[dpdk-users] VF bound to vfio-pci fails pci_map_device

[Sowmini Varadhan <sowmini05@gmail.com>]

I am using dpdk 2.0 on a machine with a Niantic card (3.8.13 kernel),
where I have set up the SR-IOV succesfully

But when I try to run any of the examples with the sriov-vf bound to
the vfio-pci driver, I run into errors, I think it might have to do
with some DPDK env settings that are in error.

I get:

# ./build/build/app/test-pmd/testpmd -c 0xf0 -n 4
   :
  EAL:   probe driver: 8086:10ed rte_ixgbevf_pmd
  EAL: Error - exiting with code: 1
    Cause: Requested device 0000:90:10.0 cannot be used

Afaict, the error is happening because pci_map_device() is returning
an error, and in my case (dpdk-2.0.0) that is happening because
VFIO_PRESENT is not defined.

Questions are the following:

0. What is the BCP to get sriov/vfio-pci to play nicely with dpdk-2.0.0

1. what is the correct way to make sure VFIO_PRESENT is defined.
   Note thataI already have this:
      [root@brm-x52-01 dpdk-2.0.0]# grep VFIO build/.config
      CONFIG_RTE_EAL_VFIO=y

2. What else needs to be defined for VFIO to stick. I see that
   pci_vfio_is_enabled() checks for vfio_cfg.vfio_enabled, so any other
   instructions here?

3. My target is a test app that reflects back tcp or udp packets, and
   I see that testpmd at least does this for icmp (i.e., for ping). Can
   someone share some "BCP" command line to do this with testpmd?

--Sowmini