On 07/30/2014 11:24 AM, Edward Cree wrote: > On 30/07/14 19:05, Don Dutile wrote: >> On 07/30/2014 01:16 PM, Edward Cree wrote: >>> Calling pci_sriov_set_totalvfs(dev, 0) has no effect, because >>> pci_sriov_get_totalvfs ignores dev->sriov->driver_max_VFs if it's 0, >>> as that is used as the 'not set' value. >>> So, three questions: >>> a) is this a bug? >>> b) if not, should the comment on pci_sriov_set_totalvfs mention that >>> passing numvfs=0 will be interpreted as numvfs=dev->sriov->total_VFs? >>> c) is there a better way of indicating "current configuration doesn't >>> support VFs" rather than calling set_totalvfs(0)? >>> >>> Thanks, >>> -Edward >> >> The file shouldn't exist if the device doesn't provide an SRIOV >> capability. >> If it does, and it's not supported, then add a patch in quirks.c. >> >> > I don't know much about quirks, but I'm not sure they're the answer > here, as it's not quite as simple as "driver doesn't support it". > It's a firmware / configuration issue, that if the device (it's a NIC) > is configured a certain way [1], the VFs - while appearing fine from a > PCI perspective - don't actually work (they can't pass traffic). > We can't detect this misconfiguration until PF probe time, and we need a > way to report that the VFs aren't usable. > > Can quirks handle this? > > -Edward > > [1] SFC9120-based NICs support multiple PFs per port and these can be > used as a kind of "poor-man's SR-IOV" (we're calling it 'PF-IOV') by > placing the firmware v-switch below the PFs. However, this then > precludes adding a v-switch above the PF to direct VF traffic, meaning > that VFs are useless in this configuration. Consequently, our > configuration tools won't allow VFs and PF-IOV to be enabled > simultaneously, but bugs or corruption could cause this to happen. My $.02 on the issue would be to simply have sriov_configure return an error indicating the resources are not available if you have the PF-IOV mode enabled it is consuming the VF v-switch resources. Thanks, Alex -- 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
