On Wed, 2012-10-31 at 17:19 -0400, Donald Dutile wrote:
> Provide files under sysfs to determine the max number of vfs
> an SRIOV-capable PCIe device supports, and methods to enable and
> disable the vfs on a per device basis.
>
> Currently, VF enablement by SRIOV-capable PCIe devices is done
> in 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.
>
> Three files are created if a PCIe device has SRIOV support:
> sriov_totalvfs -- cat-ing this file returns the maximum number
> of VFs a PCIe device supports as reported by
> the TotalVFs in the SRIOV ext cap structure.
> sriov_numvfs -- echo'ing a positive number to this file enables this
> number of VFs for this given PCIe device.
> -- echo'ing a 0 to this file disables
> any previously enabled VFs for this PCIe device.
> -- cat-ing this file will return the number of VFs
> currently enabled on this PCIe device, i.e.,
> the NumVFs field in SRIOV ext. cap structure.
>
> VF enable and disablement is invoked much like other PCIe
> configuration functions -- via registered callbacks in the driver,
> i.e., probe, release, etc.
>
> Signed-off-by: Donald Dutile <ddutile@xxxxxxxxxx>
> ---
> drivers/pci/pci-sysfs.c | 137 +++++++++++++++++++++++++++++++++++++++++++++++-
> include/linux/pci.h | 1 +
> 2 files changed, 136 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index fbbb97f..83be8ce 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
[...]
> +static ssize_t sriov_numvfs_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct pci_dev *pdev;
> + int num_vfs_enabled = 0;
> + int num_vfs;
> + int ret = 0;
> + u16 total;
> +
> + pdev = to_pci_dev(dev);
> +
> + if (kstrtoint(buf, 0, &num_vfs) < 0)
> + return -EINVAL;
> +
> + /* is PF driver loaded w/callback */
> + if (!pdev->driver || !pdev->driver->sriov_configure) {
> + dev_info(&pdev->dev,
> + "Driver doesn't support SRIOV configuration via sysfs\n");
> + return -ENOSYS;
> + }
> +
> + /* if enabling vf's ... */
> + total = pdev->sriov->total;
> + /* Requested VFs to enable < totalvfs and none enabled already */
> + if ((num_vfs > 0) && (num_vfs <= total)) {
> + if (pdev->sriov->nr_virtfn == 0) {
> + num_vfs_enabled =
> + pdev->driver->sriov_configure(pdev, num_vfs);
> + if ((num_vfs_enabled >= 0) &&
> + (num_vfs_enabled != num_vfs))
> + dev_warn(&pdev->dev,
> + "Only %d VFs enabled\n",
> + num_vfs_enabled);
> + return count;
If num_vfs_enabled < 0 then it's an error value which should be returned
instead of count.
[...]
> @@ -1409,7 +1512,7 @@ static struct attribute *pci_dev_dev_attrs[] = {
> };
>
> static umode_t pci_dev_attrs_are_visible(struct kobject *kobj,
> - struct attribute *a, int n)
> + struct attribute *a, int n)
> {
> struct device *dev = container_of(kobj, struct device, kobj);
> struct pci_dev *pdev = to_pci_dev(dev);
This hunk should be folded into patch 1.
> @@ -1421,6 +1524,33 @@ static umode_t pci_dev_attrs_are_visible(struct kobject *kobj,
> return a->mode;
> }
>
> +#ifdef CONFIG_PCI_IOV
> +static struct attribute *sriov_dev_attrs[] = {
> + &sriov_totalvfs_attr.attr,
> + &sriov_numvfs_attr.attr,
> + NULL,
> +};
> +
> +static umode_t sriov_attrs_are_visible(struct kobject *kobj,
> + struct attribute *a, int n)
> +{
> + struct device *dev = container_of(kobj, struct device, kobj);
> +
> + if ((a == &sriov_totalvfs_attr.attr) ||
> + (a == &sriov_numvfs_attr.attr)) {
> + if (!dev_is_pf(dev))
> + return 0;
> + }
Why do you check the attribute address? The whole group should be
visible or invisible depending on dev_is_pf(). Any attributes that need
another condition belong in another group.
> + return a->mode;
> +}
> +
> +static struct attribute_group sriov_dev_attr_group = {
> + .attrs = sriov_dev_attrs,
> + .is_visible = sriov_attrs_are_visible,
> +};
> +#endif /* CONFIG_PCI_IOV */
[...]
--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
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