Hi,
> > Right now, ARI Forwarding dose not support in QEMU.
> I would replace the above sentence with "ARI Forwarding is not supported".
>
OK.
> By the way, there is some support for ARI, I don't know if
> is enabled yet. I'll have a look.
>
MST had pointed out the pcie_ari_init(), but not completed.
> > According to PCIe spec section 7.3.1, only slot 0 with
> > the device attached to logic bus representing the link from
> > downstream ports and root ports.
> >
> > So, adding check about slot 0 for PCIe downstream ports and
> > root ports, which avoid useless operation, both hotplug and
> > coldplug.
> >
> > Signed-off-by: Gonglei <arei.gong...@huawei.com>
> > ---
> > hw/pci/pci.c | 41 +++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 41 insertions(+)
> >
> > diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> > index 351d320..f2d267f 100644
> > --- a/hw/pci/pci.c
> > +++ b/hw/pci/pci.c
> > @@ -773,6 +773,42 @@ static int pci_init_multifunction(PCIBus *bus,
> PCIDevice *dev)
> > return 0;
> > }
> >
> > +static int pci_check_pcie_port(PCIBus *bus, PCIDevice *dev)
> > +{
> > + Object *obj = OBJECT(bus);
> > +
> > + if (!strcmp(object_get_typename(obj), TYPE_PCIE_BUS)) {
> Maybe there is another way to check that this is a PCIe bus?
>
Yes. Paolo has said that object_dynamic_cast() is appropriated.
> > + DeviceState *parent = qbus_get_parent(BUS(obj));
> > + const char *name = object_get_typename(OBJECT(parent));
> > +
> > + /*
> > + * Root ports and downstream ports of switches are the hot
> > + * pluggable ports in a PCI Express hierarchy.
> > + * PCI Express supports chip-to-chip interconnect, a PCIe link can
> > + * only connect one pci device/Switch/EndPoint or PCI-bridge.
> > + *
> > + * 7.3. Configuration Transaction Rules (PCI Express specification
> 3.0)
> > + * 7.3.1. Device Number
> > + *
> > + * Downstream Ports that do not have ARI Forwarding enabled
> must
> > + * associate only Device 0 with the device attached to the Logical
> Bus
> > + * representing the Link from the Port.
> > + *
> > + * Right now, ARI Forwarding dose not support. So, only slot 0 is
> As above, maybe replace it with "ARI Forwarding is not supported"
>
OK.
> > + * supported, regardless of hotplug or coldplug.
> > + */
> > + if (!strcmp(name, "ioh3420") || !strcmp(name,
> "xio3130-downstream")) {
> Please use port_type flag from extended configuration space, don't use device
> names.
> If you need help for this, let me know.
>
Yes, please. I appreciate very much that you can help me.
> > + if (PCI_SLOT(dev->devfn) != 0) {
> > + error_report("Unsupported PCI slot %d for %s ports,
> only "
> > + "supported slot 0",
> PCI_SLOT(dev->devfn), name);
> > + return -1;
> > + }
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > static void pci_config_alloc(PCIDevice *pci_dev)
> > {
> > int config_size = pci_config_size(pci_dev);
> > @@ -871,6 +907,11 @@ static PCIDevice
> *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
> > return NULL;
> > }
> >
> > + if (pci_check_pcie_port(bus, pci_dev)) {
> > + do_pci_unregister_device(pci_dev);
> > + return NULL;
> > + }
> It is possible to move the above check earlier in do_pci_register_device
> function?
> Maybe move it into the first if statement(s)?
>
Agreed, Thanks, Marcel.
Best regards,
-Gonglei
