On Tue, Mar 10, 2015 at 09:55:19PM -0500, Bjorn Helgaas wrote:
>On Wed, Mar 04, 2015 at 11:01:24AM +0800, Wei Yang wrote:
>> On Tue, Feb 24, 2015 at 03:00:37AM -0600, Bjorn Helgaas wrote:
>> >On Tue, Feb 24, 2015 at 02:34:57AM -0600, Bjorn Helgaas wrote:
>> >> From: Wei Yang <weiyang@xxxxxxxxxxxxxxxxxx>
>> >>
>> >> On PowerNV platform, resource position in M64 implies the PE# the resource
>> >> belongs to. In some cases, adjustment of a resource is necessary to locate
>> >> it to a correct position in M64.
>> >>
>> >> Add pnv_pci_vf_resource_shift() to shift the 'real' PF IOV BAR address
>> >> according to an offset.
>> >>
>> >> [bhelgaas: rework loops, rework overlap check, index resource[]
>> >> conventionally, remove pci_regs.h include, squashed with next patch]
>> >> Signed-off-by: Wei Yang <weiyang@xxxxxxxxxxxxxxxxxx>
>> >> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>> >
>> >...
>> >
>> >> +#ifdef CONFIG_PCI_IOV
>> >> +static int pnv_pci_vf_resource_shift(struct pci_dev *dev, int offset)
>> >> +{
>> >> + struct pci_dn *pdn = pci_get_pdn(dev);
>> >> + int i;
>> >> + struct resource *res, res2;
>> >> + resource_size_t size;
>> >> + u16 vf_num;
>> >> +
>> >> + if (!dev->is_physfn)
>> >> + return -EINVAL;
>> >> +
>> >> + /*
>> >> + * "offset" is in VFs. The M64 windows are sized so that when they
>> >> + * are segmented, each segment is the same size as the IOV BAR.
>> >> + * Each segment is in a separate PE, and the high order bits of the
>> >> + * address are the PE number. Therefore, each VF's BAR is in a
>> >> + * separate PE, and changing the IOV BAR start address changes the
>> >> + * range of PEs the VFs are in.
>> >> + */
>> >> + vf_num = pdn->vf_pes;
>> >> + for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
>> >> + res = &dev->resource[i + PCI_IOV_RESOURCES];
>> >> + if (!res->flags || !res->parent)
>> >> + continue;
>> >> +
>> >> + if (!pnv_pci_is_mem_pref_64(res->flags))
>> >> + continue;
>> >> +
>> >> + /*
>> >> + * The actual IOV BAR range is determined by the start address
>> >> + * and the actual size for vf_num VFs BAR. This check is to
>> >> + * make sure that after shifting, the range will not overlap
>> >> + * with another device.
>> >> + */
>> >> + size = pci_iov_resource_size(dev, i + PCI_IOV_RESOURCES);
>> >> + res2.flags = res->flags;
>> >> + res2.start = res->start + (size * offset);
>> >> + res2.end = res2.start + (size * vf_num) - 1;
>> >> +
>> >> + if (res2.end > res->end) {
>> >> + dev_err(&dev->dev, "VF BAR%d: %pR would extend past %pR (trying to enable %d VFs shifted by %d)\n",
>> >> + i, &res2, res, vf_num, offset);
>> >> + return -EBUSY;
>> >> + }
>> >> + }
>> >> +
>> >> + for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
>> >> + res = &dev->resource[i + PCI_IOV_RESOURCES];
>> >> + if (!res->flags || !res->parent)
>> >> + continue;
>> >> +
>> >> + if (!pnv_pci_is_mem_pref_64(res->flags))
>> >> + continue;
>> >> +
>> >> + size = pci_iov_resource_size(dev, i + PCI_IOV_RESOURCES);
>> >> + res2 = *res;
>> >> + res->start += size * offset;
>> >
>> >I'm still not happy about this fiddling with res->start.
>> >
>> >Increasing res->start means that in principle, the "size * offset" bytes
>> >that we just removed from res are now available for allocation to somebody
>> >else. I don't think we *will* give that space to anything else because of
>> >the alignment restrictions you're enforcing, but "res" now doesn't
>> >correctly describe the real resource map.
>> >
>> >Would you be able to just update the BAR here while leaving the struct
>> >resource alone? In that case, it would look a little funny that lspci
>> >would show a BAR value in the middle of the region in /proc/iomem, but
>> >the /proc/iomem region would be more correct.
>>
>> Bjorn,
>>
>> I did some tests, while the result is not good.
>>
>> What I did is still write the shifted resource address to the device by
>> pci_update_resource(), but I revert the res->start to the original one. If
>> this step is not correct, please let me know.
>>
>> This can't work since after we revert the res->start, those VFs will be given
>> resources from res->start instead of (res->start + offset * size). This is not
>> what we expect.
>
>Hmm, yes, I suppose we'd have to have a hook in pci_bus_alloc_from_region()
>or something. That's getting a little messy. I still don't like messing
>with the resource after it's in the resource tree, but I don't have a
>better idea right now. So let's just go with what you have.
>
Thanks :-)
I would state this in the change log and add a comment in the code to note
this down. Hope this would be a little helpful.
>> >> +
>> >> + dev_info(&dev->dev, "VF BAR%d: %pR shifted to %pR (enabling %d VFs shifted by %d)\n",
>> >> + i, &res2, res, vf_num, offset);
>> >> + pci_update_resource(dev, i + PCI_IOV_RESOURCES);
>> >> + }
>> >> + pdn->max_vfs -= offset;
>> >> + return 0;
>> >> +}
>> >> +#endif /* CONFIG_PCI_IOV */
>>
>> --
>> Richard Yang
>> Help you, Help me
>>
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--
Richard Yang
Help you, Help me
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