xref: /openbmc/linux/drivers/hv/channel.c (revision d236d361)
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  */
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22 
23 #include <linux/kernel.h>
24 #include <linux/sched.h>
25 #include <linux/wait.h>
26 #include <linux/mm.h>
27 #include <linux/slab.h>
28 #include <linux/module.h>
29 #include <linux/hyperv.h>
30 #include <linux/uio.h>
31 #include <linux/interrupt.h>
32 
33 #include "hyperv_vmbus.h"
34 
35 #define NUM_PAGES_SPANNED(addr, len) \
36 ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
37 
38 /*
39  * vmbus_setevent- Trigger an event notification on the specified
40  * channel.
41  */
42 void vmbus_setevent(struct vmbus_channel *channel)
43 {
44 	struct hv_monitor_page *monitorpage;
45 
46 	/*
47 	 * For channels marked as in "low latency" mode
48 	 * bypass the monitor page mechanism.
49 	 */
50 	if (channel->offermsg.monitor_allocated && !channel->low_latency) {
51 		vmbus_send_interrupt(channel->offermsg.child_relid);
52 
53 		/* Get the child to parent monitor page */
54 		monitorpage = vmbus_connection.monitor_pages[1];
55 
56 		sync_set_bit(channel->monitor_bit,
57 			(unsigned long *)&monitorpage->trigger_group
58 					[channel->monitor_grp].pending);
59 
60 	} else {
61 		vmbus_set_event(channel);
62 	}
63 }
64 EXPORT_SYMBOL_GPL(vmbus_setevent);
65 
66 /*
67  * vmbus_open - Open the specified channel.
68  */
69 int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
70 		     u32 recv_ringbuffer_size, void *userdata, u32 userdatalen,
71 		     void (*onchannelcallback)(void *context), void *context)
72 {
73 	struct vmbus_channel_open_channel *open_msg;
74 	struct vmbus_channel_msginfo *open_info = NULL;
75 	unsigned long flags;
76 	int ret, err = 0;
77 	struct page *page;
78 
79 	if (send_ringbuffer_size % PAGE_SIZE ||
80 	    recv_ringbuffer_size % PAGE_SIZE)
81 		return -EINVAL;
82 
83 	spin_lock_irqsave(&newchannel->lock, flags);
84 	if (newchannel->state == CHANNEL_OPEN_STATE) {
85 		newchannel->state = CHANNEL_OPENING_STATE;
86 	} else {
87 		spin_unlock_irqrestore(&newchannel->lock, flags);
88 		return -EINVAL;
89 	}
90 	spin_unlock_irqrestore(&newchannel->lock, flags);
91 
92 	newchannel->onchannel_callback = onchannelcallback;
93 	newchannel->channel_callback_context = context;
94 
95 	/* Allocate the ring buffer */
96 	page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
97 				GFP_KERNEL|__GFP_ZERO,
98 				get_order(send_ringbuffer_size +
99 				recv_ringbuffer_size));
100 
101 	if (!page)
102 		page = alloc_pages(GFP_KERNEL|__GFP_ZERO,
103 				   get_order(send_ringbuffer_size +
104 					     recv_ringbuffer_size));
105 
106 	if (!page) {
107 		err = -ENOMEM;
108 		goto error_set_chnstate;
109 	}
110 
111 	newchannel->ringbuffer_pages = page_address(page);
112 	newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
113 					   recv_ringbuffer_size) >> PAGE_SHIFT;
114 
115 	ret = hv_ringbuffer_init(&newchannel->outbound, page,
116 				 send_ringbuffer_size >> PAGE_SHIFT);
117 
118 	if (ret != 0) {
119 		err = ret;
120 		goto error_free_pages;
121 	}
122 
123 	ret = hv_ringbuffer_init(&newchannel->inbound,
124 				 &page[send_ringbuffer_size >> PAGE_SHIFT],
125 				 recv_ringbuffer_size >> PAGE_SHIFT);
126 	if (ret != 0) {
127 		err = ret;
128 		goto error_free_pages;
129 	}
130 
131 
132 	/* Establish the gpadl for the ring buffer */
133 	newchannel->ringbuffer_gpadlhandle = 0;
134 
135 	ret = vmbus_establish_gpadl(newchannel,
136 				    page_address(page),
137 				    send_ringbuffer_size +
138 				    recv_ringbuffer_size,
139 				    &newchannel->ringbuffer_gpadlhandle);
140 
141 	if (ret != 0) {
142 		err = ret;
143 		goto error_free_pages;
144 	}
145 
146 	/* Create and init the channel open message */
147 	open_info = kmalloc(sizeof(*open_info) +
148 			   sizeof(struct vmbus_channel_open_channel),
149 			   GFP_KERNEL);
150 	if (!open_info) {
151 		err = -ENOMEM;
152 		goto error_free_gpadl;
153 	}
154 
155 	init_completion(&open_info->waitevent);
156 	open_info->waiting_channel = newchannel;
157 
158 	open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
159 	open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
160 	open_msg->openid = newchannel->offermsg.child_relid;
161 	open_msg->child_relid = newchannel->offermsg.child_relid;
162 	open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
163 	open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
164 						  PAGE_SHIFT;
165 	open_msg->target_vp = newchannel->target_vp;
166 
167 	if (userdatalen > MAX_USER_DEFINED_BYTES) {
168 		err = -EINVAL;
169 		goto error_free_gpadl;
170 	}
171 
172 	if (userdatalen)
173 		memcpy(open_msg->userdata, userdata, userdatalen);
174 
175 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
176 	list_add_tail(&open_info->msglistentry,
177 		      &vmbus_connection.chn_msg_list);
178 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
179 
180 	ret = vmbus_post_msg(open_msg,
181 			     sizeof(struct vmbus_channel_open_channel), true);
182 
183 	if (ret != 0) {
184 		err = ret;
185 		goto error_clean_msglist;
186 	}
187 
188 	wait_for_completion(&open_info->waitevent);
189 
190 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
191 	list_del(&open_info->msglistentry);
192 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
193 
194 	if (newchannel->rescind) {
195 		err = -ENODEV;
196 		goto error_free_gpadl;
197 	}
198 
199 	if (open_info->response.open_result.status) {
200 		err = -EAGAIN;
201 		goto error_free_gpadl;
202 	}
203 
204 	newchannel->state = CHANNEL_OPENED_STATE;
205 	kfree(open_info);
206 	return 0;
207 
208 error_clean_msglist:
209 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
210 	list_del(&open_info->msglistentry);
211 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
212 
213 error_free_gpadl:
214 	vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
215 	kfree(open_info);
216 error_free_pages:
217 	hv_ringbuffer_cleanup(&newchannel->outbound);
218 	hv_ringbuffer_cleanup(&newchannel->inbound);
219 	__free_pages(page,
220 		     get_order(send_ringbuffer_size + recv_ringbuffer_size));
221 error_set_chnstate:
222 	newchannel->state = CHANNEL_OPEN_STATE;
223 	return err;
224 }
225 EXPORT_SYMBOL_GPL(vmbus_open);
226 
227 /* Used for Hyper-V Socket: a guest client's connect() to the host */
228 int vmbus_send_tl_connect_request(const uuid_le *shv_guest_servie_id,
229 				  const uuid_le *shv_host_servie_id)
230 {
231 	struct vmbus_channel_tl_connect_request conn_msg;
232 
233 	memset(&conn_msg, 0, sizeof(conn_msg));
234 	conn_msg.header.msgtype = CHANNELMSG_TL_CONNECT_REQUEST;
235 	conn_msg.guest_endpoint_id = *shv_guest_servie_id;
236 	conn_msg.host_service_id = *shv_host_servie_id;
237 
238 	return vmbus_post_msg(&conn_msg, sizeof(conn_msg), true);
239 }
240 EXPORT_SYMBOL_GPL(vmbus_send_tl_connect_request);
241 
242 /*
243  * create_gpadl_header - Creates a gpadl for the specified buffer
244  */
245 static int create_gpadl_header(void *kbuffer, u32 size,
246 			       struct vmbus_channel_msginfo **msginfo)
247 {
248 	int i;
249 	int pagecount;
250 	struct vmbus_channel_gpadl_header *gpadl_header;
251 	struct vmbus_channel_gpadl_body *gpadl_body;
252 	struct vmbus_channel_msginfo *msgheader;
253 	struct vmbus_channel_msginfo *msgbody = NULL;
254 	u32 msgsize;
255 
256 	int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
257 
258 	pagecount = size >> PAGE_SHIFT;
259 
260 	/* do we need a gpadl body msg */
261 	pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
262 		  sizeof(struct vmbus_channel_gpadl_header) -
263 		  sizeof(struct gpa_range);
264 	pfncount = pfnsize / sizeof(u64);
265 
266 	if (pagecount > pfncount) {
267 		/* we need a gpadl body */
268 		/* fill in the header */
269 		msgsize = sizeof(struct vmbus_channel_msginfo) +
270 			  sizeof(struct vmbus_channel_gpadl_header) +
271 			  sizeof(struct gpa_range) + pfncount * sizeof(u64);
272 		msgheader =  kzalloc(msgsize, GFP_KERNEL);
273 		if (!msgheader)
274 			goto nomem;
275 
276 		INIT_LIST_HEAD(&msgheader->submsglist);
277 		msgheader->msgsize = msgsize;
278 
279 		gpadl_header = (struct vmbus_channel_gpadl_header *)
280 			msgheader->msg;
281 		gpadl_header->rangecount = 1;
282 		gpadl_header->range_buflen = sizeof(struct gpa_range) +
283 					 pagecount * sizeof(u64);
284 		gpadl_header->range[0].byte_offset = 0;
285 		gpadl_header->range[0].byte_count = size;
286 		for (i = 0; i < pfncount; i++)
287 			gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
288 				kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
289 		*msginfo = msgheader;
290 
291 		pfnsum = pfncount;
292 		pfnleft = pagecount - pfncount;
293 
294 		/* how many pfns can we fit */
295 		pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
296 			  sizeof(struct vmbus_channel_gpadl_body);
297 		pfncount = pfnsize / sizeof(u64);
298 
299 		/* fill in the body */
300 		while (pfnleft) {
301 			if (pfnleft > pfncount)
302 				pfncurr = pfncount;
303 			else
304 				pfncurr = pfnleft;
305 
306 			msgsize = sizeof(struct vmbus_channel_msginfo) +
307 				  sizeof(struct vmbus_channel_gpadl_body) +
308 				  pfncurr * sizeof(u64);
309 			msgbody = kzalloc(msgsize, GFP_KERNEL);
310 
311 			if (!msgbody) {
312 				struct vmbus_channel_msginfo *pos = NULL;
313 				struct vmbus_channel_msginfo *tmp = NULL;
314 				/*
315 				 * Free up all the allocated messages.
316 				 */
317 				list_for_each_entry_safe(pos, tmp,
318 					&msgheader->submsglist,
319 					msglistentry) {
320 
321 					list_del(&pos->msglistentry);
322 					kfree(pos);
323 				}
324 
325 				goto nomem;
326 			}
327 
328 			msgbody->msgsize = msgsize;
329 			gpadl_body =
330 				(struct vmbus_channel_gpadl_body *)msgbody->msg;
331 
332 			/*
333 			 * Gpadl is u32 and we are using a pointer which could
334 			 * be 64-bit
335 			 * This is governed by the guest/host protocol and
336 			 * so the hypervisor guarantees that this is ok.
337 			 */
338 			for (i = 0; i < pfncurr; i++)
339 				gpadl_body->pfn[i] = slow_virt_to_phys(
340 					kbuffer + PAGE_SIZE * (pfnsum + i)) >>
341 					PAGE_SHIFT;
342 
343 			/* add to msg header */
344 			list_add_tail(&msgbody->msglistentry,
345 				      &msgheader->submsglist);
346 			pfnsum += pfncurr;
347 			pfnleft -= pfncurr;
348 		}
349 	} else {
350 		/* everything fits in a header */
351 		msgsize = sizeof(struct vmbus_channel_msginfo) +
352 			  sizeof(struct vmbus_channel_gpadl_header) +
353 			  sizeof(struct gpa_range) + pagecount * sizeof(u64);
354 		msgheader = kzalloc(msgsize, GFP_KERNEL);
355 		if (msgheader == NULL)
356 			goto nomem;
357 
358 		INIT_LIST_HEAD(&msgheader->submsglist);
359 		msgheader->msgsize = msgsize;
360 
361 		gpadl_header = (struct vmbus_channel_gpadl_header *)
362 			msgheader->msg;
363 		gpadl_header->rangecount = 1;
364 		gpadl_header->range_buflen = sizeof(struct gpa_range) +
365 					 pagecount * sizeof(u64);
366 		gpadl_header->range[0].byte_offset = 0;
367 		gpadl_header->range[0].byte_count = size;
368 		for (i = 0; i < pagecount; i++)
369 			gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
370 				kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
371 
372 		*msginfo = msgheader;
373 	}
374 
375 	return 0;
376 nomem:
377 	kfree(msgheader);
378 	kfree(msgbody);
379 	return -ENOMEM;
380 }
381 
382 /*
383  * vmbus_establish_gpadl - Establish a GPADL for the specified buffer
384  *
385  * @channel: a channel
386  * @kbuffer: from kmalloc or vmalloc
387  * @size: page-size multiple
388  * @gpadl_handle: some funky thing
389  */
390 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
391 			       u32 size, u32 *gpadl_handle)
392 {
393 	struct vmbus_channel_gpadl_header *gpadlmsg;
394 	struct vmbus_channel_gpadl_body *gpadl_body;
395 	struct vmbus_channel_msginfo *msginfo = NULL;
396 	struct vmbus_channel_msginfo *submsginfo, *tmp;
397 	struct list_head *curr;
398 	u32 next_gpadl_handle;
399 	unsigned long flags;
400 	int ret = 0;
401 
402 	next_gpadl_handle =
403 		(atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
404 
405 	ret = create_gpadl_header(kbuffer, size, &msginfo);
406 	if (ret)
407 		return ret;
408 
409 	init_completion(&msginfo->waitevent);
410 	msginfo->waiting_channel = channel;
411 
412 	gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
413 	gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
414 	gpadlmsg->child_relid = channel->offermsg.child_relid;
415 	gpadlmsg->gpadl = next_gpadl_handle;
416 
417 
418 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
419 	list_add_tail(&msginfo->msglistentry,
420 		      &vmbus_connection.chn_msg_list);
421 
422 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
423 
424 	ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
425 			     sizeof(*msginfo), true);
426 	if (ret != 0)
427 		goto cleanup;
428 
429 	list_for_each(curr, &msginfo->submsglist) {
430 		submsginfo = (struct vmbus_channel_msginfo *)curr;
431 		gpadl_body =
432 			(struct vmbus_channel_gpadl_body *)submsginfo->msg;
433 
434 		gpadl_body->header.msgtype =
435 			CHANNELMSG_GPADL_BODY;
436 		gpadl_body->gpadl = next_gpadl_handle;
437 
438 		ret = vmbus_post_msg(gpadl_body,
439 				     submsginfo->msgsize - sizeof(*submsginfo),
440 				     true);
441 		if (ret != 0)
442 			goto cleanup;
443 
444 	}
445 	wait_for_completion(&msginfo->waitevent);
446 
447 	if (channel->rescind) {
448 		ret = -ENODEV;
449 		goto cleanup;
450 	}
451 
452 	/* At this point, we received the gpadl created msg */
453 	*gpadl_handle = gpadlmsg->gpadl;
454 
455 cleanup:
456 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
457 	list_del(&msginfo->msglistentry);
458 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
459 	list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
460 				 msglistentry) {
461 		kfree(submsginfo);
462 	}
463 
464 	kfree(msginfo);
465 	return ret;
466 }
467 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
468 
469 /*
470  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
471  */
472 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
473 {
474 	struct vmbus_channel_gpadl_teardown *msg;
475 	struct vmbus_channel_msginfo *info;
476 	unsigned long flags;
477 	int ret;
478 
479 	info = kmalloc(sizeof(*info) +
480 		       sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
481 	if (!info)
482 		return -ENOMEM;
483 
484 	init_completion(&info->waitevent);
485 	info->waiting_channel = channel;
486 
487 	msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
488 
489 	msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
490 	msg->child_relid = channel->offermsg.child_relid;
491 	msg->gpadl = gpadl_handle;
492 
493 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
494 	list_add_tail(&info->msglistentry,
495 		      &vmbus_connection.chn_msg_list);
496 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
497 	ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown),
498 			     true);
499 
500 	if (ret)
501 		goto post_msg_err;
502 
503 	wait_for_completion(&info->waitevent);
504 
505 post_msg_err:
506 	/*
507 	 * If the channel has been rescinded;
508 	 * we will be awakened by the rescind
509 	 * handler; set the error code to zero so we don't leak memory.
510 	 */
511 	if (channel->rescind)
512 		ret = 0;
513 
514 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
515 	list_del(&info->msglistentry);
516 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
517 
518 	kfree(info);
519 	return ret;
520 }
521 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
522 
523 static void reset_channel_cb(void *arg)
524 {
525 	struct vmbus_channel *channel = arg;
526 
527 	channel->onchannel_callback = NULL;
528 }
529 
530 static int vmbus_close_internal(struct vmbus_channel *channel)
531 {
532 	struct vmbus_channel_close_channel *msg;
533 	int ret;
534 
535 	/*
536 	 * vmbus_on_event(), running in the per-channel tasklet, can race
537 	 * with vmbus_close_internal() in the case of SMP guest, e.g., when
538 	 * the former is accessing channel->inbound.ring_buffer, the latter
539 	 * could be freeing the ring_buffer pages, so here we must stop it
540 	 * first.
541 	 */
542 	tasklet_disable(&channel->callback_event);
543 
544 	/*
545 	 * In case a device driver's probe() fails (e.g.,
546 	 * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
547 	 * rescinded later (e.g., we dynamically disable an Integrated Service
548 	 * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
549 	 * here we should skip most of the below cleanup work.
550 	 */
551 	if (channel->state != CHANNEL_OPENED_STATE) {
552 		ret = -EINVAL;
553 		goto out;
554 	}
555 
556 	channel->state = CHANNEL_OPEN_STATE;
557 	channel->sc_creation_callback = NULL;
558 	/* Stop callback and cancel the timer asap */
559 	if (channel->target_cpu != get_cpu()) {
560 		put_cpu();
561 		smp_call_function_single(channel->target_cpu, reset_channel_cb,
562 					 channel, true);
563 	} else {
564 		reset_channel_cb(channel);
565 		put_cpu();
566 	}
567 
568 	/* Send a closing message */
569 
570 	msg = &channel->close_msg.msg;
571 
572 	msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
573 	msg->child_relid = channel->offermsg.child_relid;
574 
575 	ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel),
576 			     true);
577 
578 	if (ret) {
579 		pr_err("Close failed: close post msg return is %d\n", ret);
580 		/*
581 		 * If we failed to post the close msg,
582 		 * it is perhaps better to leak memory.
583 		 */
584 		goto out;
585 	}
586 
587 	/* Tear down the gpadl for the channel's ring buffer */
588 	if (channel->ringbuffer_gpadlhandle) {
589 		ret = vmbus_teardown_gpadl(channel,
590 					   channel->ringbuffer_gpadlhandle);
591 		if (ret) {
592 			pr_err("Close failed: teardown gpadl return %d\n", ret);
593 			/*
594 			 * If we failed to teardown gpadl,
595 			 * it is perhaps better to leak memory.
596 			 */
597 			goto out;
598 		}
599 	}
600 
601 	/* Cleanup the ring buffers for this channel */
602 	hv_ringbuffer_cleanup(&channel->outbound);
603 	hv_ringbuffer_cleanup(&channel->inbound);
604 
605 	free_pages((unsigned long)channel->ringbuffer_pages,
606 		get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
607 
608 out:
609 	return ret;
610 }
611 
612 /*
613  * vmbus_close - Close the specified channel
614  */
615 void vmbus_close(struct vmbus_channel *channel)
616 {
617 	struct list_head *cur, *tmp;
618 	struct vmbus_channel *cur_channel;
619 
620 	if (channel->primary_channel != NULL) {
621 		/*
622 		 * We will only close sub-channels when
623 		 * the primary is closed.
624 		 */
625 		return;
626 	}
627 	/*
628 	 * Close all the sub-channels first and then close the
629 	 * primary channel.
630 	 */
631 	list_for_each_safe(cur, tmp, &channel->sc_list) {
632 		cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
633 		if (cur_channel->state != CHANNEL_OPENED_STATE)
634 			continue;
635 		vmbus_close_internal(cur_channel);
636 	}
637 	/*
638 	 * Now close the primary.
639 	 */
640 	vmbus_close_internal(channel);
641 }
642 EXPORT_SYMBOL_GPL(vmbus_close);
643 
644 int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
645 			 u32 bufferlen, u64 requestid,
646 			 enum vmbus_packet_type type, u32 flags)
647 {
648 	struct vmpacket_descriptor desc;
649 	u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
650 	u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
651 	struct kvec bufferlist[3];
652 	u64 aligned_data = 0;
653 	int num_vecs = ((bufferlen != 0) ? 3 : 1);
654 
655 
656 	/* Setup the descriptor */
657 	desc.type = type; /* VmbusPacketTypeDataInBand; */
658 	desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
659 	/* in 8-bytes granularity */
660 	desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
661 	desc.len8 = (u16)(packetlen_aligned >> 3);
662 	desc.trans_id = requestid;
663 
664 	bufferlist[0].iov_base = &desc;
665 	bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
666 	bufferlist[1].iov_base = buffer;
667 	bufferlist[1].iov_len = bufferlen;
668 	bufferlist[2].iov_base = &aligned_data;
669 	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
670 
671 	return hv_ringbuffer_write(channel, bufferlist, num_vecs);
672 }
673 EXPORT_SYMBOL(vmbus_sendpacket_ctl);
674 
675 /**
676  * vmbus_sendpacket() - Send the specified buffer on the given channel
677  * @channel: Pointer to vmbus_channel structure.
678  * @buffer: Pointer to the buffer you want to receive the data into.
679  * @bufferlen: Maximum size of what the the buffer will hold
680  * @requestid: Identifier of the request
681  * @type: Type of packet that is being send e.g. negotiate, time
682  * packet etc.
683  *
684  * Sends data in @buffer directly to hyper-v via the vmbus
685  * This will send the data unparsed to hyper-v.
686  *
687  * Mainly used by Hyper-V drivers.
688  */
689 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
690 			   u32 bufferlen, u64 requestid,
691 			   enum vmbus_packet_type type, u32 flags)
692 {
693 	return vmbus_sendpacket_ctl(channel, buffer, bufferlen, requestid,
694 				    type, flags);
695 }
696 EXPORT_SYMBOL(vmbus_sendpacket);
697 
698 /*
699  * vmbus_sendpacket_pagebuffer_ctl - Send a range of single-page buffer
700  * packets using a GPADL Direct packet type. This interface allows you
701  * to control notifying the host. This will be useful for sending
702  * batched data. Also the sender can control the send flags
703  * explicitly.
704  */
705 int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
706 				    struct hv_page_buffer pagebuffers[],
707 				    u32 pagecount, void *buffer, u32 bufferlen,
708 				    u64 requestid, u32 flags)
709 {
710 	int i;
711 	struct vmbus_channel_packet_page_buffer desc;
712 	u32 descsize;
713 	u32 packetlen;
714 	u32 packetlen_aligned;
715 	struct kvec bufferlist[3];
716 	u64 aligned_data = 0;
717 
718 	if (pagecount > MAX_PAGE_BUFFER_COUNT)
719 		return -EINVAL;
720 
721 	/*
722 	 * Adjust the size down since vmbus_channel_packet_page_buffer is the
723 	 * largest size we support
724 	 */
725 	descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
726 			  ((MAX_PAGE_BUFFER_COUNT - pagecount) *
727 			  sizeof(struct hv_page_buffer));
728 	packetlen = descsize + bufferlen;
729 	packetlen_aligned = ALIGN(packetlen, sizeof(u64));
730 
731 	/* Setup the descriptor */
732 	desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
733 	desc.flags = flags;
734 	desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
735 	desc.length8 = (u16)(packetlen_aligned >> 3);
736 	desc.transactionid = requestid;
737 	desc.rangecount = pagecount;
738 
739 	for (i = 0; i < pagecount; i++) {
740 		desc.range[i].len = pagebuffers[i].len;
741 		desc.range[i].offset = pagebuffers[i].offset;
742 		desc.range[i].pfn	 = pagebuffers[i].pfn;
743 	}
744 
745 	bufferlist[0].iov_base = &desc;
746 	bufferlist[0].iov_len = descsize;
747 	bufferlist[1].iov_base = buffer;
748 	bufferlist[1].iov_len = bufferlen;
749 	bufferlist[2].iov_base = &aligned_data;
750 	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
751 
752 	return hv_ringbuffer_write(channel, bufferlist, 3);
753 }
754 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer_ctl);
755 
756 /*
757  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
758  * packets using a GPADL Direct packet type.
759  */
760 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
761 				     struct hv_page_buffer pagebuffers[],
762 				     u32 pagecount, void *buffer, u32 bufferlen,
763 				     u64 requestid)
764 {
765 	u32 flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
766 
767 	return vmbus_sendpacket_pagebuffer_ctl(channel, pagebuffers, pagecount,
768 					       buffer, bufferlen,
769 					       requestid, flags);
770 
771 }
772 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
773 
774 /*
775  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
776  * using a GPADL Direct packet type.
777  * The buffer includes the vmbus descriptor.
778  */
779 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
780 			      struct vmbus_packet_mpb_array *desc,
781 			      u32 desc_size,
782 			      void *buffer, u32 bufferlen, u64 requestid)
783 {
784 	u32 packetlen;
785 	u32 packetlen_aligned;
786 	struct kvec bufferlist[3];
787 	u64 aligned_data = 0;
788 
789 	packetlen = desc_size + bufferlen;
790 	packetlen_aligned = ALIGN(packetlen, sizeof(u64));
791 
792 	/* Setup the descriptor */
793 	desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
794 	desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
795 	desc->dataoffset8 = desc_size >> 3; /* in 8-bytes granularity */
796 	desc->length8 = (u16)(packetlen_aligned >> 3);
797 	desc->transactionid = requestid;
798 	desc->rangecount = 1;
799 
800 	bufferlist[0].iov_base = desc;
801 	bufferlist[0].iov_len = desc_size;
802 	bufferlist[1].iov_base = buffer;
803 	bufferlist[1].iov_len = bufferlen;
804 	bufferlist[2].iov_base = &aligned_data;
805 	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
806 
807 	return hv_ringbuffer_write(channel, bufferlist, 3);
808 }
809 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
810 
811 /*
812  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
813  * using a GPADL Direct packet type.
814  */
815 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
816 				struct hv_multipage_buffer *multi_pagebuffer,
817 				void *buffer, u32 bufferlen, u64 requestid)
818 {
819 	struct vmbus_channel_packet_multipage_buffer desc;
820 	u32 descsize;
821 	u32 packetlen;
822 	u32 packetlen_aligned;
823 	struct kvec bufferlist[3];
824 	u64 aligned_data = 0;
825 	u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
826 					 multi_pagebuffer->len);
827 
828 	if (pfncount > MAX_MULTIPAGE_BUFFER_COUNT)
829 		return -EINVAL;
830 
831 	/*
832 	 * Adjust the size down since vmbus_channel_packet_multipage_buffer is
833 	 * the largest size we support
834 	 */
835 	descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) -
836 			  ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
837 			  sizeof(u64));
838 	packetlen = descsize + bufferlen;
839 	packetlen_aligned = ALIGN(packetlen, sizeof(u64));
840 
841 
842 	/* Setup the descriptor */
843 	desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
844 	desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
845 	desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
846 	desc.length8 = (u16)(packetlen_aligned >> 3);
847 	desc.transactionid = requestid;
848 	desc.rangecount = 1;
849 
850 	desc.range.len = multi_pagebuffer->len;
851 	desc.range.offset = multi_pagebuffer->offset;
852 
853 	memcpy(desc.range.pfn_array, multi_pagebuffer->pfn_array,
854 	       pfncount * sizeof(u64));
855 
856 	bufferlist[0].iov_base = &desc;
857 	bufferlist[0].iov_len = descsize;
858 	bufferlist[1].iov_base = buffer;
859 	bufferlist[1].iov_len = bufferlen;
860 	bufferlist[2].iov_base = &aligned_data;
861 	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
862 
863 	return hv_ringbuffer_write(channel, bufferlist, 3);
864 }
865 EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
866 
867 /**
868  * vmbus_recvpacket() - Retrieve the user packet on the specified channel
869  * @channel: Pointer to vmbus_channel structure.
870  * @buffer: Pointer to the buffer you want to receive the data into.
871  * @bufferlen: Maximum size of what the the buffer will hold
872  * @buffer_actual_len: The actual size of the data after it was received
873  * @requestid: Identifier of the request
874  *
875  * Receives directly from the hyper-v vmbus and puts the data it received
876  * into Buffer. This will receive the data unparsed from hyper-v.
877  *
878  * Mainly used by Hyper-V drivers.
879  */
880 static inline int
881 __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
882 		   u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
883 		   bool raw)
884 {
885 	return hv_ringbuffer_read(channel, buffer, bufferlen,
886 				  buffer_actual_len, requestid, raw);
887 
888 }
889 
890 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
891 		     u32 bufferlen, u32 *buffer_actual_len,
892 		     u64 *requestid)
893 {
894 	return __vmbus_recvpacket(channel, buffer, bufferlen,
895 				  buffer_actual_len, requestid, false);
896 }
897 EXPORT_SYMBOL(vmbus_recvpacket);
898 
899 /*
900  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
901  */
902 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
903 			      u32 bufferlen, u32 *buffer_actual_len,
904 			      u64 *requestid)
905 {
906 	return __vmbus_recvpacket(channel, buffer, bufferlen,
907 				  buffer_actual_len, requestid, true);
908 }
909 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
910