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kernel-ark/drivers/pci/iov.c
Jakub Kicinski 38972375ef PCI/IOV: Reset total_VFs limit after detaching PF driver 
The TotalVFs register in the SR-IOV capability is the hardware limit on the
number of VFs.  A PF driver can limit the number of VFs further with
pci_sriov_set_totalvfs().  When the PF driver is removed, reset any VF
limit that was imposed by the driver because that limit may not apply to
other drivers.

Before 8d85a7a4f2 ("PCI/IOV: Allow PF drivers to limit total_VFs to 0"),
pci_sriov_set_totalvfs(pdev, 0) meant "we can enable TotalVFs virtual
functions", and the nfp driver used that to remove the VF limit when the
driver unloads.

8d85a7a4f2 broke that because instead of removing the VF limit,
pci_sriov_set_totalvfs(pdev, 0) actually sets the limit to zero, and that
limit persists even if another driver is loaded.

We could fix that by making the nfp driver reset the limit when it unloads,
but it seems more robust to do it in the PCI core instead of relying on the
driver.

The regression scenario is:

  nfp_pci_probe (driver 1)
  ...
  nfp_pci_remove
    pci_sriov_set_totalvfs(pf->pdev, 0)   # limits VFs to 0

  ...
  nfp_pci_probe (driver 2)
    nfp_rtsym_read_le("nfd_vf_cfg_max_vfs")
    # no VF limit from firmware

Now driver 2 is broken because the VF limit is still 0 from driver 1.

Fixes: 8d85a7a4f2 ("PCI/IOV: Allow PF drivers to limit total_VFs to 0")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
[bhelgaas: changelog, rename functions]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-06-29 15:08:52 -05:00

886 lines
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// 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/mutex.h>
#include <linux/export.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/pci-ats.h>
#include "pci.h"
#define VIRTFN_ID_LEN 16
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;
}
/*
* 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;
}
out:
pci_iov_set_numvfs(dev, 0);
return rc;
}
static struct pci_bus *virtfn_add_bus(struct pci_bus *bus, int busnr)
{
struct pci_bus *child;
if (bus->number == busnr)
return bus;
child = pci_find_bus(pci_domain_nr(bus), busnr);
if (child)
return child;
child = pci_add_new_bus(bus, NULL, busnr);
if (!child)
return NULL;
pci_bus_insert_busn_res(child, busnr, busnr);
return child;
}
static void virtfn_remove_bus(struct pci_bus *physbus, struct pci_bus *virtbus)
{
if (physbus != virtbus && list_empty(&virtbus->devices))
pci_remove_bus(virtbus);
}
resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno)
{
if (!dev->is_physfn)
return 0;
return dev->sriov->barsz[resno - PCI_IOV_RESOURCES];
}
static void pci_read_vf_config_common(struct pci_dev *virtfn)
{
struct pci_dev *physfn = virtfn->physfn;
/*
* Some config registers are the same across all associated VFs.
* Read them once from VF0 so we can skip reading them from the
* other VFs.
*
* PCIe r4.0, sec 9.3.4.1, technically doesn't require all VFs to
* have the same Revision ID and Subsystem ID, but we assume they
* do.
*/
pci_read_config_dword(virtfn, PCI_CLASS_REVISION,
&physfn->sriov->class);
pci_read_config_byte(virtfn, PCI_HEADER_TYPE,
&physfn->sriov->hdr_type);
pci_read_config_word(virtfn, PCI_SUBSYSTEM_VENDOR_ID,
&physfn->sriov->subsystem_vendor);
pci_read_config_word(virtfn, PCI_SUBSYSTEM_ID,
&physfn->sriov->subsystem_device);
}
int pci_iov_add_virtfn(struct pci_dev *dev, int id)
{
int i;
int rc = -ENOMEM;
u64 size;
char buf[VIRTFN_ID_LEN];
struct pci_dev *virtfn;
struct resource *res;
struct pci_sriov *iov = dev->sriov;
struct pci_bus *bus;
bus = virtfn_add_bus(dev->bus, pci_iov_virtfn_bus(dev, id));
if (!bus)
goto failed;
virtfn = pci_alloc_dev(bus);
if (!virtfn)
goto failed0;
virtfn->devfn = pci_iov_virtfn_devfn(dev, id);
virtfn->vendor = dev->vendor;
virtfn->device = iov->vf_device;
virtfn->is_virtfn = 1;
virtfn->physfn = pci_dev_get(dev);
if (id == 0)
pci_read_vf_config_common(virtfn);
rc = pci_setup_device(virtfn);
if (rc)
goto failed1;
virtfn->dev.parent = dev->dev.parent;
virtfn->multifunction = 0;
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
res = &dev->resource[i + PCI_IOV_RESOURCES];
if (!res->parent)
continue;
virtfn->resource[i].name = pci_name(virtfn);
virtfn->resource[i].flags = res->flags;
size = pci_iov_resource_size(dev, i + PCI_IOV_RESOURCES);
virtfn->resource[i].start = res->start + size * id;
virtfn->resource[i].end = virtfn->resource[i].start + size - 1;
rc = request_resource(res, &virtfn->resource[i]);
BUG_ON(rc);
}
pci_device_add(virtfn, virtfn->bus);
sprintf(buf, "virtfn%u", id);
rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
if (rc)
goto failed2;
rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");
if (rc)
goto failed3;
kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);
pci_bus_add_device(virtfn);
return 0;
failed3:
sysfs_remove_link(&dev->dev.kobj, buf);
failed2:
pci_stop_and_remove_bus_device(virtfn);
failed1:
pci_dev_put(dev);
failed0:
virtfn_remove_bus(dev->bus, bus);
failed:
return rc;
}
void pci_iov_remove_virtfn(struct pci_dev *dev, int id)
{
char buf[VIRTFN_ID_LEN];
struct pci_dev *virtfn;
virtfn = pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus),
pci_iov_virtfn_bus(dev, id),
pci_iov_virtfn_devfn(dev, id));
if (!virtfn)
return;
sprintf(buf, "virtfn%u", id);
sysfs_remove_link(&dev->dev.kobj, buf);
/*
* pci_stop_dev() could have been called for this virtfn already,
* so the directory for the virtfn may have been removed before.
* Double check to avoid spurious sysfs warnings.
*/
if (virtfn->dev.kobj.sd)
sysfs_remove_link(&virtfn->dev.kobj, "physfn");
pci_stop_and_remove_bus_device(virtfn);
virtfn_remove_bus(dev->bus, virtfn->bus);
/* balance pci_get_domain_bus_and_slot() */
pci_dev_put(virtfn);
pci_dev_put(dev);
}
int __weak pcibios_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
{
return 0;
}
int __weak pcibios_sriov_disable(struct pci_dev *pdev)
{
return 0;
}
static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
{
int rc;
int i;
int nres;
u16 initial;
struct resource *res;
struct pci_dev *pdev;
struct pci_sriov *iov = dev->sriov;
int bars = 0;
int bus;
if (!nr_virtfn)
return 0;
if (iov->num_VFs)
return -EINVAL;
pci_read_config_word(dev, iov->pos + PCI_SRIOV_INITIAL_VF, &initial);
if (initial > iov->total_VFs ||
(!(iov->cap & PCI_SRIOV_CAP_VFM) && (initial != iov->total_VFs)))
return -EIO;
if (nr_virtfn < 0 || nr_virtfn > iov->total_VFs ||
(!(iov->cap & PCI_SRIOV_CAP_VFM) && (nr_virtfn > initial)))
return -EINVAL;
nres = 0;
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
bars |= (1 << (i + PCI_IOV_RESOURCES));
res = &dev->resource[i + PCI_IOV_RESOURCES];
if (res->parent)
nres++;
}
if (nres != iov->nres) {
pci_err(dev, "not enough MMIO resources for SR-IOV\n");
return -ENOMEM;
}
bus = pci_iov_virtfn_bus(dev, nr_virtfn - 1);
if (bus > dev->bus->busn_res.end) {
pci_err(dev, "can't enable %d VFs (bus %02x out of range of %pR)\n",
nr_virtfn, bus, &dev->bus->busn_res);
return -ENOMEM;
}
if (pci_enable_resources(dev, bars)) {
pci_err(dev, "SR-IOV: IOV BARS not allocated\n");
return -ENOMEM;
}
if (iov->link != dev->devfn) {
pdev = pci_get_slot(dev->bus, iov->link);
if (!pdev)
return -ENODEV;
if (!pdev->is_physfn) {
pci_dev_put(pdev);
return -ENOSYS;
}
rc = sysfs_create_link(&dev->dev.kobj,
&pdev->dev.kobj, "dep_link");
pci_dev_put(pdev);
if (rc)
return rc;
}
iov->initial_VFs = initial;
if (nr_virtfn < initial)
initial = nr_virtfn;
rc = pcibios_sriov_enable(dev, initial);
if (rc) {
pci_err(dev, "failure %d from pcibios_sriov_enable()\n", rc);
goto err_pcibios;
}
pci_iov_set_numvfs(dev, nr_virtfn);
iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
pci_cfg_access_lock(dev);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
msleep(100);
pci_cfg_access_unlock(dev);
for (i = 0; i < initial; i++) {
rc = pci_iov_add_virtfn(dev, i);
if (rc)
goto failed;
}
kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
iov->num_VFs = nr_virtfn;
return 0;
failed:
while (i--)
pci_iov_remove_virtfn(dev, i);
err_pcibios:
iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
pci_cfg_access_lock(dev);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
ssleep(1);
pci_cfg_access_unlock(dev);
pcibios_sriov_disable(dev);
if (iov->link != dev->devfn)
sysfs_remove_link(&dev->dev.kobj, "dep_link");
pci_iov_set_numvfs(dev, 0);
return rc;
}
static void sriov_disable(struct pci_dev *dev)
{
int i;
struct pci_sriov *iov = dev->sriov;
if (!iov->num_VFs)
return;
for (i = 0; i < iov->num_VFs; i++)
pci_iov_remove_virtfn(dev, i);
iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
pci_cfg_access_lock(dev);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
ssleep(1);
pci_cfg_access_unlock(dev);
pcibios_sriov_disable(dev);
if (iov->link != dev->devfn)
sysfs_remove_link(&dev->dev.kobj, "dep_link");
iov->num_VFs = 0;
pci_iov_set_numvfs(dev, 0);
}
static int sriov_init(struct pci_dev *dev, int pos)
{
int i, bar64;
int rc;
int nres;
u32 pgsz;
u16 ctrl, total;
struct pci_sriov *iov;
struct resource *res;
struct pci_dev *pdev;
pci_read_config_word(dev, pos + PCI_SRIOV_CTRL, &ctrl);
if (ctrl & PCI_SRIOV_CTRL_VFE) {
pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, 0);
ssleep(1);
}
ctrl = 0;
list_for_each_entry(pdev, &dev->bus->devices, bus_list)
if (pdev->is_physfn)
goto found;
pdev = NULL;
if (pci_ari_enabled(dev->bus))
ctrl |= PCI_SRIOV_CTRL_ARI;
found:
pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total);
if (!total)
return 0;
pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz);
i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0;
pgsz &= ~((1 << i) - 1);
if (!pgsz)
return -EIO;
pgsz &= ~(pgsz - 1);
pci_write_config_dword(dev, pos + PCI_SRIOV_SYS_PGSIZE, pgsz);
iov = kzalloc(sizeof(*iov), GFP_KERNEL);
if (!iov)
return -ENOMEM;
nres = 0;
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
res = &dev->resource[i + PCI_IOV_RESOURCES];
/*
* If it is already FIXED, don't change it, something
* (perhaps EA or header fixups) wants it this way.
*/
if (res->flags & IORESOURCE_PCI_FIXED)
bar64 = (res->flags & IORESOURCE_MEM_64) ? 1 : 0;
else
bar64 = __pci_read_base(dev, pci_bar_unknown, res,
pos + PCI_SRIOV_BAR + i * 4);
if (!res->flags)
continue;
if (resource_size(res) & (PAGE_SIZE - 1)) {
rc = -EIO;
goto failed;
}
iov->barsz[i] = resource_size(res);
res->end = res->start + resource_size(res) * total - 1;
pci_info(dev, "VF(n) BAR%d space: %pR (contains BAR%d for %d VFs)\n",
i, res, i, total);
i += bar64;
nres++;
}
iov->pos = pos;
iov->nres = nres;
iov->ctrl = ctrl;
iov->total_VFs = total;
iov->driver_max_VFs = total;
pci_read_config_word(dev, pos + PCI_SRIOV_VF_DID, &iov->vf_device);
iov->pgsz = pgsz;
iov->self = dev;
iov->drivers_autoprobe = true;
pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link);
if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
iov->link = PCI_DEVFN(PCI_SLOT(dev->devfn), iov->link);
if (pdev)
iov->dev = pci_dev_get(pdev);
else
iov->dev = dev;
dev->sriov = iov;
dev->is_physfn = 1;
rc = compute_max_vf_buses(dev);
if (rc)
goto fail_max_buses;
return 0;
fail_max_buses:
dev->sriov = NULL;
dev->is_physfn = 0;
failed:
for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
res = &dev->resource[i + PCI_IOV_RESOURCES];
res->flags = 0;
}
kfree(iov);
return rc;
}
static void sriov_release(struct pci_dev *dev)
{
BUG_ON(dev->sriov->num_VFs);
if (dev != dev->sriov->dev)
pci_dev_put(dev->sriov->dev);
kfree(dev->sriov);
dev->sriov = NULL;
}
static void sriov_restore_state(struct pci_dev *dev)
{
int i;
u16 ctrl;
struct pci_sriov *iov = dev->sriov;
pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &ctrl);
if (ctrl & PCI_SRIOV_CTRL_VFE)
return;
/*
* Restore PCI_SRIOV_CTRL_ARI before pci_iov_set_numvfs() because
* it reads offset & stride, which depend on PCI_SRIOV_CTRL_ARI.
*/
ctrl &= ~PCI_SRIOV_CTRL_ARI;
ctrl |= iov->ctrl & PCI_SRIOV_CTRL_ARI;
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, ctrl);
for (i = PCI_IOV_RESOURCES; i <= PCI_IOV_RESOURCE_END; i++)
pci_update_resource(dev, i);
pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
pci_iov_set_numvfs(dev, iov->num_VFs);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
if (iov->ctrl & PCI_SRIOV_CTRL_VFE)
msleep(100);
}
/**
* pci_iov_init - initialize the IOV capability
* @dev: the PCI device
*
* Returns 0 on success, or negative on failure.
*/
int pci_iov_init(struct pci_dev *dev)
{
int pos;
if (!pci_is_pcie(dev))
return -ENODEV;
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
if (pos)
return sriov_init(dev, pos);
return -ENODEV;
}
/**
* pci_iov_release - release resources used by the IOV capability
* @dev: the PCI device
*/
void pci_iov_release(struct pci_dev *dev)
{
if (dev->is_physfn)
sriov_release(dev);
}
/**
* pci_iov_remove - clean up SR-IOV state after PF driver is detached
* @dev: the PCI device
*/
void pci_iov_remove(struct pci_dev *dev)
{
struct pci_sriov *iov = dev->sriov;
if (!dev->is_physfn)
return;
iov->driver_max_VFs = iov->total_VFs;
if (iov->num_VFs)
pci_warn(dev, "driver left SR-IOV enabled after remove\n");
}
/**
* pci_iov_update_resource - update a VF BAR
* @dev: the PCI device
* @resno: the resource number
*
* Update a VF BAR in the SR-IOV capability of a PF.
*/
void pci_iov_update_resource(struct pci_dev *dev, int resno)
{
struct pci_sriov *iov = dev->is_physfn ? dev->sriov : NULL;
struct resource *res = dev->resource + resno;
int vf_bar = resno - PCI_IOV_RESOURCES;
struct pci_bus_region region;
u16 cmd;
u32 new;
int reg;
/*
* The generic pci_restore_bars() path calls this for all devices,
* including VFs and non-SR-IOV devices. If this is not a PF, we
* have nothing to do.
*/
if (!iov)
return;
pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &cmd);
if ((cmd & PCI_SRIOV_CTRL_VFE) && (cmd & PCI_SRIOV_CTRL_MSE)) {
dev_WARN(&dev->dev, "can't update enabled VF BAR%d %pR\n",
vf_bar, res);
return;
}
/*
* Ignore unimplemented BARs, unused resource slots for 64-bit
* BARs, and non-movable resources, e.g., those described via
* Enhanced Allocation.
*/
if (!res->flags)
return;
if (res->flags & IORESOURCE_UNSET)
return;
if (res->flags & IORESOURCE_PCI_FIXED)
return;
pcibios_resource_to_bus(dev->bus, &region, res);
new = region.start;
new |= res->flags & ~PCI_BASE_ADDRESS_MEM_MASK;
reg = iov->pos + PCI_SRIOV_BAR + 4 * vf_bar;
pci_write_config_dword(dev, reg, new);
if (res->flags & IORESOURCE_MEM_64) {
new = region.start >> 16 >> 16;
pci_write_config_dword(dev, reg + 4, new);
}
}
resource_size_t __weak pcibios_iov_resource_alignment(struct pci_dev *dev,
int resno)
{
return pci_iov_resource_size(dev, resno);
}
/**
* pci_sriov_resource_alignment - get resource alignment for VF BAR
* @dev: the PCI device
* @resno: the resource number
*
* Returns the alignment of the VF BAR found in the SR-IOV capability.
* This is not the same as the resource size which is defined as
* the VF BAR size multiplied by the number of VFs. The alignment
* is just the VF BAR size.
*/
resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
{
return pcibios_iov_resource_alignment(dev, resno);
}
/**
* pci_restore_iov_state - restore the state of the IOV capability
* @dev: the PCI device
*/
void pci_restore_iov_state(struct pci_dev *dev)
{
if (dev->is_physfn)
sriov_restore_state(dev);
}
/**
* pci_vf_drivers_autoprobe - set PF property drivers_autoprobe for VFs
* @dev: the PCI device
* @auto_probe: set VF drivers auto probe flag
*/
void pci_vf_drivers_autoprobe(struct pci_dev *dev, bool auto_probe)
{
if (dev->is_physfn)
dev->sriov->drivers_autoprobe = auto_probe;
}
/**
* pci_iov_bus_range - find bus range used by Virtual Function
* @bus: the PCI bus
*
* Returns max number of buses (exclude current one) used by Virtual
* Functions.
*/
int pci_iov_bus_range(struct pci_bus *bus)
{
int max = 0;
struct pci_dev *dev;
list_for_each_entry(dev, &bus->devices, bus_list) {
if (!dev->is_physfn)
continue;
if (dev->sriov->max_VF_buses > max)
max = dev->sriov->max_VF_buses;
}
return max ? max - bus->number : 0;
}
/**
* pci_enable_sriov - enable the SR-IOV capability
* @dev: the PCI device
* @nr_virtfn: number of virtual functions to enable
*
* Returns 0 on success, or negative on failure.
*/
int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
{
might_sleep();
if (!dev->is_physfn)
return -ENOSYS;
return sriov_enable(dev, nr_virtfn);
}
EXPORT_SYMBOL_GPL(pci_enable_sriov);
/**
* pci_disable_sriov - disable the SR-IOV capability
* @dev: the PCI device
*/
void pci_disable_sriov(struct pci_dev *dev)
{
might_sleep();
if (!dev->is_physfn)
return;
sriov_disable(dev);
}
EXPORT_SYMBOL_GPL(pci_disable_sriov);
/**
* pci_num_vf - return number of VFs associated with a PF device_release_driver
* @dev: the PCI device
*
* Returns number of VFs, or 0 if SR-IOV is not enabled.
*/
int pci_num_vf(struct pci_dev *dev)
{
if (!dev->is_physfn)
return 0;
return dev->sriov->num_VFs;
}
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 0.
*/
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
*/
dev_id = dev->sriov->vf_device;
/* 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) &&
pci_is_dev_assigned(vfdev))
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
* @numvfs: number that should be used for TotalVFs supported
*
* Should be called from PF driver's probe routine with
* device's mutex held.
*
* Returns 0 if PF is an SRIOV-capable device and
* value of numvfs valid. If not a PF return -ENOSYS;
* if numvfs is invalid return -EINVAL;
* if VFs already enabled, return -EBUSY.
*/
int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)
{
if (!dev->is_physfn)
return -ENOSYS;
if (numvfs > dev->sriov->total_VFs)
return -EINVAL;
/* Shouldn't change if VFs already enabled */
if (dev->sriov->ctrl & PCI_SRIOV_CTRL_VFE)
return -EBUSY;
else
dev->sriov->driver_max_VFs = numvfs;
return 0;
}
EXPORT_SYMBOL_GPL(pci_sriov_set_totalvfs);
/**
* pci_sriov_get_totalvfs -- get total VFs supported on this device
* @dev: the PCI PF device
*
* For a PCIe device with SRIOV support, return the PCIe
* SRIOV capability value of TotalVFs or the value of driver_max_VFs
* if the driver reduced it. Otherwise 0.
*/
int pci_sriov_get_totalvfs(struct pci_dev *dev)
{
if (!dev->is_physfn)
return 0;
return dev->sriov->driver_max_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);
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