xref: /linux/drivers/s390/cio/vfio_ccw_drv.c (revision 66242ef25eedc5b48d46c4b60f5d453763adf2b8)
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