[PATCH v1] examples/l3fwd: relax the RSS/Offload requirement

[Trevor Tao]

Now the port Rx mq_mode had been set to RTE_ETH_MQ_RX_RSS, and offload
mode set to RTE_ETH_RX_OFFLOAD_CHECKSUM by default, but some hardware
and/or virtual interface does not support the RSS and offload mode
presupposed, e.g., some virtio interfaces in the cloud don't support
RSS and may only partly support RTE_ETH_RX_OFFLOAD_UDP_CKSUM/
RTE_ETH_RX_OFFLOAD_TCP_CKSUM,
but not RTE_ETH_RX_OFFLOAD_IPV4_CKSUM, and the error msg here:

virtio_dev_configure(): RSS support requested but not supported by
the device
Port0 dev_configure = -95

and:
Ethdev port_id=0 requested Rx offloads 0xe does not match Rx offloads
capabilities 0x201d in rte_eth_dev_configure()

So to enable the l3fwd running in that environment, the Rx mode requirement
can be relaxed to reflect the hardware feature reality here, and the l3fwd
can run smoothly then.
A warning msg would be provided to user in case it happens here.

Fixes: af75078fece3 ("first public release")
Cc: stable at dpdk.org

Signed-off-by: Trevor Tao <trevor.tao at arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
Reviewed-by: Feifei Wang <feifei.wang2 at arm.com>
---
 .mailmap              |  1 +
 examples/l3fwd/main.c | 19 ++++++++++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/.mailmap b/.mailmap
index 8e3940a253..602d8cbc6b 100644
--- a/.mailmap
+++ b/.mailmap
@@ -1403,6 +1403,7 @@ Tom Rix <trix at redhat.com>
 Tone Zhang <tone.zhang at arm.com>
 Tonghao Zhang <xiangxia.m.yue at gmail.com> <nic at opencloud.tech>
 Tony Nguyen <anthony.l.nguyen at intel.com>
+Trevor Tao <trevor.tao at arm.com>
 Tsotne Chakhvadze <tsotne.chakhvadze at intel.com>
 Tudor Brindus <me at tbrindus.ca>
 Tudor Cornea <tudor.cornea at gmail.com> <tudor.cornea at keysight.com>
diff --git a/examples/l3fwd/main.c b/examples/l3fwd/main.c
index a4f061537e..cec87d95d1 100644
--- a/examples/l3fwd/main.c
+++ b/examples/l3fwd/main.c
@@ -1233,8 +1233,12 @@ l3fwd_poll_resource_setup(void)
 		local_port_conf.rx_adv_conf.rss_conf.rss_hf &=
 			dev_info.flow_type_rss_offloads;
 
-		if (dev_info.max_rx_queues == 1)
+		/* relax the rx rss requirement */
+		if (dev_info.max_rx_queues == 1 || !local_port_conf.rx_adv_conf.rss_conf.rss_hf) {
+			printf("warning: modified the rx mq_mode to RTE_ETH_MQ_RX_NONE base on"
+				" device capability\n");
 			local_port_conf.rxmode.mq_mode = RTE_ETH_MQ_RX_NONE;
+		}
 
 		if (local_port_conf.rx_adv_conf.rss_conf.rss_hf !=
 				port_conf.rx_adv_conf.rss_conf.rss_hf) {
@@ -1245,6 +1249,19 @@ l3fwd_poll_resource_setup(void)
 				local_port_conf.rx_adv_conf.rss_conf.rss_hf);
 		}
 
+		/* relax the rx offload requirement */
+		if ((local_port_conf.rxmode.offloads & dev_info.rx_offload_capa) !=
+			local_port_conf.rxmode.offloads) {
+			printf("Port %u requested Rx offloads 0x%"PRIx64" does not"
+				" match Rx offloads capabilities 0x%"PRIx64"\n",
+				portid, local_port_conf.rxmode.offloads,
+				dev_info.rx_offload_capa);
+			local_port_conf.rxmode.offloads &= dev_info.rx_offload_capa;
+			port_conf.rxmode.offloads = local_port_conf.rxmode.offloads;
+			printf("warning: modified the rx offload to 0x%"PRIx64" based on device"
+				" capability\n", local_port_conf.rxmode.offloads);
+		}
+
 		ret = rte_eth_dev_configure(portid, nb_rx_queue,
 					(uint16_t)n_tx_queue, &local_port_conf);
 		if (ret < 0)
-- 
2.41.0