On Sat, Feb 14, 2009 at 12:56:44AM +0800, Andi Kleen wrote:
> Yu Zhao <[email protected]> writes:
> > +
> > +
> > +static int sriov_init(struct pci_dev *dev, int pos)
> > +{
> > + int i;
> > + int rc;
> > + int nres;
> > + u32 pgsz;
> > + u16 ctrl, total, offset, stride;
> > + struct pci_sriov *iov;
> > + struct resource *res;
> > + struct pci_dev *pdev;
> > +
> > + if (dev->pcie_type != PCI_EXP_TYPE_RC_END &&
> > + dev->pcie_type != PCI_EXP_TYPE_ENDPOINT)
> > + return -ENODEV;
> > +
>
> It would be a good idea to put a might_sleep() here just in
> case the msleep happens below and drivers call it incorrectly.
Yes, will do.
> > + pci_read_config_word(dev, pos + PCI_SRIOV_CTRL, &ctrl);
> > + if (ctrl & PCI_SRIOV_CTRL_VFE) {
> > + pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, 0);
> > + msleep(100);
>
> That's really long. Hopefully that's really needed.
It's needed according to SR-IOV spec, however, these lines clear
the VF Enable bit if the BIOS or something else has set it. So it
doesn't always run into this.
> > +
> > + pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
> > + pci_write_config_word(dev, pos + PCI_SRIOV_NUM_VF, total);
> > + pci_read_config_word(dev, pos + PCI_SRIOV_VF_OFFSET, &offset);
> > + pci_read_config_word(dev, pos + PCI_SRIOV_VF_STRIDE, &stride);
> > + if (!offset || (total > 1 && !stride))
> > + return -EIO;
> > +
> > + pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz);
> > + i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0;
> > + pgsz &= ~((1 << i) - 1);
> > + if (!pgsz)
> > + return -EIO;
>
> All the error paths don't seem to undo the config space writes.
> How will the devices behave with half initialized context?
Since the VF Enable bit is cleared before the initialization, setting
others SR-IOV registers won't change state of the device. So it should
be OK even without undo these writes as long as the VF Enable bit is
not set.
Thanks,
Yu
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