[PATCH v3] net/vmxnet3: disable RSS for single queue configuration for ESX8.0+ versions

[Amiya Ranjan Mohakud <amiyaranjan.mohakud@gmail.com>]

It fixes the issue of v4 RSS configuration failure in
vmxnet3_v4_rss_configure() while writing to BAR register. It's very
specific to single queue configuration.

https://mails.dpdk.org/archives/users/2025-April/008236.html

Bugzilla ID:1789
Fixes: 52ec00f ("net/vmxnet3: fix RSS setting on v4")
Cc: stable@dpdk.org

v2:
 - Fixed typo in commit message
v3:
 - Checking if RSS is already enabled

Signed-off-by: Amiya Ranjan Mohakud <amiyaranjan.mohakud@gmail.com>
---
 drivers/net/vmxnet3/vmxnet3_ethdev.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/vmxnet3/vmxnet3_ethdev.c b/drivers/net/vmxnet3/vmxnet3_ethdev.c
index f4cdb1bb31..a0306af86c 100644
--- a/drivers/net/vmxnet3/vmxnet3_ethdev.c
+++ b/drivers/net/vmxnet3/vmxnet3_ethdev.c
@@ -534,6 +534,13 @@ vmxnet3_dev_configure(struct rte_eth_dev *dev)
 
 	PMD_INIT_FUNC_TRACE();
 
+	/* Disabling RSS for single queue pair */
+	if (dev->data->nb_rx_queues == 1 &&
+	    dev->data->dev_conf.rxmode.mq_mode == RTE_ETH_MQ_RX_RSS) {
+		dev->data->dev_conf.rxmode.mq_mode = RTE_ETH_MQ_RX_NONE;
+		PMD_INIT_LOG(ERR, "WARN: Disabling RSS for single Rx queue");
+	}
+
 	if (dev->data->dev_conf.rxmode.mq_mode & RTE_ETH_MQ_RX_RSS_FLAG)
 		dev->data->dev_conf.rxmode.offloads |= RTE_ETH_RX_OFFLOAD_RSS_HASH;
 
-- 
2.39.5 (Apple Git-154)