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/slab.h>
16 #include <linux/mdev.h>
17
18 #include <asm/isc.h>
19
20 #include "chp.h"
21 #include "ioasm.h"
22 #include "css.h"
23 #include "vfio_ccw_private.h"
24
25 struct workqueue_struct *vfio_ccw_work_q;
26 struct kmem_cache *vfio_ccw_io_region;
27 struct kmem_cache *vfio_ccw_cmd_region;
28 struct kmem_cache *vfio_ccw_schib_region;
29 struct kmem_cache *vfio_ccw_crw_region;
30
31 debug_info_t *vfio_ccw_debug_msg_id;
32 debug_info_t *vfio_ccw_debug_trace_id;
33
34 /*
35 * Helpers
36 */
vfio_ccw_sch_quiesce(struct subchannel * sch)37 int vfio_ccw_sch_quiesce(struct subchannel *sch)
38 {
39 struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
40 struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
41 DECLARE_COMPLETION_ONSTACK(completion);
42 int iretry, ret = 0;
43
44 /*
45 * Probably an impossible situation, after being called through
46 * FSM callbacks. But in the event it did, register a warning
47 * and return as if things were fine.
48 */
49 if (WARN_ON(!private))
50 return 0;
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
79 return ret;
80 }
81
vfio_ccw_sch_io_todo(struct work_struct * work)82 void vfio_ccw_sch_io_todo(struct work_struct *work)
83 {
84 struct vfio_ccw_private *private;
85 struct irb *irb;
86 bool is_final;
87 bool cp_is_finished = false;
88
89 private = container_of(work, struct vfio_ccw_private, io_work);
90 irb = &private->irb;
91
92 is_final = !(scsw_actl(&irb->scsw) &
93 (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
94 if (scsw_is_solicited(&irb->scsw)) {
95 cp_update_scsw(&private->cp, &irb->scsw);
96 if (is_final && private->state == VFIO_CCW_STATE_CP_PENDING) {
97 cp_free(&private->cp);
98 cp_is_finished = true;
99 }
100 }
101 mutex_lock(&private->io_mutex);
102 memcpy(private->io_region->irb_area, irb, sizeof(*irb));
103 mutex_unlock(&private->io_mutex);
104
105 /*
106 * Reset to IDLE only if processing of a channel program
107 * has finished. Do not overwrite a possible processing
108 * state if the interrupt was unsolicited, or if the final
109 * interrupt was for HSCH or CSCH.
110 */
111 if (cp_is_finished)
112 private->state = VFIO_CCW_STATE_IDLE;
113
114 if (private->io_trigger)
115 eventfd_signal(private->io_trigger);
116 }
117
vfio_ccw_crw_todo(struct work_struct * work)118 void vfio_ccw_crw_todo(struct work_struct *work)
119 {
120 struct vfio_ccw_private *private;
121
122 private = container_of(work, struct vfio_ccw_private, crw_work);
123
124 if (!list_empty(&private->crw) && private->crw_trigger)
125 eventfd_signal(private->crw_trigger);
126 }
127
128 /*
129 * Css driver callbacks
130 */
vfio_ccw_sch_irq(struct subchannel * sch)131 static void vfio_ccw_sch_irq(struct subchannel *sch)
132 {
133 struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
134 struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
135
136 /*
137 * The subchannel should still be disabled at this point,
138 * so an interrupt would be quite surprising. As with an
139 * interrupt while the FSM is closed, let's attempt to
140 * disable the subchannel again.
141 */
142 if (!private) {
143 VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: unexpected interrupt\n",
144 sch->schid.cssid, sch->schid.ssid,
145 sch->schid.sch_no);
146
147 cio_disable_subchannel(sch);
148 return;
149 }
150
151 inc_irq_stat(IRQIO_CIO);
152 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
153 }
154
vfio_ccw_free_parent(struct device * dev)155 static void vfio_ccw_free_parent(struct device *dev)
156 {
157 struct vfio_ccw_parent *parent = container_of(dev, struct vfio_ccw_parent, dev);
158
159 kfree(parent);
160 }
161
vfio_ccw_sch_probe(struct subchannel * sch)162 static int vfio_ccw_sch_probe(struct subchannel *sch)
163 {
164 struct pmcw *pmcw = &sch->schib.pmcw;
165 struct vfio_ccw_parent *parent;
166 int ret = -ENOMEM;
167
168 if (pmcw->qf) {
169 dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
170 dev_name(&sch->dev));
171 return -ENODEV;
172 }
173
174 parent = kzalloc(struct_size(parent, mdev_types, 1), GFP_KERNEL);
175 if (!parent)
176 return -ENOMEM;
177
178 dev_set_name(&parent->dev, "parent");
179 parent->dev.parent = &sch->dev;
180 parent->dev.release = &vfio_ccw_free_parent;
181 ret = device_register(&parent->dev);
182 if (ret)
183 goto out_free;
184
185 dev_set_drvdata(&sch->dev, parent);
186
187 parent->mdev_type.sysfs_name = "io";
188 parent->mdev_type.pretty_name = "I/O subchannel (Non-QDIO)";
189 parent->mdev_types[0] = &parent->mdev_type;
190 ret = mdev_register_parent(&parent->parent, &sch->dev,
191 &vfio_ccw_mdev_driver,
192 parent->mdev_types, 1);
193 if (ret)
194 goto out_unreg;
195
196 VFIO_CCW_MSG_EVENT(4, "bound to subchannel %x.%x.%04x\n",
197 sch->schid.cssid, sch->schid.ssid,
198 sch->schid.sch_no);
199 return 0;
200
201 out_unreg:
202 device_del(&parent->dev);
203 out_free:
204 put_device(&parent->dev);
205 dev_set_drvdata(&sch->dev, NULL);
206 return ret;
207 }
208
vfio_ccw_sch_remove(struct subchannel * sch)209 static void vfio_ccw_sch_remove(struct subchannel *sch)
210 {
211 struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
212
213 mdev_unregister_parent(&parent->parent);
214
215 device_unregister(&parent->dev);
216 dev_set_drvdata(&sch->dev, NULL);
217
218 VFIO_CCW_MSG_EVENT(4, "unbound from subchannel %x.%x.%04x\n",
219 sch->schid.cssid, sch->schid.ssid,
220 sch->schid.sch_no);
221 }
222
vfio_ccw_sch_shutdown(struct subchannel * sch)223 static void vfio_ccw_sch_shutdown(struct subchannel *sch)
224 {
225 struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
226 struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
227
228 if (!private)
229 return;
230
231 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
232 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
233 }
234
235 /**
236 * vfio_ccw_sch_event - process subchannel event
237 * @sch: subchannel
238 * @process: non-zero if function is called in process context
239 *
240 * An unspecified event occurred for this subchannel. Adjust data according
241 * to the current operational state of the subchannel. Return zero when the
242 * event has been handled sufficiently or -EAGAIN when this function should
243 * be called again in process context.
244 */
vfio_ccw_sch_event(struct subchannel * sch,int process)245 static int vfio_ccw_sch_event(struct subchannel *sch, int process)
246 {
247 struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
248 struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
249 unsigned long flags;
250 int rc = -EAGAIN;
251
252 spin_lock_irqsave(&sch->lock, flags);
253 if (!device_is_registered(&sch->dev))
254 goto out_unlock;
255
256 if (work_pending(&sch->todo_work))
257 goto out_unlock;
258
259 rc = 0;
260
261 if (cio_update_schib(sch)) {
262 if (private)
263 vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
264 }
265
266 out_unlock:
267 spin_unlock_irqrestore(&sch->lock, flags);
268
269 return rc;
270 }
271
vfio_ccw_queue_crw(struct vfio_ccw_private * private,unsigned int rsc,unsigned int erc,unsigned int rsid)272 static void vfio_ccw_queue_crw(struct vfio_ccw_private *private,
273 unsigned int rsc,
274 unsigned int erc,
275 unsigned int rsid)
276 {
277 struct vfio_ccw_crw *crw;
278
279 /*
280 * If unable to allocate a CRW, just drop the event and
281 * carry on. The guest will either see a later one or
282 * learn when it issues its own store subchannel.
283 */
284 crw = kzalloc(sizeof(*crw), GFP_ATOMIC);
285 if (!crw)
286 return;
287
288 /*
289 * Build the CRW based on the inputs given to us.
290 */
291 crw->crw.rsc = rsc;
292 crw->crw.erc = erc;
293 crw->crw.rsid = rsid;
294
295 list_add_tail(&crw->next, &private->crw);
296 queue_work(vfio_ccw_work_q, &private->crw_work);
297 }
298
vfio_ccw_chp_event(struct subchannel * sch,struct chp_link * link,int event)299 static int vfio_ccw_chp_event(struct subchannel *sch,
300 struct chp_link *link, int event)
301 {
302 struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
303 struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
304 int mask = chp_ssd_get_mask(&sch->ssd_info, link);
305 int retry = 255;
306
307 if (!private || !mask)
308 return 0;
309
310 trace_vfio_ccw_chp_event(sch->schid, mask, event);
311 VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: mask=0x%x event=%d\n",
312 sch->schid.cssid,
313 sch->schid.ssid, sch->schid.sch_no,
314 mask, event);
315
316 if (cio_update_schib(sch))
317 return -ENODEV;
318
319 switch (event) {
320 case CHP_VARY_OFF:
321 /* Path logically turned off */
322 sch->opm &= ~mask;
323 sch->lpm &= ~mask;
324 if (sch->schib.pmcw.lpum & mask)
325 cio_cancel_halt_clear(sch, &retry);
326 break;
327 case CHP_OFFLINE:
328 /* Path is gone */
329 if (sch->schib.pmcw.lpum & mask)
330 cio_cancel_halt_clear(sch, &retry);
331 vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_PERRN,
332 link->chpid.id);
333 break;
334 case CHP_VARY_ON:
335 /* Path logically turned on */
336 sch->opm |= mask;
337 sch->lpm |= mask;
338 break;
339 case CHP_ONLINE:
340 /* Path became available */
341 sch->lpm |= mask & sch->opm;
342 vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_INIT,
343 link->chpid.id);
344 break;
345 }
346
347 return 0;
348 }
349
350 static struct css_device_id vfio_ccw_sch_ids[] = {
351 { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
352 { /* end of list */ },
353 };
354 MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);
355
356 static struct css_driver vfio_ccw_sch_driver = {
357 .drv = {
358 .name = "vfio_ccw",
359 .owner = THIS_MODULE,
360 },
361 .subchannel_type = vfio_ccw_sch_ids,
362 .irq = vfio_ccw_sch_irq,
363 .probe = vfio_ccw_sch_probe,
364 .remove = vfio_ccw_sch_remove,
365 .shutdown = vfio_ccw_sch_shutdown,
366 .sch_event = vfio_ccw_sch_event,
367 .chp_event = vfio_ccw_chp_event,
368 };
369
vfio_ccw_debug_init(void)370 static int __init vfio_ccw_debug_init(void)
371 {
372 vfio_ccw_debug_msg_id = debug_register("vfio_ccw_msg", 16, 1,
373 11 * sizeof(long));
374 if (!vfio_ccw_debug_msg_id)
375 goto out_unregister;
376 debug_register_view(vfio_ccw_debug_msg_id, &debug_sprintf_view);
377 debug_set_level(vfio_ccw_debug_msg_id, 2);
378 vfio_ccw_debug_trace_id = debug_register("vfio_ccw_trace", 16, 1, 16);
379 if (!vfio_ccw_debug_trace_id)
380 goto out_unregister;
381 debug_register_view(vfio_ccw_debug_trace_id, &debug_hex_ascii_view);
382 debug_set_level(vfio_ccw_debug_trace_id, 2);
383 return 0;
384
385 out_unregister:
386 debug_unregister(vfio_ccw_debug_msg_id);
387 debug_unregister(vfio_ccw_debug_trace_id);
388 return -1;
389 }
390
vfio_ccw_debug_exit(void)391 static void vfio_ccw_debug_exit(void)
392 {
393 debug_unregister(vfio_ccw_debug_msg_id);
394 debug_unregister(vfio_ccw_debug_trace_id);
395 }
396
vfio_ccw_destroy_regions(void)397 static void vfio_ccw_destroy_regions(void)
398 {
399 kmem_cache_destroy(vfio_ccw_crw_region);
400 kmem_cache_destroy(vfio_ccw_schib_region);
401 kmem_cache_destroy(vfio_ccw_cmd_region);
402 kmem_cache_destroy(vfio_ccw_io_region);
403 }
404
vfio_ccw_sch_init(void)405 static int __init vfio_ccw_sch_init(void)
406 {
407 int ret;
408
409 ret = vfio_ccw_debug_init();
410 if (ret)
411 return ret;
412
413 vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
414 if (!vfio_ccw_work_q) {
415 ret = -ENOMEM;
416 goto out_regions;
417 }
418
419 vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
420 sizeof(struct ccw_io_region), 0,
421 SLAB_ACCOUNT, 0,
422 sizeof(struct ccw_io_region), NULL);
423 if (!vfio_ccw_io_region) {
424 ret = -ENOMEM;
425 goto out_regions;
426 }
427
428 vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
429 sizeof(struct ccw_cmd_region), 0,
430 SLAB_ACCOUNT, 0,
431 sizeof(struct ccw_cmd_region), NULL);
432 if (!vfio_ccw_cmd_region) {
433 ret = -ENOMEM;
434 goto out_regions;
435 }
436
437 vfio_ccw_schib_region = kmem_cache_create_usercopy("vfio_ccw_schib_region",
438 sizeof(struct ccw_schib_region), 0,
439 SLAB_ACCOUNT, 0,
440 sizeof(struct ccw_schib_region), NULL);
441
442 if (!vfio_ccw_schib_region) {
443 ret = -ENOMEM;
444 goto out_regions;
445 }
446
447 vfio_ccw_crw_region = kmem_cache_create_usercopy("vfio_ccw_crw_region",
448 sizeof(struct ccw_crw_region), 0,
449 SLAB_ACCOUNT, 0,
450 sizeof(struct ccw_crw_region), NULL);
451
452 if (!vfio_ccw_crw_region) {
453 ret = -ENOMEM;
454 goto out_regions;
455 }
456
457 ret = mdev_register_driver(&vfio_ccw_mdev_driver);
458 if (ret)
459 goto out_regions;
460
461 isc_register(VFIO_CCW_ISC);
462 ret = css_driver_register(&vfio_ccw_sch_driver);
463 if (ret) {
464 isc_unregister(VFIO_CCW_ISC);
465 goto out_driver;
466 }
467
468 return ret;
469
470 out_driver:
471 mdev_unregister_driver(&vfio_ccw_mdev_driver);
472 out_regions:
473 vfio_ccw_destroy_regions();
474 destroy_workqueue(vfio_ccw_work_q);
475 vfio_ccw_debug_exit();
476 return ret;
477 }
478
vfio_ccw_sch_exit(void)479 static void __exit vfio_ccw_sch_exit(void)
480 {
481 css_driver_unregister(&vfio_ccw_sch_driver);
482 mdev_unregister_driver(&vfio_ccw_mdev_driver);
483 isc_unregister(VFIO_CCW_ISC);
484 vfio_ccw_destroy_regions();
485 destroy_workqueue(vfio_ccw_work_q);
486 vfio_ccw_debug_exit();
487 }
488 module_init(vfio_ccw_sch_init);
489 module_exit(vfio_ccw_sch_exit);
490
491 MODULE_DESCRIPTION("VFIO based Subchannel device driver");
492 MODULE_LICENSE("GPL v2");
493