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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2012
*
* Author(s):
* Jan Glauber <jang@linux.vnet.ibm.com>
*/
#define KMSG_COMPONENT "zpci"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/kernel.h>
#include <linux/pci.h>
#include <asm/pci_debug.h>
#include <asm/pci_dma.h>
#include <asm/sclp.h>
#include "pci_bus.h"
/* Content Code Description for PCI Function Error */
struct zpci_ccdf_err {
u32 reserved1;
u32 fh; /* function handle */
u32 fid; /* function id */
u32 ett : 4; /* expected table type */
u32 mvn : 12; /* MSI vector number */
u32 dmaas : 8; /* DMA address space */
u32 : 6;
u32 q : 1; /* event qualifier */
u32 rw : 1; /* read/write */
u64 faddr; /* failing address */
u32 reserved3;
u16 reserved4;
u16 pec; /* PCI event code */
} __packed;
/* Content Code Description for PCI Function Availability */
struct zpci_ccdf_avail {
u32 reserved1;
u32 fh; /* function handle */
u32 fid; /* function id */
u32 reserved2;
u32 reserved3;
u32 reserved4;
u32 reserved5;
u16 reserved6;
u16 pec; /* PCI event code */
} __packed;
static inline bool ers_result_indicates_abort(pci_ers_result_t ers_res)
{
switch (ers_res) {
case PCI_ERS_RESULT_CAN_RECOVER:
case PCI_ERS_RESULT_RECOVERED:
case PCI_ERS_RESULT_NEED_RESET:
return false;
default:
return true;
}
}
static bool is_passed_through(struct zpci_dev *zdev)
{
return zdev->s390_domain;
}
static bool is_driver_supported(struct pci_driver *driver)
{
if (!driver || !driver->err_handler)
return false;
if (!driver->err_handler->error_detected)
return false;
if (!driver->err_handler->slot_reset)
return false;
if (!driver->err_handler->resume)
return false;
return true;
}
static pci_ers_result_t zpci_event_notify_error_detected(struct pci_dev *pdev,
struct pci_driver *driver)
{
pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT;
ers_res = driver->err_handler->error_detected(pdev, pdev->error_state);
if (ers_result_indicates_abort(ers_res))
pr_info("%s: Automatic recovery failed after initial reporting\n", pci_name(pdev));
else if (ers_res == PCI_ERS_RESULT_NEED_RESET)
pr_debug("%s: Driver needs reset to recover\n", pci_name(pdev));
return ers_res;
}
static pci_ers_result_t zpci_event_do_error_state_clear(struct pci_dev *pdev,
struct pci_driver *driver)
{
pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT;
struct zpci_dev *zdev = to_zpci(pdev);
int rc;
pr_info("%s: Unblocking device access for examination\n", pci_name(pdev));
rc = zpci_reset_load_store_blocked(zdev);
if (rc) {
pr_err("%s: Unblocking device access failed\n", pci_name(pdev));
/* Let's try a full reset instead */
return PCI_ERS_RESULT_NEED_RESET;
}
if (driver->err_handler->mmio_enabled) {
ers_res = driver->err_handler->mmio_enabled(pdev);
if (ers_result_indicates_abort(ers_res)) {
pr_info("%s: Automatic recovery failed after MMIO re-enable\n",
pci_name(pdev));
return ers_res;
} else if (ers_res == PCI_ERS_RESULT_NEED_RESET) {
pr_debug("%s: Driver needs reset to recover\n", pci_name(pdev));
return ers_res;
}
}
pr_debug("%s: Unblocking DMA\n", pci_name(pdev));
rc = zpci_clear_error_state(zdev);
if (!rc) {
pdev->error_state = pci_channel_io_normal;
} else {
pr_err("%s: Unblocking DMA failed\n", pci_name(pdev));
/* Let's try a full reset instead */
return PCI_ERS_RESULT_NEED_RESET;
}
return ers_res;
}
static pci_ers_result_t zpci_event_do_reset(struct pci_dev *pdev,
struct pci_driver *driver)
{
pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT;
pr_info("%s: Initiating reset\n", pci_name(pdev));
if (zpci_hot_reset_device(to_zpci(pdev))) {
pr_err("%s: The reset request failed\n", pci_name(pdev));
return ers_res;
}
pdev->error_state = pci_channel_io_normal;
ers_res = driver->err_handler->slot_reset(pdev);
if (ers_result_indicates_abort(ers_res)) {
pr_info("%s: Automatic recovery failed after slot reset\n", pci_name(pdev));
return ers_res;
}
return ers_res;
}
/* zpci_event_attempt_error_recovery - Try to recover the given PCI function
* @pdev: PCI function to recover currently in the error state
*
* We follow the scheme outlined in Documentation/PCI/pci-error-recovery.rst.
* With the simplification that recovery always happens per function
* and the platform determines which functions are affected for
* multi-function devices.
*/
static pci_ers_result_t zpci_event_attempt_error_recovery(struct pci_dev *pdev)
{
pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT;
struct pci_driver *driver;
/*
* Ensure that the PCI function is not removed concurrently, no driver
* is unbound or probed and that userspace can't access its
* configuration space while we perform recovery.
*/
pci_dev_lock(pdev);
if (pdev->error_state == pci_channel_io_perm_failure) {
ers_res = PCI_ERS_RESULT_DISCONNECT;
goto out_unlock;
}
pdev->error_state = pci_channel_io_frozen;
if (is_passed_through(to_zpci(pdev))) {
pr_info("%s: Cannot be recovered in the host because it is a pass-through device\n",
pci_name(pdev));
goto out_unlock;
}
driver = to_pci_driver(pdev->dev.driver);
if (!is_driver_supported(driver)) {
if (!driver)
pr_info("%s: Cannot be recovered because no driver is bound to the device\n",
pci_name(pdev));
else
pr_info("%s: The %s driver bound to the device does not support error recovery\n",
pci_name(pdev),
driver->name);
goto out_unlock;
}
ers_res = zpci_event_notify_error_detected(pdev, driver);
if (ers_result_indicates_abort(ers_res))
goto out_unlock;
if (ers_res == PCI_ERS_RESULT_CAN_RECOVER) {
ers_res = zpci_event_do_error_state_clear(pdev, driver);
if (ers_result_indicates_abort(ers_res))
goto out_unlock;
}
if (ers_res == PCI_ERS_RESULT_NEED_RESET)
ers_res = zpci_event_do_reset(pdev, driver);
if (ers_res != PCI_ERS_RESULT_RECOVERED) {
pr_err("%s: Automatic recovery failed; operator intervention is required\n",
pci_name(pdev));
goto out_unlock;
}
pr_info("%s: The device is ready to resume operations\n", pci_name(pdev));
if (driver->err_handler->resume)
driver->err_handler->resume(pdev);
out_unlock:
pci_dev_unlock(pdev);
return ers_res;
}
/* zpci_event_io_failure - Report PCI channel failure state to driver
* @pdev: PCI function for which to report
* @es: PCI channel failure state to report
*/
static void zpci_event_io_failure(struct pci_dev *pdev, pci_channel_state_t es)
{
struct pci_driver *driver;
pci_dev_lock(pdev);
pdev->error_state = es;
/**
* While vfio-pci's error_detected callback notifies user-space QEMU
* reacts to this by freezing the guest. In an s390 environment PCI
* errors are rarely fatal so this is overkill. Instead in the future
* we will inject the error event and let the guest recover the device
* itself.
*/
if (is_passed_through(to_zpci(pdev)))
goto out;
driver = to_pci_driver(pdev->dev.driver);
if (driver && driver->err_handler && driver->err_handler->error_detected)
driver->err_handler->error_detected(pdev, pdev->error_state);
out:
pci_dev_unlock(pdev);
}
static void __zpci_event_error(struct zpci_ccdf_err *ccdf)
{
struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
struct pci_dev *pdev = NULL;
pci_ers_result_t ers_res;
zpci_dbg(3, "err fid:%x, fh:%x, pec:%x\n",
ccdf->fid, ccdf->fh, ccdf->pec);
zpci_err("error CCDF:\n");
zpci_err_hex(ccdf, sizeof(*ccdf));
if (zdev) {
zpci_update_fh(zdev, ccdf->fh);
if (zdev->zbus->bus)
pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
}
pr_err("%s: Event 0x%x reports an error for PCI function 0x%x\n",
pdev ? pci_name(pdev) : "n/a", ccdf->pec, ccdf->fid);
if (!pdev)
goto no_pdev;
switch (ccdf->pec) {
case 0x003a: /* Service Action or Error Recovery Successful */
ers_res = zpci_event_attempt_error_recovery(pdev);
if (ers_res != PCI_ERS_RESULT_RECOVERED)
zpci_event_io_failure(pdev, pci_channel_io_perm_failure);
break;
default:
/*
* Mark as frozen not permanently failed because the device
* could be subsequently recovered by the platform.
*/
zpci_event_io_failure(pdev, pci_channel_io_frozen);
break;
}
pci_dev_put(pdev);
no_pdev:
zpci_zdev_put(zdev);
}
void zpci_event_error(void *data)
{
if (zpci_is_enabled())
__zpci_event_error(data);
}
static void zpci_event_hard_deconfigured(struct zpci_dev *zdev, u32 fh)
{
zpci_update_fh(zdev, fh);
/* Give the driver a hint that the function is
* already unusable.
*/
zpci_bus_remove_device(zdev, true);
/* Even though the device is already gone we still
* need to free zPCI resources as part of the disable.
*/
if (zdev->dma_table)
zpci_dma_exit_device(zdev);
if (zdev_enabled(zdev))
zpci_disable_device(zdev);
zdev->state = ZPCI_FN_STATE_STANDBY;
}
static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
{
struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
bool existing_zdev = !!zdev;
enum zpci_state state;
zpci_dbg(3, "avl fid:%x, fh:%x, pec:%x\n",
ccdf->fid, ccdf->fh, ccdf->pec);
switch (ccdf->pec) {
case 0x0301: /* Reserved|Standby -> Configured */
if (!zdev) {
zdev = zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_CONFIGURED);
if (IS_ERR(zdev))
break;
} else {
/* the configuration request may be stale */
if (zdev->state != ZPCI_FN_STATE_STANDBY)
break;
zdev->state = ZPCI_FN_STATE_CONFIGURED;
}
zpci_scan_configured_device(zdev, ccdf->fh);
break;
case 0x0302: /* Reserved -> Standby */
if (!zdev)
zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_STANDBY);
else
zpci_update_fh(zdev, ccdf->fh);
break;
case 0x0303: /* Deconfiguration requested */
if (zdev) {
/* The event may have been queued before we confirgured
* the device.
*/
if (zdev->state != ZPCI_FN_STATE_CONFIGURED)
break;
zpci_update_fh(zdev, ccdf->fh);
zpci_deconfigure_device(zdev);
}
break;
case 0x0304: /* Configured -> Standby|Reserved */
if (zdev) {
/* The event may have been queued before we confirgured
* the device.:
*/
if (zdev->state == ZPCI_FN_STATE_CONFIGURED)
zpci_event_hard_deconfigured(zdev, ccdf->fh);
/* The 0x0304 event may immediately reserve the device */
if (!clp_get_state(zdev->fid, &state) &&
state == ZPCI_FN_STATE_RESERVED) {
zpci_device_reserved(zdev);
}
}
break;
case 0x0306: /* 0x308 or 0x302 for multiple devices */
zpci_remove_reserved_devices();
clp_scan_pci_devices();
break;
case 0x0308: /* Standby -> Reserved */
if (!zdev)
break;
zpci_device_reserved(zdev);
break;
default:
break;
}
if (existing_zdev)
zpci_zdev_put(zdev);
}
void zpci_event_availability(void *data)
{
if (zpci_is_enabled())
__zpci_event_availability(data);
}