On Wed, Sep 22, 2021 at 04:59:30PM -0500, Bjorn Helgaas wrote:
> 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()?
Yes, I gave same comment internally and we decided to simply reduce the
amount of changes in mlx5_core to have less distractions and submit as a
followup. Most likely will add this hunk in v1.
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/sriov.c b/drivers/net/ethernet/mellanox/mlx5/core/sriov.c
index e8185b69ac6c..b66be0b4244a 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/sriov.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/sriov.c
@@ -209,15 +209,8 @@ int mlx5_core_sriov_set_msix_vec_count(struct pci_dev *vf, int msix_vec_count)
/* Reversed translation of PCI VF function number to the internal
* function_id, which exists in the name of virtfn symlink.
*/
- for (id = 0; id < pci_num_vf(pf); id++) {
- if (!sriov->vfs_ctx[id].enabled)
- continue;
-
- if (vf->devfn == pci_iov_virtfn_devfn(pf, id))
- break;
- }
-
- if (id == pci_num_vf(pf) || !sriov->vfs_ctx[id].enabled)
+ id = pci_iov_vf_id(vf);
+ if (id < 0 || !sriov->vfs_ctx[id].enabled)
return -EINVAL;
return mlx5_set_msix_vec_count(dev, id + 1, msix_vec_count);
Thanks
>
> > ---
> > 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.
Sure, thanks
>
> > static inline int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
> > { return -ENODEV; }
>
