On Tue, 4 Jul, 2023, 5:45 pm Igor Mammedov, <imamm...@redhat.com> wrote:
> On Tue, 4 Jul 2023 16:55:55 +0530
> Ani Sinha <anisi...@redhat.com> wrote:
>
> > This change is cosmetic. A comment is added explaining why we need to
> check for
> > the availability of function 0 when we hotplug a device.
> >
> > CC: m...@redhat.com
> > Signed-off-by: Ani Sinha <anisi...@redhat.com>
> > ---
> > hw/pci/pci.c | 12 +++++++++---
> > 1 file changed, 9 insertions(+), 3 deletions(-)
> >
> > diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> > index 47517ba3db..e3ff3808b6 100644
> > --- a/hw/pci/pci.c
> > +++ b/hw/pci/pci.c
> > @@ -1181,9 +1181,15 @@ static PCIDevice
> *do_pci_register_device(PCIDevice *pci_dev,
> > PCI_SLOT(devfn), PCI_FUNC(devfn), name,
> > bus->devices[devfn]->name, bus->devices[devfn]->
> qdev.id);
> > return NULL;
> > - } else if (dev->hotplugged &&
> > - !pci_is_vf(pci_dev) &&
> > - pci_get_function_0(pci_dev)) {
> > + } /*
> > + * Populating function 0 triggers a scan from the guest that
> > + * exposes other non-zero functions. Hence we need to ensure that
> > + * function 0 wasn't added yet.
>
> > With SRIOV and with or without ARI
> > + * the PF must be hotplugged into function 0 for it to be
> detected.
> Wouldn't the same apply to non-SR-IOV devices as well?
>
I was trying to emphasize PFs and SRIOV. But may be it adds more confusion
and better left out.
>
> > + */
> > + else if (dev->hotplugged &&
> > + !pci_is_vf(pci_dev) &&
> > + pci_get_function_0(pci_dev)) {
> > error_setg(errp, "PCI: slot %d function 0 already occupied by
> %s,"
> > " new func %s cannot be exposed to guest.",
> > PCI_SLOT(pci_get_function_0(pci_dev)->devfn),
>
>
