linux/arch/s390/pci/pci_bus.c
Niklas Schnelle 3cddb79afc s390/pci: fix zpci_bus_link_virtfn()
We were missing the pci_dev_put() for candidate PFs.  Furhtermore in
discussion with upstream it turns out that somewhat counterintuitively
some common code, in particular the vfio-pci driver, assumes that
pdev->is_virtfn always implies that pdev->physfn is set, i.e. that VFs
are always linked.
While POWER does seem to set pdev->is_virtfn even for unlinked functions
(see comments in arch/powerpc/kernel/eeh.c:eeh_debugfs_break_device())
for now just be safe and only set pdev->is_virtfn on linking.
Also make sure that we only search for parent PFs if the zbus is
multifunction and we thus know the devfn values supplied by firmware
come from the RID.

Fixes: e5794cf1a2 ("s390/pci: create links between PFs and VFs")
Cc: <stable@vger.kernel.org> # 5.8
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-08-17 13:17:18 +02:00

334 lines
7.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2020
*
* Author(s):
* Pierre Morel <pmorel@linux.ibm.com>
*
*/
#define KMSG_COMPONENT "zpci"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/delay.h>
#include <linux/seq_file.h>
#include <linux/jump_label.h>
#include <linux/pci.h>
#include <linux/printk.h>
#include <asm/pci_clp.h>
#include <asm/pci_dma.h>
#include "pci_bus.h"
static LIST_HEAD(zbus_list);
static DEFINE_SPINLOCK(zbus_list_lock);
static int zpci_nb_devices;
/* zpci_bus_scan
* @zbus: the zbus holding the zdevices
* @ops: the pci operations
*
* The domain number must be set before pci_scan_root_bus is called.
* This function can be called once the domain is known, hence
* when the function_0 is dicovered.
*/
static int zpci_bus_scan(struct zpci_bus *zbus, int domain, struct pci_ops *ops)
{
struct pci_bus *bus;
int rc;
rc = zpci_alloc_domain(domain);
if (rc < 0)
return rc;
zbus->domain_nr = rc;
bus = pci_scan_root_bus(NULL, ZPCI_BUS_NR, ops, zbus, &zbus->resources);
if (!bus) {
zpci_free_domain(zbus->domain_nr);
return -EFAULT;
}
zbus->bus = bus;
pci_bus_add_devices(bus);
return 0;
}
static void zpci_bus_release(struct kref *kref)
{
struct zpci_bus *zbus = container_of(kref, struct zpci_bus, kref);
if (zbus->bus) {
pci_lock_rescan_remove();
pci_stop_root_bus(zbus->bus);
zpci_free_domain(zbus->domain_nr);
pci_free_resource_list(&zbus->resources);
pci_remove_root_bus(zbus->bus);
pci_unlock_rescan_remove();
}
spin_lock(&zbus_list_lock);
list_del(&zbus->bus_next);
spin_unlock(&zbus_list_lock);
kfree(zbus);
}
static void zpci_bus_put(struct zpci_bus *zbus)
{
kref_put(&zbus->kref, zpci_bus_release);
}
static struct zpci_bus *zpci_bus_get(int pchid)
{
struct zpci_bus *zbus;
spin_lock(&zbus_list_lock);
list_for_each_entry(zbus, &zbus_list, bus_next) {
if (pchid == zbus->pchid) {
kref_get(&zbus->kref);
goto out_unlock;
}
}
zbus = NULL;
out_unlock:
spin_unlock(&zbus_list_lock);
return zbus;
}
static struct zpci_bus *zpci_bus_alloc(int pchid)
{
struct zpci_bus *zbus;
zbus = kzalloc(sizeof(*zbus), GFP_KERNEL);
if (!zbus)
return NULL;
zbus->pchid = pchid;
INIT_LIST_HEAD(&zbus->bus_next);
spin_lock(&zbus_list_lock);
list_add_tail(&zbus->bus_next, &zbus_list);
spin_unlock(&zbus_list_lock);
kref_init(&zbus->kref);
INIT_LIST_HEAD(&zbus->resources);
zbus->bus_resource.start = 0;
zbus->bus_resource.end = ZPCI_BUS_NR;
zbus->bus_resource.flags = IORESOURCE_BUS;
pci_add_resource(&zbus->resources, &zbus->bus_resource);
return zbus;
}
#ifdef CONFIG_PCI_IOV
static int zpci_bus_link_virtfn(struct pci_dev *pdev,
struct pci_dev *virtfn, int vfid)
{
int rc;
rc = pci_iov_sysfs_link(pdev, virtfn, vfid);
if (rc)
return rc;
virtfn->is_virtfn = 1;
virtfn->multifunction = 0;
virtfn->physfn = pci_dev_get(pdev);
return 0;
}
static int zpci_bus_setup_virtfn(struct zpci_bus *zbus,
struct pci_dev *virtfn, int vfn)
{
int i, cand_devfn;
struct zpci_dev *zdev;
struct pci_dev *pdev;
int vfid = vfn - 1; /* Linux' vfid's start at 0 vfn at 1*/
int rc = 0;
if (!zbus->multifunction)
return 0;
/* If the parent PF for the given VF is also configured in the
* instance, it must be on the same zbus.
* We can then identify the parent PF by checking what
* devfn the VF would have if it belonged to that PF using the PF's
* stride and offset. Only if this candidate devfn matches the
* actual devfn will we link both functions.
*/
for (i = 0; i < ZPCI_FUNCTIONS_PER_BUS; i++) {
zdev = zbus->function[i];
if (zdev && zdev->is_physfn) {
pdev = pci_get_slot(zbus->bus, zdev->devfn);
if (!pdev)
continue;
cand_devfn = pci_iov_virtfn_devfn(pdev, vfid);
if (cand_devfn == virtfn->devfn) {
rc = zpci_bus_link_virtfn(pdev, virtfn, vfid);
/* balance pci_get_slot() */
pci_dev_put(pdev);
break;
}
/* balance pci_get_slot() */
pci_dev_put(pdev);
}
}
return rc;
}
#else
static inline int zpci_bus_setup_virtfn(struct zpci_bus *zbus,
struct pci_dev *virtfn, int vfn)
{
return 0;
}
#endif
static int zpci_bus_add_device(struct zpci_bus *zbus, struct zpci_dev *zdev)
{
struct pci_bus *bus;
struct resource_entry *window, *n;
struct resource *res;
struct pci_dev *pdev;
int rc;
bus = zbus->bus;
if (!bus)
return -EINVAL;
pdev = pci_get_slot(bus, zdev->devfn);
if (pdev) {
/* Device is already known. */
pci_dev_put(pdev);
return 0;
}
rc = zpci_init_slot(zdev);
if (rc)
return rc;
zdev->has_hp_slot = 1;
resource_list_for_each_entry_safe(window, n, &zbus->resources) {
res = window->res;
pci_bus_add_resource(bus, res, 0);
}
pdev = pci_scan_single_device(bus, zdev->devfn);
if (pdev) {
if (!zdev->is_physfn) {
rc = zpci_bus_setup_virtfn(zbus, pdev, zdev->vfn);
if (rc)
goto failed_with_pdev;
}
pci_bus_add_device(pdev);
}
return 0;
failed_with_pdev:
pci_stop_and_remove_bus_device(pdev);
pci_dev_put(pdev);
return rc;
}
static void zpci_bus_add_devices(struct zpci_bus *zbus)
{
int i;
for (i = 1; i < ZPCI_FUNCTIONS_PER_BUS; i++)
if (zbus->function[i])
zpci_bus_add_device(zbus, zbus->function[i]);
pci_lock_rescan_remove();
pci_bus_add_devices(zbus->bus);
pci_unlock_rescan_remove();
}
int zpci_bus_device_register(struct zpci_dev *zdev, struct pci_ops *ops)
{
struct zpci_bus *zbus = NULL;
int rc = -EBADF;
if (zpci_nb_devices == ZPCI_NR_DEVICES) {
pr_warn("Adding PCI function %08x failed because the configured limit of %d is reached\n",
zdev->fid, ZPCI_NR_DEVICES);
return -ENOSPC;
}
zpci_nb_devices++;
if (zdev->devfn >= ZPCI_FUNCTIONS_PER_BUS)
return -EINVAL;
if (!s390_pci_no_rid && zdev->rid_available)
zbus = zpci_bus_get(zdev->pchid);
if (!zbus) {
zbus = zpci_bus_alloc(zdev->pchid);
if (!zbus)
return -ENOMEM;
}
zdev->zbus = zbus;
if (zbus->function[zdev->devfn]) {
pr_err("devfn %04x is already assigned\n", zdev->devfn);
goto error; /* rc already set */
}
zbus->function[zdev->devfn] = zdev;
zpci_setup_bus_resources(zdev, &zbus->resources);
if (zbus->bus) {
if (!zbus->multifunction) {
WARN_ONCE(1, "zbus is not multifunction\n");
goto error_bus;
}
if (!zdev->rid_available) {
WARN_ONCE(1, "rid_available not set for multifunction\n");
goto error_bus;
}
rc = zpci_bus_add_device(zbus, zdev);
if (rc)
goto error_bus;
} else if (zdev->devfn == 0) {
if (zbus->multifunction && !zdev->rid_available) {
WARN_ONCE(1, "rid_available not set on function 0 for multifunction\n");
goto error_bus;
}
rc = zpci_bus_scan(zbus, (u16)zdev->uid, ops);
if (rc)
goto error_bus;
zpci_bus_add_devices(zbus);
rc = zpci_init_slot(zdev);
if (rc)
goto error_bus;
zdev->has_hp_slot = 1;
zbus->multifunction = zdev->rid_available;
zbus->max_bus_speed = zdev->max_bus_speed;
} else {
zbus->multifunction = 1;
}
return 0;
error_bus:
zpci_nb_devices--;
zbus->function[zdev->devfn] = NULL;
error:
pr_err("Adding PCI function %08x failed\n", zdev->fid);
zpci_bus_put(zbus);
return rc;
}
void zpci_bus_device_unregister(struct zpci_dev *zdev)
{
struct zpci_bus *zbus = zdev->zbus;
zpci_nb_devices--;
zbus->function[zdev->devfn] = NULL;
zpci_bus_put(zbus);
}