On Wed, Sep 22, 2021 at 01:38:50PM +0300, Leon Romanovsky wrote:
> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
>
> The PCI core uses the VF index internally, often called the vf_id,
> during the setup of the VF, eg pci_iov_add_virtfn().
>
> This index is needed for device drivers that implement live migration
> for their internal operations that configure/control their VFs.
>
> Specifically, mlx5_vfio_pci driver that is introduced in coming patches
> from this series needs it and not the bus/device/function which is
> exposed today.
>
> Add pci_iov_vf_id() which computes the vf_id by reversing the math that
> was used to create the bus/device/function.
>
> Signed-off-by: Yishai Hadas <yishaih@xxxxxxxxxx>
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
mlx5_core_sriov_set_msix_vec_count() looks like it does basically the
same thing as pci_iov_vf_id() by iterating through VFs until it finds
one with a matching devfn (although it *doesn't* check for a matching
bus number, which seems like a bug).
Maybe that should use pci_iov_vf_id()?
> ---
> drivers/pci/iov.c | 14 ++++++++++++++
> include/linux/pci.h | 7 ++++++-
> 2 files changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index dafdc652fcd0..e7751fa3fe0b 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -33,6 +33,20 @@ int pci_iov_virtfn_devfn(struct pci_dev *dev, int vf_id)
> }
> EXPORT_SYMBOL_GPL(pci_iov_virtfn_devfn);
>
> +int pci_iov_vf_id(struct pci_dev *dev)
> +{
> + struct pci_dev *pf;
> +
> + if (!dev->is_virtfn)
> + return -EINVAL;
> +
> + pf = pci_physfn(dev);
> + return (((dev->bus->number << 8) + dev->devfn) -
> + ((pf->bus->number << 8) + pf->devfn + pf->sriov->offset)) /
> + pf->sriov->stride;
> +}
> +EXPORT_SYMBOL_GPL(pci_iov_vf_id);
> +
> /*
> * Per SR-IOV spec sec 3.3.10 and 3.3.11, First VF Offset and VF Stride may
> * change when NumVFs changes.
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index cd8aa6fce204..4d6c73506e18 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -2153,7 +2153,7 @@ void __iomem *pci_ioremap_wc_bar(struct pci_dev *pdev, int bar);
> #ifdef CONFIG_PCI_IOV
> int pci_iov_virtfn_bus(struct pci_dev *dev, int id);
> int pci_iov_virtfn_devfn(struct pci_dev *dev, int id);
> -
> +int pci_iov_vf_id(struct pci_dev *dev);
> int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn);
> void pci_disable_sriov(struct pci_dev *dev);
>
> @@ -2181,6 +2181,11 @@ static inline int pci_iov_virtfn_devfn(struct pci_dev *dev, int id)
> {
> return -ENOSYS;
> }
> +static inline int pci_iov_vf_id(struct pci_dev *dev)
> +{
> + return -ENOSYS;
> +}
> +
Drop the blank line to match the surrounding stubs.
> static inline int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
> { return -ENODEV; }
