On 9/11/24 11:15 AM, Akihiko Odaki wrote:
On 2024/09/11 22:53, Matthew Rosato wrote:
On 9/11/24 6:58 AM, Akihiko Odaki wrote:
On 2024/09/11 18:38, Cédric Le Goater wrote:
+Matthew +Eric
Side note for the maintainers :
Before this change, the igb device, which is multifunction, was working
fine under Linux.
Was there a fix in Linux since :
57da367b9ec4 ("s390x/pci: forbid multifunction pci device")
6069bcdeacee ("s390x/pci: Move some hotplug checks to the pre_plug
handler")
?
The timing of those particular commits predates the linux s390 kernel support
of multifunction/SR-IOV. At that time it was simply not possible on s390.
Is it OK to remove this check of multifunction now?
Yes, I think removing the check (which AFAIU was broken since 6069bcdeacee)
will get us back to the behavior Cedric was seeing, where a device that reports
multifunction in the config space is still allowed through but only the PF will
be usable in the guest.
This code is not working properly with SR-IOV and misleading. It is better to
remove the code if it does no good.
It would be nice if anyone confirms multifunction works for s390x with the code
removed.
Even if you remove the check, multifunction itself won't work in the s390x
guest without these missing CLP pieces too. When I have some time I'll hack
something together to fabricate some CLP data and try it out, but it sounds
like Cedric could use his setup to right now at least verify that the PF itself
should remain usable in the guest (current behavior).