> From: Marcel Apfelbaum [mailto:[email protected]] > Subject: Re: [PATCH 2/2] pci: add check for pcie root ports and downstream > ports > > On Wed, 2014-08-20 at 03:20 +0000, Gonglei (Arei) wrote: > > 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 <[email protected]> > > > > --- > > > > 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. > Sure, > > I checked and we already have the pcie_cap_get_type function that returns the > port type. > > port_type = pcie_cap_get_type(dev); > if (port_type == PCI_EXP_TYPE_DOWNSTREAM || > port_type == PCI_EXP_TYPE_ROOT_PORT) { > ... > } > Great! Thanks a lot. :)
Best regards, -Gonglei
