From: Jason Gunthorpe <jgg@nvidia.com>
Date: Thu, 24 Feb 2022 16:20:10 +0200
Subject: PCI/IOV: Add pci_iov_vf_id() to get VF index
Patch-mainline: v5.18-rc1
Git-commit: 21ca9fb62d4688da41825e0f05d8e7e26afc69d6
References: jsc#PED-1549

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.

Link: https://lore.kernel.org/all/20220224142024.147653-2-yishaih@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/pci/iov.c   |   14 ++++++++++++++
 include/linux/pci.h |    8 +++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -33,6 +33,20 @@ int pci_iov_virtfn_devfn(struct pci_dev
 }
 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.
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2129,7 +2129,7 @@ void __iomem *pci_ioremap_wc_bar(struct
 #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);
 
@@ -2157,6 +2157,12 @@ static inline int pci_iov_virtfn_devfn(s
 {
 	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; }