Commit 5a8eb242 authored by Alexander Duyck's avatar Alexander Duyck Committed by Jeff Kirsher
Browse files

pci: Add SRIOV helper function to determine if VFs are assigned to guest 



This function is meant to add a helper function that will determine if a PF
has any VFs that are currently assigned to a guest.  We currently have been
implementing this function per driver, and going forward I would like to avoid
that by making this function generic and using this helper.

v2: Removed extern from declaration of pci_vfs_assigned in pci.h and return
    0 if SR-IOV is disabled with is inline with other PCI SRIOV functions.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Acked-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent d44e7a9a

drivers/pci/iov.c

+41 −0
Original line number Diff line number Diff line
@@ -728,6 +728,47 @@ int pci_num_vf(struct pci_dev *dev) 
}

EXPORT_SYMBOL_GPL(pci_num_vf);



/**

 * pci_vfs_assigned - returns number of VFs are assigned to a guest

 * @dev: the PCI device

 *

 * Returns number of VFs belonging to this device that are assigned to a guest.

 * If device is not a physical function returns -ENODEV.

 */

int pci_vfs_assigned(struct pci_dev *dev)

{

	struct pci_dev *vfdev;

	unsigned int vfs_assigned = 0;

	unsigned short dev_id;



	/* only search if we are a PF */

	if (!dev->is_physfn)

		return 0;



	/*

	 * determine the device ID for the VFs, the vendor ID will be the

	 * same as the PF so there is no need to check for that one

	 */

	pci_read_config_word(dev, dev->sriov->pos + PCI_SRIOV_VF_DID, &dev_id);



	/* loop through all the VFs to see if we own any that are assigned */

	vfdev = pci_get_device(dev->vendor, dev_id, NULL);

	while (vfdev) {

		/*

		 * It is considered assigned if it is a virtual function with

		 * our dev as the physical function and the assigned bit is set

		 */

		if (vfdev->is_virtfn && (vfdev->physfn == dev) &&

		    (vfdev->dev_flags & PCI_DEV_FLAGS_ASSIGNED))

			vfs_assigned++;



		vfdev = pci_get_device(dev->vendor, dev_id, vfdev);

	}



	return vfs_assigned;

}

EXPORT_SYMBOL_GPL(pci_vfs_assigned);



/**

 * pci_sriov_set_totalvfs -- reduce the TotalVFs available

 * @dev: the PCI PF device

include/linux/pci.h

+5 −0
Original line number Diff line number Diff line
@@ -1644,6 +1644,7 @@ extern int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn); 
extern void pci_disable_sriov(struct pci_dev *dev);

extern irqreturn_t pci_sriov_migration(struct pci_dev *dev);

extern int pci_num_vf(struct pci_dev *dev);

int pci_vfs_assigned(struct pci_dev *dev);

extern int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs);

extern int pci_sriov_get_totalvfs(struct pci_dev *dev);

#else
@@ -1662,6 +1663,10 @@ static inline int pci_num_vf(struct pci_dev *dev) 
{

	return 0;

}

static inline int pci_vfs_assigned(struct pci_dev *dev)

{

	return 0;

}

static inline int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)

{

	return 0;

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