[dpdk-stable] [PATCH v2] net/ixgbe: fix configuration of max frame size

["Zhang,Alvin" <alvinx.zhang@intel.com>]

From: Alvin Zhang <alvinx.zhang@intel.com>

For 82599 NIC, jumbo frame feature is not supported in IOV mode,
but if a VF requests to configure the frame size to that not
bigger than RTE_ETHER_MAX_LEN, the PMD should not return -1.
This patch keeps ixgbe PMD's handling mode consistent with kernel
driver in above situation.

In addition, the value set by the command IXGBE_VF_SET_LPE
represents the max frame size, not the mtu.

Fixes: 1b9ea09c067b ("ixgbe: support X550")
Fixes: 95a27b3ba5f5 ("net/ixgbe: enable jumbo frame for VF")
Cc: stable@dpdk.org

Signed-off-by: Alvin Zhang <alvinx.zhang@intel.com>
---
 drivers/net/ixgbe/ixgbe_pf.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ixgbe/ixgbe_pf.c b/drivers/net/ixgbe/ixgbe_pf.c
index 833863a..4cedaa5 100644
--- a/drivers/net/ixgbe/ixgbe_pf.c
+++ b/drivers/net/ixgbe/ixgbe_pf.c
@@ -555,27 +555,30 @@ int ixgbe_pf_host_configure(struct rte_eth_dev *eth_dev)
 ixgbe_set_vf_lpe(struct rte_eth_dev *dev, __rte_unused uint32_t vf, uint32_t *msgbuf)
 {
 	struct ixgbe_hw *hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
-	uint32_t new_mtu = msgbuf[1];
-	uint32_t max_frs;
+	uint32_t max_frame = msgbuf[1];
+	uint32_t cur_frame_size;
 	uint32_t hlreg0;
-	int max_frame = new_mtu + RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN;
 
 	/* X540 and X550 support jumbo frames in IOV mode */
 	if (hw->mac.type != ixgbe_mac_X540 &&
 		hw->mac.type != ixgbe_mac_X550 &&
 		hw->mac.type != ixgbe_mac_X550EM_x &&
-		hw->mac.type != ixgbe_mac_X550EM_a)
-		return -1;
+		hw->mac.type != ixgbe_mac_X550EM_a) {
+		if (max_frame > dev->data->dev_conf.rxmode.max_rx_pkt_len)
+			return -1;
+
+		return 0;
+	}
 
 	if (max_frame < RTE_ETHER_MIN_LEN ||
 			max_frame > RTE_ETHER_MAX_JUMBO_FRAME_LEN)
 		return -1;
 
-	max_frs = (IXGBE_READ_REG(hw, IXGBE_MAXFRS) &
-		   IXGBE_MHADD_MFS_MASK) >> IXGBE_MHADD_MFS_SHIFT;
-	if (max_frs < new_mtu) {
+	cur_frame_size = (IXGBE_READ_REG(hw, IXGBE_MAXFRS) &
+			 IXGBE_MHADD_MFS_MASK) >> IXGBE_MHADD_MFS_SHIFT;
+	if (cur_frame_size < max_frame) {
 		hlreg0 = IXGBE_READ_REG(hw, IXGBE_HLREG0);
-		if (new_mtu > RTE_ETHER_MAX_LEN) {
+		if (max_frame > RTE_ETHER_MAX_LEN) {
 			dev->data->dev_conf.rxmode.offloads |=
 				DEV_RX_OFFLOAD_JUMBO_FRAME;
 			hlreg0 |= IXGBE_HLREG0_JUMBOEN;
@@ -586,8 +589,8 @@ int ixgbe_pf_host_configure(struct rte_eth_dev *eth_dev)
 		}
 		IXGBE_WRITE_REG(hw, IXGBE_HLREG0, hlreg0);
 
-		max_frs = new_mtu << IXGBE_MHADD_MFS_SHIFT;
-		IXGBE_WRITE_REG(hw, IXGBE_MAXFRS, max_frs);
+		IXGBE_WRITE_REG(hw, IXGBE_MAXFRS,
+				max_frame << IXGBE_MHADD_MFS_SHIFT);
 	}
 
 	return 0;
-- 
1.8.3.1