Messages in this thread | | | Subject | Re: [PATCH] pci/sriov: Add an option to probe VFs or not before enabling SR-IOV | From | Bodong Wang <> | Date | Mon, 20 Mar 2017 18:34:23 -0500 |
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On 3/20/2017 6:07 PM, Gavin Shan wrote: > On Mon, Mar 20, 2017 at 05:14:34PM +0200, bodong@mellanox.com wrote: >> From: Bodong Wang <bodong@mellanox.com> >> >> Sometimes it is not desirable to probe the virtual functions after >> SRIOV is enabled. This can save host side resource usage by VF >> instances which would be eventually probed to VMs. >> >> Added a new PCI sysfs interface "sriov_probe_vfs" to control that > >from PF, all current callers still retain the same functionality. >> To modify it, echo 0/n/N (disable probe) or 1/y/Y (enable probe) to >> >> /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_probe_vfs >> >> Note that, the choice must be made before enabling VFs. The change >> will not take effect if VFs are already enabled. Simply, one can set >> sriov_numvfs to 0, choose whether to probe or not, and then resume >> sriov_numvfs. >> > Bodong, I'm not sure if there is a requirement to load driver for the > specified number of VFs? That indicates no driver will be loaded for > other VFs. If so, this interface might serve the purpose as well. Gavin, thanks for the review. That is indeed an interesting suggestion. Theoretically, we can change that probe_vfs from boolean to integer. And use it as a counter to probe the first N VFs(if N < total_vfs). Let's see if there are any objections. > > > +#ifdef CONFIG_PCI_IOV > + if (!pci_dev->is_virtfn || > + (pci_dev->is_virtfn && pci_dev->physfn->sriov->probe_vfs)) { > +#endif > + error = __pci_device_probe(drv, pci_dev); > + if (error) { > + pcibios_free_irq(pci_dev); > + pci_dev_put(pci_dev); > + } > +#ifdef CONFIG_PCI_IOV > } > +#endif > > I think it's reasonable to have a inline function for this check: It's doable, but what's the benefit? > > #ifdef CONFIG_PCI_IOV > static inline bool pci_device_can_probe(struct pci_dev *pdev) > { > return (!pdev->is_virtfn || pdev->physfn->sriov->probe_vfs); should be return (!pdev->is_virtfn || (pci_dev->is_virtfn && pci_dev->physfn->sriov->probe_vfs));
We want to probe that device if 1) it's a PF 2) it'a VF and probe_vfs is set > } > #else > static inline bool pci_device_can_probe(struct pci_dev *pdev) > { > return true; > } This function will be a waste if CONFIG_PCI_IOV is not defined. > #endif
> Thanks, > Gavin >
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