On 15/07/2019 13.09, Cornelia Huck wrote: > On Mon, 15 Jul 2019 13:04:28 +0200 > Philippe Mathieu-Daudé <phi...@redhat.com> wrote: > >> On 7/15/19 12:56 PM, Cornelia Huck wrote: >>> On Mon, 15 Jul 2019 12:48:55 +0200 >>> Thomas Huth <th...@redhat.com> wrote: >>> >>>> On 15/07/2019 12.19, Peter Maydell wrote: >>>>> On Mon, 15 Jul 2019 at 11:15, Thomas Huth <th...@redhat.com> wrote: >>>>>> >>>>>> On 15/07/2019 11.55, Philippe Mathieu-Daudé wrote: >>>>>>> If a controller device provides a PCI bus, we can plug any PCI >>>>>>> daughter card on it. >>>>>>> >>>>>>> Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com> >>>>>>> --- >>>>> >>>>>>> diff --git a/hw/pci/Kconfig b/hw/pci/Kconfig >>>>>>> index 77f8b005ff..0f7267db35 100644 >>>>>>> --- a/hw/pci/Kconfig >>>>>>> +++ b/hw/pci/Kconfig >>>>>>> @@ -1,5 +1,6 @@ >>>>>>> config PCI >>>>>>> bool >>>>>>> + imply PCI_DEVICES >>>>>> >>>>>> No, please don't change this. This was done on purpose, since almost all >>>>>> PCI_DEVICES do not work on s390x (so s390x does *not* imply >>>>>> PCI_DEVICES). >>>>> >>>>> But that means that every board that provides PCI has to have an >>>>> "imply PCI_DEVICES" line, which is pretty clunky just to work >>>>> around an s390x limitation. >>>>> >>>>> Is there some way in the Kconfig syntax for s390x to say >>>>> "no PCI_DEVICES" so we can have the corner-case be handled >>>>> by the s390x Kconfig in one place rather than in 20 places >>>>> affecting everywhere except s390x? >>>> >>>> IIRC the problem on s390x are the legacy IRQs. s390x has only MSIs. So I >>>> guess the correct way to fix this would be to introduce some >>>> PCI_LEGACY_IRQ switch and let all old devices that do not work with MSI >>>> depend on it. >>> >>> s/MSI/MSI-X/, IIRC. Not sure how far 'legacy' would stretch. >> >> Maybe we can have something like PCI_LEGACY_DEVICES and PCI_MSI_DEVICES? >> >> So if s390x only selects PCI_LEGACY (not PCI_MSI) bus, then it only get >> legacy devices? > > Wrong way around? We need MSI-X for s390x, not plain MSI or > 'legacy' (whatever that is).
With "legacy" I meant the old level-triggered interrupts from the early PCI (non-express) days. Sorry for being imprecise here. So maybe we need two new switches, PCI_CLASSIC (or so) and PCI_MSIX, and then the PCI devices should be marked with "default y if PCI_CLASSIC" if they do not have MSIX support, and with "default y if PCI_MSIX" if they have MSI-X support? Thomas Thomas
