On 15/07/2019 15.38, Philippe Mathieu-Daudé wrote: > On 7/15/19 3:19 PM, Thomas Huth wrote: >> 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? > > Something like that :) > > Per Wikipedia: > > Conventional PCI and PCI-X are sometimes called Parallel PCI > in order to distinguish them technologically from their more > recent successor PCI Express, which adopted a serial, > lane-based architecture. > > The PCI-SIG introduced the serial PCI Express in c. 2004. At > the same time, they renamed PCI as Conventional PCI. > > PCI Express does not have physical interrupt lines at all. > It uses message-signaled interrupts exclusively. > > What about PCI_CONVENTIONAL then?
Sounds good to me. Thomas
