> -----Original Message----- > From: Alex Williamson [mailto:alex.williamson@xxxxxxxxxx] > Sent: Friday, December 08, 2017 6:35 PM > To: Alexander Duyck <alexander.duyck@xxxxxxxxx> > Cc: Kirsher, Jeffrey T <jeffrey.t.kirsher@xxxxxxxxx>; Wang, Liang-min <liang- > min.wang@xxxxxxxxx>; kvm@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; Bjorn Helgaas <bhelgaas@xxxxxxxxxx>; Duyck, > Alexander H <alexander.h.duyck@xxxxxxxxx> > Subject: Re: [PATCH v2] Enable SR-IOV instantiation through /sys file > > On Fri, 8 Dec 2017 15:19:18 -0800 > Alexander Duyck <alexander.duyck@xxxxxxxxx> wrote: > > > On Fri, Dec 8, 2017 at 2:58 PM, Alex Williamson > > <alex.williamson@xxxxxxxxxx> wrote: > > > On Fri, 8 Dec 2017 13:47:58 -0800 > > > Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx> wrote: > > > > > >> From: Liang-Min Wang <liang-min.wang@xxxxxxxxx> > > >> > > >> When a SR-IOV capable device is bound with vfio-pci, the > > >> device loses capability of creating SR-IOV instances through /sy/bus/ > > >> pci/devices/.../sriov_numvfs. This patch re-activates this capability > > >> for a PCIe device that is SR-IOV capable and is bound with vfio-pci.ko. > > >> This patch also disables drivers_autoprobe attribute of SR-IOV devices > > >> created from vfio-pci bound device by default, so user-space PF device > > >> can coordinate the bring-up of SR-IOV devices > > >> > > >> Signed-off-by: Liang-Min Wang <liang-min.wang@xxxxxxxxx> > > >> --- > > >> drivers/pci/pci-driver.c | 12 ++++++++++++ > > >> drivers/vfio/pci/vfio_pci.c | 22 ++++++++++++++++++++++ > > >> include/linux/pci.h | 1 + > > >> 3 files changed, 35 insertions(+) > > >> > > >> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c > > >> index 7f47bb7..19522fe 100644 > > >> --- a/drivers/pci/pci-driver.c > > >> +++ b/drivers/pci/pci-driver.c > > >> @@ -1467,6 +1467,18 @@ void pci_dev_put(struct pci_dev *dev) > > >> } > > >> EXPORT_SYMBOL(pci_dev_put); > > >> > > >> +/** > > >> + * pci_dev_sriov_autoprobe_set - set device sriov driver autoprobe > > >> + * @dev: device with which sriov autoprobe will be set > > >> + * > > >> + */ > > >> +void pci_dev_sriov_autoprobe_set(struct pci_dev *dev, bool autoprobe) > > >> +{ > > >> + if (dev && dev->sriov) > > >> + dev->sriov->drivers_autoprobe = autoprobe; > > >> +} > > >> +EXPORT_SYMBOL(pci_dev_sriov_autoprobe_set); > > > > > > _GPL? > > > > > > It'd also be best to separate the pci and vfio changes into different > > > patches. Bjorn would need to at least ack this PCI interface. > > > > > >> + > > >> static int pci_uevent(struct device *dev, struct kobj_uevent_env *env) > > >> { > > >> struct pci_dev *pdev; > > >> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c > > >> index f041b1a..004836c 100644 > > >> --- a/drivers/vfio/pci/vfio_pci.c > > >> +++ b/drivers/vfio/pci/vfio_pci.c > > >> @@ -1213,6 +1213,8 @@ static int vfio_pci_probe(struct pci_dev *pdev, > const struct pci_device_id *id) > > >> return -ENOMEM; > > >> } > > >> > > >> + /* disable sriov automatic driver attachment */ > > >> + pci_dev_sriov_autoprobe_set(pdev, false); > > > > > > This looks stateful, VF autoprobe is not restored on release. Also, > > > how would we know the initial state to restore it to? > > > > The initial state is whatever the user set it to. It is something that > > can be toggled on and off via sysfs, and it defaults to true at > > initialization. In this case we are opting to toggle it off when VFIO > > is attached to the device. Restoring it after unloading the driver > > might be even more confusing since it is something the user could > > toggle at any time so a restore would end up overwriting that. > > I'm not really willing to sign up for the inevitable bug reports when > users can't figure out how to make their VFs work again in the host > after they've used the PF for userspace drivers with vfio-pci. I > agree, both options are confusing, how do we make it not confusing? > Can PCI core reset the autoprobe attribute to the default at some > obvious point? Thanks, > I would like to confirm the scenario discussed here is to unload PF driver, right? Since users need to release all SR-IOV from PF driver first before PF driver is released, does it make sense to restore autoprobe when VFs are released? > Alex
