[dpdk-dev] [PATCH v4 2/4] eal: fix IOVA mode selection as VA for PCI drivers

[Thomas Monjalon]

25/11/2019 10:33, Ferruh Yigit:
> It looks like DPDK application initialized as IOVA=VA,
> and the new device is bound to 'igb_uio' which forces it to PA,
> fails on above check.

Do you mean this use case was not tested earlier with DPDK 19.08?


> I would like to get your comment on the issue.
> 
> For the OvS mode, hopefully binding the device to 'vfio-pci'
> can be a solution, but for the cases we don't have that option,
> can/should we force the DPDK to PA mode after initialization?

I think this is expected, because VA is the new default since 19.08:
http://doc.dpdk.org/guides/rel_notes/release_19_08.html#new-features

In case, there is no constraint on initialization,
we have to decide which mode is preferred.
Previously PA was preferred.
For the sake of modernity (and because it fits with some new devices),
the preference has been changed to VA.

If igb_uio device is used at initialization,
the PA mode should be used.
If igb_uio (PA-only) device is hotplugged, no luck!
If VA-only device is hotplugged, it works!

I think this change is one step in deprecating igb_uio.