On Thu, Apr 13, 2017 at 01:51:40AM +0300, [email protected] wrote: > From: Bodong Wang <[email protected]> > > 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. > > Add a new PCI sysfs interface "sriov_drivers_autoprobe" to control > that from the 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_drivers_autoprobe > > 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. > > Signed-off-by: Bodong Wang <[email protected]> > Signed-off-by: Eli Cohen <[email protected]> > Reviewed-by: Gavin Shan <[email protected]> > Reviewed-by: Alex Williamson <[email protected]> > Reviewed-by: Bjorn Helgaas <[email protected]>
Applied to pci/virtualization for v4.12, thanks, Bodong! > --- > Documentation/ABI/testing/sysfs-bus-pci | 18 ++++++++++++++++++ > Documentation/PCI/pci-iov-howto.txt | 12 ++++++++++++ > drivers/pci/iov.c | 1 + > drivers/pci/pci-driver.c | 22 ++++++++++++++++++---- > drivers/pci/pci-sysfs.c | 28 ++++++++++++++++++++++++++++ > drivers/pci/pci.h | 1 + > 6 files changed, 78 insertions(+), 4 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-bus-pci > b/Documentation/ABI/testing/sysfs-bus-pci > index 5a1732b..0878520 100644 > --- a/Documentation/ABI/testing/sysfs-bus-pci > +++ b/Documentation/ABI/testing/sysfs-bus-pci > @@ -301,3 +301,21 @@ Contact: Emil Velikov <[email protected]> > Description: > This file contains the revision field of the the PCI device. > The value comes from device config space. The file is read only. > + > +What: /sys/bus/pci/devices/.../sriov_drivers_autoprobe > +Date: April 2017 > +Contact: Bodong Wang<[email protected]> > +Description: > + This file appears when a physical PCIe device supports SR-IOV. > + Userspace applications can read and write to this file to > + determine and control the enablement(1/y/Y) or disablement > + (0/n/N) of probing Virtual Functions (VFs) by a compatible > + driver on host side. The default value is 1(enabled) which means > + VFs will be probed and bound to a compatible driver on the host > + side if SR-IOV is enabled. A typical use case is writing 0 to > + this file to disable SR-IOV drivers auto probe, then admin from > + host is able to assign the newly created VFs to virtual machines > + directly after SR-IOV is enabled. Note that, changing this file > + will not affect VFs which are already probed by host. In this > + scenario, the user must first disable SR-IOV, make the change, > + then resume SR-IOV. > diff --git a/Documentation/PCI/pci-iov-howto.txt > b/Documentation/PCI/pci-iov-howto.txt > index 2d91ae2..b6807df 100644 > --- a/Documentation/PCI/pci-iov-howto.txt > +++ b/Documentation/PCI/pci-iov-howto.txt > @@ -68,6 +68,18 @@ To disable SR-IOV capability: > echo 0 > \ > /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_numvfs > > +To enable auto probing VFs by a compatible driver on the host, run > +command bellow before enabling SR-IOV capabilities. This is the > +default behavior. > + echo 1 > \ > + > /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_drivers_autoprobe > + > +To disable auto probing VFs by a compatible driver on the host, run > +command bellow before enabling SR-IOV capabilities. Updating this > +entry will not affect VFs which are already probed. > + echo 0 > \ > + > /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_drivers_autoprobe > + > 3.2 Usage example > > Following piece of code illustrates the usage of the SR-IOV API. > diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c > index 2479ae8..d9dc736 100644 > --- a/drivers/pci/iov.c > +++ b/drivers/pci/iov.c > @@ -450,6 +450,7 @@ static int sriov_init(struct pci_dev *dev, int pos) > iov->total_VFs = total; > iov->pgsz = pgsz; > iov->self = dev; > + iov->drivers_autoprobe = true; > pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap); > pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link); > if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c > index afa7271..f99f7fe 100644 > --- a/drivers/pci/pci-driver.c > +++ b/drivers/pci/pci-driver.c > @@ -394,6 +394,18 @@ void __weak pcibios_free_irq(struct pci_dev *dev) > { > } > > +#ifdef CONFIG_PCI_IOV > +static inline bool pci_device_can_probe(struct pci_dev *pdev) > +{ > + return (!pdev->is_virtfn || pdev->physfn->sriov->drivers_autoprobe); > +} > +#else > +static inline bool pci_device_can_probe(struct pci_dev *pdev) > +{ > + return true; > +} > +#endif > + > static int pci_device_probe(struct device *dev) > { > int error; > @@ -405,10 +417,12 @@ static int pci_device_probe(struct device *dev) > return error; > > pci_dev_get(pci_dev); > - error = __pci_device_probe(drv, pci_dev); > - if (error) { > - pcibios_free_irq(pci_dev); > - pci_dev_put(pci_dev); > + if (pci_device_can_probe(pci_dev)) { > + error = __pci_device_probe(drv, pci_dev); > + if (error) { > + pcibios_free_irq(pci_dev); > + pci_dev_put(pci_dev); > + } > } > > return error; > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > index 25d010d..369c999 100644 > --- a/drivers/pci/pci-sysfs.c > +++ b/drivers/pci/pci-sysfs.c > @@ -526,10 +526,37 @@ static ssize_t sriov_numvfs_store(struct device *dev, > return count; > } > > +static ssize_t sriov_drivers_autoprobe_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct pci_dev *pdev = to_pci_dev(dev); > + > + return sprintf(buf, "%u\n", pdev->sriov->drivers_autoprobe); > +} > + > +static ssize_t sriov_drivers_autoprobe_store(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct pci_dev *pdev = to_pci_dev(dev); > + bool drivers_autoprobe; > + > + if (kstrtobool(buf, &drivers_autoprobe) < 0) > + return -EINVAL; > + > + pdev->sriov->drivers_autoprobe = drivers_autoprobe; > + > + return count; > +} > + > static struct device_attribute sriov_totalvfs_attr = > __ATTR_RO(sriov_totalvfs); > static struct device_attribute sriov_numvfs_attr = > __ATTR(sriov_numvfs, (S_IRUGO|S_IWUSR|S_IWGRP), > sriov_numvfs_show, sriov_numvfs_store); > +static struct device_attribute sriov_drivers_autoprobe_attr = > + __ATTR(sriov_drivers_autoprobe, (S_IRUGO|S_IWUSR|S_IWGRP), > + sriov_drivers_autoprobe_show, > sriov_drivers_autoprobe_store); > #endif /* CONFIG_PCI_IOV */ > > static ssize_t driver_override_store(struct device *dev, > @@ -1549,6 +1576,7 @@ static umode_t pci_dev_hp_attrs_are_visible(struct > kobject *kobj, > static struct attribute *sriov_dev_attrs[] = { > &sriov_totalvfs_attr.attr, > &sriov_numvfs_attr.attr, > + &sriov_drivers_autoprobe_attr.attr, > NULL, > }; > > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > index 8dd38e6..3ba7d58 100644 > --- a/drivers/pci/pci.h > +++ b/drivers/pci/pci.h > @@ -272,6 +272,7 @@ struct pci_sriov { > struct pci_dev *self; /* this PF */ > struct mutex lock; /* lock for setting sriov_numvfs in sysfs */ > resource_size_t barsz[PCI_SRIOV_NUM_BARS]; /* VF BAR size */ > + bool drivers_autoprobe; /* auto probing of VFs by driver */ > }; > > #ifdef CONFIG_PCI_ATS > -- > 1.7.1 >
