xref: /linux/drivers/hv/vmbus_drv.c (revision c98be0c96db00e9b6b02d31e0fa7590c54cdaaac)
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 <asm/hyperv.h>
36 #include <asm/hypervisor.h>
37 #include <asm/mshyperv.h>
38 #include "hyperv_vmbus.h"
39 
40 static struct acpi_device  *hv_acpi_dev;
41 
42 static struct tasklet_struct msg_dpc;
43 static struct completion probe_event;
44 static int irq;
45 
46 struct resource hyperv_mmio = {
47 	.name  = "hyperv mmio",
48 	.flags = IORESOURCE_MEM,
49 };
50 EXPORT_SYMBOL_GPL(hyperv_mmio);
51 
52 static int vmbus_exists(void)
53 {
54 	if (hv_acpi_dev == NULL)
55 		return -ENODEV;
56 
57 	return 0;
58 }
59 
60 #define VMBUS_ALIAS_LEN ((sizeof((struct hv_vmbus_device_id *)0)->guid) * 2)
61 static void print_alias_name(struct hv_device *hv_dev, char *alias_name)
62 {
63 	int i;
64 	for (i = 0; i < VMBUS_ALIAS_LEN; i += 2)
65 		sprintf(&alias_name[i], "%02x", hv_dev->dev_type.b[i/2]);
66 }
67 
68 static u8 channel_monitor_group(struct vmbus_channel *channel)
69 {
70 	return (u8)channel->offermsg.monitorid / 32;
71 }
72 
73 static u8 channel_monitor_offset(struct vmbus_channel *channel)
74 {
75 	return (u8)channel->offermsg.monitorid % 32;
76 }
77 
78 static u32 channel_pending(struct vmbus_channel *channel,
79 			   struct hv_monitor_page *monitor_page)
80 {
81 	u8 monitor_group = channel_monitor_group(channel);
82 	return monitor_page->trigger_group[monitor_group].pending;
83 }
84 
85 static u32 channel_latency(struct vmbus_channel *channel,
86 			   struct hv_monitor_page *monitor_page)
87 {
88 	u8 monitor_group = channel_monitor_group(channel);
89 	u8 monitor_offset = channel_monitor_offset(channel);
90 	return monitor_page->latency[monitor_group][monitor_offset];
91 }
92 
93 static u32 channel_conn_id(struct vmbus_channel *channel,
94 			   struct hv_monitor_page *monitor_page)
95 {
96 	u8 monitor_group = channel_monitor_group(channel);
97 	u8 monitor_offset = channel_monitor_offset(channel);
98 	return monitor_page->parameter[monitor_group][monitor_offset].connectionid.u.id;
99 }
100 
101 static ssize_t id_show(struct device *dev, struct device_attribute *dev_attr,
102 		       char *buf)
103 {
104 	struct hv_device *hv_dev = device_to_hv_device(dev);
105 
106 	if (!hv_dev->channel)
107 		return -ENODEV;
108 	return sprintf(buf, "%d\n", hv_dev->channel->offermsg.child_relid);
109 }
110 static DEVICE_ATTR_RO(id);
111 
112 static ssize_t state_show(struct device *dev, struct device_attribute *dev_attr,
113 			  char *buf)
114 {
115 	struct hv_device *hv_dev = device_to_hv_device(dev);
116 
117 	if (!hv_dev->channel)
118 		return -ENODEV;
119 	return sprintf(buf, "%d\n", hv_dev->channel->state);
120 }
121 static DEVICE_ATTR_RO(state);
122 
123 static ssize_t monitor_id_show(struct device *dev,
124 			       struct device_attribute *dev_attr, char *buf)
125 {
126 	struct hv_device *hv_dev = device_to_hv_device(dev);
127 
128 	if (!hv_dev->channel)
129 		return -ENODEV;
130 	return sprintf(buf, "%d\n", hv_dev->channel->offermsg.monitorid);
131 }
132 static DEVICE_ATTR_RO(monitor_id);
133 
134 static ssize_t class_id_show(struct device *dev,
135 			       struct device_attribute *dev_attr, char *buf)
136 {
137 	struct hv_device *hv_dev = device_to_hv_device(dev);
138 
139 	if (!hv_dev->channel)
140 		return -ENODEV;
141 	return sprintf(buf, "{%pUl}\n",
142 		       hv_dev->channel->offermsg.offer.if_type.b);
143 }
144 static DEVICE_ATTR_RO(class_id);
145 
146 static ssize_t device_id_show(struct device *dev,
147 			      struct device_attribute *dev_attr, char *buf)
148 {
149 	struct hv_device *hv_dev = device_to_hv_device(dev);
150 
151 	if (!hv_dev->channel)
152 		return -ENODEV;
153 	return sprintf(buf, "{%pUl}\n",
154 		       hv_dev->channel->offermsg.offer.if_instance.b);
155 }
156 static DEVICE_ATTR_RO(device_id);
157 
158 static ssize_t modalias_show(struct device *dev,
159 			     struct device_attribute *dev_attr, char *buf)
160 {
161 	struct hv_device *hv_dev = device_to_hv_device(dev);
162 	char alias_name[VMBUS_ALIAS_LEN + 1];
163 
164 	print_alias_name(hv_dev, alias_name);
165 	return sprintf(buf, "vmbus:%s\n", alias_name);
166 }
167 static DEVICE_ATTR_RO(modalias);
168 
169 static ssize_t server_monitor_pending_show(struct device *dev,
170 					   struct device_attribute *dev_attr,
171 					   char *buf)
172 {
173 	struct hv_device *hv_dev = device_to_hv_device(dev);
174 
175 	if (!hv_dev->channel)
176 		return -ENODEV;
177 	return sprintf(buf, "%d\n",
178 		       channel_pending(hv_dev->channel,
179 				       vmbus_connection.monitor_pages[1]));
180 }
181 static DEVICE_ATTR_RO(server_monitor_pending);
182 
183 static ssize_t client_monitor_pending_show(struct device *dev,
184 					   struct device_attribute *dev_attr,
185 					   char *buf)
186 {
187 	struct hv_device *hv_dev = device_to_hv_device(dev);
188 
189 	if (!hv_dev->channel)
190 		return -ENODEV;
191 	return sprintf(buf, "%d\n",
192 		       channel_pending(hv_dev->channel,
193 				       vmbus_connection.monitor_pages[1]));
194 }
195 static DEVICE_ATTR_RO(client_monitor_pending);
196 
197 static ssize_t server_monitor_latency_show(struct device *dev,
198 					   struct device_attribute *dev_attr,
199 					   char *buf)
200 {
201 	struct hv_device *hv_dev = device_to_hv_device(dev);
202 
203 	if (!hv_dev->channel)
204 		return -ENODEV;
205 	return sprintf(buf, "%d\n",
206 		       channel_latency(hv_dev->channel,
207 				       vmbus_connection.monitor_pages[0]));
208 }
209 static DEVICE_ATTR_RO(server_monitor_latency);
210 
211 static ssize_t client_monitor_latency_show(struct device *dev,
212 					   struct device_attribute *dev_attr,
213 					   char *buf)
214 {
215 	struct hv_device *hv_dev = device_to_hv_device(dev);
216 
217 	if (!hv_dev->channel)
218 		return -ENODEV;
219 	return sprintf(buf, "%d\n",
220 		       channel_latency(hv_dev->channel,
221 				       vmbus_connection.monitor_pages[1]));
222 }
223 static DEVICE_ATTR_RO(client_monitor_latency);
224 
225 static ssize_t server_monitor_conn_id_show(struct device *dev,
226 					   struct device_attribute *dev_attr,
227 					   char *buf)
228 {
229 	struct hv_device *hv_dev = device_to_hv_device(dev);
230 
231 	if (!hv_dev->channel)
232 		return -ENODEV;
233 	return sprintf(buf, "%d\n",
234 		       channel_conn_id(hv_dev->channel,
235 				       vmbus_connection.monitor_pages[0]));
236 }
237 static DEVICE_ATTR_RO(server_monitor_conn_id);
238 
239 static ssize_t client_monitor_conn_id_show(struct device *dev,
240 					   struct device_attribute *dev_attr,
241 					   char *buf)
242 {
243 	struct hv_device *hv_dev = device_to_hv_device(dev);
244 
245 	if (!hv_dev->channel)
246 		return -ENODEV;
247 	return sprintf(buf, "%d\n",
248 		       channel_conn_id(hv_dev->channel,
249 				       vmbus_connection.monitor_pages[1]));
250 }
251 static DEVICE_ATTR_RO(client_monitor_conn_id);
252 
253 static ssize_t out_intr_mask_show(struct device *dev,
254 				  struct device_attribute *dev_attr, char *buf)
255 {
256 	struct hv_device *hv_dev = device_to_hv_device(dev);
257 	struct hv_ring_buffer_debug_info outbound;
258 
259 	if (!hv_dev->channel)
260 		return -ENODEV;
261 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
262 	return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
263 }
264 static DEVICE_ATTR_RO(out_intr_mask);
265 
266 static ssize_t out_read_index_show(struct device *dev,
267 				   struct device_attribute *dev_attr, char *buf)
268 {
269 	struct hv_device *hv_dev = device_to_hv_device(dev);
270 	struct hv_ring_buffer_debug_info outbound;
271 
272 	if (!hv_dev->channel)
273 		return -ENODEV;
274 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
275 	return sprintf(buf, "%d\n", outbound.current_read_index);
276 }
277 static DEVICE_ATTR_RO(out_read_index);
278 
279 static ssize_t out_write_index_show(struct device *dev,
280 				    struct device_attribute *dev_attr,
281 				    char *buf)
282 {
283 	struct hv_device *hv_dev = device_to_hv_device(dev);
284 	struct hv_ring_buffer_debug_info outbound;
285 
286 	if (!hv_dev->channel)
287 		return -ENODEV;
288 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
289 	return sprintf(buf, "%d\n", outbound.current_write_index);
290 }
291 static DEVICE_ATTR_RO(out_write_index);
292 
293 static ssize_t out_read_bytes_avail_show(struct device *dev,
294 					 struct device_attribute *dev_attr,
295 					 char *buf)
296 {
297 	struct hv_device *hv_dev = device_to_hv_device(dev);
298 	struct hv_ring_buffer_debug_info outbound;
299 
300 	if (!hv_dev->channel)
301 		return -ENODEV;
302 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
303 	return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
304 }
305 static DEVICE_ATTR_RO(out_read_bytes_avail);
306 
307 static ssize_t out_write_bytes_avail_show(struct device *dev,
308 					  struct device_attribute *dev_attr,
309 					  char *buf)
310 {
311 	struct hv_device *hv_dev = device_to_hv_device(dev);
312 	struct hv_ring_buffer_debug_info outbound;
313 
314 	if (!hv_dev->channel)
315 		return -ENODEV;
316 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
317 	return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
318 }
319 static DEVICE_ATTR_RO(out_write_bytes_avail);
320 
321 static ssize_t in_intr_mask_show(struct device *dev,
322 				 struct device_attribute *dev_attr, char *buf)
323 {
324 	struct hv_device *hv_dev = device_to_hv_device(dev);
325 	struct hv_ring_buffer_debug_info inbound;
326 
327 	if (!hv_dev->channel)
328 		return -ENODEV;
329 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
330 	return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
331 }
332 static DEVICE_ATTR_RO(in_intr_mask);
333 
334 static ssize_t in_read_index_show(struct device *dev,
335 				  struct device_attribute *dev_attr, char *buf)
336 {
337 	struct hv_device *hv_dev = device_to_hv_device(dev);
338 	struct hv_ring_buffer_debug_info inbound;
339 
340 	if (!hv_dev->channel)
341 		return -ENODEV;
342 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
343 	return sprintf(buf, "%d\n", inbound.current_read_index);
344 }
345 static DEVICE_ATTR_RO(in_read_index);
346 
347 static ssize_t in_write_index_show(struct device *dev,
348 				   struct device_attribute *dev_attr, char *buf)
349 {
350 	struct hv_device *hv_dev = device_to_hv_device(dev);
351 	struct hv_ring_buffer_debug_info inbound;
352 
353 	if (!hv_dev->channel)
354 		return -ENODEV;
355 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
356 	return sprintf(buf, "%d\n", inbound.current_write_index);
357 }
358 static DEVICE_ATTR_RO(in_write_index);
359 
360 static ssize_t in_read_bytes_avail_show(struct device *dev,
361 					struct device_attribute *dev_attr,
362 					char *buf)
363 {
364 	struct hv_device *hv_dev = device_to_hv_device(dev);
365 	struct hv_ring_buffer_debug_info inbound;
366 
367 	if (!hv_dev->channel)
368 		return -ENODEV;
369 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
370 	return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
371 }
372 static DEVICE_ATTR_RO(in_read_bytes_avail);
373 
374 static ssize_t in_write_bytes_avail_show(struct device *dev,
375 					 struct device_attribute *dev_attr,
376 					 char *buf)
377 {
378 	struct hv_device *hv_dev = device_to_hv_device(dev);
379 	struct hv_ring_buffer_debug_info inbound;
380 
381 	if (!hv_dev->channel)
382 		return -ENODEV;
383 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
384 	return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
385 }
386 static DEVICE_ATTR_RO(in_write_bytes_avail);
387 
388 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
389 static struct attribute *vmbus_attrs[] = {
390 	&dev_attr_id.attr,
391 	&dev_attr_state.attr,
392 	&dev_attr_monitor_id.attr,
393 	&dev_attr_class_id.attr,
394 	&dev_attr_device_id.attr,
395 	&dev_attr_modalias.attr,
396 	&dev_attr_server_monitor_pending.attr,
397 	&dev_attr_client_monitor_pending.attr,
398 	&dev_attr_server_monitor_latency.attr,
399 	&dev_attr_client_monitor_latency.attr,
400 	&dev_attr_server_monitor_conn_id.attr,
401 	&dev_attr_client_monitor_conn_id.attr,
402 	&dev_attr_out_intr_mask.attr,
403 	&dev_attr_out_read_index.attr,
404 	&dev_attr_out_write_index.attr,
405 	&dev_attr_out_read_bytes_avail.attr,
406 	&dev_attr_out_write_bytes_avail.attr,
407 	&dev_attr_in_intr_mask.attr,
408 	&dev_attr_in_read_index.attr,
409 	&dev_attr_in_write_index.attr,
410 	&dev_attr_in_read_bytes_avail.attr,
411 	&dev_attr_in_write_bytes_avail.attr,
412 	NULL,
413 };
414 ATTRIBUTE_GROUPS(vmbus);
415 
416 /*
417  * vmbus_uevent - add uevent for our device
418  *
419  * This routine is invoked when a device is added or removed on the vmbus to
420  * generate a uevent to udev in the userspace. The udev will then look at its
421  * rule and the uevent generated here to load the appropriate driver
422  *
423  * The alias string will be of the form vmbus:guid where guid is the string
424  * representation of the device guid (each byte of the guid will be
425  * represented with two hex characters.
426  */
427 static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
428 {
429 	struct hv_device *dev = device_to_hv_device(device);
430 	int ret;
431 	char alias_name[VMBUS_ALIAS_LEN + 1];
432 
433 	print_alias_name(dev, alias_name);
434 	ret = add_uevent_var(env, "MODALIAS=vmbus:%s", alias_name);
435 	return ret;
436 }
437 
438 static uuid_le null_guid;
439 
440 static inline bool is_null_guid(const __u8 *guid)
441 {
442 	if (memcmp(guid, &null_guid, sizeof(uuid_le)))
443 		return false;
444 	return true;
445 }
446 
447 /*
448  * Return a matching hv_vmbus_device_id pointer.
449  * If there is no match, return NULL.
450  */
451 static const struct hv_vmbus_device_id *hv_vmbus_get_id(
452 					const struct hv_vmbus_device_id *id,
453 					__u8 *guid)
454 {
455 	for (; !is_null_guid(id->guid); id++)
456 		if (!memcmp(&id->guid, guid, sizeof(uuid_le)))
457 			return id;
458 
459 	return NULL;
460 }
461 
462 
463 
464 /*
465  * vmbus_match - Attempt to match the specified device to the specified driver
466  */
467 static int vmbus_match(struct device *device, struct device_driver *driver)
468 {
469 	struct hv_driver *drv = drv_to_hv_drv(driver);
470 	struct hv_device *hv_dev = device_to_hv_device(device);
471 
472 	if (hv_vmbus_get_id(drv->id_table, hv_dev->dev_type.b))
473 		return 1;
474 
475 	return 0;
476 }
477 
478 /*
479  * vmbus_probe - Add the new vmbus's child device
480  */
481 static int vmbus_probe(struct device *child_device)
482 {
483 	int ret = 0;
484 	struct hv_driver *drv =
485 			drv_to_hv_drv(child_device->driver);
486 	struct hv_device *dev = device_to_hv_device(child_device);
487 	const struct hv_vmbus_device_id *dev_id;
488 
489 	dev_id = hv_vmbus_get_id(drv->id_table, dev->dev_type.b);
490 	if (drv->probe) {
491 		ret = drv->probe(dev, dev_id);
492 		if (ret != 0)
493 			pr_err("probe failed for device %s (%d)\n",
494 			       dev_name(child_device), ret);
495 
496 	} else {
497 		pr_err("probe not set for driver %s\n",
498 		       dev_name(child_device));
499 		ret = -ENODEV;
500 	}
501 	return ret;
502 }
503 
504 /*
505  * vmbus_remove - Remove a vmbus device
506  */
507 static int vmbus_remove(struct device *child_device)
508 {
509 	struct hv_driver *drv = drv_to_hv_drv(child_device->driver);
510 	struct hv_device *dev = device_to_hv_device(child_device);
511 
512 	if (drv->remove)
513 		drv->remove(dev);
514 	else
515 		pr_err("remove not set for driver %s\n",
516 			dev_name(child_device));
517 
518 	return 0;
519 }
520 
521 
522 /*
523  * vmbus_shutdown - Shutdown a vmbus device
524  */
525 static void vmbus_shutdown(struct device *child_device)
526 {
527 	struct hv_driver *drv;
528 	struct hv_device *dev = device_to_hv_device(child_device);
529 
530 
531 	/* The device may not be attached yet */
532 	if (!child_device->driver)
533 		return;
534 
535 	drv = drv_to_hv_drv(child_device->driver);
536 
537 	if (drv->shutdown)
538 		drv->shutdown(dev);
539 
540 	return;
541 }
542 
543 
544 /*
545  * vmbus_device_release - Final callback release of the vmbus child device
546  */
547 static void vmbus_device_release(struct device *device)
548 {
549 	struct hv_device *hv_dev = device_to_hv_device(device);
550 
551 	kfree(hv_dev);
552 
553 }
554 
555 /* The one and only one */
556 static struct bus_type  hv_bus = {
557 	.name =		"vmbus",
558 	.match =		vmbus_match,
559 	.shutdown =		vmbus_shutdown,
560 	.remove =		vmbus_remove,
561 	.probe =		vmbus_probe,
562 	.uevent =		vmbus_uevent,
563 	.dev_groups =		vmbus_groups,
564 };
565 
566 struct onmessage_work_context {
567 	struct work_struct work;
568 	struct hv_message msg;
569 };
570 
571 static void vmbus_onmessage_work(struct work_struct *work)
572 {
573 	struct onmessage_work_context *ctx;
574 
575 	ctx = container_of(work, struct onmessage_work_context,
576 			   work);
577 	vmbus_onmessage(&ctx->msg);
578 	kfree(ctx);
579 }
580 
581 static void vmbus_on_msg_dpc(unsigned long data)
582 {
583 	int cpu = smp_processor_id();
584 	void *page_addr = hv_context.synic_message_page[cpu];
585 	struct hv_message *msg = (struct hv_message *)page_addr +
586 				  VMBUS_MESSAGE_SINT;
587 	struct onmessage_work_context *ctx;
588 
589 	while (1) {
590 		if (msg->header.message_type == HVMSG_NONE) {
591 			/* no msg */
592 			break;
593 		} else {
594 			ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
595 			if (ctx == NULL)
596 				continue;
597 			INIT_WORK(&ctx->work, vmbus_onmessage_work);
598 			memcpy(&ctx->msg, msg, sizeof(*msg));
599 			queue_work(vmbus_connection.work_queue, &ctx->work);
600 		}
601 
602 		msg->header.message_type = HVMSG_NONE;
603 
604 		/*
605 		 * Make sure the write to MessageType (ie set to
606 		 * HVMSG_NONE) happens before we read the
607 		 * MessagePending and EOMing. Otherwise, the EOMing
608 		 * will not deliver any more messages since there is
609 		 * no empty slot
610 		 */
611 		mb();
612 
613 		if (msg->header.message_flags.msg_pending) {
614 			/*
615 			 * This will cause message queue rescan to
616 			 * possibly deliver another msg from the
617 			 * hypervisor
618 			 */
619 			wrmsrl(HV_X64_MSR_EOM, 0);
620 		}
621 	}
622 }
623 
624 static void vmbus_isr(void)
625 {
626 	int cpu = smp_processor_id();
627 	void *page_addr;
628 	struct hv_message *msg;
629 	union hv_synic_event_flags *event;
630 	bool handled = false;
631 
632 	page_addr = hv_context.synic_event_page[cpu];
633 	if (page_addr == NULL)
634 		return;
635 
636 	event = (union hv_synic_event_flags *)page_addr +
637 					 VMBUS_MESSAGE_SINT;
638 	/*
639 	 * Check for events before checking for messages. This is the order
640 	 * in which events and messages are checked in Windows guests on
641 	 * Hyper-V, and the Windows team suggested we do the same.
642 	 */
643 
644 	if ((vmbus_proto_version == VERSION_WS2008) ||
645 		(vmbus_proto_version == VERSION_WIN7)) {
646 
647 		/* Since we are a child, we only need to check bit 0 */
648 		if (sync_test_and_clear_bit(0,
649 			(unsigned long *) &event->flags32[0])) {
650 			handled = true;
651 		}
652 	} else {
653 		/*
654 		 * Our host is win8 or above. The signaling mechanism
655 		 * has changed and we can directly look at the event page.
656 		 * If bit n is set then we have an interrup on the channel
657 		 * whose id is n.
658 		 */
659 		handled = true;
660 	}
661 
662 	if (handled)
663 		tasklet_schedule(hv_context.event_dpc[cpu]);
664 
665 
666 	page_addr = hv_context.synic_message_page[cpu];
667 	msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
668 
669 	/* Check if there are actual msgs to be processed */
670 	if (msg->header.message_type != HVMSG_NONE)
671 		tasklet_schedule(&msg_dpc);
672 }
673 
674 /*
675  * vmbus_bus_init -Main vmbus driver initialization routine.
676  *
677  * Here, we
678  *	- initialize the vmbus driver context
679  *	- invoke the vmbus hv main init routine
680  *	- get the irq resource
681  *	- retrieve the channel offers
682  */
683 static int vmbus_bus_init(int irq)
684 {
685 	int ret;
686 
687 	/* Hypervisor initialization...setup hypercall page..etc */
688 	ret = hv_init();
689 	if (ret != 0) {
690 		pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
691 		return ret;
692 	}
693 
694 	tasklet_init(&msg_dpc, vmbus_on_msg_dpc, 0);
695 
696 	ret = bus_register(&hv_bus);
697 	if (ret)
698 		goto err_cleanup;
699 
700 	hv_setup_vmbus_irq(vmbus_isr);
701 
702 	ret = hv_synic_alloc();
703 	if (ret)
704 		goto err_alloc;
705 	/*
706 	 * Initialize the per-cpu interrupt state and
707 	 * connect to the host.
708 	 */
709 	on_each_cpu(hv_synic_init, NULL, 1);
710 	ret = vmbus_connect();
711 	if (ret)
712 		goto err_alloc;
713 
714 	vmbus_request_offers();
715 
716 	return 0;
717 
718 err_alloc:
719 	hv_synic_free();
720 	hv_remove_vmbus_irq();
721 
722 	bus_unregister(&hv_bus);
723 
724 err_cleanup:
725 	hv_cleanup();
726 
727 	return ret;
728 }
729 
730 /**
731  * __vmbus_child_driver_register - Register a vmbus's driver
732  * @drv: Pointer to driver structure you want to register
733  * @owner: owner module of the drv
734  * @mod_name: module name string
735  *
736  * Registers the given driver with Linux through the 'driver_register()' call
737  * and sets up the hyper-v vmbus handling for this driver.
738  * It will return the state of the 'driver_register()' call.
739  *
740  */
741 int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
742 {
743 	int ret;
744 
745 	pr_info("registering driver %s\n", hv_driver->name);
746 
747 	ret = vmbus_exists();
748 	if (ret < 0)
749 		return ret;
750 
751 	hv_driver->driver.name = hv_driver->name;
752 	hv_driver->driver.owner = owner;
753 	hv_driver->driver.mod_name = mod_name;
754 	hv_driver->driver.bus = &hv_bus;
755 
756 	ret = driver_register(&hv_driver->driver);
757 
758 	return ret;
759 }
760 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
761 
762 /**
763  * vmbus_driver_unregister() - Unregister a vmbus's driver
764  * @drv: Pointer to driver structure you want to un-register
765  *
766  * Un-register the given driver that was previous registered with a call to
767  * vmbus_driver_register()
768  */
769 void vmbus_driver_unregister(struct hv_driver *hv_driver)
770 {
771 	pr_info("unregistering driver %s\n", hv_driver->name);
772 
773 	if (!vmbus_exists())
774 		driver_unregister(&hv_driver->driver);
775 }
776 EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
777 
778 /*
779  * vmbus_device_create - Creates and registers a new child device
780  * on the vmbus.
781  */
782 struct hv_device *vmbus_device_create(uuid_le *type,
783 					    uuid_le *instance,
784 					    struct vmbus_channel *channel)
785 {
786 	struct hv_device *child_device_obj;
787 
788 	child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
789 	if (!child_device_obj) {
790 		pr_err("Unable to allocate device object for child device\n");
791 		return NULL;
792 	}
793 
794 	child_device_obj->channel = channel;
795 	memcpy(&child_device_obj->dev_type, type, sizeof(uuid_le));
796 	memcpy(&child_device_obj->dev_instance, instance,
797 	       sizeof(uuid_le));
798 
799 
800 	return child_device_obj;
801 }
802 
803 /*
804  * vmbus_device_register - Register the child device
805  */
806 int vmbus_device_register(struct hv_device *child_device_obj)
807 {
808 	int ret = 0;
809 
810 	static atomic_t device_num = ATOMIC_INIT(0);
811 
812 	dev_set_name(&child_device_obj->device, "vmbus_0_%d",
813 		     atomic_inc_return(&device_num));
814 
815 	child_device_obj->device.bus = &hv_bus;
816 	child_device_obj->device.parent = &hv_acpi_dev->dev;
817 	child_device_obj->device.release = vmbus_device_release;
818 
819 	/*
820 	 * Register with the LDM. This will kick off the driver/device
821 	 * binding...which will eventually call vmbus_match() and vmbus_probe()
822 	 */
823 	ret = device_register(&child_device_obj->device);
824 
825 	if (ret)
826 		pr_err("Unable to register child device\n");
827 	else
828 		pr_debug("child device %s registered\n",
829 			dev_name(&child_device_obj->device));
830 
831 	return ret;
832 }
833 
834 /*
835  * vmbus_device_unregister - Remove the specified child device
836  * from the vmbus.
837  */
838 void vmbus_device_unregister(struct hv_device *device_obj)
839 {
840 	pr_debug("child device %s unregistered\n",
841 		dev_name(&device_obj->device));
842 
843 	/*
844 	 * Kick off the process of unregistering the device.
845 	 * This will call vmbus_remove() and eventually vmbus_device_release()
846 	 */
847 	device_unregister(&device_obj->device);
848 }
849 
850 
851 /*
852  * VMBUS is an acpi enumerated device. Get the the information we
853  * need from DSDT.
854  */
855 
856 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
857 {
858 	switch (res->type) {
859 	case ACPI_RESOURCE_TYPE_IRQ:
860 		irq = res->data.irq.interrupts[0];
861 		break;
862 
863 	case ACPI_RESOURCE_TYPE_ADDRESS64:
864 		hyperv_mmio.start = res->data.address64.minimum;
865 		hyperv_mmio.end = res->data.address64.maximum;
866 		break;
867 	}
868 
869 	return AE_OK;
870 }
871 
872 static int vmbus_acpi_add(struct acpi_device *device)
873 {
874 	acpi_status result;
875 	int ret_val = -ENODEV;
876 
877 	hv_acpi_dev = device;
878 
879 	result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
880 					vmbus_walk_resources, NULL);
881 
882 	if (ACPI_FAILURE(result))
883 		goto acpi_walk_err;
884 	/*
885 	 * The parent of the vmbus acpi device (Gen2 firmware) is the VMOD that
886 	 * has the mmio ranges. Get that.
887 	 */
888 	if (device->parent) {
889 		result = acpi_walk_resources(device->parent->handle,
890 					METHOD_NAME__CRS,
891 					vmbus_walk_resources, NULL);
892 
893 		if (ACPI_FAILURE(result))
894 			goto acpi_walk_err;
895 		if (hyperv_mmio.start && hyperv_mmio.end)
896 			request_resource(&iomem_resource, &hyperv_mmio);
897 	}
898 	ret_val = 0;
899 
900 acpi_walk_err:
901 	complete(&probe_event);
902 	return ret_val;
903 }
904 
905 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
906 	{"VMBUS", 0},
907 	{"VMBus", 0},
908 	{"", 0},
909 };
910 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
911 
912 static struct acpi_driver vmbus_acpi_driver = {
913 	.name = "vmbus",
914 	.ids = vmbus_acpi_device_ids,
915 	.ops = {
916 		.add = vmbus_acpi_add,
917 	},
918 };
919 
920 static int __init hv_acpi_init(void)
921 {
922 	int ret, t;
923 
924 	if (x86_hyper != &x86_hyper_ms_hyperv)
925 		return -ENODEV;
926 
927 	init_completion(&probe_event);
928 
929 	/*
930 	 * Get irq resources first.
931 	 */
932 	ret = acpi_bus_register_driver(&vmbus_acpi_driver);
933 
934 	if (ret)
935 		return ret;
936 
937 	t = wait_for_completion_timeout(&probe_event, 5*HZ);
938 	if (t == 0) {
939 		ret = -ETIMEDOUT;
940 		goto cleanup;
941 	}
942 
943 	if (irq <= 0) {
944 		ret = -ENODEV;
945 		goto cleanup;
946 	}
947 
948 	ret = vmbus_bus_init(irq);
949 	if (ret)
950 		goto cleanup;
951 
952 	return 0;
953 
954 cleanup:
955 	acpi_bus_unregister_driver(&vmbus_acpi_driver);
956 	hv_acpi_dev = NULL;
957 	return ret;
958 }
959 
960 static void __exit vmbus_exit(void)
961 {
962 	hv_remove_vmbus_irq();
963 	vmbus_free_channels();
964 	bus_unregister(&hv_bus);
965 	hv_cleanup();
966 	acpi_bus_unregister_driver(&vmbus_acpi_driver);
967 }
968 
969 
970 MODULE_LICENSE("GPL");
971 
972 subsys_initcall(hv_acpi_init);
973 module_exit(vmbus_exit);
974