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;
+}
+
+#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;
+
+ 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;
+}
+
+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,
+};
+
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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