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Diffstat (limited to 'arch/s390/pci/pci_event.c')
-rw-r--r--arch/s390/pci/pci_event.c389
1 files changed, 389 insertions, 0 deletions
diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c
new file mode 100644
index 0000000000..b9324ca2eb
--- /dev/null
+++ b/arch/s390/pci/pci_event.c
@@ -0,0 +1,389 @@
+// 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);
+}