Messages in this thread | | | Subject | Re: [PATCH v2] PCI: Introduce flag for detached virtual functions | From | Matthew Rosato <> | Date | Thu, 13 Aug 2020 09:11:20 -0400 |
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On 8/13/20 8:34 AM, Niklas Schnelle wrote: > > > On 8/13/20 12:40 PM, Niklas Schnelle wrote: >> >> >> On 8/13/20 11:59 AM, Oliver O'Halloran wrote: >>> On Thu, Aug 13, 2020 at 7:00 PM Niklas Schnelle <schnelle@linux.ibm.com> wrote: >>>> >>>> >>>> On 8/13/20 3:55 AM, Oliver O'Halloran wrote: >>>>> On Thu, Aug 13, 2020 at 5:21 AM Matthew Rosato <mjrosato@linux.ibm.com> wrote: >>>>>> *snip* >>>>>> diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c >>>>>> index 3902c9f..04ac76d 100644 >>>>>> --- a/arch/s390/pci/pci.c >>>>>> +++ b/arch/s390/pci/pci.c >>>>>> @@ -581,6 +581,14 @@ int pcibios_enable_device(struct pci_dev *pdev, int mask) >>>>>> { >>>>>> struct zpci_dev *zdev = to_zpci(pdev); >>>>>> >>>>>> + /* >>>>>> + * If we have a VF on a non-multifunction bus, it must be a VF that is >>>>>> + * detached from its parent PF. We rely on firmware emulation to >>>>>> + * provide underlying PF details. >>>>>> + */ >>>>>> + if (zdev->vfn && !zdev->zbus->multifunction) >>>>>> + pdev->detached_vf = 1; >>>>> >>>>> The enable hook seems like it's a bit too late for this sort of >>>>> screwing around with the pci_dev. Anything in the setup path that >>>>> looks at ->detached_vf would see it cleared while anything that looks >>>>> after the device is enabled will see it set. Can this go into >>>>> pcibios_add_device() or a fixup instead? >>>>> >>>> >>>> This particular check could go into pcibios_add_device() yes. >>>> We're also currently working on a slight rework of how >>>> we establish the VF to parent PF linking including the sysfs >>>> part of that. The latter sadly can only go after the sysfs >>>> for the virtfn has been created and that only happens >>>> after all fixups. We would like to do both together because >>>> the latter sets pdev->is_virtfn which I think is closely related. >>>> >>>> I was thinking of starting another discussion >>>> about adding a hook that is executed just after the sysfs entries >>>> for the PCI device are created but haven't yet. >>> >>> if all you need is sysfs then pcibios_bus_add_device() or a bus >>> notifier should work >> >> So this might go a bit off track but the problem is that >> on s390 a VF can be disabled and reenabled with disable_slot()/enable_slot(). >> In this case pcibios_bus_add_device() is not called again but >> the PF/VF link needs to be reestablished. > > Scratch that I must have made some stupid mistake last time I tried > this, with your suggestion I tried again and it works perfectly > moving the setup into pcibios_bus_add_device(). > Thank you, this is actually much nicer! >
OK, and I can likewise relocate the setting of detached_vf to pcibios_bus_add_device().
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