On 28-Oct-21 3:53 PM, Thomas Monjalon wrote:
28/10/2021 13:32, Ferruh Yigit:
On 10/28/2021 12:11 PM, Xia, Chenbo wrote:
-----Original Message-----
From: Burakov, Anatoly <anatoly.bura...@intel.com>
Sent: Thursday, October 28, 2021 6:30 PM
To: Xia, Chenbo <chenbo....@intel.com>; dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v1 1/2] vfio: make API return values consistent
Hi Chenbo,
And do we need backport? As 'return -1' does not align with the API doxygen.
Thanks,
Chenbo
Maybe it's the FreeBSD implementation that needs to be adjusted then,
because none of those functions are valid on FreeBSD, and the
documentation for VFIO functions explicitly mentions that on FreeBSD,
they should return an error. I went with adjusting Linux implementation
to minimize the amount of changes we have to make (and only change code
path that no one uses in the first place), but maybe that was a wrong
decision.
I'm not sure if changing the API return value to match what was
documented counts as an API change, so maybe backport to stable is not
advised here.
It's not a API change. My point is whether VFIO is present, users just use
the API to check if vfio support is there. In a kernel version that does not
support VFIO, he uses 'if(rte_vfio_is_enabled(XXX))' to check as the doxygen
says its return value should be 1 as true or 0 as false. He will get true (-1)
but VFIO is not there. That's why I think it's a bug and should be backported.
But I think we can first discuss if we should drop the dummy implementation
as DPDK requires Linux kernel version >= 4.4 now so VFIO is always present.
I think it depends on by saying 'DPDK requires kernel version >= 4.4'. It's
a real _requirement_ or only a recommendation?
Ferruh, David & Thomas, What do you think?
My understanding is, it is a requirement. DPDK does not guarantee support for
kernels < 4.4.
Do we have a kernel version check at runtime?
I think we should add a warning if running too old kernel.
Perhaps we should (there's a `uname()` call, should be fairly
straightforward to implement), but obviously this would be outside the
scope for this patchset.
--
Thanks,
Anatoly
