On Thu, 2012-10-25 at 14:38 -0400, Donald Dutile wrote:
> 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 <ddutile@xxxxxxxxxx>
> ---
> drivers/pci/iov.c | 24 +++++++++++++++++++++++-
> drivers/pci/pci-sysfs.c | 10 ++++++++--
> drivers/pci/pci.h | 1 +
> include/linux/pci.h | 5 +++++
> 4 files changed, 37 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index aeccc91..f1357b0 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -682,7 +682,6 @@ int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
>
> if (!dev->is_physfn)
> return -ENODEV;
> -
> return sriov_enable(dev, nr_virtfn);
> }
> EXPORT_SYMBOL_GPL(pci_enable_sriov);
> @@ -735,3 +734,26 @@ 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
> + *
> + * Returns 0 if PF is an SRIOV-capable device and
> + * value of numvfs valid, otherwise -EINVAL
What are the locking requirements? Presumably this is expected to be
called from the probe function, with the device's mutex held?
> + */
> +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)
Missing parentheses.
> + return -EIO;
> +
> + dev->sriov->drvttl = numvfs;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(pci_sriov_set_totalvfs);
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index c2894ca..1cf6c15 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -414,7 +414,10 @@ static ssize_t sriov_totalvfs_show(struct device *dev,
> u16 total;
>
> pdev = to_pci_dev(dev);
> - total = pdev->sriov->total;
> + if (pdev->sriov->drvttl)
> + total = pdev->sriov->drvttl;
> + else
> + total = pdev->sriov->total;
> return sprintf (buf, "%u\n", total);
> }
>
> @@ -462,7 +465,10 @@ static ssize_t sriov_numvfs_store(struct device *dev,
> }
>
> /* if enabling vf's ... */
> - total = pdev->sriov->total;
> + if (pdev->sriov->drvttl)
> + total = pdev->sriov->drvttl;
> + else
> + total = pdev->sriov->total;
> if ((num_vfs > 0) && (num_vfs <= total)) {
> if (pdev->sriov->nr_virtfn == 0) { /* if not already enabled */
> num_vfs_enabled = pdev->driver->sriov_configure(pdev, num_vfs);
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 6f6cd14..553bbba 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 */
It's a rather obscure possibility, but the device could be switched
between two different versions of a driver where one has a lower limit
and the other doesn't. So this should be reset to 0 when the driver is
removed.
> 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 1d60a23..a5e08f2 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1633,6 +1633,7 @@ 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);
> #else
> static inline int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
> {
> @@ -1649,6 +1650,10 @@ 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 -EINVAL;
> +}
I think this should return 0, as the number of VFs certainly will be
limited to <= numvfs.
Ben.
> #endif
>
> #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
--
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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