linux_dsm_epyc7002/arch/s390/pci/pci_bus.c
Niklas Schnelle b97bf44f99 s390/pci: fix PF/VF linking on hot plug
Currently there are four places in which a PCI function is scanned
and made available to drivers:
 1. In pci_scan_root_bus() as part of the initial zbus
    creation.
 2. In zpci_bus_add_devices() when registering
    a device in configured state on a zbus that has already been
    scanned.
 3. When a function is already known to zPCI (in reserved/standby state)
    and configuration is triggered through firmware by PEC 0x301.
 4. When a device is already known to zPCI (in standby/reserved state)
    and configuration is triggered from within Linux using
    enable_slot().

The PF/VF linking step and setting of pdev->is_virtfn introduced with
commit e5794cf1a2 ("s390/pci: create links between PFs and VFs") was
only triggered for the second case, which is where VFs created through
sriov_numvfs usually land. However unlike some other platforms but like
POWER VFs can be individually enabled/disabled through
/sys/bus/pci/slots.

Fix this by doing VF setup as part of pcibios_bus_add_device() which is
called in all of the above cases.

Finally to remove the PF/VF links call the common code
pci_iov_remove_virtfn() function to remove linked VFs.
This takes care of the necessary sysfs cleanup.

Fixes: e5794cf1a2 ("s390/pci: create links between PFs and VFs")
Cc: <stable@vger.kernel.org> # 5.8: 2f0230b2f2: s390/pci: re-introduce zpci_remove_device()
Cc: <stable@vger.kernel.org> # 5.8
Acked-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 13:17:34 +02:00

337 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
void pcibios_bus_add_device(struct pci_dev *pdev)
{
struct zpci_dev *zdev = to_zpci(pdev);
/*
* With pdev->no_vf_scan the common PCI probing code does not
* perform PF/VF linking.
*/
if (zdev->vfn)
zpci_bus_setup_virtfn(zdev->zbus, pdev, zdev->vfn);
}
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)
pci_bus_add_device(pdev);
return 0;
}
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);
}