN from Guest

[Souvik Dey <sodey@rbbn.com>]

In case of i40evf pmd, when ADD_VLAN is sent down the linux i40e driver,
along with add the vlan the kernel driver also enables the vlan stripping
by default.
This might have issues if the app configured DEV_RX_OFFLOAD_VLAN_STRIP
as off at the port configuration. The app after adding the VLAN will
expect the VLAN to be coming in the received packets but, due to
VLAN_STRIP enabled at the PF, it will get stripped.
This behavior of the Linux driver causes confussion with the DPDK app
using i40e_pmd. So it is better to reconfigure the vlan_offload, which
checks for DEV_RX_OFFLOAD_VLAN_STRIP flag in the dev_conf and enables or
disables the vlan strip in the PF.
Also rte_eth_dev_set_vlan_offload() to disable VLAN_STRIP cannot be used
from the application, as this will only work for the first time when
original and current confi mismatch, but for all subsequent call it will
ignore it.

Signed-off-by: Souvik Dey <sodey@rbbn.com>
---
 drivers/net/i40e/i40e_ethdev_vf.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/net/i40e/i40e_ethdev_vf.c b/drivers/net/i40e/i40e_ethdev_vf.c
index c26b036..2ecf74b 100644
--- a/drivers/net/i40e/i40e_ethdev_vf.c
+++ b/drivers/net/i40e/i40e_ethdev_vf.c
@@ -1078,8 +1078,19 @@ i40evf_add_vlan(struct rte_eth_dev *dev, uint16_t vlanid)
 	args.out_buffer = vf->aq_resp;
 	args.out_size = I40E_AQ_BUF_SZ;
 	err = i40evf_execute_vf_cmd(dev, &args);
-	if (err)
+	if (err) {
 		PMD_DRV_LOG(ERR, "fail to execute command OP_ADD_VLAN");
+		return err;
+	}
+	/*
+	 * In linux kernel driver on receiving ADD_VLAN it enables
+	 * VLAN_STRIP by default. So reconfigure the vlan_offload
+	 * as it was done by the app earlier.
+	 */
+	err = i40evf_vlan_offload_set(dev, ETH_VLAN_STRIP_MASK)
+	if (err)
+		PMD_DRV_LOG(ERR, "fail to execute command disable_vlan_strip "
+			"as a part of OP_ADD_VLAN");
 
 	return err;
 }
-- 
2.9.3.windows.1