path: root/drivers/pci/iov.c

// SPDX-License-Identifier: GPL-2.0
/*
 * PCI Express I/O Virtualization (IOV) support
 *   Single Root IOV 1.0
 *   Address Translation Service 1.0
 *
 * Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
 */

#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/string.h>
#include <linux/delay.h>
#include "pci.h"

#define VIRTFN_ID_LEN	17	/* "virtfn%u\0" for 2^32 - 1 */

int pci_iov_virtfn_bus(struct pci_dev *dev, int vf_id)
{
	if (!dev->is_physfn)
		return -EINVAL;
	return dev->bus->number + ((dev->devfn + dev->sriov->offset +
				    dev->sriov->stride * vf_id) >> 8);
}

int pci_iov_virtfn_devfn(struct pci_dev *dev, int vf_id)
{
	if (!dev->is_physfn)
		return -EINVAL;
	return (dev->devfn + dev->sriov->offset +
		dev->sriov->stride * vf_id) & 0xff;
}
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);

/**
 * pci_iov_get_pf_drvdata - Return the drvdata of a PF
 * @dev: VF pci_dev
 * @pf_driver: Device driver required to own the PF
 *
 * This must be called from a context that ensures that a VF driver is attached.
 * The value returned is invalid once the VF driver completes its remove()
 * callback.
 *
 * Locking is achieved by the driver core. A VF driver cannot be probed until
 * pci_enable_sriov() is called and pci_disable_sriov() does not return until
 * all VF drivers have completed their remove().
 *
 * The PF driver must call pci_disable_sriov() before it begins to destroy the
 * drvdata.
 */
void *pci_iov_get_pf_drvdata(struct pci_dev *dev, struct pci_driver *pf_driver)
{
	struct pci_dev *pf_dev;

	if (!dev->is_virtfn)
		return ERR_PTR(-EINVAL);
	pf_dev = dev->physfn;
	if (pf_dev->driver != pf_driver)
		return ERR_PTR(-EINVAL);
	return pci_get_drvdata(pf_dev);
}
EXPORT_SYMBOL_GPL(pci_iov_get_pf_drvdata);

/*
 * Per SR-IOV spec sec 3.3.10 and 3.3.11, First VF Offset and VF Stride may
 * change when NumVFs changes.
 *
 * Update iov->offset and iov->stride when NumVFs is written.
 */
static inline void pci_iov_set_numvfs(struct pci_dev *dev, int nr_virtfn)
{
	struct pci_sriov *iov = dev->sriov;

	pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, nr_virtfn);
	pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_OFFSET, &iov->offset);
	pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_STRIDE, &iov->stride);
}

/*
 * The PF consumes one bus number.  NumVFs, First VF Offset, and VF Stride
 * determine how many additional bus numbers will be consumed by VFs.
 *
 * Iterate over all valid NumVFs, validate offset and stride, and calculate
 * the maximum number of bus numbers that could ever be required.
 */
static int compute_max_vf_buses(struct pci_dev *dev)
{
	struct pci_sriov *iov = dev->sriov;
	int nr_virtfn, busnr, rc = 0;

	for (nr_virtfn = iov->total_VFs; nr_virtfn; nr_virtfn--) {
		pci_iov_set_numvfs(dev, nr_virtfn);
		if (!iov->offset || (nr_virtfn > 1 && !iov->stride)) {
			rc = -EIO;
			goto out;
		}

		busnr = pci_iov_virtfn_bus(dev, nr_virtfn - 1);
		if (busnr > iov->max_VF_buses)
			iov->max_VF_buses = busnr;