On Wed, Dec 22, 2021 at 08:19:57PM +0100, Lukasz Maniak wrote:
> As per PCI Express specification, FLR to a PF resets the PF state as
> well as the SR-IOV extended capability including VF Enable which means
> that VFs no longer exist.
Can you add a specific reference to the spec, please?
> Currently, the IOV state is not updated during FLR, resulting in
> non-compliant PCI driver behavior.
And include a little detail about what problem is observed? How would
a user know this problem is occurring?
> This patch introduces a simple function, called on the FLR path, that
> removes the virtual function devices from the PCI bus and their
> corresponding sysfs links with a final clear of the num_vfs value in IOV
> state.
>
> Signed-off-by: Lukasz Maniak <lukasz.maniak@xxxxxxxxxxxxxxx>
> ---
> drivers/pci/iov.c | 21 +++++++++++++++++++++
> drivers/pci/pci.c | 2 ++
> drivers/pci/pci.h | 4 ++++
> 3 files changed, 27 insertions(+)
>
> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index 0267977c9f17..69ee321027b4 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -1013,6 +1013,27 @@ int pci_iov_bus_range(struct pci_bus *bus)
> return max ? max - bus->number : 0;
> }
>
> +/**
> + * pci_reset_iov_state - reset the state of the IOV capability
> + * @dev: the PCI device
> + */
> +void pci_reset_iov_state(struct pci_dev *dev)
> +{
> + struct pci_sriov *iov = dev->sriov;
> +
> + if (!dev->is_physfn)
> + return;
> + if (!iov->num_VFs)
> + return;
> +
> + sriov_del_vfs(dev);
> +
> + if (iov->link != dev->devfn)
> + sysfs_remove_link(&dev->dev.kobj, "dep_link");
> +
> + iov->num_VFs = 0;
> +}
> +
> /**
> * pci_enable_sriov - enable the SR-IOV capability
> * @dev: the PCI device
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 3d2fb394986a..535f19d37e8d 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4694,6 +4694,8 @@ EXPORT_SYMBOL(pci_wait_for_pending_transaction);
> */
> int pcie_flr(struct pci_dev *dev)
> {
> + pci_reset_iov_state(dev);
> +
> if (!pci_wait_for_pending_transaction(dev))
> pci_err(dev, "timed out waiting for pending transaction; performing function level reset anyway\n");
>
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 3d60cabde1a1..7bb144fbec76 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -480,6 +480,7 @@ void pci_iov_update_resource(struct pci_dev *dev, int resno);
> resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno);
> void pci_restore_iov_state(struct pci_dev *dev);
> int pci_iov_bus_range(struct pci_bus *bus);
> +void pci_reset_iov_state(struct pci_dev *dev);
> extern const struct attribute_group sriov_pf_dev_attr_group;
> extern const struct attribute_group sriov_vf_dev_attr_group;
> #else
> @@ -501,6 +502,9 @@ static inline int pci_iov_bus_range(struct pci_bus *bus)
> {
> return 0;
> }
> +static inline void pci_reset_iov_state(struct pci_dev *dev)
> +{
> +}
>
> #endif /* CONFIG_PCI_IOV */
>
>
> base-commit: fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf
> --
> 2.25.1
>
