summaryrefslogtreecommitdiff
path: root/drivers/s390/cio/vfio_ccw_drv.c
blob: 8ad49030a7bf3044e75cf43c51c10af9c71ce7bd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
// SPDX-License-Identifier: GPL-2.0
/*
 * VFIO based Physical Subchannel device driver
 *
 * Copyright IBM Corp. 2017
 * Copyright Red Hat, Inc. 2019
 *
 * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
 *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
 *            Cornelia Huck <cohuck@redhat.com>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/mdev.h>

#include <asm/isc.h>

#include "chp.h"
#include "ioasm.h"
#include "css.h"
#include "vfio_ccw_private.h"

struct workqueue_struct *vfio_ccw_work_q;
struct kmem_cache *vfio_ccw_io_region;
struct kmem_cache *vfio_ccw_cmd_region;
struct kmem_cache *vfio_ccw_schib_region;
struct kmem_cache *vfio_ccw_crw_region;

debug_info_t *vfio_ccw_debug_msg_id;
debug_info_t *vfio_ccw_debug_trace_id;

/*
 * Helpers
 */
int vfio_ccw_sch_quiesce(struct subchannel *sch)
{
	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
	DECLARE_COMPLETION_ONSTACK(completion);
	int iretry, ret = 0;

	/*
	 * Probably an impossible situation, after being called through
	 * FSM callbacks. But in the event it did, register a warning
	 * and return as if things were fine.
	 */
	if (WARN_ON(!private))
		return 0;

	iretry = 255;
	do {

		ret = cio_cancel_halt_clear(sch, &iretry);

		if (ret == -EIO) {
			pr_err("vfio_ccw: could not quiesce subchannel 0.%x.%04x!\n",
			       sch->schid.ssid, sch->schid.sch_no);
			break;
		}

		/*
		 * Flush all I/O and wait for
		 * cancel/halt/clear completion.
		 */
		private->completion = &completion;
		spin_unlock_irq(&sch->lock);

		if (ret == -EBUSY)
			wait_for_completion_timeout(&completion, 3*HZ);

		private->completion = NULL;
		flush_workqueue(vfio_ccw_work_q);
		spin_lock_irq(&sch->lock);
		ret = cio_disable_subchannel(sch);
	} while (ret == -EBUSY);

	return ret;
}

void vfio_ccw_sch_io_todo(struct work_struct *work)
{
	struct vfio_ccw_private *private;
	struct irb *irb;
	bool is_final;
	bool cp_is_finished = false;

	private = container_of(work, struct vfio_ccw_private, io_work);
	irb = &private->irb;

	is_final = !(scsw_actl(&irb->scsw) &
		     (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
	if (scsw_is_solicited(&irb->scsw)) {
		cp_update_scsw(&private->cp, &irb->scsw);
		if (is_final && private->state == VFIO_CCW_STATE_CP_PENDING) {
			cp_free(&private->cp);
			cp_is_finished = true;
		}
	}
	mutex_lock(&private->io_mutex);
	memcpy(private->io_region->irb_area, irb, sizeof(*irb));
	mutex_unlock(&private->io_mutex);

	/*
	 * Reset to IDLE only if processing of a channel program
	 * has finished. Do not overwrite a possible processing
	 * state if the interrupt was unsolicited, or if the final
	 * interrupt was for HSCH or CSCH.
	 */
	if (cp_is_finished)
		private->state = VFIO_CCW_STATE_IDLE;

	if (private->io_trigger)
		eventfd_signal(private->io_trigger);
}

void vfio_ccw_crw_todo(struct work_struct *work)
{
	struct vfio_ccw_private *private;

	private = container_of(work, struct vfio_ccw_private, crw_work);

	if (!list_empty(&private->crw) && private->crw_trigger)
		eventfd_signal(private->crw_trigger);
}

/*
 * Css driver callbacks
 */
static void vfio_ccw_sch_irq(struct subchannel *sch)
{
	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);

	/*
	 * The subchannel should still be disabled at this point,
	 * so an interrupt would be quite surprising. As with an
	 * interrupt while the FSM is closed, let's attempt to
	 * disable the subchannel again.
	 */
	if (!private) {
		VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: unexpected interrupt\n",
				   sch->schid.cssid, sch->schid.ssid,
				   sch->schid.sch_no);

		cio_disable_subchannel(sch);
		return;
	}

	inc_irq_stat(IRQIO_CIO);
	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_INTERRUPT);
}

static void vfio_ccw_free_parent(struct device *dev)
{
	struct vfio_ccw_parent *parent = container_of(dev, struct vfio_ccw_parent, dev);

	kfree(parent);
}

static int vfio_ccw_sch_probe(struct subchannel *sch)
{
	struct pmcw *pmcw = &sch->schib.pmcw;
	struct vfio_ccw_parent *parent;
	int ret = -ENOMEM;

	if (pmcw->qf) {
		dev_warn(&sch->dev, "vfio: ccw: does not support QDIO: %s\n",
			 dev_name(&sch->dev));
		return -ENODEV;
	}

	parent = kzalloc(struct_size(parent, mdev_types, 1), GFP_KERNEL);
	if (!parent)
		return -ENOMEM;

	dev_set_name(&parent->dev, "parent");
	parent->dev.parent = &sch->dev;
	parent->dev.release = &vfio_ccw_free_parent;
	ret = device_register(&parent->dev);
	if (ret)
		goto out_free;

	dev_set_drvdata(&sch->dev, parent);

	parent->mdev_type.sysfs_name = "io";
	parent->mdev_type.pretty_name = "I/O subchannel (Non-QDIO)";
	parent->mdev_types[0] = &parent->mdev_type;
	ret = mdev_register_parent(&parent->parent, &sch->dev,
				   &vfio_ccw_mdev_driver,
				   parent->mdev_types, 1);
	if (ret)
		goto out_unreg;

	VFIO_CCW_MSG_EVENT(4, "bound to subchannel %x.%x.%04x\n",
			   sch->schid.cssid, sch->schid.ssid,
			   sch->schid.sch_no);
	return 0;

out_unreg:
	device_del(&parent->dev);
out_free:
	put_device(&parent->dev);
	dev_set_drvdata(&sch->dev, NULL);
	return ret;
}

static void vfio_ccw_sch_remove(struct subchannel *sch)
{
	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);

	mdev_unregister_parent(&parent->parent);

	device_unregister(&parent->dev);
	dev_set_drvdata(&sch->dev, NULL);

	VFIO_CCW_MSG_EVENT(4, "unbound from subchannel %x.%x.%04x\n",
			   sch->schid.cssid, sch->schid.ssid,
			   sch->schid.sch_no);
}

static void vfio_ccw_sch_shutdown(struct subchannel *sch)
{
	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);

	if (!private)
		return;

	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_CLOSE);
	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
}

/**
 * vfio_ccw_sch_event - process subchannel event
 * @sch: subchannel
 * @process: non-zero if function is called in process context
 *
 * An unspecified event occurred for this subchannel. Adjust data according
 * to the current operational state of the subchannel. Return zero when the
 * event has been handled sufficiently or -EAGAIN when this function should
 * be called again in process context.
 */
static int vfio_ccw_sch_event(struct subchannel *sch, int process)
{
	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
	unsigned long flags;
	int rc = -EAGAIN;

	spin_lock_irqsave(&sch->lock, flags);
	if (!device_is_registered(&sch->dev))
		goto out_unlock;

	if (work_pending(&sch->todo_work))
		goto out_unlock;

	rc = 0;

	if (cio_update_schib(sch)) {
		if (private)
			vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER);
	}

out_unlock:
	spin_unlock_irqrestore(&sch->lock, flags);

	return rc;
}

static void vfio_ccw_queue_crw(struct vfio_ccw_private *private,
			       unsigned int rsc,
			       unsigned int erc,
			       unsigned int rsid)
{
	struct vfio_ccw_crw *crw;

	/*
	 * If unable to allocate a CRW, just drop the event and
	 * carry on.  The guest will either see a later one or
	 * learn when it issues its own store subchannel.
	 */
	crw = kzalloc(sizeof(*crw), GFP_ATOMIC);
	if (!crw)
		return;

	/*
	 * Build the CRW based on the inputs given to us.
	 */
	crw->crw.rsc = rsc;
	crw->crw.erc = erc;
	crw->crw.rsid = rsid;

	list_add_tail(&crw->next, &private->crw);
	queue_work(vfio_ccw_work_q, &private->crw_work);
}

static int vfio_ccw_chp_event(struct subchannel *sch,
			      struct chp_link *link, int event)
{
	struct vfio_ccw_parent *parent = dev_get_drvdata(&sch->dev);
	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
	int mask = chp_ssd_get_mask(&sch->ssd_info, link);
	int retry = 255;

	if (!private || !mask)
		return 0;

	trace_vfio_ccw_chp_event(sch->schid, mask, event);
	VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: mask=0x%x event=%d\n",
			   sch->schid.cssid,
			   sch->schid.ssid, sch->schid.sch_no,
			   mask, event);

	if (cio_update_schib(sch))
		return -ENODEV;

	switch (event) {
	case CHP_VARY_OFF:
		/* Path logically turned off */
		sch->opm &= ~mask;
		sch->lpm &= ~mask;
		if (sch->schib.pmcw.lpum & mask)
			cio_cancel_halt_clear(sch, &retry);
		break;
	case CHP_OFFLINE:
		/* Path is gone */
		if (sch->schib.pmcw.lpum & mask)
			cio_cancel_halt_clear(sch, &retry);
		vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_PERRN,
				   link->chpid.id);
		break;
	case CHP_VARY_ON:
		/* Path logically turned on */
		sch->opm |= mask;
		sch->lpm |= mask;
		break;
	case CHP_ONLINE:
		/* Path became available */
		sch->lpm |= mask & sch->opm;
		vfio_ccw_queue_crw(private, CRW_RSC_CPATH, CRW_ERC_INIT,
				   link->chpid.id);
		break;
	}

	return 0;
}

static struct css_device_id vfio_ccw_sch_ids[] = {
	{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
	{ /* end of list */ },
};
MODULE_DEVICE_TABLE(css, vfio_ccw_sch_ids);

static struct css_driver vfio_ccw_sch_driver = {
	.drv = {
		.name = "vfio_ccw",
		.owner = THIS_MODULE,
	},
	.subchannel_type = vfio_ccw_sch_ids,
	.irq = vfio_ccw_sch_irq,
	.probe = vfio_ccw_sch_probe,
	.remove = vfio_ccw_sch_remove,
	.shutdown = vfio_ccw_sch_shutdown,
	.sch_event = vfio_ccw_sch_event,
	.chp_event = vfio_ccw_chp_event,
};

static int __init vfio_ccw_debug_init(void)
{
	vfio_ccw_debug_msg_id = debug_register("vfio_ccw_msg", 16, 1,
					       11 * sizeof(long));
	if (!vfio_ccw_debug_msg_id)
		goto out_unregister;
	debug_register_view(vfio_ccw_debug_msg_id, &debug_sprintf_view);
	debug_set_level(vfio_ccw_debug_msg_id, 2);
	vfio_ccw_debug_trace_id = debug_register("vfio_ccw_trace", 16, 1, 16);
	if (!vfio_ccw_debug_trace_id)
		goto out_unregister;
	debug_register_view(vfio_ccw_debug_trace_id, &debug_hex_ascii_view);
	debug_set_level(vfio_ccw_debug_trace_id, 2);
	return 0;

out_unregister:
	debug_unregister(vfio_ccw_debug_msg_id);
	debug_unregister(vfio_ccw_debug_trace_id);
	return -1;
}

static void vfio_ccw_debug_exit(void)
{
	debug_unregister(vfio_ccw_debug_msg_id);
	debug_unregister(vfio_ccw_debug_trace_id);
}

static void vfio_ccw_destroy_regions(void)
{
	kmem_cache_destroy(vfio_ccw_crw_region);
	kmem_cache_destroy(vfio_ccw_schib_region);
	kmem_cache_destroy(vfio_ccw_cmd_region);
	kmem_cache_destroy(vfio_ccw_io_region);
}

static int __init vfio_ccw_sch_init(void)
{
	int ret;

	ret = vfio_ccw_debug_init();
	if (ret)
		return ret;

	vfio_ccw_work_q = create_singlethread_workqueue("vfio-ccw");
	if (!vfio_ccw_work_q) {
		ret = -ENOMEM;
		goto out_regions;
	}

	vfio_ccw_io_region = kmem_cache_create_usercopy("vfio_ccw_io_region",
					sizeof(struct ccw_io_region), 0,
					SLAB_ACCOUNT, 0,
					sizeof(struct ccw_io_region), NULL);
	if (!vfio_ccw_io_region) {
		ret = -ENOMEM;
		goto out_regions;
	}

	vfio_ccw_cmd_region = kmem_cache_create_usercopy("vfio_ccw_cmd_region",
					sizeof(struct ccw_cmd_region), 0,
					SLAB_ACCOUNT, 0,
					sizeof(struct ccw_cmd_region), NULL);
	if (!vfio_ccw_cmd_region) {
		ret = -ENOMEM;
		goto out_regions;
	}

	vfio_ccw_schib_region = kmem_cache_create_usercopy("vfio_ccw_schib_region",
					sizeof(struct ccw_schib_region), 0,
					SLAB_ACCOUNT, 0,
					sizeof(struct ccw_schib_region), NULL);

	if (!vfio_ccw_schib_region) {
		ret = -ENOMEM;
		goto out_regions;
	}

	vfio_ccw_crw_region = kmem_cache_create_usercopy("vfio_ccw_crw_region",
					sizeof(struct ccw_crw_region), 0,
					SLAB_ACCOUNT, 0,
					sizeof(struct ccw_crw_region), NULL);

	if (!vfio_ccw_crw_region) {
		ret = -ENOMEM;
		goto out_regions;
	}

	ret = mdev_register_driver(&vfio_ccw_mdev_driver);
	if (ret)
		goto out_regions;

	isc_register(VFIO_CCW_ISC);
	ret = css_driver_register(&vfio_ccw_sch_driver);
	if (ret) {
		isc_unregister(VFIO_CCW_ISC);
		goto out_driver;
	}

	return ret;

out_driver:
	mdev_unregister_driver(&vfio_ccw_mdev_driver);
out_regions:
	vfio_ccw_destroy_regions();
	destroy_workqueue(vfio_ccw_work_q);
	vfio_ccw_debug_exit();
	return ret;
}

static void __exit vfio_ccw_sch_exit(void)
{
	css_driver_unregister(&vfio_ccw_sch_driver);
	mdev_unregister_driver(&vfio_ccw_mdev_driver);
	isc_unregister(VFIO_CCW_ISC);
	vfio_ccw_destroy_regions();
	destroy_workqueue(vfio_ccw_work_q);
	vfio_ccw_debug_exit();
}
module_init(vfio_ccw_sch_init);
module_exit(vfio_ccw_sch_exit);

MODULE_LICENSE("GPL v2");