override B:D:F assignments for SRIOV VFs

override B:D:F assignments for SRIOV VFs

[Andre Richter]

Hello all,

i have an SRIOV capable device which has its PF behind 01:00.0.
After enabling SRIOV, the VFs show up as 01:08.0, 01:08.1 and so on.

Due to several stupid reasons, I'd like to do a quick and dirty hack
that makes my VFs show up as 01:00.1, 01:00.2 and so on.

I'd be so happy for any hints where to start with this.

What I found already is virtfn_devfn() in iov.c, where the devfns for
the VFs are computed, but changing it here doesn't work. I guess this
has to be done way before?
However, I wonder where the rule for computing the devfn comes from?

Thanks, Andre

Re: override B:D:F assignments for SRIOV VFs

[Alex Williamson]

On Wed, 2013-10-02 at 21:10 +0200, Andre Richter wrote:
> Hello all,
> 
> i have an SRIOV capable device which has its PF behind 01:00.0.
> After enabling SRIOV, the VFs show up as 01:08.0, 01:08.1 and so on.
> 
> Due to several stupid reasons, I'd like to do a quick and dirty hack
> that makes my VFs show up as 01:00.1, 01:00.2 and so on.
> 
> I'd be so happy for any hints where to start with this.
> 
> What I found already is virtfn_devfn() in iov.c, where the devfns for
> the VFs are computed, but changing it here doesn't work. I guess this
> has to be done way before?
> However, I wonder where the rule for computing the devfn comes from?

Can't be done, the VF address is determined by the stride and offset in
the SR-IOV capability on the PF which are read-only per the SR-IOV spec.
The kernel doesn't get to decide where they appear.  Thanks,

Alex