1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * VFIO based Physical Subchannel device driver
4 *
5 * Copyright IBM Corp. 2017
6 * Copyright Red Hat, Inc. 2019
7 *
8 * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
9 * Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
10 * Cornelia Huck <cohuck@redhat.com>
11 */
12
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/device.h>
16 #include <linux/slab.h>
17 #include <linux/uuid.h>
18 #include <linux/mdev.h>
19
20 #include <asm/isc.h>
21
22 #include "chp.h"
23 #include "ioasm.h"
24 #include "css.h"
25 #include "vfio_ccw_private.h"
26
27 struct workqueue_struct *vfio_ccw_work_q;
28 static struct kmem_cache *vfio_ccw_io_region;
29 static struct kmem_cache *vfio_ccw_cmd_region;
30 static struct kmem_cache *vfio_ccw_schib_region;
31 static struct kmem_cache *vfio_ccw_crw_region;
32
33 debug_info_t *vfio_ccw_debug_msg_id;
34 debug_info_t *vfio_ccw_debug_trace_id;
35
36 /*
37 * Helpers
38 */
vfio_ccw_sch_quiesce(struct subchannel * sch)39 int vfio_ccw_sch_quiesce(struct subchannel *sch)
40 {
41 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
42 DECLARE_COMPLETION_ONSTACK(completion);
43 int iretry, ret = 0;
44
45 spin_lock_irq(sch->lock);
46 if (!sch->schib.pmcw.ena)
47 goto out_unlock;
48 ret = cio_disable_subchannel(sch);
49 if (ret != -EBUSY)
50 goto out_unlock;
51
52 iretry = 255;
53 do {
54
55 ret = cio_cancel_halt_clear(sch, &iretry);
56
57 if (ret == -EIO) {
58 pr_err("vfio_ccw: could not quiesce subchannel 0.%x.%04x!\n",
59 sch->schid.ssid, sch->schid.sch_no);
60 break;
61 }
62
63 /*
64 * Flush all I/O and wait for
65 * cancel/halt/clear completion.
66 */
67 private->completion = &completion;
68 spin_unlock_irq(sch->lock);
69
70 if (ret == -EBUSY)
71 wait_for_completion_timeout(&completion, 3*HZ);
72
73 private->completion = NULL;
74 flush_workqueue(vfio_ccw_work_q);
75 spin_lock_irq(sch->lock);
76 ret = cio_disable_subchannel(sch);
77 } while (ret == -EBUSY);
78 out_unlock:
79 private->state = VFIO_CCW_STATE_NOT_OPER;
80 spin_unlock_irq(sch->lock);
81 return ret;
82 }
83
vfio_ccw_sch_io_todo(struct work_struct * work)84 static void vfio_ccw_sch_io_todo(struct work_struct *work)
85 {
86 struct vfio_ccw_private *private;
87 struct irb *irb;
88 bool is_final;
89 bool cp_is_finished = false;
90
91 private = container_of(work, struct vfio_ccw_private, io_work);
92 irb = &private->irb;
93
94 is_final = !(scsw_actl(&irb->scsw) &
95 (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
96 if (scsw_is_solicited(&irb->scsw)) {
97 cp_update_scsw(&private->cp, &irb->scsw);
98 if (is_final && private->state == VFIO_CCW_STATE_CP_PENDING) {
99 cp_free(&private->cp);
100 cp_is_finished = true;
101 }
102 }
103 mutex_lock(&private->io_mutex);
104 memcpy(private->io_region->irb_area, irb, sizeof(*irb));
105 mutex_unlock(&private->io_mutex);
106
107 /*
108 * Reset to IDLE only if processing of a channel program
109 * has finished. Do not overwrite a possible processing
110 * state if the final interrupt was for HSCH or CSCH.
111 */
112 if (private->mdev && cp_is_finished)
113 private->state = VFIO_CCW_STATE_IDLE;
114
115 if (private->io_trigger)
116 eventfd_signal(private->io_trigger, 1);
117 }
118
vfio_ccw_crw_todo(struct work_struct * work)119 static void vfio_ccw_crw_todo(struct work_struct *work)
120 {
121 struct vfio_ccw_private *private;
122
123 private = container_of(work, struct vfio_ccw_private, crw_work);
124
125 if (!list_empty(&private->crw) && private->crw_trigger)
126 eventfd_signal(private->crw_trigger, 1);
127 }
128
129 /*
130 * Css driver callbacks
131 */
vfio_ccw_sch_irq(struct subchannel * sch)132 static void vfio_ccw_sch_irq(struct subchannel *sch)
133 {
134 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
135
136 inc_irq_stat(IRQIO_CIO);
137 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
138 }
139
vfio_ccw_free_regions(struct vfio_ccw_private * private)140 static void vfio_ccw_free_regions(struct vfio_ccw_private *private)
141 {
142 if (private->crw_region)
143 kmem_cache_free(vfio_ccw_crw_region, private->crw_region);
144 if (private->schib_region)
145 kmem_cache_free(vfio_ccw_schib_region, private->schib_region);
146 if (private->cmd_region)
147 kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region);
148 if (private->io_region)
149 kmem_cache_free(vfio_ccw_io_region, private->io_region);
150 }
151
vfio_ccw_sch_probe(struct subchannel * sch)152 static int vfio_ccw_sch_probe(struct subchannel *sch)
153 {
154 struct pmcw *pmcw = &sch->schib.pmcw;
155 struct vfio_ccw_private *private;
156 int ret = -ENOMEM;
157
158 if (pmcw->qf) {
159 dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
160 dev_name(&sch->dev));
161 return -ENODEV;
162 }
163
164 private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
165 if (!private)
166 return -ENOMEM;
167
168 private->cp.guest_cp = kcalloc(CCWCHAIN_LEN_MAX, sizeof(struct ccw1),
169 GFP_KERNEL);
170 if (!private->cp.guest_cp)
171 goto out_free;
172
173 private->io_region = kmem_cache_zalloc(vfio_ccw_io_region,
174 GFP_KERNEL | GFP_DMA);
175 if (!private->io_region)
176 goto out_free;
177
178 private->cmd_region = kmem_cache_zalloc(vfio_ccw_cmd_region,
179 GFP_KERNEL | GFP_DMA);
180 if (!private->cmd_region)
181 goto out_free;
182
183 private->schib_region = kmem_cache_zalloc(vfio_ccw_schib_region,
184 GFP_KERNEL | GFP_DMA);
185
186 if (!private->schib_region)
187 goto out_free;
188
189 private->crw_region = kmem_cache_zalloc(vfio_ccw_crw_region,
190 GFP_KERNEL | GFP_DMA);
191
192 if (!private->crw_region)
193 goto out_free;
194
195 private->sch = sch;
196 dev_set_drvdata(&sch->dev, private);
197 mutex_init(&private->io_mutex);
198
199 spin_lock_irq(sch->lock);
200 private->state = VFIO_CCW_STATE_NOT_OPER;
201 sch->isc = VFIO_CCW_ISC;
202 ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
203 spin_unlock_irq(sch->lock);
204 if (ret)
205 goto out_free;
206
207 INIT_LIST_HEAD(&private->crw);
208 INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo);
209 INIT_WORK(&private->crw_work, vfio_ccw_crw_todo);
210 atomic_set(&private->avail, 1);
211 private->state = VFIO_CCW_STATE_STANDBY;
212
213 ret = vfio_ccw_mdev_reg(sch);
214 if (ret)
215 goto out_disable;
216
217 if (dev_get_uevent_suppress(&sch->dev)) {
218 dev_set_uevent_suppress(&sch->dev, 0);
219 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
220 }
221
222 VFIO_CCW_MSG_EVENT(4, "bound to subchannel %x.%x.%04x\n",
223 sch->schid.cssid, sch->schid.ssid,
224 sch->schid.sch_no);
225 return 0;
226
227 out_disable:
228 cio_disable_subchannel(sch);
229 out_free:
230 dev_set_drvdata(&sch->dev, NULL);
231 vfio_ccw_free_regions(private);
232 kfree(private->cp.guest_cp);
233 kfree(private);
234 return ret;
235 }
236
vfio_ccw_sch_remove(struct subchannel * sch)237 static int vfio_ccw_sch_remove(struct subchannel *sch)
238 {
239 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
240 struct vfio_ccw_crw *crw, *temp;
241
242 vfio_ccw_sch_quiesce(sch);
243
244 list_for_each_entry_safe(crw, temp, &private->crw, next) {
245 list_del(&crw->next);
246 kfree(crw);
247 }
248
249 vfio_ccw_mdev_unreg(sch);
250
251 dev_set_drvdata(&sch->dev, NULL);
252
253 vfio_ccw_free_regions(private);
254 kfree(private->cp.guest_cp);
255 kfree(private);
256
257 VFIO_CCW_MSG_EVENT(4, "unbound from subchannel %x.%x.%04x\n",
258 sch->schid.cssid, sch->schid.ssid,
259 sch->schid.sch_no);
260 return 0;
261 }
262
vfio_ccw_sch_shutdown(struct subchannel * sch)263 static void vfio_ccw_sch_shutdown(struct subchannel *sch)
264 {
265 vfio_ccw_sch_quiesce(sch);
266 }
267
268 /**
269 * vfio_ccw_sch_event - process subchannel event
270 * @sch: subchannel
271 * @process: non-zero if function is called in process context
272 *
273 * An unspecified event occurred for this subchannel. Adjust data according
274 * to the current operational state of the subchannel. Return zero when the
275 * event has been handled sufficiently or -EAGAIN when this function should
276 * be called again in process context.
277 */
vfio_ccw_sch_event(struct subchannel * sch,int process)278 static int vfio_ccw_sch_event(struct subchannel *sch, int process)
279 {
280 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
281 unsigned long flags;
282 int rc = -EAGAIN;
283
284 spin_lock_irqsave(sch->lock, flags);
285 if (!device_is_registered(&sch->dev))
286 goto out_unlock;
287
288 if (work_pending(&sch->todo_work))
289 goto out_unlock;
290
291 if (cio_update_schib(sch)) {
292 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
293 rc = 0;
294 goto out_unlock;
295 }
296
297 private = dev_get_drvdata(&sch->dev);
298 if (private->state == VFIO_CCW_STATE_NOT_OPER) {
299 private->state = private->mdev ? VFIO_CCW_STATE_IDLE :
300 VFIO_CCW_STATE_STANDBY;
301 }
302 rc = 0;
303
304 out_unlock:
305 spin_unlock_irqrestore(sch->lock, flags);
306
307 return rc;
308 }
309
vfio_ccw_queue_crw(struct vfio_ccw_private * private,unsigned int rsc,unsigned int erc,unsigned int rsid)310 static void vfio_ccw_queue_crw(struct vfio_ccw_private *private,
311 unsigned int rsc,
312 unsigned int erc,
313 unsigned int rsid)
314 {
315 struct vfio_ccw_crw *crw;
316
317 /*
318 * If unable to allocate a CRW, just drop the event and
319 * carry on. The guest will either see a later one or
320 * learn when it issues its own store subchannel.
321 */
322 crw = kzalloc(sizeof(*crw), GFP_ATOMIC);
323 if (!crw)
324 return;
325
326 /*
327 * Build the CRW based on the inputs given to us.
328 */
329 crw->crw.rsc = rsc;
330 crw->crw.erc = erc;
331 crw->crw.rsid = rsid;
332
333 list_add_tail(&crw->next, &private->crw);
334 queue_work(vfio_ccw_work_q, &private->crw_work);
335 }
336
vfio_ccw_chp_event(struct subchannel * sch,struct chp_link * link,int event)337 static int vfio_ccw_chp_event(struct subchannel *sch,
338 struct chp_link *link, int event)
339 {
340 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
341 int mask = chp_ssd_get_mask(&sch->ssd_info, link);
342 int retry = 255;
343
344 if (!private || !mask)
345 return 0;
346
347 trace_vfio_ccw_chp_event(private->sch->schid, mask, event);
348 VFIO_CCW_MSG_EVENT(2, "%pUl (%x.%x.%04x): mask=0x%x event=%d\n",
349 mdev_uuid(private->mdev), sch->schid.cssid,
350 sch->schid.ssid, sch->schid.sch_no,
351 mask, event);
352
353 if (cio_update_schib(sch))
354 return -ENODEV;
355
356 switch (event) {
357 case CHP_VARY_OFF:
358 /* Path logically turned off */
359 sch->opm &= ~mask;
360 sch->lpm &= ~mask;
361 if (sch->schib.pmcw.lpum & mask)
362 cio_cancel_halt_clear(sch, &retry);
363 break;
364 case CHP_OFFLINE:
365 /* Path is gone */
366 if (sch->schib.pmcw.lpum & mask)
367 cio_cancel_halt_clear(sch, &retry);
368 vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_PERRN,
369 link->chpid.id);
370 break;
371 case CHP_VARY_ON:
372 /* Path logically turned on */
373 sch->opm |= mask;
374 sch->lpm |= mask;
375 break;
376 case CHP_ONLINE:
377 /* Path became available */
378 sch->lpm |= mask & sch->opm;
379 vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_INIT,
380 link->chpid.id);
381 break;
382 }
383
384 return 0;
385 }
386
387 static struct css_device_id vfio_ccw_sch_ids[] = {
388 { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
389 { /* end of list */ },
390 };
391 MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
392
393 static struct css_driver vfio_ccw_sch_driver = {
394 .drv = {
395 .name = "vfio_ccw",
396 .owner = THIS_MODULE,
397 },
398 .subchannel_type = vfio_ccw_sch_ids,
399 .irq = vfio_ccw_sch_irq,
400 .probe = vfio_ccw_sch_probe,
401 .remove = vfio_ccw_sch_remove,
402 .shutdown = vfio_ccw_sch_shutdown,
403 .sch_event = vfio_ccw_sch_event,
404 .chp_event = vfio_ccw_chp_event,
405 };
406
vfio_ccw_debug_init(void)407 static int __init vfio_ccw_debug_init(void)
408 {
409 vfio_ccw_debug_msg_id = debug_register("vfio_ccw_msg", 16, 1,
410 11 * sizeof(long));
411 if (!vfio_ccw_debug_msg_id)
412 goto out_unregister;
413 debug_register_view(vfio_ccw_debug_msg_id, &debug_sprintf_view);
414 debug_set_level(vfio_ccw_debug_msg_id, 2);
415 vfio_ccw_debug_trace_id = debug_register("vfio_ccw_trace", 16, 1, 16);
416 if (!vfio_ccw_debug_trace_id)
417 goto out_unregister;
418 debug_register_view(vfio_ccw_debug_trace_id, &debug_hex_ascii_view);
419 debug_set_level(vfio_ccw_debug_trace_id, 2);
420 return 0;
421
422 out_unregister:
423 debug_unregister(vfio_ccw_debug_msg_id);
424 debug_unregister(vfio_ccw_debug_trace_id);
425 return -1;
426 }
427
vfio_ccw_debug_exit(void)428 static void vfio_ccw_debug_exit(void)
429 {
430 debug_unregister(vfio_ccw_debug_msg_id);
431 debug_unregister(vfio_ccw_debug_trace_id);
432 }
433
vfio_ccw_destroy_regions(void)434 static void vfio_ccw_destroy_regions(void)
435 {
436 kmem_cache_destroy(vfio_ccw_crw_region);
437 kmem_cache_destroy(vfio_ccw_schib_region);
438 kmem_cache_destroy(vfio_ccw_cmd_region);
439 kmem_cache_destroy(vfio_ccw_io_region);
440 }
441
vfio_ccw_sch_init(void)442 static int __init vfio_ccw_sch_init(void)
443 {
444 int ret;
445
446 ret = vfio_ccw_debug_init();
447 if (ret)
448 return ret;
449
450 vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
451 if (!vfio_ccw_work_q) {
452 ret = -ENOMEM;
453 goto out_err;
454 }
455
456 vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
457 sizeof(struct ccw_io_region), 0,
458 SLAB_ACCOUNT, 0,
459 sizeof(struct ccw_io_region), NULL);
460 if (!vfio_ccw_io_region) {
461 ret = -ENOMEM;
462 goto out_err;
463 }
464
465 vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
466 sizeof(struct ccw_cmd_region), 0,
467 SLAB_ACCOUNT, 0,
468 sizeof(struct ccw_cmd_region), NULL);
469 if (!vfio_ccw_cmd_region) {
470 ret = -ENOMEM;
471 goto out_err;
472 }
473
474 vfio_ccw_schib_region = kmem_cache_create_usercopy("vfio_ccw_schib_region",
475 sizeof(struct ccw_schib_region), 0,
476 SLAB_ACCOUNT, 0,
477 sizeof(struct ccw_schib_region), NULL);
478
479 if (!vfio_ccw_schib_region) {
480 ret = -ENOMEM;
481 goto out_err;
482 }
483
484 vfio_ccw_crw_region = kmem_cache_create_usercopy("vfio_ccw_crw_region",
485 sizeof(struct ccw_crw_region), 0,
486 SLAB_ACCOUNT, 0,
487 sizeof(struct ccw_crw_region), NULL);
488
489 if (!vfio_ccw_crw_region) {
490 ret = -ENOMEM;
491 goto out_err;
492 }
493
494 isc_register(VFIO_CCW_ISC);
495 ret = css_driver_register(&vfio_ccw_sch_driver);
496 if (ret) {
497 isc_unregister(VFIO_CCW_ISC);
498 goto out_err;
499 }
500
501 return ret;
502
503 out_err:
504 vfio_ccw_destroy_regions();
505 destroy_workqueue(vfio_ccw_work_q);
506 vfio_ccw_debug_exit();
507 return ret;
508 }
509
vfio_ccw_sch_exit(void)510 static void __exit vfio_ccw_sch_exit(void)
511 {
512 css_driver_unregister(&vfio_ccw_sch_driver);
513 isc_unregister(VFIO_CCW_ISC);
514 vfio_ccw_destroy_regions();
515 destroy_workqueue(vfio_ccw_work_q);
516 vfio_ccw_debug_exit();
517 }
518 module_init(vfio_ccw_sch_init);
519 module_exit(vfio_ccw_sch_exit);
520
521 MODULE_LICENSE("GPL v2");
522