Re: [dpdk-dev] [PATCH v3] net/mlx5: fix loopback for DV queue

[Thomas Monjalon <thomas@monjalon.net>]

17/05/2021 17:18, Bing Zhao:
> In the past, all the queues and other hardware objects were created
> through Verbs interface. Currently, most of the objects creation are
> migrated to Devx interface by default, including queues. Only when
> the DV is disabled by device arg or eswitch is enabled, all or some
> of the objects are created through Verbs interface.
> 
> When using Devx interface to create queues, the kernel driver
> behavior is different from the case using Verbs. The Tx loopback
> cannot work properly even if the Tx and Rx queues are configured
> with loopback attribute. To fix the support self loopback for Tx, a
> Verbs dummy queue pair needs to be created to trigger the kernel to
> enable the global loopback capability.
> 
> This is only required when TIR is created for Rx and loopback is
> needed. Only CQ and QP are needed for this case, no WQ(RQ) needs to
> be created.
> 
> This requirement comes from bugzilla 645, more details can be found
> in the bugzilla link.
> 
> Bugzilla ID: 645
> 
> Fixes: 6deb19e1b2d2 ("net/mlx5: separate Rx queue object creations")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Bing Zhao <bingz@nvidia.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

Applied to next-net-mlx, thanks.