On Wed, Mar 30, 2016 at 10:31:18AM -0500, Babu Moger wrote: > Hi David, > > On 3/29/2016 7:57 PM, David Miller wrote: > > From: Babu Moger <babu.moger@xxxxxxxxxx> > > Date: Thu, 24 Mar 2016 13:02:22 -0700 > > > >> We noticed this panic while enabling SR-IOV in sparc. > > ... > >> SR-IOV code looks for arch specific data while enabling > >> VFs. When VF device is added, driver probe function makes set > >> of calls to initialize the pci device. Because the VF device is > >> added different way than the normal PF device(which happens via > >> of_create_pci_dev for sparc), some of the arch specific initialization > >> does not happen for VF device. That causes panic when archdata is > >> accessed. > >> > >> To fix this, I have used already defined weak function > >> pcibios_setup_device to copy archdata from PF to VF. > >> Also verified the fix. > >> > >> Signed-off-by: Babu Moger <babu.moger@xxxxxxxxxx> > >> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx> > >> Reviewed-by: Ethan Zhao <ethan.zhao@xxxxxxxxxx> > > > > Looks good, applied and queued up for -stable, thanks. > > Thanks. > > > > > Just a note, I am assuming that the VFs are not instantiated in the > > device tree. Because when you just memcpy the arch data over from the > > PF, one thing we end up doing is using the device node of the PF. > > No. VFs are not instantiated in device tree(/proc/device-tree) > > > > > I slightly cringed at the memcpy, because at least one of these > > pointers are to objects which are reference counted, the OF device. > > > > Generally speaking we don't really support hot-plug for OF probed > > devices, but if we did all of the device tree pointers have to be > > refcounted properly. > > > > So in the long term that whole sequence where we go: > > > > struct dev_archdata *sd; > > ... > > sd = &dev->dev.archdata; > > sd->iommu = pbm->iommu; > > sd->stc = &pbm->stc; > > sd->host_controller = pbm; > > sd->op = op = of_find_device_by_node(node); > > sd->numa_node = pbm->numa_node; > > > > should be encapsulated into a helper function, and both > > of_create_pci_dev() and this new pcibios_setup_device() can > > invoke it. > > > > Yes. Agree. We need to refactor the whole of_create_pci_dev path to support > hot-plug for the long term. I will start looking at it. For now we should be > fine with the current patch. thanks of_create_pci_dev() duplicates a lot of the code in pci_setup_device(). I wish we didn't have to do that because it's easy to let them get out of sync, but I don't know if there are any reasonable alternatives. I've wondered in the past whether it would be possible to use the pci_setup_device() path on sparc & powerpc by writing PCI config accessors that look up OF properties as needed to fabricate responses to config reads. Several of the drivers in drivers/pci/host/* do a little bit of this fabrication, although I don't think any go to the extent of using OF. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
