On Thu, Oct 4, 2012 at 3:14 PM, Donald Dutile <ddutile@xxxxxxxxxx> 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_max_vfs -- cat-ing this file returns the maximum number
> of VFs a PCIe device supports.
> sriov_enable_vfs -- echo'ing a number to this file enables this
> number of VFs for this given PCIe device.
> -- cat-ing this file will return the number of VFs
> currently enabled on this PCIe device.
> sriov_disable_vfs -- echo-ing any number other than 0 disables all
> VFs associated with this PCIe device.
>
> VF enable and disablement is invoked much like other PCIe
> configuration functions -- via registered callbacks in the driver,
> i.e., probe, release, etc.
>
> v1->v2:
> This patch is based on previous 2 patches by Yinghai Lu
> that cleaned up the vga attributes for PCI devices under sysfs,
> and uses visibility-checking group attributes as recommended by
> Greg K-H.
>
> Signed-off-by: Donald Dutile <ddutile@xxxxxxxxxx>
> ---
> drivers/pci/pci-sysfs.c | 153 +++++++++++++++++++++++++++++++++++++++++++++++-
> include/linux/pci.h | 2 +
> 2 files changed, 154 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index fbbb97f..e6522c2 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -404,6 +404,128 @@ static ssize_t d3cold_allowed_show(struct device *dev,
> }
> #endif
>
> +bool pci_dev_has_sriov(struct pci_dev *pdev)
> +{
> + int ret = false;
> + int pos;
> +
> + if (!pci_is_pcie(pdev))
> + goto out;
> +
> + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_SRIOV);
> + if (pos)
> + ret = true;
> +out:
> + return ret;
> +}
should use dev_is_pf?
cap does not mean you have sriov_init return successfully.
> +
> +#ifdef CONFIG_PCI_IOV
> +static ssize_t sriov_max_vfs_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct pci_dev *pdev;
> +
> + pdev = to_pci_dev(dev);
> + return sprintf (buf, "%u\n", pdev->sriov->total);
> +}
> +
> +
> +static ssize_t sriov_enable_vfs_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct pci_dev *pdev;
> +
> + pdev = to_pci_dev(dev);
> +
> + return sprintf (buf, "%u\n", pdev->sriov->nr_virtfn);
> +}
> +
> +static ssize_t sriov_enable_vfs_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct pci_dev *pdev;
> + int num_vf_enabled = 0;
> + unsigned long num_vfs;
> + pdev = to_pci_dev(dev);
> +
> + /* Requested VFs to enable < max_vfs
> + * and none enabled already
> + */
> + if (strict_strtoul(buf, 0, &num_vfs) < 0)
> + return -EINVAL;
checkpatch.pl should ask you to change to kstrtoul instead.
> +
> + if ((num_vfs > pdev->sriov->total) ||
> + (pdev->sriov->nr_virtfn != 0))
> + return -EINVAL;
> +
> + /* Ready for lift-off! */
> + if (pdev->driver && pdev->driver->sriov_enable) {
> + num_vf_enabled = pdev->driver->sriov_enable(pdev, num_vfs);
> + }
> +
> + if (num_vf_enabled != num_vfs)
> + printk(KERN_WARNING
> + "%s: %04x:%02x:%02x.%d: Only %d VFs enabled \n",
> + pci_name(pdev), pci_domain_nr(pdev->bus),
> + pdev->bus->number, PCI_SLOT(pdev->devfn),
> + PCI_FUNC(pdev->devfn), num_vf_enabled);
> +
> + return count;
do you need pci_remove_rescan_mutex ?
also that enable could take a while ..., may need to use
device_schedule_callback to start one callback.
> +}
> +
> +static ssize_t sriov_disable_vfs_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct pci_dev *pdev;
> + int ret = 0;
> +
> + pdev = to_pci_dev(dev);
> +
> + /* make sure sriov device & at least 1 vf enabled */
> + if (pdev->sriov->nr_virtfn == 0) {
> + ret = -ENODEV;
> + goto out;
> + }
> +
> + /* Ready for landing! */
> + /* Note: Disabling VF can fail if VF assigned to virtualized guest */
> + if (pdev->driver && pdev->driver->sriov_disable) {
> + ret = pdev->driver->sriov_disable(pdev);
> + }
> +out:
> + return ret ? ret : count;
> +}
> +#else
> +static ssize_t sriov_max_vfs_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{ return 0; }
> +static ssize_t sriov_enable_vfs_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{ return 0; }
> +static ssize_t sriov_enable_vfs_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{ return count; }
> +static ssize_t sriov_disable_vfs_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{ return count; }
> +#endif /* CONFIG_PCI_IOV */
> +
> +static struct device_attribute sriov_max_vfs_attr = __ATTR_RO(sriov_max_vfs);
> +static struct device_attribute sriov_enable_vfs_attr =
> + __ATTR(sriov_enable_vfs, (S_IRUGO|S_IWUSR|S_IWGRP),
> + sriov_enable_vfs_show, sriov_enable_vfs_store);
> +static struct device_attribute sriov_disable_vfs_attr =
> + __ATTR(sriov_disable_vfs, (S_IWUSR|S_IWGRP),
> + NULL, sriov_disable_vfs_store);
> +
> struct device_attribute pci_dev_attrs[] = {
> __ATTR_RO(resource),
> __ATTR_RO(vendor),
> @@ -1408,8 +1530,15 @@ static struct attribute *pci_dev_dev_attrs[] = {
> NULL,
> };
>
> +static struct attribute *sriov_dev_attrs[] = {
> + &sriov_max_vfs_attr.attr,
> + &sriov_enable_vfs_attr.attr,
> + &sriov_disable_vfs_attr.attr,
> + NULL,
> +};
> +
> 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);
> @@ -1421,13 +1550,35 @@ static umode_t pci_dev_attrs_are_visible(struct kobject *kobj,
> return a->mode;
> }
>
> +static umode_t sriov_attrs_are_visible(struct kobject *kobj,
> + struct attribute *a, int n)
> +{
> + struct device *dev = container_of(kobj, struct device, kobj);
> + struct pci_dev *pdev = to_pci_dev(dev);
> +
> + if ((a == &sriov_max_vfs_attr.attr) ||
> + (a == &sriov_enable_vfs_attr.attr) ||
> + (a == &sriov_disable_vfs_attr.attr)) {
> + if (!pci_dev_has_sriov(pdev))
> + return 0;
> + }
> +
> + return a->mode;
> +}
> +
> static struct attribute_group pci_dev_attr_group = {
> .attrs = pci_dev_dev_attrs,
> .is_visible = pci_dev_attrs_are_visible,
> };
>
> +static struct attribute_group sriov_dev_attr_group = {
> + .attrs = sriov_dev_attrs,
> + .is_visible = sriov_attrs_are_visible,
you could fold contents in sriov_dev_attrs and sriov_attrs_are_visible into
pci_dev_dev_attrs and pci_dev_attrs_are_visible.
> +};
> +
> static const struct attribute_group *pci_dev_attr_groups[] = {
> &pci_dev_attr_group,
> + &sriov_dev_attr_group,
> NULL,
> };
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index be1de01..b3e25a8 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -595,6 +595,8 @@ 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_enable) (struct pci_dev *dev, int num_vfs); /* PF pci dev */
> + int (*sriov_disable) (struct pci_dev *dev);
> const struct pci_error_handlers *err_handler;
> struct device_driver driver;
> struct pci_dynids dynids;
> --
> 1.7.10.2.552.gaa3bb87
>
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