Virtio_user for kernel interface.

Virtio_user for kernel interface.

[Carlos de Souza Moraes Neto]

Hello!
I'm attempting to utilize virtio_user for packet transmission and reception via the kernel's network stack. I transmitted packets from a NIC to virtio_user0 and captured them on the tap0 interface. However, when trying to send a packet from tap0 (for instance, a basic ping) and route it to DPDK, the function rte_eth_rx_burst returns zero packets. My initialization is set as follows: 
	-l 0-4 --vdev=virtio_user0,path=/dev/vhost-net,queues=3,queue_size=1024. 
With the forthcoming removal of KNI from DPDK, I have to rely on virtio but I cant find a way to use it as a bridge to the kernel stack and my dpdk app. I could not find any example or similar application for reference.

Sincerely,

Carlos Moraes
WEG Equipamentos Elétricos S/A. - Transmissão & Distribuição
www.weg.net

Re: Virtio_user for kernel interface.

[David Marchand]

On Mon, Aug 28, 2023 at 10:07 AM Carlos de Souza Moraes Neto
<carlosmn@weg.net> wrote:
> I'm attempting to utilize virtio_user for packet transmission and reception via the kernel's network stack. I transmitted packets from a NIC to virtio_user0 and captured them on the tap0 interface. However, when trying to send a packet from tap0 (for instance, a basic ping) and route it to DPDK, the function rte_eth_rx_burst returns zero packets. My initialization is set as follows:
>         -l 0-4 --vdev=virtio_user0,path=/dev/vhost-net,queues=3,queue_size=1024.

Just an idea.
If you ask for 3 queue pairs, your application must poll packets from
all 3 rxqs, as the kernel may choose to send packets through any of
those queues.
Are you perhaps only polling one rxq?


-- 
David Marchand

RES: Virtio_user for kernel interface.

[Carlos de Souza Moraes Neto]

Hi David,
Thankyou it worked.


Sincerely,

Carlos de Souza Moraes Neto
WEG Equipamentos Elétricos S/A. - Transmissão & Distribuição
www.weg.net



-----Mensagem original-----
De: David Marchand <david.marchand@redhat.com> 
Enviada em: segunda-feira, 28 de agosto de 2023 05:31
Para: Carlos de Souza Moraes Neto <carlosmn@weg.net>
Cc: users@dpdk.org
Assunto: Re: Virtio_user for kernel interface.

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On Mon, Aug 28, 2023 at 10:07 AM Carlos de Souza Moraes Neto <carlosmn@weg.net> wrote:
> I'm attempting to utilize virtio_user for packet transmission and reception via the kernel's network stack. I transmitted packets from a NIC to virtio_user0 and captured them on the tap0 interface. However, when trying to send a packet from tap0 (for instance, a basic ping) and route it to DPDK, the function rte_eth_rx_burst returns zero packets. My initialization is set as follows:
>         -l 0-4 --vdev=virtio_user0,path=/dev/vhost-net,queues=3,queue_size=1024.

Just an idea.
If you ask for 3 queue pairs, your application must poll packets from all 3 rxqs, as the kernel may choose to send packets through any of those queues.
Are you perhaps only polling one rxq?


--
David Marchand