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Commit 8effc395 authored by Alexander Duyck's avatar Alexander Duyck Committed by Bjorn Helgaas
Browse files

PCI/IOV: Add pci_sriov_configure_simple() 



SR-IOV (Single Root I/O Virtualization) is an optional PCIe capability (see
PCIe r4.0, sec 9).  A PCIe Function with the SR-IOV capability is referred
to as a PF (Physical Function).  If SR-IOV is enabled on the PF, several
VFs (Virtual Functions) may be created.  The VFs can be individually
assigned to virtual machines, which allows them to share a single hardware
device while being isolated from each other.

Some SR-IOV devices have resources such as queues and interrupts that must
be set up in the PF before enabling the VFs, so they require a PF driver to
do that.

Other SR-IOV devices don't require any PF setup before enabling VFs.  Add a
pci_sriov_configure_simple() interface so PF drivers for such devices can
use it without repeating the VF-enabling code.

Tested-by: default avatarMark Rustad <mark.d.rustad@intel.com>
Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
[bhelgaas: changelog, comment]
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarGreg Rose <gvrose8192@gmail.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de&gt;:wq>
parent 60cc43fc

drivers/pci/iov.c

+36 −0
Original line number Diff line number Diff line
@@ -833,3 +833,39 @@ 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 SR-IOV

 * @dev: the PCI device

 * @nr_virtfn: number of virtual functions to enable, 0 to disable

 *

 * Enable or disable SR-IOV for devices that don't require any PF setup

 * before enabling SR-IOV.  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)

{

	int rc;



	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 == 0) {

		sriov_disable(dev);

		return 0;

	}



	rc = sriov_enable(dev, nr_virtfn);

	if (rc < 0)

		return rc;



	return nr_virtfn;

}

EXPORT_SYMBOL_GPL(pci_sriov_configure_simple);

include/linux/pci.h

+2 −0
Original line number Diff line number Diff line
@@ -1954,6 +1954,7 @@ int pci_num_vf(struct pci_dev *dev); 
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);
@@ -1986,6 +1987,7 @@ 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; }

#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) { }