[dpdk-dev] vfio detection

["Richardson, Bruce" <bruce.richardson@intel.com>]

Hi all,

Now that vfio support has merged into the dpdk.org mainline, I'm seeing a number of issues with running applications, and I'm hoping someone can explain the observed behaviour.

I have a number of NIC ports which were working correctly yesterday and are bound correctly to the igb_uio driver - and I want to keep using them through the igb_uio driver for now, not vfio. However, whenever I run a dpdk application today, I find that the vfio kernel module is getting loaded each time - even after I manually remove it, and verify that it has been removed by checking lsmod. Is this expected? If so, why are we loading the vfio driver when I just want to continue using igb_uio which works fine?
Secondly, then, when testpmd or any other app loads, it automatically tries to map the NIC using vfio and then aborts on the very first NIC port when it fails to do so. This a) prevents the port from being mapped using igb_uio, and b) for ports which are meant to stay under linux control, forces me to start enumerating ports using blacklist or whitelisting, rather than having things "just work" on a properly configured system as before, i.e. if a port is bound to igb_uio or vfio it is used, if not bound, it is ignored. Again, is this by design and expected, because it seems a major regression in usability?

Regards,
/Bruce