Re: [Xen-devel] [PATCH] Dom0 PCI: fix SR-IOV function dependency link problem

[Yu Zhao <yu.zhao@xxxxxxxxx>]

Isaku Yamahata wrote:
> On Wed, Jun 03, 2009 at 01:41:34PM +0800, Yu Zhao wrote:
> > PCIe Root Complex Integrated Endpoint does not implement ARI, so this
> > kind of endpoint uses 3-bit function number. The function dependency
> > link of the integrated endpoint should be calculated using the device
> > number field in conjunction with the value from function dependency
> > link register.
> >
> > Normal SR-IOV endpoint always implements ARI and the function dependency
> > link register contains 8-bit function number (i.e. `devfn' from software
> > perspective).
> >
> > Signed-off-by: Yu Zhao <yu.zhao@xxxxxxxxx>
> > # HG changeset patch
> > # User Yu Zhao <yu.zhao@xxxxxxxxx>
> > # Date 1244007161 -28800
> > # Node ID 3a959a6975152b741389d2eed1823d55be4f2889
> > # Parent  ec3442c2ed48eb11fcacd3fe31af48932f0a6645
> > PCI: fix SR-IOV function dependency link problem
> >
> > PCIe Root Complex Integrated Endpoint does not implement ARI, so this
> > kind of endpoint uses 3-bit function number. The function dependency
> > link of the integrated endpoint should be calculated using the device
> > number field in conjunction with the value from function dependency
> > link register.
> >
> > Normal SR-IOV endpoint always implements ARI and the function dependency
> > link register contains 8-bit function number (i.e. `devfn' from software
> > perspective).
> >
> > Signed-off-by: Yu Zhao <yu.zhao@xxxxxxxxx>
> >
> > diff -r ec3442c2ed48 -r 3a959a697515 drivers/pci/iov.c
> > --- a/drivers/pci/iov.c Wed Jun 03 13:30:08 2009 +0800
> > +++ b/drivers/pci/iov.c Wed Jun 03 13:32:41 2009 +0800
> > @@ -366,6 +366,8 @@
> >         iov->self = dev;
> >         pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
> >         pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link);
> > +       if (!dev->bus->number)    /* Root Complex Integrated Endpoint */
> > +               iov->link = PCI_DEVFN(PCI_SLOT(dev->devfn), iov->link);
> >  
> >  	if (pdev)
> >                 iov->dev = pci_dev_get(pdev);
> Possibly the above check may work.
> But pci capability list should be examined.
> something like
>   rpcap = pci_find_capability(pdev, PCI_CAP_ID_EXP);
>   if (!rpcap)
>           pci_read_config_word(pdev, rpcap + PCI_CAP_FLAGS, &cap);
>           if (cap == PCI_EXP_TYPE_RC_END)
It will works well since the capability check is already done before 
doing anything else:
int pci_iov_init(struct pci_dev *dev)
{
        int pos;

        pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
        if (pos)
                return sriov_init(dev, pos);

        return -ENODEV;
}

Thanks,
Yu

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel