From 1789382a72a537447d65ea4131d8bcc1ad85ce7b Mon Sep 17 00:00:00 2001 From: Donald Dutile Date: Mon, 5 Nov 2012 15:20:36 -0500 Subject: PCI: SRIOV control and status via sysfs Provide files under sysfs to determine the maximum number of VFs an SR-IOV-capable PCIe device supports, and methods to enable and disable the VFs on a per-device basis. Currently, VF enablement by SR-IOV-capable PCIe devices is done via driver-specific module parameters. If not setup in modprobe files, it requires admin to unload & reload PF drivers with number of desired VFs to enable. Additionally, the enablement is system wide: all devices controlled by the same driver have the same number of VFs enabled. Although the latter is probably desired, there are PCI configurations setup by system BIOS that may not enable that to occur. Two files are created for the PF of PCIe devices with SR-IOV support: sriov_totalvfs Contains the maximum number of VFs the device could support as reported by the TotalVFs register in the SR-IOV extended capability. sriov_numvfs Contains the number of VFs currently enabled on this device as reported by the NumVFs register in the SR-IOV extended capability. Writing zero to this file disables all VFs. Writing a positive number to this file enables that number of VFs. These files are readable for all SR-IOV PF devices. Writes to the sriov_numvfs file are effective only if a driver that supports the sriov_configure() method is attached. Signed-off-by: Donald Dutile Signed-off-by: Bjorn Helgaas --- include/linux/pci.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/pci.h') diff --git a/include/linux/pci.h b/include/linux/pci.h index ee2179546c6..7ef8fba319d 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -573,6 +573,7 @@ struct pci_driver { int (*resume_early) (struct pci_dev *dev); int (*resume) (struct pci_dev *dev); /* Device woken up */ void (*shutdown) (struct pci_dev *dev); + int (*sriov_configure) (struct pci_dev *dev, int num_vfs); /* PF pdev */ const struct pci_error_handlers *err_handler; struct device_driver driver; struct pci_dynids dynids; -- cgit v1.2.3-70-g09d2 From bff73156d3ad661655e6d9ef04c2284cf3abb0f1 Mon Sep 17 00:00:00 2001 From: Donald Dutile Date: Mon, 5 Nov 2012 15:20:37 -0500 Subject: PCI: Provide method to reduce the number of total VFs supported Some implementations of SRIOV provide a capability structure value of TotalVFs that is greater than what the software can support. Provide a method to reduce the capability structure reported value to the value the driver can support. This ensures sysfs reports the current capability of the system, hardware and software. Example for its use: igb & ixgbe -- report 8 & 64 as TotalVFs, but drivers only support 7 & 63 maximum. Signed-off-by: Donald Dutile Signed-off-by: Bjorn Helgaas --- drivers/pci/iov.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ drivers/pci/pci-sysfs.c | 4 ++-- drivers/pci/pci.h | 1 + include/linux/pci.h | 10 ++++++++++ 4 files changed, 60 insertions(+), 2 deletions(-) (limited to 'include/linux/pci.h') diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index aeccc911abb..f6781e42d00 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -735,3 +735,50 @@ int pci_num_vf(struct pci_dev *dev) return dev->sriov->nr_virtfn; } EXPORT_SYMBOL_GPL(pci_num_vf); + +/** + * pci_sriov_set_totalvfs -- reduce the TotalVFs available + * @dev: the PCI PF device + * numvfs: number that should be used for TotalVFs supported + * + * Should be called from PF driver's probe routine with + * device's mutex held. + * + * Returns 0 if PF is an SRIOV-capable device and + * value of numvfs valid. If not a PF with VFS, return -EINVAL; + * if VFs already enabled, return -EBUSY. + */ +int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs) +{ + if (!dev || !dev->is_physfn || (numvfs > dev->sriov->total)) + return -EINVAL; + + /* Shouldn't change if VFs already enabled */ + if (dev->sriov->ctrl & PCI_SRIOV_CTRL_VFE) + return -EBUSY; + else + dev->sriov->drvttl = numvfs; + + return 0; +} +EXPORT_SYMBOL_GPL(pci_sriov_set_totalvfs); + +/** + * pci_sriov_get_totalvfs -- get total VFs supported on this devic3 + * @dev: the PCI PF device + * + * For a PCIe device with SRIOV support, return the PCIe + * SRIOV capability value of TotalVFs or the value of drvttl + * if the driver reduced it. Otherwise, -EINVAL. + */ +int pci_sriov_get_totalvfs(struct pci_dev *dev) +{ + if (!dev || !dev->is_physfn) + return -EINVAL; + + if (dev->sriov->drvttl) + return dev->sriov->drvttl; + else + return dev->sriov->total; +} +EXPORT_SYMBOL_GPL(pci_sriov_get_totalvfs); diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 74508c63bd4..99b5f83d246 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -411,7 +411,7 @@ static ssize_t sriov_totalvfs_show(struct device *dev, { struct pci_dev *pdev = to_pci_dev(dev); - return sprintf(buf, "%u\n", pdev->sriov->total); + return sprintf(buf, "%u\n", pci_sriov_get_totalvfs(pdev)); } @@ -452,7 +452,7 @@ static ssize_t sriov_numvfs_store(struct device *dev, } /* if enabling vf's ... */ - total = pdev->sriov->total; + total = pci_sriov_get_totalvfs(pdev); /* Requested VFs to enable < totalvfs and none enabled already */ if ((num_vfs > 0) && (num_vfs <= total)) { if (pdev->sriov->nr_virtfn == 0) { diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 6f6cd145bb7..553bbba76ee 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -240,6 +240,7 @@ struct pci_sriov { u16 stride; /* following VF stride */ u32 pgsz; /* page size for BAR alignment */ u8 link; /* Function Dependency Link */ + u16 drvttl; /* max num VFs driver supports */ struct pci_dev *dev; /* lowest numbered PF */ struct pci_dev *self; /* this PF */ struct mutex lock; /* lock for VF bus */ diff --git a/include/linux/pci.h b/include/linux/pci.h index 7ef8fba319d..1ad824966e6 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1611,6 +1611,8 @@ extern int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn); extern void pci_disable_sriov(struct pci_dev *dev); extern irqreturn_t pci_sriov_migration(struct pci_dev *dev); extern int pci_num_vf(struct pci_dev *dev); +extern int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs); +extern int pci_sriov_get_totalvfs(struct pci_dev *dev); #else static inline int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn) { @@ -1627,6 +1629,14 @@ static inline int pci_num_vf(struct pci_dev *dev) { return 0; } +static inline int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs) +{ + return 0; +} +static inline int pci_sriov_get_totalvfs(struct pci_dev *dev) +{ + return 0; +} #endif #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE) -- cgit v1.2.3-70-g09d2