Virtio_user as Exception Path insted of rte_kni on virtio driver is possible

[Stephen Hemminger]

On Fri, 7 Apr 2023 13:49:47 +0000
Yasin CANER <yasin.caner at ulakhaberlesme.com.tr> wrote:

> Hello all,
> 
> I would like to run a DPDK application on virtio driver that is in a Ubuntu-20 VM.
> 
> 
>   1.  Can DPDK-22.11 create a virtio_user on virtio driver? Or is there a another way to create KNI? I could not create VF .
>   2.  Is there a way to run virtio_user as Exception path via igb_uio instead of VFIO?
>   3.  Or do i have to run via rte_kni?

Virtio has two sides, the host and guest side. Virtio_user has DPDK place the role of host
and the kernel device is the guest side.  If running in a VM, the usual case is that
the virtio device is managed by the kernel (host side) and the DPDK application is using
the guest side.

> 
> I try to follow VFIO guide to create VF but it doesnt work. There is no srvio support in virtio driver as expected.
> 
> Best regards.
> 
> This parts not possible to run
> 
> echo 1 | sudo tee /sys/module/vfio_pci/parameters/enable_sriov
> 
> echo 2 > /sys/bus/pci/devices/0000:86:00.0/sriov_numvfs

SRIOV VF is a host (not guest VM) side feature.
So the above lines don't make any sense.


> DPDK version 22.11
> Ubuntu 20.04.5
> 5.4.0-146-generic
> https://doc.dpdk.org/guides-22.11/howto/virtio_user_as_exception_path.html#virtio-user-as-exception-path
> 55. Tun|Tap Poll Mode Driver - Data Plane Development Kit 22.11.1 documentation (dpdk.org)<https://doc.dpdk.org/guides-22.11/nics/tap.html>
> https://doc.dpdk.org/guides-22.11/linux_gsg/linux_drivers.html#linux-gsg-linux-drivers
> https://docs.kernel.org/driver-api/vfio.html
> 
> ethtool -i ens6
> driver: virtio_net
> version: 1.0.0
> firmware-version:
> expansion-rom-version:
> bus-info: 0000:00:06.0
> supports-statistics: yes
> supports-test: no
> supports-eeprom-access: no
> supports-register-dump: no
> supports-priv-flags: no
> 

What is kernel log (dmesg) output?