xref: /linux/drivers/hv/vmbus_drv.c (revision 2ba9268dd603d23e17643437b2246acb6844953b)
1 /*
2  * Copyright (c) 2009, Microsoft Corporation.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15  * Place - Suite 330, Boston, MA 02111-1307 USA.
16  *
17  * Authors:
18  *   Haiyang Zhang <haiyangz@microsoft.com>
19  *   Hank Janssen  <hjanssen@microsoft.com>
20  *   K. Y. Srinivasan <kys@microsoft.com>
21  *
22  */
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24 
25 #include <linux/init.h>
26 #include <linux/module.h>
27 #include <linux/device.h>
28 #include <linux/interrupt.h>
29 #include <linux/sysctl.h>
30 #include <linux/slab.h>
31 #include <linux/acpi.h>
32 #include <linux/completion.h>
33 #include <linux/hyperv.h>
34 #include <linux/kernel_stat.h>
35 #include <linux/clockchips.h>
36 #include <asm/hyperv.h>
37 #include <asm/hypervisor.h>
38 #include <asm/mshyperv.h>
39 #include "hyperv_vmbus.h"
40 
41 static struct acpi_device  *hv_acpi_dev;
42 
43 static struct tasklet_struct msg_dpc;
44 static struct completion probe_event;
45 static int irq;
46 
47 struct resource hyperv_mmio = {
48 	.name  = "hyperv mmio",
49 	.flags = IORESOURCE_MEM,
50 };
51 EXPORT_SYMBOL_GPL(hyperv_mmio);
52 
53 static int vmbus_exists(void)
54 {
55 	if (hv_acpi_dev == NULL)
56 		return -ENODEV;
57 
58 	return 0;
59 }
60 
61 #define VMBUS_ALIAS_LEN ((sizeof((struct hv_vmbus_device_id *)0)->guid) * 2)
62 static void print_alias_name(struct hv_device *hv_dev, char *alias_name)
63 {
64 	int i;
65 	for (i = 0; i < VMBUS_ALIAS_LEN; i += 2)
66 		sprintf(&alias_name[i], "%02x", hv_dev->dev_type.b[i/2]);
67 }
68 
69 static u8 channel_monitor_group(struct vmbus_channel *channel)
70 {
71 	return (u8)channel->offermsg.monitorid / 32;
72 }
73 
74 static u8 channel_monitor_offset(struct vmbus_channel *channel)
75 {
76 	return (u8)channel->offermsg.monitorid % 32;
77 }
78 
79 static u32 channel_pending(struct vmbus_channel *channel,
80 			   struct hv_monitor_page *monitor_page)
81 {
82 	u8 monitor_group = channel_monitor_group(channel);
83 	return monitor_page->trigger_group[monitor_group].pending;
84 }
85 
86 static u32 channel_latency(struct vmbus_channel *channel,
87 			   struct hv_monitor_page *monitor_page)
88 {
89 	u8 monitor_group = channel_monitor_group(channel);
90 	u8 monitor_offset = channel_monitor_offset(channel);
91 	return monitor_page->latency[monitor_group][monitor_offset];
92 }
93 
94 static u32 channel_conn_id(struct vmbus_channel *channel,
95 			   struct hv_monitor_page *monitor_page)
96 {
97 	u8 monitor_group = channel_monitor_group(channel);
98 	u8 monitor_offset = channel_monitor_offset(channel);
99 	return monitor_page->parameter[monitor_group][monitor_offset].connectionid.u.id;
100 }
101 
102 static ssize_t id_show(struct device *dev, struct device_attribute *dev_attr,
103 		       char *buf)
104 {
105 	struct hv_device *hv_dev = device_to_hv_device(dev);
106 
107 	if (!hv_dev->channel)
108 		return -ENODEV;
109 	return sprintf(buf, "%d\n", hv_dev->channel->offermsg.child_relid);
110 }
111 static DEVICE_ATTR_RO(id);
112 
113 static ssize_t state_show(struct device *dev, struct device_attribute *dev_attr,
114 			  char *buf)
115 {
116 	struct hv_device *hv_dev = device_to_hv_device(dev);
117 
118 	if (!hv_dev->channel)
119 		return -ENODEV;
120 	return sprintf(buf, "%d\n", hv_dev->channel->state);
121 }
122 static DEVICE_ATTR_RO(state);
123 
124 static ssize_t monitor_id_show(struct device *dev,
125 			       struct device_attribute *dev_attr, char *buf)
126 {
127 	struct hv_device *hv_dev = device_to_hv_device(dev);
128 
129 	if (!hv_dev->channel)
130 		return -ENODEV;
131 	return sprintf(buf, "%d\n", hv_dev->channel->offermsg.monitorid);
132 }
133 static DEVICE_ATTR_RO(monitor_id);
134 
135 static ssize_t class_id_show(struct device *dev,
136 			       struct device_attribute *dev_attr, char *buf)
137 {
138 	struct hv_device *hv_dev = device_to_hv_device(dev);
139 
140 	if (!hv_dev->channel)
141 		return -ENODEV;
142 	return sprintf(buf, "{%pUl}\n",
143 		       hv_dev->channel->offermsg.offer.if_type.b);
144 }
145 static DEVICE_ATTR_RO(class_id);
146 
147 static ssize_t device_id_show(struct device *dev,
148 			      struct device_attribute *dev_attr, char *buf)
149 {
150 	struct hv_device *hv_dev = device_to_hv_device(dev);
151 
152 	if (!hv_dev->channel)
153 		return -ENODEV;
154 	return sprintf(buf, "{%pUl}\n",
155 		       hv_dev->channel->offermsg.offer.if_instance.b);
156 }
157 static DEVICE_ATTR_RO(device_id);
158 
159 static ssize_t modalias_show(struct device *dev,
160 			     struct device_attribute *dev_attr, char *buf)
161 {
162 	struct hv_device *hv_dev = device_to_hv_device(dev);
163 	char alias_name[VMBUS_ALIAS_LEN + 1];
164 
165 	print_alias_name(hv_dev, alias_name);
166 	return sprintf(buf, "vmbus:%s\n", alias_name);
167 }
168 static DEVICE_ATTR_RO(modalias);
169 
170 static ssize_t server_monitor_pending_show(struct device *dev,
171 					   struct device_attribute *dev_attr,
172 					   char *buf)
173 {
174 	struct hv_device *hv_dev = device_to_hv_device(dev);
175 
176 	if (!hv_dev->channel)
177 		return -ENODEV;
178 	return sprintf(buf, "%d\n",
179 		       channel_pending(hv_dev->channel,
180 				       vmbus_connection.monitor_pages[1]));
181 }
182 static DEVICE_ATTR_RO(server_monitor_pending);
183 
184 static ssize_t client_monitor_pending_show(struct device *dev,
185 					   struct device_attribute *dev_attr,
186 					   char *buf)
187 {
188 	struct hv_device *hv_dev = device_to_hv_device(dev);
189 
190 	if (!hv_dev->channel)
191 		return -ENODEV;
192 	return sprintf(buf, "%d\n",
193 		       channel_pending(hv_dev->channel,
194 				       vmbus_connection.monitor_pages[1]));
195 }
196 static DEVICE_ATTR_RO(client_monitor_pending);
197 
198 static ssize_t server_monitor_latency_show(struct device *dev,
199 					   struct device_attribute *dev_attr,
200 					   char *buf)
201 {
202 	struct hv_device *hv_dev = device_to_hv_device(dev);
203 
204 	if (!hv_dev->channel)
205 		return -ENODEV;
206 	return sprintf(buf, "%d\n",
207 		       channel_latency(hv_dev->channel,
208 				       vmbus_connection.monitor_pages[0]));
209 }
210 static DEVICE_ATTR_RO(server_monitor_latency);
211 
212 static ssize_t client_monitor_latency_show(struct device *dev,
213 					   struct device_attribute *dev_attr,
214 					   char *buf)
215 {
216 	struct hv_device *hv_dev = device_to_hv_device(dev);
217 
218 	if (!hv_dev->channel)
219 		return -ENODEV;
220 	return sprintf(buf, "%d\n",
221 		       channel_latency(hv_dev->channel,
222 				       vmbus_connection.monitor_pages[1]));
223 }
224 static DEVICE_ATTR_RO(client_monitor_latency);
225 
226 static ssize_t server_monitor_conn_id_show(struct device *dev,
227 					   struct device_attribute *dev_attr,
228 					   char *buf)
229 {
230 	struct hv_device *hv_dev = device_to_hv_device(dev);
231 
232 	if (!hv_dev->channel)
233 		return -ENODEV;
234 	return sprintf(buf, "%d\n",
235 		       channel_conn_id(hv_dev->channel,
236 				       vmbus_connection.monitor_pages[0]));
237 }
238 static DEVICE_ATTR_RO(server_monitor_conn_id);
239 
240 static ssize_t client_monitor_conn_id_show(struct device *dev,
241 					   struct device_attribute *dev_attr,
242 					   char *buf)
243 {
244 	struct hv_device *hv_dev = device_to_hv_device(dev);
245 
246 	if (!hv_dev->channel)
247 		return -ENODEV;
248 	return sprintf(buf, "%d\n",
249 		       channel_conn_id(hv_dev->channel,
250 				       vmbus_connection.monitor_pages[1]));
251 }
252 static DEVICE_ATTR_RO(client_monitor_conn_id);
253 
254 static ssize_t out_intr_mask_show(struct device *dev,
255 				  struct device_attribute *dev_attr, char *buf)
256 {
257 	struct hv_device *hv_dev = device_to_hv_device(dev);
258 	struct hv_ring_buffer_debug_info outbound;
259 
260 	if (!hv_dev->channel)
261 		return -ENODEV;
262 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
263 	return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
264 }
265 static DEVICE_ATTR_RO(out_intr_mask);
266 
267 static ssize_t out_read_index_show(struct device *dev,
268 				   struct device_attribute *dev_attr, char *buf)
269 {
270 	struct hv_device *hv_dev = device_to_hv_device(dev);
271 	struct hv_ring_buffer_debug_info outbound;
272 
273 	if (!hv_dev->channel)
274 		return -ENODEV;
275 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
276 	return sprintf(buf, "%d\n", outbound.current_read_index);
277 }
278 static DEVICE_ATTR_RO(out_read_index);
279 
280 static ssize_t out_write_index_show(struct device *dev,
281 				    struct device_attribute *dev_attr,
282 				    char *buf)
283 {
284 	struct hv_device *hv_dev = device_to_hv_device(dev);
285 	struct hv_ring_buffer_debug_info outbound;
286 
287 	if (!hv_dev->channel)
288 		return -ENODEV;
289 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
290 	return sprintf(buf, "%d\n", outbound.current_write_index);
291 }
292 static DEVICE_ATTR_RO(out_write_index);
293 
294 static ssize_t out_read_bytes_avail_show(struct device *dev,
295 					 struct device_attribute *dev_attr,
296 					 char *buf)
297 {
298 	struct hv_device *hv_dev = device_to_hv_device(dev);
299 	struct hv_ring_buffer_debug_info outbound;
300 
301 	if (!hv_dev->channel)
302 		return -ENODEV;
303 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
304 	return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
305 }
306 static DEVICE_ATTR_RO(out_read_bytes_avail);
307 
308 static ssize_t out_write_bytes_avail_show(struct device *dev,
309 					  struct device_attribute *dev_attr,
310 					  char *buf)
311 {
312 	struct hv_device *hv_dev = device_to_hv_device(dev);
313 	struct hv_ring_buffer_debug_info outbound;
314 
315 	if (!hv_dev->channel)
316 		return -ENODEV;
317 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
318 	return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
319 }
320 static DEVICE_ATTR_RO(out_write_bytes_avail);
321 
322 static ssize_t in_intr_mask_show(struct device *dev,
323 				 struct device_attribute *dev_attr, char *buf)
324 {
325 	struct hv_device *hv_dev = device_to_hv_device(dev);
326 	struct hv_ring_buffer_debug_info inbound;
327 
328 	if (!hv_dev->channel)
329 		return -ENODEV;
330 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
331 	return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
332 }
333 static DEVICE_ATTR_RO(in_intr_mask);
334 
335 static ssize_t in_read_index_show(struct device *dev,
336 				  struct device_attribute *dev_attr, char *buf)
337 {
338 	struct hv_device *hv_dev = device_to_hv_device(dev);
339 	struct hv_ring_buffer_debug_info inbound;
340 
341 	if (!hv_dev->channel)
342 		return -ENODEV;
343 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
344 	return sprintf(buf, "%d\n", inbound.current_read_index);
345 }
346 static DEVICE_ATTR_RO(in_read_index);
347 
348 static ssize_t in_write_index_show(struct device *dev,
349 				   struct device_attribute *dev_attr, char *buf)
350 {
351 	struct hv_device *hv_dev = device_to_hv_device(dev);
352 	struct hv_ring_buffer_debug_info inbound;
353 
354 	if (!hv_dev->channel)
355 		return -ENODEV;
356 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
357 	return sprintf(buf, "%d\n", inbound.current_write_index);
358 }
359 static DEVICE_ATTR_RO(in_write_index);
360 
361 static ssize_t in_read_bytes_avail_show(struct device *dev,
362 					struct device_attribute *dev_attr,
363 					char *buf)
364 {
365 	struct hv_device *hv_dev = device_to_hv_device(dev);
366 	struct hv_ring_buffer_debug_info inbound;
367 
368 	if (!hv_dev->channel)
369 		return -ENODEV;
370 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
371 	return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
372 }
373 static DEVICE_ATTR_RO(in_read_bytes_avail);
374 
375 static ssize_t in_write_bytes_avail_show(struct device *dev,
376 					 struct device_attribute *dev_attr,
377 					 char *buf)
378 {
379 	struct hv_device *hv_dev = device_to_hv_device(dev);
380 	struct hv_ring_buffer_debug_info inbound;
381 
382 	if (!hv_dev->channel)
383 		return -ENODEV;
384 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
385 	return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
386 }
387 static DEVICE_ATTR_RO(in_write_bytes_avail);
388 
389 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
390 static struct attribute *vmbus_attrs[] = {
391 	&dev_attr_id.attr,
392 	&dev_attr_state.attr,
393 	&dev_attr_monitor_id.attr,
394 	&dev_attr_class_id.attr,
395 	&dev_attr_device_id.attr,
396 	&dev_attr_modalias.attr,
397 	&dev_attr_server_monitor_pending.attr,
398 	&dev_attr_client_monitor_pending.attr,
399 	&dev_attr_server_monitor_latency.attr,
400 	&dev_attr_client_monitor_latency.attr,
401 	&dev_attr_server_monitor_conn_id.attr,
402 	&dev_attr_client_monitor_conn_id.attr,
403 	&dev_attr_out_intr_mask.attr,
404 	&dev_attr_out_read_index.attr,
405 	&dev_attr_out_write_index.attr,
406 	&dev_attr_out_read_bytes_avail.attr,
407 	&dev_attr_out_write_bytes_avail.attr,
408 	&dev_attr_in_intr_mask.attr,
409 	&dev_attr_in_read_index.attr,
410 	&dev_attr_in_write_index.attr,
411 	&dev_attr_in_read_bytes_avail.attr,
412 	&dev_attr_in_write_bytes_avail.attr,
413 	NULL,
414 };
415 ATTRIBUTE_GROUPS(vmbus);
416 
417 /*
418  * vmbus_uevent - add uevent for our device
419  *
420  * This routine is invoked when a device is added or removed on the vmbus to
421  * generate a uevent to udev in the userspace. The udev will then look at its
422  * rule and the uevent generated here to load the appropriate driver
423  *
424  * The alias string will be of the form vmbus:guid where guid is the string
425  * representation of the device guid (each byte of the guid will be
426  * represented with two hex characters.
427  */
428 static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
429 {
430 	struct hv_device *dev = device_to_hv_device(device);
431 	int ret;
432 	char alias_name[VMBUS_ALIAS_LEN + 1];
433 
434 	print_alias_name(dev, alias_name);
435 	ret = add_uevent_var(env, "MODALIAS=vmbus:%s", alias_name);
436 	return ret;
437 }
438 
439 static const uuid_le null_guid;
440 
441 static inline bool is_null_guid(const __u8 *guid)
442 {
443 	if (memcmp(guid, &null_guid, sizeof(uuid_le)))
444 		return false;
445 	return true;
446 }
447 
448 /*
449  * Return a matching hv_vmbus_device_id pointer.
450  * If there is no match, return NULL.
451  */
452 static const struct hv_vmbus_device_id *hv_vmbus_get_id(
453 					const struct hv_vmbus_device_id *id,
454 					const __u8 *guid)
455 {
456 	for (; !is_null_guid(id->guid); id++)
457 		if (!memcmp(&id->guid, guid, sizeof(uuid_le)))
458 			return id;
459 
460 	return NULL;
461 }
462 
463 
464 
465 /*
466  * vmbus_match - Attempt to match the specified device to the specified driver
467  */
468 static int vmbus_match(struct device *device, struct device_driver *driver)
469 {
470 	struct hv_driver *drv = drv_to_hv_drv(driver);
471 	struct hv_device *hv_dev = device_to_hv_device(device);
472 
473 	if (hv_vmbus_get_id(drv->id_table, hv_dev->dev_type.b))
474 		return 1;
475 
476 	return 0;
477 }
478 
479 /*
480  * vmbus_probe - Add the new vmbus's child device
481  */
482 static int vmbus_probe(struct device *child_device)
483 {
484 	int ret = 0;
485 	struct hv_driver *drv =
486 			drv_to_hv_drv(child_device->driver);
487 	struct hv_device *dev = device_to_hv_device(child_device);
488 	const struct hv_vmbus_device_id *dev_id;
489 
490 	dev_id = hv_vmbus_get_id(drv->id_table, dev->dev_type.b);
491 	if (drv->probe) {
492 		ret = drv->probe(dev, dev_id);
493 		if (ret != 0)
494 			pr_err("probe failed for device %s (%d)\n",
495 			       dev_name(child_device), ret);
496 
497 	} else {
498 		pr_err("probe not set for driver %s\n",
499 		       dev_name(child_device));
500 		ret = -ENODEV;
501 	}
502 	return ret;
503 }
504 
505 /*
506  * vmbus_remove - Remove a vmbus device
507  */
508 static int vmbus_remove(struct device *child_device)
509 {
510 	struct hv_driver *drv = drv_to_hv_drv(child_device->driver);
511 	struct hv_device *dev = device_to_hv_device(child_device);
512 
513 	if (drv->remove)
514 		drv->remove(dev);
515 	else
516 		pr_err("remove not set for driver %s\n",
517 			dev_name(child_device));
518 
519 	return 0;
520 }
521 
522 
523 /*
524  * vmbus_shutdown - Shutdown a vmbus device
525  */
526 static void vmbus_shutdown(struct device *child_device)
527 {
528 	struct hv_driver *drv;
529 	struct hv_device *dev = device_to_hv_device(child_device);
530 
531 
532 	/* The device may not be attached yet */
533 	if (!child_device->driver)
534 		return;
535 
536 	drv = drv_to_hv_drv(child_device->driver);
537 
538 	if (drv->shutdown)
539 		drv->shutdown(dev);
540 
541 	return;
542 }
543 
544 
545 /*
546  * vmbus_device_release - Final callback release of the vmbus child device
547  */
548 static void vmbus_device_release(struct device *device)
549 {
550 	struct hv_device *hv_dev = device_to_hv_device(device);
551 
552 	kfree(hv_dev);
553 
554 }
555 
556 /* The one and only one */
557 static struct bus_type  hv_bus = {
558 	.name =		"vmbus",
559 	.match =		vmbus_match,
560 	.shutdown =		vmbus_shutdown,
561 	.remove =		vmbus_remove,
562 	.probe =		vmbus_probe,
563 	.uevent =		vmbus_uevent,
564 	.dev_groups =		vmbus_groups,
565 };
566 
567 struct onmessage_work_context {
568 	struct work_struct work;
569 	struct hv_message msg;
570 };
571 
572 static void vmbus_onmessage_work(struct work_struct *work)
573 {
574 	struct onmessage_work_context *ctx;
575 
576 	ctx = container_of(work, struct onmessage_work_context,
577 			   work);
578 	vmbus_onmessage(&ctx->msg);
579 	kfree(ctx);
580 }
581 
582 static void hv_process_timer_expiration(struct hv_message *msg, int cpu)
583 {
584 	struct clock_event_device *dev = hv_context.clk_evt[cpu];
585 
586 	if (dev->event_handler)
587 		dev->event_handler(dev);
588 
589 	msg->header.message_type = HVMSG_NONE;
590 
591 	/*
592 	 * Make sure the write to MessageType (ie set to
593 	 * HVMSG_NONE) happens before we read the
594 	 * MessagePending and EOMing. Otherwise, the EOMing
595 	 * will not deliver any more messages since there is
596 	 * no empty slot
597 	 */
598 	mb();
599 
600 	if (msg->header.message_flags.msg_pending) {
601 		/*
602 		 * This will cause message queue rescan to
603 		 * possibly deliver another msg from the
604 		 * hypervisor
605 		 */
606 		wrmsrl(HV_X64_MSR_EOM, 0);
607 	}
608 }
609 
610 static void vmbus_on_msg_dpc(unsigned long data)
611 {
612 	int cpu = smp_processor_id();
613 	void *page_addr = hv_context.synic_message_page[cpu];
614 	struct hv_message *msg = (struct hv_message *)page_addr +
615 				  VMBUS_MESSAGE_SINT;
616 	struct onmessage_work_context *ctx;
617 
618 	while (1) {
619 		if (msg->header.message_type == HVMSG_NONE) {
620 			/* no msg */
621 			break;
622 		} else {
623 			ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
624 			if (ctx == NULL)
625 				continue;
626 			INIT_WORK(&ctx->work, vmbus_onmessage_work);
627 			memcpy(&ctx->msg, msg, sizeof(*msg));
628 			queue_work(vmbus_connection.work_queue, &ctx->work);
629 		}
630 
631 		msg->header.message_type = HVMSG_NONE;
632 
633 		/*
634 		 * Make sure the write to MessageType (ie set to
635 		 * HVMSG_NONE) happens before we read the
636 		 * MessagePending and EOMing. Otherwise, the EOMing
637 		 * will not deliver any more messages since there is
638 		 * no empty slot
639 		 */
640 		mb();
641 
642 		if (msg->header.message_flags.msg_pending) {
643 			/*
644 			 * This will cause message queue rescan to
645 			 * possibly deliver another msg from the
646 			 * hypervisor
647 			 */
648 			wrmsrl(HV_X64_MSR_EOM, 0);
649 		}
650 	}
651 }
652 
653 static void vmbus_isr(void)
654 {
655 	int cpu = smp_processor_id();
656 	void *page_addr;
657 	struct hv_message *msg;
658 	union hv_synic_event_flags *event;
659 	bool handled = false;
660 
661 	page_addr = hv_context.synic_event_page[cpu];
662 	if (page_addr == NULL)
663 		return;
664 
665 	event = (union hv_synic_event_flags *)page_addr +
666 					 VMBUS_MESSAGE_SINT;
667 	/*
668 	 * Check for events before checking for messages. This is the order
669 	 * in which events and messages are checked in Windows guests on
670 	 * Hyper-V, and the Windows team suggested we do the same.
671 	 */
672 
673 	if ((vmbus_proto_version == VERSION_WS2008) ||
674 		(vmbus_proto_version == VERSION_WIN7)) {
675 
676 		/* Since we are a child, we only need to check bit 0 */
677 		if (sync_test_and_clear_bit(0,
678 			(unsigned long *) &event->flags32[0])) {
679 			handled = true;
680 		}
681 	} else {
682 		/*
683 		 * Our host is win8 or above. The signaling mechanism
684 		 * has changed and we can directly look at the event page.
685 		 * If bit n is set then we have an interrup on the channel
686 		 * whose id is n.
687 		 */
688 		handled = true;
689 	}
690 
691 	if (handled)
692 		tasklet_schedule(hv_context.event_dpc[cpu]);
693 
694 
695 	page_addr = hv_context.synic_message_page[cpu];
696 	msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
697 
698 	/* Check if there are actual msgs to be processed */
699 	if (msg->header.message_type != HVMSG_NONE) {
700 		if (msg->header.message_type == HVMSG_TIMER_EXPIRED)
701 			hv_process_timer_expiration(msg, cpu);
702 		else
703 			tasklet_schedule(&msg_dpc);
704 	}
705 }
706 
707 /*
708  * vmbus_bus_init -Main vmbus driver initialization routine.
709  *
710  * Here, we
711  *	- initialize the vmbus driver context
712  *	- invoke the vmbus hv main init routine
713  *	- get the irq resource
714  *	- retrieve the channel offers
715  */
716 static int vmbus_bus_init(int irq)
717 {
718 	int ret;
719 
720 	/* Hypervisor initialization...setup hypercall page..etc */
721 	ret = hv_init();
722 	if (ret != 0) {
723 		pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
724 		return ret;
725 	}
726 
727 	tasklet_init(&msg_dpc, vmbus_on_msg_dpc, 0);
728 
729 	ret = bus_register(&hv_bus);
730 	if (ret)
731 		goto err_cleanup;
732 
733 	hv_setup_vmbus_irq(vmbus_isr);
734 
735 	ret = hv_synic_alloc();
736 	if (ret)
737 		goto err_alloc;
738 	/*
739 	 * Initialize the per-cpu interrupt state and
740 	 * connect to the host.
741 	 */
742 	on_each_cpu(hv_synic_init, NULL, 1);
743 	ret = vmbus_connect();
744 	if (ret)
745 		goto err_alloc;
746 
747 	vmbus_request_offers();
748 
749 	return 0;
750 
751 err_alloc:
752 	hv_synic_free();
753 	hv_remove_vmbus_irq();
754 
755 	bus_unregister(&hv_bus);
756 
757 err_cleanup:
758 	hv_cleanup();
759 
760 	return ret;
761 }
762 
763 /**
764  * __vmbus_child_driver_register - Register a vmbus's driver
765  * @drv: Pointer to driver structure you want to register
766  * @owner: owner module of the drv
767  * @mod_name: module name string
768  *
769  * Registers the given driver with Linux through the 'driver_register()' call
770  * and sets up the hyper-v vmbus handling for this driver.
771  * It will return the state of the 'driver_register()' call.
772  *
773  */
774 int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
775 {
776 	int ret;
777 
778 	pr_info("registering driver %s\n", hv_driver->name);
779 
780 	ret = vmbus_exists();
781 	if (ret < 0)
782 		return ret;
783 
784 	hv_driver->driver.name = hv_driver->name;
785 	hv_driver->driver.owner = owner;
786 	hv_driver->driver.mod_name = mod_name;
787 	hv_driver->driver.bus = &hv_bus;
788 
789 	ret = driver_register(&hv_driver->driver);
790 
791 	return ret;
792 }
793 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
794 
795 /**
796  * vmbus_driver_unregister() - Unregister a vmbus's driver
797  * @drv: Pointer to driver structure you want to un-register
798  *
799  * Un-register the given driver that was previous registered with a call to
800  * vmbus_driver_register()
801  */
802 void vmbus_driver_unregister(struct hv_driver *hv_driver)
803 {
804 	pr_info("unregistering driver %s\n", hv_driver->name);
805 
806 	if (!vmbus_exists())
807 		driver_unregister(&hv_driver->driver);
808 }
809 EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
810 
811 /*
812  * vmbus_device_create - Creates and registers a new child device
813  * on the vmbus.
814  */
815 struct hv_device *vmbus_device_create(const uuid_le *type,
816 				      const uuid_le *instance,
817 				      struct vmbus_channel *channel)
818 {
819 	struct hv_device *child_device_obj;
820 
821 	child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
822 	if (!child_device_obj) {
823 		pr_err("Unable to allocate device object for child device\n");
824 		return NULL;
825 	}
826 
827 	child_device_obj->channel = channel;
828 	memcpy(&child_device_obj->dev_type, type, sizeof(uuid_le));
829 	memcpy(&child_device_obj->dev_instance, instance,
830 	       sizeof(uuid_le));
831 
832 
833 	return child_device_obj;
834 }
835 
836 /*
837  * vmbus_device_register - Register the child device
838  */
839 int vmbus_device_register(struct hv_device *child_device_obj)
840 {
841 	int ret = 0;
842 
843 	static atomic_t device_num = ATOMIC_INIT(0);
844 
845 	dev_set_name(&child_device_obj->device, "vmbus_0_%d",
846 		     atomic_inc_return(&device_num));
847 
848 	child_device_obj->device.bus = &hv_bus;
849 	child_device_obj->device.parent = &hv_acpi_dev->dev;
850 	child_device_obj->device.release = vmbus_device_release;
851 
852 	/*
853 	 * Register with the LDM. This will kick off the driver/device
854 	 * binding...which will eventually call vmbus_match() and vmbus_probe()
855 	 */
856 	ret = device_register(&child_device_obj->device);
857 
858 	if (ret)
859 		pr_err("Unable to register child device\n");
860 	else
861 		pr_debug("child device %s registered\n",
862 			dev_name(&child_device_obj->device));
863 
864 	return ret;
865 }
866 
867 /*
868  * vmbus_device_unregister - Remove the specified child device
869  * from the vmbus.
870  */
871 void vmbus_device_unregister(struct hv_device *device_obj)
872 {
873 	pr_debug("child device %s unregistered\n",
874 		dev_name(&device_obj->device));
875 
876 	/*
877 	 * Kick off the process of unregistering the device.
878 	 * This will call vmbus_remove() and eventually vmbus_device_release()
879 	 */
880 	device_unregister(&device_obj->device);
881 }
882 
883 
884 /*
885  * VMBUS is an acpi enumerated device. Get the the information we
886  * need from DSDT.
887  */
888 
889 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
890 {
891 	switch (res->type) {
892 	case ACPI_RESOURCE_TYPE_IRQ:
893 		irq = res->data.irq.interrupts[0];
894 		break;
895 
896 	case ACPI_RESOURCE_TYPE_ADDRESS64:
897 		hyperv_mmio.start = res->data.address64.address.minimum;
898 		hyperv_mmio.end = res->data.address64.address.maximum;
899 		break;
900 	}
901 
902 	return AE_OK;
903 }
904 
905 static int vmbus_acpi_add(struct acpi_device *device)
906 {
907 	acpi_status result;
908 	int ret_val = -ENODEV;
909 
910 	hv_acpi_dev = device;
911 
912 	result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
913 					vmbus_walk_resources, NULL);
914 
915 	if (ACPI_FAILURE(result))
916 		goto acpi_walk_err;
917 	/*
918 	 * The parent of the vmbus acpi device (Gen2 firmware) is the VMOD that
919 	 * has the mmio ranges. Get that.
920 	 */
921 	if (device->parent) {
922 		result = acpi_walk_resources(device->parent->handle,
923 					METHOD_NAME__CRS,
924 					vmbus_walk_resources, NULL);
925 
926 		if (ACPI_FAILURE(result))
927 			goto acpi_walk_err;
928 		if (hyperv_mmio.start && hyperv_mmio.end)
929 			request_resource(&iomem_resource, &hyperv_mmio);
930 	}
931 	ret_val = 0;
932 
933 acpi_walk_err:
934 	complete(&probe_event);
935 	return ret_val;
936 }
937 
938 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
939 	{"VMBUS", 0},
940 	{"VMBus", 0},
941 	{"", 0},
942 };
943 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
944 
945 static struct acpi_driver vmbus_acpi_driver = {
946 	.name = "vmbus",
947 	.ids = vmbus_acpi_device_ids,
948 	.ops = {
949 		.add = vmbus_acpi_add,
950 	},
951 };
952 
953 static int __init hv_acpi_init(void)
954 {
955 	int ret, t;
956 
957 	if (x86_hyper != &x86_hyper_ms_hyperv)
958 		return -ENODEV;
959 
960 	init_completion(&probe_event);
961 
962 	/*
963 	 * Get irq resources first.
964 	 */
965 	ret = acpi_bus_register_driver(&vmbus_acpi_driver);
966 
967 	if (ret)
968 		return ret;
969 
970 	t = wait_for_completion_timeout(&probe_event, 5*HZ);
971 	if (t == 0) {
972 		ret = -ETIMEDOUT;
973 		goto cleanup;
974 	}
975 
976 	if (irq <= 0) {
977 		ret = -ENODEV;
978 		goto cleanup;
979 	}
980 
981 	ret = vmbus_bus_init(irq);
982 	if (ret)
983 		goto cleanup;
984 
985 	return 0;
986 
987 cleanup:
988 	acpi_bus_unregister_driver(&vmbus_acpi_driver);
989 	hv_acpi_dev = NULL;
990 	return ret;
991 }
992 
993 static void __exit vmbus_exit(void)
994 {
995 	hv_remove_vmbus_irq();
996 	vmbus_free_channels();
997 	bus_unregister(&hv_bus);
998 	hv_cleanup();
999 	acpi_bus_unregister_driver(&vmbus_acpi_driver);
1000 }
1001 
1002 
1003 MODULE_LICENSE("GPL");
1004 
1005 subsys_initcall(hv_acpi_init);
1006 module_exit(vmbus_exit);
1007