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 rc = 0;
292
293 if (cio_update_schib(sch))
294 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
295
296 out_unlock:
297 spin_unlock_irqrestore(sch->lock, flags);
298
299 return rc;
300 }
301
vfio_ccw_queue_crw(struct vfio_ccw_private * private,unsigned int rsc,unsigned int erc,unsigned int rsid)302 static void vfio_ccw_queue_crw(struct vfio_ccw_private *private,
303 unsigned int rsc,
304 unsigned int erc,
305 unsigned int rsid)
306 {
307 struct vfio_ccw_crw *crw;
308
309 /*
310 * If unable to allocate a CRW, just drop the event and
311 * carry on. The guest will either see a later one or
312 * learn when it issues its own store subchannel.
313 */
314 crw = kzalloc(sizeof(*crw), GFP_ATOMIC);
315 if (!crw)
316 return;
317
318 /*
319 * Build the CRW based on the inputs given to us.
320 */
321 crw->crw.rsc = rsc;
322 crw->crw.erc = erc;
323 crw->crw.rsid = rsid;
324
325 list_add_tail(&crw->next, &private->crw);
326 queue_work(vfio_ccw_work_q, &private->crw_work);
327 }
328
vfio_ccw_chp_event(struct subchannel * sch,struct chp_link * link,int event)329 static int vfio_ccw_chp_event(struct subchannel *sch,
330 struct chp_link *link, int event)
331 {
332 struct vfio_ccw_private *private = dev_get_drvdata(&sch->dev);
333 int mask = chp_ssd_get_mask(&sch->ssd_info, link);
334 int retry = 255;
335
336 if (!private || !mask)
337 return 0;
338
339 trace_vfio_ccw_chp_event(private->sch->schid, mask, event);
340 VFIO_CCW_MSG_EVENT(2, "%pUl (%x.%x.%04x): mask=0x%x event=%d\n",
341 mdev_uuid(private->mdev), sch->schid.cssid,
342 sch->schid.ssid, sch->schid.sch_no,
343 mask, event);
344
345 if (cio_update_schib(sch))
346 return -ENODEV;
347
348 switch (event) {
349 case CHP_VARY_OFF:
350 /* Path logically turned off */
351 sch->opm &= ~mask;
352 sch->lpm &= ~mask;
353 if (sch->schib.pmcw.lpum & mask)
354 cio_cancel_halt_clear(sch, &retry);
355 break;
356 case CHP_OFFLINE:
357 /* Path is gone */
358 if (sch->schib.pmcw.lpum & mask)
359 cio_cancel_halt_clear(sch, &retry);
360 vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_PERRN,
361 link->chpid.id);
362 break;
363 case CHP_VARY_ON:
364 /* Path logically turned on */
365 sch->opm |= mask;
366 sch->lpm |= mask;
367 break;
368 case CHP_ONLINE:
369 /* Path became available */
370 sch->lpm |= mask & sch->opm;
371 vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_INIT,
372 link->chpid.id);
373 break;
374 }
375
376 return 0;
377 }
378
379 static struct css_device_id vfio_ccw_sch_ids[] = {
380 { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
381 { /* end of list */ },
382 };
383 MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
384
385 static struct css_driver vfio_ccw_sch_driver = {
386 .drv = {
387 .name = "vfio_ccw",
388 .owner = THIS_MODULE,
389 },
390 .subchannel_type = vfio_ccw_sch_ids,
391 .irq = vfio_ccw_sch_irq,
392 .probe = vfio_ccw_sch_probe,
393 .remove = vfio_ccw_sch_remove,
394 .shutdown = vfio_ccw_sch_shutdown,
395 .sch_event = vfio_ccw_sch_event,
396 .chp_event = vfio_ccw_chp_event,
397 };
398
vfio_ccw_debug_init(void)399 static int __init vfio_ccw_debug_init(void)
400 {
401 vfio_ccw_debug_msg_id = debug_register("vfio_ccw_msg", 16, 1,
402 11 * sizeof(long));
403 if (!vfio_ccw_debug_msg_id)
404 goto out_unregister;
405 debug_register_view(vfio_ccw_debug_msg_id, &debug_sprintf_view);
406 debug_set_level(vfio_ccw_debug_msg_id, 2);
407 vfio_ccw_debug_trace_id = debug_register("vfio_ccw_trace", 16, 1, 16);
408 if (!vfio_ccw_debug_trace_id)
409 goto out_unregister;
410 debug_register_view(vfio_ccw_debug_trace_id, &debug_hex_ascii_view);
411 debug_set_level(vfio_ccw_debug_trace_id, 2);
412 return 0;
413
414 out_unregister:
415 debug_unregister(vfio_ccw_debug_msg_id);
416 debug_unregister(vfio_ccw_debug_trace_id);
417 return -1;
418 }
419
vfio_ccw_debug_exit(void)420 static void vfio_ccw_debug_exit(void)
421 {
422 debug_unregister(vfio_ccw_debug_msg_id);
423 debug_unregister(vfio_ccw_debug_trace_id);
424 }
425
vfio_ccw_destroy_regions(void)426 static void vfio_ccw_destroy_regions(void)
427 {
428 kmem_cache_destroy(vfio_ccw_crw_region);
429 kmem_cache_destroy(vfio_ccw_schib_region);
430 kmem_cache_destroy(vfio_ccw_cmd_region);
431 kmem_cache_destroy(vfio_ccw_io_region);
432 }
433
vfio_ccw_sch_init(void)434 static int __init vfio_ccw_sch_init(void)
435 {
436 int ret;
437
438 ret = vfio_ccw_debug_init();
439 if (ret)
440 return ret;
441
442 vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
443 if (!vfio_ccw_work_q) {
444 ret = -ENOMEM;
445 goto out_err;
446 }
447
448 vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
449 sizeof(struct ccw_io_region), 0,
450 SLAB_ACCOUNT, 0,
451 sizeof(struct ccw_io_region), NULL);
452 if (!vfio_ccw_io_region) {
453 ret = -ENOMEM;
454 goto out_err;
455 }
456
457 vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
458 sizeof(struct ccw_cmd_region), 0,
459 SLAB_ACCOUNT, 0,
460 sizeof(struct ccw_cmd_region), NULL);
461 if (!vfio_ccw_cmd_region) {
462 ret = -ENOMEM;
463 goto out_err;
464 }
465
466 vfio_ccw_schib_region = kmem_cache_create_usercopy("vfio_ccw_schib_region",
467 sizeof(struct ccw_schib_region), 0,
468 SLAB_ACCOUNT, 0,
469 sizeof(struct ccw_schib_region), NULL);
470
471 if (!vfio_ccw_schib_region) {
472 ret = -ENOMEM;
473 goto out_err;
474 }
475
476 vfio_ccw_crw_region = kmem_cache_create_usercopy("vfio_ccw_crw_region",
477 sizeof(struct ccw_crw_region), 0,
478 SLAB_ACCOUNT, 0,
479 sizeof(struct ccw_crw_region), NULL);
480
481 if (!vfio_ccw_crw_region) {
482 ret = -ENOMEM;
483 goto out_err;
484 }
485
486 isc_register(VFIO_CCW_ISC);
487 ret = css_driver_register(&vfio_ccw_sch_driver);
488 if (ret) {
489 isc_unregister(VFIO_CCW_ISC);
490 goto out_err;
491 }
492
493 return ret;
494
495 out_err:
496 vfio_ccw_destroy_regions();
497 destroy_workqueue(vfio_ccw_work_q);
498 vfio_ccw_debug_exit();
499 return ret;
500 }
501
vfio_ccw_sch_exit(void)502 static void __exit vfio_ccw_sch_exit(void)
503 {
504 css_driver_unregister(&vfio_ccw_sch_driver);
505 isc_unregister(VFIO_CCW_ISC);
506 vfio_ccw_destroy_regions();
507 destroy_workqueue(vfio_ccw_work_q);
508 vfio_ccw_debug_exit();
509 }
510 module_init(vfio_ccw_sch_init);
511 module_exit(vfio_ccw_sch_exit);
512
513 MODULE_LICENSE("GPL v2");
514