[PATCH V4 mlx5-next 01/13] PCI/IOV: Add pci_iov_vf_id() to get VF index

Yishai Hadas
2021-10-26T09:07:20Z

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>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
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