On 10/13/2021 9:14 PM, Bjorn Helgaas wrote:

On Wed, Oct 13, 2021 at 12:46:55PM +0300, Yishai Hadas wrote:

quoted

From: Jason Gunthorpe <jgg@nvidia.com>

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@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>

I already acked this:

   https://lore.kernel.org/r/20210922215930.GA231505@bhelgaas (local)

Saves me time if you carry the ack so I don't have to look at this
again.  But since I *am* looking at it again, I think it's nice if the
subject line includes the actual interface you're adding, e.g.,

   PCI/IOV: Add pci_iov_vf_id() to get VF index

Sure, will change as part of V2 and add your Acked-by.

quoted

---
  drivers/pci/iov.c   | 14 ++++++++++++++
  include/linux/pci.h |  8 +++++++-
  2 files changed, 21 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..2337512e67f0 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 +2181,12 @@ 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;
+}
+
  static inline int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
  { return -ENODEV; }
  

-- 
2.18.1