On Wed, 17 Jul 2019 17:04:54 +0200
Paolo Bonzini <pbonz...@redhat.com> wrote:
> On 17/07/19 16:54, Collin Walling wrote:
> > PCI host plugging will check for the MSI-X capability on the
> > PCI device. If the MSI-X cap is missing, we fail device plugging.
> > We do not check for MSI. Only MSI-X.
> >
> > Specifically, the capability is represented by PCI_CAP_ID_MSIX
> > in pci_regs.h
>
> The code in Linux says that single MSIs are supported too:
>
> if (type == PCI_CAP_ID_MSI && nvec > 1)
> return 1;
Interestingly, the check for MSI-X in QEMU seems to have been
introduced in 857cc71985dc ("s390x/pci: merge msix init functions"),
but that commit does not give a rationale (maybe it just referred to the
existing code structure?)
A quick look through the code suggests that single MSIs should be
supportable; can someone with access to the details verify?
