[dpdk-dev] [PATCH v4 3/3] ixgbe: fix incorrect max tx queue number

[Pablo de Lara]

From: Wenzhuo Lu <wenzhuo.lu at intel.com>

IXGBE supports 128 TX queues. However, the full 128 queues
are only available in VT and DCB mode.
In normal default "none" mode (VT/DCB off) the maximum number
of available queues is only 64.
IXGBE doesn't check the mode when reporting the available
number of queues. If a queue larger than 64 is used in default mode,
the TX packets will be dropped silently.

This change adds a check to forbid using a queue number larger than 64
during device configuration (in default mode), so that the problem is
reported as early as possible.

Signed-off-by: Wenzhuo Lu <wenzhuo.lu at intel.com>
Signed-off-by: Pablo de Lara <pablo.de.lara.guarch at intel.com>
---
 doc/guides/rel_notes/release_16_04.rst |  6 ++++++
 drivers/net/ixgbe/ixgbe_ethdev.c       | 26 ++++++++++++++++++++++++++
 drivers/net/ixgbe/ixgbe_ethdev.h       |  1 +
 3 files changed, 33 insertions(+)

diff --git a/doc/guides/rel_notes/release_16_04.rst b/doc/guides/rel_notes/release_16_04.rst
index 9922bcb..d0d5c89 100644
--- a/doc/guides/rel_notes/release_16_04.rst
+++ b/doc/guides/rel_notes/release_16_04.rst
@@ -302,6 +302,12 @@ Drivers
   The driver now set the MDIO clock speed prior to initializing PHY ops and
   again after the MAC reset.
 
+* **ixgbe: Fixed maximum number of available TX queues.**
+
+  In IXGBE, the maximum number of TX queues varies depending on the NIC operating
+  mode. This was not being updated in the device information, providing
+  an incorrect number in some cases.
+
 * **i40e: Generated MAC address for each VFs.**
 
   It generates a MAC address for each VFs during PF host initialization,
diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c b/drivers/net/ixgbe/ixgbe_ethdev.c
index 0d867fc..bfd8cb3 100644
--- a/drivers/net/ixgbe/ixgbe_ethdev.c
+++ b/drivers/net/ixgbe/ixgbe_ethdev.c
@@ -1861,6 +1861,7 @@ static int
 ixgbe_check_mq_mode(struct rte_eth_dev *dev)
 {
 	struct rte_eth_conf *dev_conf = &dev->data->dev_conf;
+	struct ixgbe_hw *hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
 	uint16_t nb_rx_q = dev->data->nb_rx_queues;
 	uint16_t nb_tx_q = dev->data->nb_tx_queues;
 
@@ -2002,6 +2003,21 @@ ixgbe_check_mq_mode(struct rte_eth_dev *dev)
 				return -EINVAL;
 			}
 		}
+
+		/*
+		 * When DCB/VT is off, maximum number of queues changes,
+		 * except for 82598EB, which remains constant.
+		 */
+		if (dev_conf->txmode.mq_mode == ETH_MQ_TX_NONE &&
+				hw->mac.type != ixgbe_mac_82598EB) {
+			if (nb_tx_q > IXGBE_NONE_MODE_TX_NB_QUEUES) {
+				PMD_INIT_LOG(ERR,
+					     "Neither VT nor DCB are enabled, "
+					     "nb_tx_q > %d.",
+					     IXGBE_NONE_MODE_TX_NB_QUEUES);
+				return -EINVAL;
+			}
+		}
 	}
 	return 0;
 }
@@ -2856,9 +2872,19 @@ static void
 ixgbe_dev_info_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
 {
 	struct ixgbe_hw *hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
+	struct rte_eth_conf *dev_conf = &dev->data->dev_conf;
 
 	dev_info->max_rx_queues = (uint16_t)hw->mac.max_rx_queues;
 	dev_info->max_tx_queues = (uint16_t)hw->mac.max_tx_queues;
+	if (RTE_ETH_DEV_SRIOV(dev).active == 0) {
+		/*
+		 * When DCB/VT is off, maximum number of queues changes,
+		 * except for 82598EB, which remains constant.
+		 */
+		if (dev_conf->txmode.mq_mode == ETH_MQ_TX_NONE &&
+				hw->mac.type != ixgbe_mac_82598EB)
+			dev_info->max_tx_queues = IXGBE_NONE_MODE_TX_NB_QUEUES;
+	}
 	dev_info->min_rx_bufsize = 1024; /* cf BSIZEPACKET in SRRCTL register */
 	dev_info->max_rx_pktlen = 15872; /* includes CRC, cf MAXFRS register */
 	dev_info->max_mac_addrs = hw->mac.num_rar_entries;
diff --git a/drivers/net/ixgbe/ixgbe_ethdev.h b/drivers/net/ixgbe/ixgbe_ethdev.h
index 5c3aa16..691c62f 100644
--- a/drivers/net/ixgbe/ixgbe_ethdev.h
+++ b/drivers/net/ixgbe/ixgbe_ethdev.h
@@ -61,6 +61,7 @@
 #define IXGBE_MAX_RX_QUEUE_NUM	128
 #define IXGBE_VMDQ_DCB_NB_QUEUES     IXGBE_MAX_RX_QUEUE_NUM
 #define IXGBE_DCB_NB_QUEUES          IXGBE_MAX_RX_QUEUE_NUM
+#define IXGBE_NONE_MODE_TX_NB_QUEUES 64
 
 #ifndef NBBY
 #define NBBY	8	/* number of bits in a byte */
-- 
2.5.5