1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright IBM Corp. 2012
4 *
5 * Author(s):
6 * Jan Glauber <jang@linux.vnet.ibm.com>
7 */
8
9 #define KMSG_COMPONENT "zpci"
10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11
12 #include <linux/kernel.h>
13 #include <linux/pci.h>
14 #include <asm/pci_debug.h>
15 #include <asm/pci_dma.h>
16 #include <asm/sclp.h>
17
18 #include "pci_bus.h"
19
20 /* Content Code Description for PCI Function Error */
21 struct zpci_ccdf_err {
22 u32 reserved1;
23 u32 fh; /* function handle */
24 u32 fid; /* function id */
25 u32 ett : 4; /* expected table type */
26 u32 mvn : 12; /* MSI vector number */
27 u32 dmaas : 8; /* DMA address space */
28 u32 : 6;
29 u32 q : 1; /* event qualifier */
30 u32 rw : 1; /* read/write */
31 u64 faddr; /* failing address */
32 u32 reserved3;
33 u16 reserved4;
34 u16 pec; /* PCI event code */
35 } __packed;
36
37 /* Content Code Description for PCI Function Availability */
38 struct zpci_ccdf_avail {
39 u32 reserved1;
40 u32 fh; /* function handle */
41 u32 fid; /* function id */
42 u32 reserved2;
43 u32 reserved3;
44 u32 reserved4;
45 u32 reserved5;
46 u16 reserved6;
47 u16 pec; /* PCI event code */
48 } __packed;
49
ers_result_indicates_abort(pci_ers_result_t ers_res)50 static inline bool ers_result_indicates_abort(pci_ers_result_t ers_res)
51 {
52 switch (ers_res) {
53 case PCI_ERS_RESULT_CAN_RECOVER:
54 case PCI_ERS_RESULT_RECOVERED:
55 case PCI_ERS_RESULT_NEED_RESET:
56 return false;
57 default:
58 return true;
59 }
60 }
61
is_passed_through(struct zpci_dev * zdev)62 static bool is_passed_through(struct zpci_dev *zdev)
63 {
64 return zdev->s390_domain;
65 }
66
is_driver_supported(struct pci_driver * driver)67 static bool is_driver_supported(struct pci_driver *driver)
68 {
69 if (!driver || !driver->err_handler)
70 return false;
71 if (!driver->err_handler->error_detected)
72 return false;
73 if (!driver->err_handler->slot_reset)
74 return false;
75 if (!driver->err_handler->resume)
76 return false;
77 return true;
78 }
79
zpci_event_notify_error_detected(struct pci_dev * pdev,struct pci_driver * driver)80 static pci_ers_result_t zpci_event_notify_error_detected(struct pci_dev *pdev,
81 struct pci_driver *driver)
82 {
83 pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT;
84
85 ers_res = driver->err_handler->error_detected(pdev, pdev->error_state);
86 if (ers_result_indicates_abort(ers_res))
87 pr_info("%s: Automatic recovery failed after initial reporting\n", pci_name(pdev));
88 else if (ers_res == PCI_ERS_RESULT_NEED_RESET)
89 pr_debug("%s: Driver needs reset to recover\n", pci_name(pdev));
90
91 return ers_res;
92 }
93
zpci_event_do_error_state_clear(struct pci_dev * pdev,struct pci_driver * driver)94 static pci_ers_result_t zpci_event_do_error_state_clear(struct pci_dev *pdev,
95 struct pci_driver *driver)
96 {
97 pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT;
98 struct zpci_dev *zdev = to_zpci(pdev);
99 int rc;
100
101 pr_info("%s: Unblocking device access for examination\n", pci_name(pdev));
102 rc = zpci_reset_load_store_blocked(zdev);
103 if (rc) {
104 pr_err("%s: Unblocking device access failed\n", pci_name(pdev));
105 /* Let's try a full reset instead */
106 return PCI_ERS_RESULT_NEED_RESET;
107 }
108
109 if (driver->err_handler->mmio_enabled) {
110 ers_res = driver->err_handler->mmio_enabled(pdev);
111 if (ers_result_indicates_abort(ers_res)) {
112 pr_info("%s: Automatic recovery failed after MMIO re-enable\n",
113 pci_name(pdev));
114 return ers_res;
115 } else if (ers_res == PCI_ERS_RESULT_NEED_RESET) {
116 pr_debug("%s: Driver needs reset to recover\n", pci_name(pdev));
117 return ers_res;
118 }
119 }
120
121 pr_debug("%s: Unblocking DMA\n", pci_name(pdev));
122 rc = zpci_clear_error_state(zdev);
123 if (!rc) {
124 pdev->error_state = pci_channel_io_normal;
125 } else {
126 pr_err("%s: Unblocking DMA failed\n", pci_name(pdev));
127 /* Let's try a full reset instead */
128 return PCI_ERS_RESULT_NEED_RESET;
129 }
130
131 return ers_res;
132 }
133
zpci_event_do_reset(struct pci_dev * pdev,struct pci_driver * driver)134 static pci_ers_result_t zpci_event_do_reset(struct pci_dev *pdev,
135 struct pci_driver *driver)
136 {
137 pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT;
138
139 pr_info("%s: Initiating reset\n", pci_name(pdev));
140 if (zpci_hot_reset_device(to_zpci(pdev))) {
141 pr_err("%s: The reset request failed\n", pci_name(pdev));
142 return ers_res;
143 }
144 pdev->error_state = pci_channel_io_normal;
145 ers_res = driver->err_handler->slot_reset(pdev);
146 if (ers_result_indicates_abort(ers_res)) {
147 pr_info("%s: Automatic recovery failed after slot reset\n", pci_name(pdev));
148 return ers_res;
149 }
150
151 return ers_res;
152 }
153
154 /* zpci_event_attempt_error_recovery - Try to recover the given PCI function
155 * @pdev: PCI function to recover currently in the error state
156 *
157 * We follow the scheme outlined in Documentation/PCI/pci-error-recovery.rst.
158 * With the simplification that recovery always happens per function
159 * and the platform determines which functions are affected for
160 * multi-function devices.
161 */
zpci_event_attempt_error_recovery(struct pci_dev * pdev)162 static pci_ers_result_t zpci_event_attempt_error_recovery(struct pci_dev *pdev)
163 {
164 pci_ers_result_t ers_res = PCI_ERS_RESULT_DISCONNECT;
165 struct pci_driver *driver;
166
167 /*
168 * Ensure that the PCI function is not removed concurrently, no driver
169 * is unbound or probed and that userspace can't access its
170 * configuration space while we perform recovery.
171 */
172 pci_dev_lock(pdev);
173 if (pdev->error_state == pci_channel_io_perm_failure) {
174 ers_res = PCI_ERS_RESULT_DISCONNECT;
175 goto out_unlock;
176 }
177 pdev->error_state = pci_channel_io_frozen;
178
179 if (is_passed_through(to_zpci(pdev))) {
180 pr_info("%s: Cannot be recovered in the host because it is a pass-through device\n",
181 pci_name(pdev));
182 goto out_unlock;
183 }
184
185 driver = to_pci_driver(pdev->dev.driver);
186 if (!is_driver_supported(driver)) {
187 if (!driver)
188 pr_info("%s: Cannot be recovered because no driver is bound to the device\n",
189 pci_name(pdev));
190 else
191 pr_info("%s: The %s driver bound to the device does not support error recovery\n",
192 pci_name(pdev),
193 driver->name);
194 goto out_unlock;
195 }
196
197 ers_res = zpci_event_notify_error_detected(pdev, driver);
198 if (ers_result_indicates_abort(ers_res))
199 goto out_unlock;
200
201 if (ers_res == PCI_ERS_RESULT_CAN_RECOVER) {
202 ers_res = zpci_event_do_error_state_clear(pdev, driver);
203 if (ers_result_indicates_abort(ers_res))
204 goto out_unlock;
205 }
206
207 if (ers_res == PCI_ERS_RESULT_NEED_RESET)
208 ers_res = zpci_event_do_reset(pdev, driver);
209
210 if (ers_res != PCI_ERS_RESULT_RECOVERED) {
211 pr_err("%s: Automatic recovery failed; operator intervention is required\n",
212 pci_name(pdev));
213 goto out_unlock;
214 }
215
216 pr_info("%s: The device is ready to resume operations\n", pci_name(pdev));
217 if (driver->err_handler->resume)
218 driver->err_handler->resume(pdev);
219 out_unlock:
220 pci_dev_unlock(pdev);
221
222 return ers_res;
223 }
224
225 /* zpci_event_io_failure - Report PCI channel failure state to driver
226 * @pdev: PCI function for which to report
227 * @es: PCI channel failure state to report
228 */
zpci_event_io_failure(struct pci_dev * pdev,pci_channel_state_t es)229 static void zpci_event_io_failure(struct pci_dev *pdev, pci_channel_state_t es)
230 {
231 struct pci_driver *driver;
232
233 pci_dev_lock(pdev);
234 pdev->error_state = es;
235 /**
236 * While vfio-pci's error_detected callback notifies user-space QEMU
237 * reacts to this by freezing the guest. In an s390 environment PCI
238 * errors are rarely fatal so this is overkill. Instead in the future
239 * we will inject the error event and let the guest recover the device
240 * itself.
241 */
242 if (is_passed_through(to_zpci(pdev)))
243 goto out;
244 driver = to_pci_driver(pdev->dev.driver);
245 if (driver && driver->err_handler && driver->err_handler->error_detected)
246 driver->err_handler->error_detected(pdev, pdev->error_state);
247 out:
248 pci_dev_unlock(pdev);
249 }
250
__zpci_event_error(struct zpci_ccdf_err * ccdf)251 static void __zpci_event_error(struct zpci_ccdf_err *ccdf)
252 {
253 struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
254 struct pci_dev *pdev = NULL;
255 pci_ers_result_t ers_res;
256
257 zpci_dbg(3, "err fid:%x, fh:%x, pec:%x\n",
258 ccdf->fid, ccdf->fh, ccdf->pec);
259 zpci_err("error CCDF:\n");
260 zpci_err_hex(ccdf, sizeof(*ccdf));
261
262 if (zdev) {
263 zpci_update_fh(zdev, ccdf->fh);
264 if (zdev->zbus->bus)
265 pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
266 }
267
268 pr_err("%s: Event 0x%x reports an error for PCI function 0x%x\n",
269 pdev ? pci_name(pdev) : "n/a", ccdf->pec, ccdf->fid);
270
271 if (!pdev)
272 goto no_pdev;
273
274 switch (ccdf->pec) {
275 case 0x002a: /* Error event concerns FMB */
276 case 0x002b:
277 case 0x002c:
278 break;
279 case 0x0040: /* Service Action or Error Recovery Failed */
280 case 0x003b:
281 zpci_event_io_failure(pdev, pci_channel_io_perm_failure);
282 break;
283 default: /* PCI function left in the error state attempt to recover */
284 ers_res = zpci_event_attempt_error_recovery(pdev);
285 if (ers_res != PCI_ERS_RESULT_RECOVERED)
286 zpci_event_io_failure(pdev, pci_channel_io_perm_failure);
287 break;
288 }
289 pci_dev_put(pdev);
290 no_pdev:
291 zpci_zdev_put(zdev);
292 }
293
zpci_event_error(void * data)294 void zpci_event_error(void *data)
295 {
296 if (zpci_is_enabled())
297 __zpci_event_error(data);
298 }
299
zpci_event_hard_deconfigured(struct zpci_dev * zdev,u32 fh)300 static void zpci_event_hard_deconfigured(struct zpci_dev *zdev, u32 fh)
301 {
302 zpci_update_fh(zdev, fh);
303 /* Give the driver a hint that the function is
304 * already unusable.
305 */
306 zpci_bus_remove_device(zdev, true);
307 /* Even though the device is already gone we still
308 * need to free zPCI resources as part of the disable.
309 */
310 if (zdev->dma_table)
311 zpci_dma_exit_device(zdev);
312 if (zdev_enabled(zdev))
313 zpci_disable_device(zdev);
314 zdev->state = ZPCI_FN_STATE_STANDBY;
315 }
316
__zpci_event_availability(struct zpci_ccdf_avail * ccdf)317 static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
318 {
319 struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
320 bool existing_zdev = !!zdev;
321 enum zpci_state state;
322
323 zpci_dbg(3, "avl fid:%x, fh:%x, pec:%x\n",
324 ccdf->fid, ccdf->fh, ccdf->pec);
325 switch (ccdf->pec) {
326 case 0x0301: /* Reserved|Standby -> Configured */
327 if (!zdev) {
328 zdev = zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_CONFIGURED);
329 if (IS_ERR(zdev))
330 break;
331 } else {
332 /* the configuration request may be stale */
333 if (zdev->state != ZPCI_FN_STATE_STANDBY)
334 break;
335 zdev->state = ZPCI_FN_STATE_CONFIGURED;
336 }
337 zpci_scan_configured_device(zdev, ccdf->fh);
338 break;
339 case 0x0302: /* Reserved -> Standby */
340 if (!zdev)
341 zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_STANDBY);
342 else
343 zpci_update_fh(zdev, ccdf->fh);
344 break;
345 case 0x0303: /* Deconfiguration requested */
346 if (zdev) {
347 /* The event may have been queued before we confirgured
348 * the device.
349 */
350 if (zdev->state != ZPCI_FN_STATE_CONFIGURED)
351 break;
352 zpci_update_fh(zdev, ccdf->fh);
353 zpci_deconfigure_device(zdev);
354 }
355 break;
356 case 0x0304: /* Configured -> Standby|Reserved */
357 if (zdev) {
358 /* The event may have been queued before we confirgured
359 * the device.:
360 */
361 if (zdev->state == ZPCI_FN_STATE_CONFIGURED)
362 zpci_event_hard_deconfigured(zdev, ccdf->fh);
363 /* The 0x0304 event may immediately reserve the device */
364 if (!clp_get_state(zdev->fid, &state) &&
365 state == ZPCI_FN_STATE_RESERVED) {
366 zpci_device_reserved(zdev);
367 }
368 }
369 break;
370 case 0x0306: /* 0x308 or 0x302 for multiple devices */
371 zpci_remove_reserved_devices();
372 clp_scan_pci_devices();
373 break;
374 case 0x0308: /* Standby -> Reserved */
375 if (!zdev)
376 break;
377 zpci_device_reserved(zdev);
378 break;
379 default:
380 break;
381 }
382 if (existing_zdev)
383 zpci_zdev_put(zdev);
384 }
385
zpci_event_availability(void * data)386 void zpci_event_availability(void *data)
387 {
388 if (zpci_is_enabled())
389 __zpci_event_availability(data);
390 }
391