On 07/31/2014 09:57 AM, Edward Cree wrote: > On 31/07/14 17:40, Alexander Duyck wrote: >> If this PF-IOV mode is enabled what would be the layout of the PF >> devices? It seems like you should be able to scan for multiple PFs all >> showing up on the same bus with a certain stride if you wanted to detect it. > Alas, it's (once again) more complicated than that. There's another > mode, NIC partitioning, which has multiple PFs per port but connected > with a VLAN aggregator rather than a v-switch, which means that each PF > then can support VFs (the firmware limitation is that v-switches can't > be stacked). > So having multiple PFs on the port doesn't necessarily mean we can't do > SR-IOV. Okay, so this is purely a vswitch issue then. If it is allocated for the PF-IOV it isn't available for SR-IOV. I think I understand now. >>>> In addition this solution would >>>> also resolve the fact that the driver wouldn't actually have to be >>>> loaded for it to work so if someone were to load a driver that didn't >>>> contain the fix they would be blocked from enabling SR-IOV as well. >>> The current driver fails to probe the PF because it assumes the vswitch >>> creation failure is fatal. There should never be a driver that knows it >>> can live without the vswitch but doesn't know that that breaks SR-IOV. >>> >>> -Edward >> Is the vswitch a hard requirement for something other than SR-IOV? If >> not then maybe you should consider modifying the driver so it simply >> disabled SR-IOV if you cannot allocate the vswitch instead of blocking >> probe. >> > That's exactly what I'm trying to do with pci_sriov_set_totalvfs(dev, > 0); that's the whole point. It sounds reasonable. My only real concern is the fact that the error reported when attempting to enable the interface will be a ERANGE when really a more appropriate error return might be something like a EBUSY since it is the vswitch that is occupied. You might want to take a look at modifying sriov_numvfs_store so that if the only option is 0 you return EBUSY for all non-zero values requested. This way it will be more in sync with how we handle the case of attempting to update the number of VFs when SR-IOV is already enabled. 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
