On 16/07/2019 15.06, Markus Armbruster wrote: > Paolo Bonzini <pbonz...@redhat.com> writes: > >> On 15/07/19 18:12, Cornelia Huck wrote: >>>> Is it INTx vs. MSI vs. MSI-X? >>> >>> I think for s390x we need (INTx || MSI) vs MSI-X... >> >> I think MSI vs MSI-X is just how it's configured, not the actual >> behavior, so it should be irrelevant. > > My best guesses from confusing information, please correct > misunderstandings: > > 1. PCI devices need to support MSI or MSI-X to work with s390x.
I think Cornelia mentioned that we might even require MSI-X there ... Collin (being listed as "S390 PCI" maintainer), can you confirm? > 2. We want a way to Kconfig the PCI devices that work, i.e. only the > ones that support MSI or MSI-X. > > I don't like calling devices without any MSI capability "classic" or > "conventional devices". I'd rather call them "MSI-capable" or > "MSI/MSI-X devices". But you still need a config switch that you can set to enable the non-MSI devices ... what's so wrong with "conventional" if that's even the wording from the PCI SIG? > Since PCI-E devices must implement MSI or MSI-X, we could perhaps > configure just the PCI-E devices for s390x. No need to invent a new > name then. Do we even have device models that can do MSI but not E? I don't know if anybody ever tried a non-virtio PCIe device from QEMU on s390x ... I guess there will be quite a bit of other hurdles, too (e.g. the Linux driver also has to work without MMIO), so I'm not sure whether we really want to enable all PCIe devices there... Thomas
