linux-kernel - Re: [pci PATCH v8 1/4] pci: Add pci_sriov_configure_simple for PFs that don't manage VF resources

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Date:   Fri, 20 Apr 2018 15:06:24 -0700
From:   Gregory Rose <gvrose8192@...il.com>
To:     Alexander Duyck <alexander.h.duyck@...el.com>, bhelgaas@...gle.com,
        linux-pci@...r.kernel.org
Cc:     virtio-dev@...ts.oasis-open.org, kvm@...r.kernel.org,
        netdev@...r.kernel.org, dan.daly@...el.com,
        linux-kernel@...r.kernel.org, linux-nvme@...ts.infradead.org,
        keith.busch@...el.com, netanel@...zon.com, ddutile@...hat.com,
        mheyne@...zon.de, liang-min.wang@...el.com,
        mark.d.rustad@...el.com, dwmw2@...radead.org, hch@....de,
        dwmw@...zon.co.uk
Subject: Re: [pci PATCH v8 1/4] pci: Add pci_sriov_configure_simple for PFs
 that don't manage VF resources


On 4/20/2018 9:28 AM, Alexander Duyck wrote:
> This patch adds a common configuration function called
> pci_sriov_configure_simple that will allow for managing VFs on devices
> where the PF is not capable of managing VF resources.
>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
> Tested-by: Mark Rustad <mark.d.rustad@...el.com>
> ---
>
> v5: New patch replacing pci_sriov_configure_unmanaged with
>        pci_sriov_configure_simple
>      Dropped bits related to autoprobe changes
> v6: Defined pci_sriov_configure_simple as NULL if IOV is disabled
> v7: Updated pci_sriov_configure_simple to drop need for err value
>      Fixed comment explaining why pci_sriov_configure_simple is NULL
>
>   drivers/pci/iov.c   |   31 +++++++++++++++++++++++++++++++
>   include/linux/pci.h |    3 +++
>   2 files changed, 34 insertions(+)
>
> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index 677924a..3e0a7fd 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -807,3 +807,34 @@ int pci_sriov_get_totalvfs(struct pci_dev *dev)
>   	return dev->sriov->total_VFs;
>   }
>   EXPORT_SYMBOL_GPL(pci_sriov_get_totalvfs);
> +
> +/**
> + * pci_sriov_configure_simple - helper to configure unmanaged SR-IOV
> + * @dev: the PCI device
> + * @nr_virtfn: number of virtual functions to enable, 0 to disable
> + *
> + * Used to provide generic enable/disable SR-IOV option for devices
> + * that do not manage the VFs generated by their driver. Return value
> + * is negative on error, or number of VFs allocated on success.
> + */
> +int pci_sriov_configure_simple(struct pci_dev *dev, int nr_virtfn)
> +{
> +	might_sleep();
> +
> +	if (!dev->is_physfn)
> +		return -ENODEV;
> +
> +	if (pci_vfs_assigned(dev)) {
> +		pci_warn(dev,
> +			 "Cannot modify SR-IOV while VFs are assigned\n");
> +		return -EPERM;
> +	}
> +
> +	if (!nr_virtfn) {
> +		sriov_disable(dev);
> +		return 0;
> +	}
> +
> +	return sriov_enable(dev, nr_virtfn) ? : nr_virtfn;
> +}
> +EXPORT_SYMBOL_GPL(pci_sriov_configure_simple);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index ae42289..7d36e39 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1955,6 +1955,7 @@ static inline void pci_mmcfg_late_init(void) { }
>   int pci_vfs_assigned(struct pci_dev *dev);
>   int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs);
>   int pci_sriov_get_totalvfs(struct pci_dev *dev);
> +int pci_sriov_configure_simple(struct pci_dev *dev, int nr_virtfn);
>   resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno);
>   void pci_vf_drivers_autoprobe(struct pci_dev *dev, bool probe);
>   #else
> @@ -1982,6 +1983,8 @@ static inline int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)
>   { return 0; }
>   static inline int pci_sriov_get_totalvfs(struct pci_dev *dev)
>   { return 0; }
> +/* this is expected to be used as a function pointer, just define as NULL */
> +#define pci_sriov_configure_simple NULL
>   static inline resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno)
>   { return 0; }
>   static inline void pci_vf_drivers_autoprobe(struct pci_dev *dev, bool probe) { }
>

Thanks Alex!

Reviewed-by: Greg Rose <gvrose8192@...il.com>