I sent the following documentation patch. You are welcome to review/comment:
http://patches.dpdk.org/project/dpdk/patch/20220228081117.3013452-1-asafp@nvidia.com/

Regards,
Asaf Penso

From: Asaf Penso <asafp@nvidia.com>
Sent: Tuesday, February 22, 2022 7:57 PM
To: Haider Ali <haider@dreambigsemi.com>; Muhammad Zain-ul-Abideen <zain2294@gmail.com>
Cc: users <users@dpdk.org>
Subject: RE: Mellanox VF failed to start with hairpin queues

I worked with Haider and found that the VF should be configured as trusted both in driver and FW.
I am working on a documentation patch in mlx5.rst to describe the needed steps.

Regards,
Asaf Penso

From: Haider Ali <haider@dreambigsemi.com<mailto:haider@dreambigsemi.com>>
Sent: Monday, February 7, 2022 3:12 PM
To: Muhammad Zain-ul-Abideen <zain2294@gmail.com<mailto:zain2294@gmail.com>>
Cc: users <users@dpdk.org<mailto:users@dpdk.org>>
Subject: Re: Mellanox VF failed to start with hairpin queues

I am not using mlx5 VF in VM. Can you please elaborate on what type of setup information you require?

Regards,
Haider Ali
________________________________
From: Muhammad Zain-ul-Abideen <zain2294@gmail.com<mailto:zain2294@gmail.com>>
Sent: Friday, February 4, 2022 5:23 PM
To: Haider Ali <haider@dreambigsemi.com<mailto:haider@dreambigsemi.com>>
Cc: users <users@dpdk.org<mailto:users@dpdk.org>>
Subject: Re: Mellanox VF failed to start with hairpin queues

You don't often get email from zain2294@gmail.com<mailto:zain2294@gmail.com>. Learn why this is important<http://aka.ms/LearnAboutSenderIdentification>
Haider, have u installed mlx5 drivers in vm server? What setup u r using. A little more detail will help

On Fri, Feb 4, 2022, 1:06 PM Haider Ali <haider@dreambigsemi.com<mailto:haider@dreambigsemi.com>> wrote:
Hi,

Can anyone please guide me on why I am not able to do hairpin on VF? I am running the testpmd application with 1 Hairpin queue and 1 standard queue pair on Mellanox VF but getting following error:

$ sudo ./build/app/dpdk-testpmd -l 1,3 -n 4 -a 04:01.2 -- -i --rxq=1 --txq=1 --hairpinq=1 --hairpin-mode=0x00

EAL: Probe PCI driver: mlx5_pci (15b3:101e) device: 0000:04:01.2 (socket 0)
TELEMETRY: No legacy callbacks, legacy socket not created
Interactive-mode selected
testpmd: create a new mbuf pool <mb_pool_1>: n=155456, size=2176, socket=1
testpmd: preferred mempool ops selected: ring_mp_mc
testpmd: create a new mbuf pool <mb_pool_0>: n=155456, size=2176, socket=0
testpmd: preferred mempool ops selected: ring_mp_mc

Warning! port-topology=paired and odd forward ports number, the last port will pair with itself.

Configuring Port 0 (socket 0)
mlx5_net: port 0 failed to set defaults flows
Fail to start port 0: Operation not supported
Please stop the ports first
Done
testpmd> quit

Regards,
Haider Ali