xref: /linux/drivers/hv/channel.c (revision 3a07362fab1653d3aca31a9155c8cc776138fd02)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2009, Microsoft Corporation.
4  *
5  * Authors:
6  *   Haiyang Zhang <haiyangz@microsoft.com>
7  *   Hank Janssen  <hjanssen@microsoft.com>
8  */
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/kernel.h>
12 #include <linux/sched.h>
13 #include <linux/wait.h>
14 #include <linux/mm.h>
15 #include <linux/slab.h>
16 #include <linux/module.h>
17 #include <linux/hyperv.h>
18 #include <linux/uio.h>
19 #include <linux/interrupt.h>
20 #include <linux/set_memory.h>
21 #include <asm/page.h>
22 #include <asm/mshyperv.h>
23 
24 #include "hyperv_vmbus.h"
25 
26 /*
27  * hv_gpadl_size - Return the real size of a gpadl, the size that Hyper-V uses
28  *
29  * For BUFFER gpadl, Hyper-V uses the exact same size as the guest does.
30  *
31  * For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the header
32  * (because of the alignment requirement), however, the hypervisor only
33  * uses the first HV_HYP_PAGE_SIZE as the header, therefore leaving a
34  * (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap. And since there are two rings in a
35  * ringbuffer, the total size for a RING gpadl that Hyper-V uses is the
36  * total size that the guest uses minus twice of the gap size.
37  */
hv_gpadl_size(enum hv_gpadl_type type,u32 size)38 static inline u32 hv_gpadl_size(enum hv_gpadl_type type, u32 size)
39 {
40 	switch (type) {
41 	case HV_GPADL_BUFFER:
42 		return size;
43 	case HV_GPADL_RING:
44 		/* The size of a ringbuffer must be page-aligned */
45 		BUG_ON(size % PAGE_SIZE);
46 		/*
47 		 * Two things to notice here:
48 		 * 1) We're processing two ring buffers as a unit
49 		 * 2) We're skipping any space larger than HV_HYP_PAGE_SIZE in
50 		 * the first guest-size page of each of the two ring buffers.
51 		 * So we effectively subtract out two guest-size pages, and add
52 		 * back two Hyper-V size pages.
53 		 */
54 		return size - 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE);
55 	}
56 	BUG();
57 	return 0;
58 }
59 
60 /*
61  * hv_ring_gpadl_send_hvpgoffset - Calculate the send offset (in unit of
62  *                                 HV_HYP_PAGE) in a ring gpadl based on the
63  *                                 offset in the guest
64  *
65  * @offset: the offset (in bytes) where the send ringbuffer starts in the
66  *               virtual address space of the guest
67  */
hv_ring_gpadl_send_hvpgoffset(u32 offset)68 static inline u32 hv_ring_gpadl_send_hvpgoffset(u32 offset)
69 {
70 
71 	/*
72 	 * For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the
73 	 * header (because of the alignment requirement), however, the
74 	 * hypervisor only uses the first HV_HYP_PAGE_SIZE as the header,
75 	 * therefore leaving a (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap.
76 	 *
77 	 * And to calculate the effective send offset in gpadl, we need to
78 	 * substract this gap.
79 	 */
80 	return (offset - (PAGE_SIZE - HV_HYP_PAGE_SIZE)) >> HV_HYP_PAGE_SHIFT;
81 }
82 
83 /*
84  * hv_gpadl_hvpfn - Return the Hyper-V page PFN of the @i th Hyper-V page in
85  *                  the gpadl
86  *
87  * @type: the type of the gpadl
88  * @kbuffer: the pointer to the gpadl in the guest
89  * @size: the total size (in bytes) of the gpadl
90  * @send_offset: the offset (in bytes) where the send ringbuffer starts in the
91  *               virtual address space of the guest
92  * @i: the index
93  */
hv_gpadl_hvpfn(enum hv_gpadl_type type,void * kbuffer,u32 size,u32 send_offset,int i)94 static inline u64 hv_gpadl_hvpfn(enum hv_gpadl_type type, void *kbuffer,
95 				 u32 size, u32 send_offset, int i)
96 {
97 	int send_idx = hv_ring_gpadl_send_hvpgoffset(send_offset);
98 	unsigned long delta = 0UL;
99 
100 	switch (type) {
101 	case HV_GPADL_BUFFER:
102 		break;
103 	case HV_GPADL_RING:
104 		if (i == 0)
105 			delta = 0;
106 		else if (i <= send_idx)
107 			delta = PAGE_SIZE - HV_HYP_PAGE_SIZE;
108 		else
109 			delta = 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE);
110 		break;
111 	default:
112 		BUG();
113 		break;
114 	}
115 
116 	return virt_to_hvpfn(kbuffer + delta + (HV_HYP_PAGE_SIZE * i));
117 }
118 
119 /*
120  * vmbus_setevent- Trigger an event notification on the specified
121  * channel.
122  */
vmbus_setevent(struct vmbus_channel * channel)123 void vmbus_setevent(struct vmbus_channel *channel)
124 {
125 	struct hv_monitor_page *monitorpage;
126 
127 	trace_vmbus_setevent(channel);
128 
129 	/*
130 	 * For channels marked as in "low latency" mode
131 	 * bypass the monitor page mechanism.
132 	 */
133 	if (channel->offermsg.monitor_allocated && !channel->low_latency) {
134 		vmbus_send_interrupt(channel->offermsg.child_relid);
135 
136 		/* Get the child to parent monitor page */
137 		monitorpage = vmbus_connection.monitor_pages[1];
138 
139 		sync_set_bit(channel->monitor_bit,
140 			(unsigned long *)&monitorpage->trigger_group
141 					[channel->monitor_grp].pending);
142 
143 	} else {
144 		vmbus_set_event(channel);
145 	}
146 }
147 EXPORT_SYMBOL_GPL(vmbus_setevent);
148 
149 /* vmbus_free_ring - drop mapping of ring buffer */
vmbus_free_ring(struct vmbus_channel * channel)150 void vmbus_free_ring(struct vmbus_channel *channel)
151 {
152 	hv_ringbuffer_cleanup(&channel->outbound);
153 	hv_ringbuffer_cleanup(&channel->inbound);
154 
155 	if (channel->ringbuffer_page) {
156 		/* In a CoCo VM leak the memory if it didn't get re-encrypted */
157 		if (!channel->ringbuffer_gpadlhandle.decrypted)
158 			__free_pages(channel->ringbuffer_page,
159 			     get_order(channel->ringbuffer_pagecount
160 				       << PAGE_SHIFT));
161 		channel->ringbuffer_page = NULL;
162 	}
163 }
164 EXPORT_SYMBOL_GPL(vmbus_free_ring);
165 
166 /* vmbus_alloc_ring - allocate and map pages for ring buffer */
vmbus_alloc_ring(struct vmbus_channel * newchannel,u32 send_size,u32 recv_size)167 int vmbus_alloc_ring(struct vmbus_channel *newchannel,
168 		     u32 send_size, u32 recv_size)
169 {
170 	struct page *page;
171 	int order;
172 
173 	if (send_size % PAGE_SIZE || recv_size % PAGE_SIZE)
174 		return -EINVAL;
175 
176 	/* Allocate the ring buffer */
177 	order = get_order(send_size + recv_size);
178 	page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
179 				GFP_KERNEL|__GFP_ZERO, order);
180 
181 	if (!page)
182 		page = alloc_pages(GFP_KERNEL|__GFP_ZERO, order);
183 
184 	if (!page)
185 		return -ENOMEM;
186 
187 	newchannel->ringbuffer_page = page;
188 	newchannel->ringbuffer_pagecount = (send_size + recv_size) >> PAGE_SHIFT;
189 	newchannel->ringbuffer_send_offset = send_size >> PAGE_SHIFT;
190 
191 	return 0;
192 }
193 EXPORT_SYMBOL_GPL(vmbus_alloc_ring);
194 
195 /* Used for Hyper-V Socket: a guest client's connect() to the host */
vmbus_send_tl_connect_request(const guid_t * shv_guest_servie_id,const guid_t * shv_host_servie_id)196 int vmbus_send_tl_connect_request(const guid_t *shv_guest_servie_id,
197 				  const guid_t *shv_host_servie_id)
198 {
199 	struct vmbus_channel_tl_connect_request conn_msg;
200 	int ret;
201 
202 	memset(&conn_msg, 0, sizeof(conn_msg));
203 	conn_msg.header.msgtype = CHANNELMSG_TL_CONNECT_REQUEST;
204 	conn_msg.guest_endpoint_id = *shv_guest_servie_id;
205 	conn_msg.host_service_id = *shv_host_servie_id;
206 
207 	ret = vmbus_post_msg(&conn_msg, sizeof(conn_msg), true);
208 
209 	trace_vmbus_send_tl_connect_request(&conn_msg, ret);
210 
211 	return ret;
212 }
213 EXPORT_SYMBOL_GPL(vmbus_send_tl_connect_request);
214 
send_modifychannel_without_ack(struct vmbus_channel * channel,u32 target_vp)215 static int send_modifychannel_without_ack(struct vmbus_channel *channel, u32 target_vp)
216 {
217 	struct vmbus_channel_modifychannel msg;
218 	int ret;
219 
220 	memset(&msg, 0, sizeof(msg));
221 	msg.header.msgtype = CHANNELMSG_MODIFYCHANNEL;
222 	msg.child_relid = channel->offermsg.child_relid;
223 	msg.target_vp = target_vp;
224 
225 	ret = vmbus_post_msg(&msg, sizeof(msg), true);
226 	trace_vmbus_send_modifychannel(&msg, ret);
227 
228 	return ret;
229 }
230 
send_modifychannel_with_ack(struct vmbus_channel * channel,u32 target_vp)231 static int send_modifychannel_with_ack(struct vmbus_channel *channel, u32 target_vp)
232 {
233 	struct vmbus_channel_modifychannel *msg;
234 	struct vmbus_channel_msginfo *info;
235 	unsigned long flags;
236 	int ret;
237 
238 	info = kzalloc(sizeof(struct vmbus_channel_msginfo) +
239 				sizeof(struct vmbus_channel_modifychannel),
240 		       GFP_KERNEL);
241 	if (!info)
242 		return -ENOMEM;
243 
244 	init_completion(&info->waitevent);
245 	info->waiting_channel = channel;
246 
247 	msg = (struct vmbus_channel_modifychannel *)info->msg;
248 	msg->header.msgtype = CHANNELMSG_MODIFYCHANNEL;
249 	msg->child_relid = channel->offermsg.child_relid;
250 	msg->target_vp = target_vp;
251 
252 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
253 	list_add_tail(&info->msglistentry, &vmbus_connection.chn_msg_list);
254 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
255 
256 	ret = vmbus_post_msg(msg, sizeof(*msg), true);
257 	trace_vmbus_send_modifychannel(msg, ret);
258 	if (ret != 0) {
259 		spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
260 		list_del(&info->msglistentry);
261 		spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
262 		goto free_info;
263 	}
264 
265 	/*
266 	 * Release channel_mutex; otherwise, vmbus_onoffer_rescind() could block on
267 	 * the mutex and be unable to signal the completion.
268 	 *
269 	 * See the caller target_cpu_store() for information about the usage of the
270 	 * mutex.
271 	 */
272 	mutex_unlock(&vmbus_connection.channel_mutex);
273 	wait_for_completion(&info->waitevent);
274 	mutex_lock(&vmbus_connection.channel_mutex);
275 
276 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
277 	list_del(&info->msglistentry);
278 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
279 
280 	if (info->response.modify_response.status)
281 		ret = -EAGAIN;
282 
283 free_info:
284 	kfree(info);
285 	return ret;
286 }
287 
288 /*
289  * Set/change the vCPU (@target_vp) the channel (@child_relid) will interrupt.
290  *
291  * CHANNELMSG_MODIFYCHANNEL messages are aynchronous.  When VMbus version 5.3
292  * or later is negotiated, Hyper-V always sends an ACK in response to such a
293  * message.  For VMbus version 5.2 and earlier, it never sends an ACK.  With-
294  * out an ACK, we can not know when the host will stop interrupting the "old"
295  * vCPU and start interrupting the "new" vCPU for the given channel.
296  *
297  * The CHANNELMSG_MODIFYCHANNEL message type is supported since VMBus version
298  * VERSION_WIN10_V4_1.
299  */
vmbus_send_modifychannel(struct vmbus_channel * channel,u32 target_vp)300 int vmbus_send_modifychannel(struct vmbus_channel *channel, u32 target_vp)
301 {
302 	if (vmbus_proto_version >= VERSION_WIN10_V5_3)
303 		return send_modifychannel_with_ack(channel, target_vp);
304 	return send_modifychannel_without_ack(channel, target_vp);
305 }
306 EXPORT_SYMBOL_GPL(vmbus_send_modifychannel);
307 
308 /*
309  * create_gpadl_header - Creates a gpadl for the specified buffer
310  */
create_gpadl_header(enum hv_gpadl_type type,void * kbuffer,u32 size,u32 send_offset,struct vmbus_channel_msginfo ** msginfo)311 static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
312 			       u32 size, u32 send_offset,
313 			       struct vmbus_channel_msginfo **msginfo)
314 {
315 	int i;
316 	int pagecount;
317 	struct vmbus_channel_gpadl_header *gpadl_header;
318 	struct vmbus_channel_gpadl_body *gpadl_body;
319 	struct vmbus_channel_msginfo *msgheader;
320 	struct vmbus_channel_msginfo *msgbody = NULL;
321 	u32 msgsize;
322 
323 	int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
324 
325 	pagecount = hv_gpadl_size(type, size) >> HV_HYP_PAGE_SHIFT;
326 
327 	pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
328 		  sizeof(struct vmbus_channel_gpadl_header) -
329 		  sizeof(struct gpa_range);
330 	pfncount = umin(pagecount, pfnsize / sizeof(u64));
331 
332 	msgsize = sizeof(struct vmbus_channel_msginfo) +
333 		  sizeof(struct vmbus_channel_gpadl_header) +
334 		  sizeof(struct gpa_range) + pfncount * sizeof(u64);
335 	msgheader =  kzalloc(msgsize, GFP_KERNEL);
336 	if (!msgheader)
337 		return -ENOMEM;
338 
339 	INIT_LIST_HEAD(&msgheader->submsglist);
340 	msgheader->msgsize = msgsize;
341 
342 	gpadl_header = (struct vmbus_channel_gpadl_header *)
343 		msgheader->msg;
344 	gpadl_header->rangecount = 1;
345 	gpadl_header->range_buflen = sizeof(struct gpa_range) +
346 				 pagecount * sizeof(u64);
347 	gpadl_header->range[0].byte_offset = 0;
348 	gpadl_header->range[0].byte_count = hv_gpadl_size(type, size);
349 	for (i = 0; i < pfncount; i++)
350 		gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn(
351 			type, kbuffer, size, send_offset, i);
352 	*msginfo = msgheader;
353 
354 	pfnsum = pfncount;
355 	pfnleft = pagecount - pfncount;
356 
357 	/* how many pfns can we fit in a body message */
358 	pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
359 		  sizeof(struct vmbus_channel_gpadl_body);
360 	pfncount = pfnsize / sizeof(u64);
361 
362 	/*
363 	 * If pfnleft is zero, everything fits in the header and no body
364 	 * messages are needed
365 	 */
366 	while (pfnleft) {
367 		pfncurr = umin(pfncount, pfnleft);
368 		msgsize = sizeof(struct vmbus_channel_msginfo) +
369 			  sizeof(struct vmbus_channel_gpadl_body) +
370 			  pfncurr * sizeof(u64);
371 		msgbody = kzalloc(msgsize, GFP_KERNEL);
372 
373 		if (!msgbody) {
374 			struct vmbus_channel_msginfo *pos = NULL;
375 			struct vmbus_channel_msginfo *tmp = NULL;
376 			/*
377 			 * Free up all the allocated messages.
378 			 */
379 			list_for_each_entry_safe(pos, tmp,
380 				&msgheader->submsglist,
381 				msglistentry) {
382 
383 				list_del(&pos->msglistentry);
384 				kfree(pos);
385 			}
386 			kfree(msgheader);
387 			return -ENOMEM;
388 		}
389 
390 		msgbody->msgsize = msgsize;
391 		gpadl_body = (struct vmbus_channel_gpadl_body *)msgbody->msg;
392 
393 		/*
394 		 * Gpadl is u32 and we are using a pointer which could
395 		 * be 64-bit
396 		 * This is governed by the guest/host protocol and
397 		 * so the hypervisor guarantees that this is ok.
398 		 */
399 		for (i = 0; i < pfncurr; i++)
400 			gpadl_body->pfn[i] = hv_gpadl_hvpfn(type,
401 				kbuffer, size, send_offset, pfnsum + i);
402 
403 		/* add to msg header */
404 		list_add_tail(&msgbody->msglistentry, &msgheader->submsglist);
405 		pfnsum += pfncurr;
406 		pfnleft -= pfncurr;
407 	}
408 
409 	return 0;
410 }
411 
412 /*
413  * __vmbus_establish_gpadl - Establish a GPADL for a buffer or ringbuffer
414  *
415  * @channel: a channel
416  * @type: the type of the corresponding GPADL, only meaningful for the guest.
417  * @kbuffer: from kmalloc or vmalloc
418  * @size: page-size multiple
419  * @send_offset: the offset (in bytes) where the send ring buffer starts,
420  *              should be 0 for BUFFER type gpadl
421  * @gpadl_handle: some funky thing
422  */
__vmbus_establish_gpadl(struct vmbus_channel * channel,enum hv_gpadl_type type,void * kbuffer,u32 size,u32 send_offset,struct vmbus_gpadl * gpadl)423 static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
424 				   enum hv_gpadl_type type, void *kbuffer,
425 				   u32 size, u32 send_offset,
426 				   struct vmbus_gpadl *gpadl)
427 {
428 	struct vmbus_channel_gpadl_header *gpadlmsg;
429 	struct vmbus_channel_gpadl_body *gpadl_body;
430 	struct vmbus_channel_msginfo *msginfo = NULL;
431 	struct vmbus_channel_msginfo *submsginfo, *tmp;
432 	struct list_head *curr;
433 	u32 next_gpadl_handle;
434 	unsigned long flags;
435 	int ret = 0;
436 
437 	next_gpadl_handle =
438 		(atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
439 
440 	ret = create_gpadl_header(type, kbuffer, size, send_offset, &msginfo);
441 	if (ret) {
442 		gpadl->decrypted = false;
443 		return ret;
444 	}
445 
446 	/*
447 	 * Set the "decrypted" flag to true for the set_memory_decrypted()
448 	 * success case. In the failure case, the encryption state of the
449 	 * memory is unknown. Leave "decrypted" as true to ensure the
450 	 * memory will be leaked instead of going back on the free list.
451 	 */
452 	gpadl->decrypted = true;
453 	ret = set_memory_decrypted((unsigned long)kbuffer,
454 				   PFN_UP(size));
455 	if (ret) {
456 		dev_warn(&channel->device_obj->device,
457 			 "Failed to set host visibility for new GPADL %d.\n",
458 			 ret);
459 		return ret;
460 	}
461 
462 	init_completion(&msginfo->waitevent);
463 	msginfo->waiting_channel = channel;
464 
465 	gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
466 	gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
467 	gpadlmsg->child_relid = channel->offermsg.child_relid;
468 	gpadlmsg->gpadl = next_gpadl_handle;
469 
470 
471 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
472 	list_add_tail(&msginfo->msglistentry,
473 		      &vmbus_connection.chn_msg_list);
474 
475 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
476 
477 	if (channel->rescind) {
478 		ret = -ENODEV;
479 		goto cleanup;
480 	}
481 
482 	ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
483 			     sizeof(*msginfo), true);
484 
485 	trace_vmbus_establish_gpadl_header(gpadlmsg, ret);
486 
487 	if (ret != 0)
488 		goto cleanup;
489 
490 	list_for_each(curr, &msginfo->submsglist) {
491 		submsginfo = (struct vmbus_channel_msginfo *)curr;
492 		gpadl_body =
493 			(struct vmbus_channel_gpadl_body *)submsginfo->msg;
494 
495 		gpadl_body->header.msgtype =
496 			CHANNELMSG_GPADL_BODY;
497 		gpadl_body->gpadl = next_gpadl_handle;
498 
499 		ret = vmbus_post_msg(gpadl_body,
500 				     submsginfo->msgsize - sizeof(*submsginfo),
501 				     true);
502 
503 		trace_vmbus_establish_gpadl_body(gpadl_body, ret);
504 
505 		if (ret != 0)
506 			goto cleanup;
507 
508 	}
509 	wait_for_completion(&msginfo->waitevent);
510 
511 	if (msginfo->response.gpadl_created.creation_status != 0) {
512 		pr_err("Failed to establish GPADL: err = 0x%x\n",
513 		       msginfo->response.gpadl_created.creation_status);
514 
515 		ret = -EDQUOT;
516 		goto cleanup;
517 	}
518 
519 	if (channel->rescind) {
520 		ret = -ENODEV;
521 		goto cleanup;
522 	}
523 
524 	/* At this point, we received the gpadl created msg */
525 	gpadl->gpadl_handle = gpadlmsg->gpadl;
526 	gpadl->buffer = kbuffer;
527 	gpadl->size = size;
528 
529 
530 cleanup:
531 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
532 	list_del(&msginfo->msglistentry);
533 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
534 	list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
535 				 msglistentry) {
536 		kfree(submsginfo);
537 	}
538 
539 	kfree(msginfo);
540 
541 	if (ret) {
542 		/*
543 		 * If set_memory_encrypted() fails, the decrypted flag is
544 		 * left as true so the memory is leaked instead of being
545 		 * put back on the free list.
546 		 */
547 		if (!set_memory_encrypted((unsigned long)kbuffer, PFN_UP(size)))
548 			gpadl->decrypted = false;
549 	}
550 
551 	return ret;
552 }
553 
554 /*
555  * vmbus_establish_gpadl - Establish a GPADL for the specified buffer
556  *
557  * @channel: a channel
558  * @kbuffer: from kmalloc or vmalloc
559  * @size: page-size multiple
560  * @gpadl_handle: some funky thing
561  */
vmbus_establish_gpadl(struct vmbus_channel * channel,void * kbuffer,u32 size,struct vmbus_gpadl * gpadl)562 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
563 			  u32 size, struct vmbus_gpadl *gpadl)
564 {
565 	return __vmbus_establish_gpadl(channel, HV_GPADL_BUFFER, kbuffer, size,
566 				       0U, gpadl);
567 }
568 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
569 
570 /**
571  * request_arr_init - Allocates memory for the requestor array. Each slot
572  * keeps track of the next available slot in the array. Initially, each
573  * slot points to the next one (as in a Linked List). The last slot
574  * does not point to anything, so its value is U64_MAX by default.
575  * @size The size of the array
576  */
request_arr_init(u32 size)577 static u64 *request_arr_init(u32 size)
578 {
579 	int i;
580 	u64 *req_arr;
581 
582 	req_arr = kcalloc(size, sizeof(u64), GFP_KERNEL);
583 	if (!req_arr)
584 		return NULL;
585 
586 	for (i = 0; i < size - 1; i++)
587 		req_arr[i] = i + 1;
588 
589 	/* Last slot (no more available slots) */
590 	req_arr[i] = U64_MAX;
591 
592 	return req_arr;
593 }
594 
595 /*
596  * vmbus_alloc_requestor - Initializes @rqstor's fields.
597  * Index 0 is the first free slot
598  * @size: Size of the requestor array
599  */
vmbus_alloc_requestor(struct vmbus_requestor * rqstor,u32 size)600 static int vmbus_alloc_requestor(struct vmbus_requestor *rqstor, u32 size)
601 {
602 	u64 *rqst_arr;
603 	unsigned long *bitmap;
604 
605 	rqst_arr = request_arr_init(size);
606 	if (!rqst_arr)
607 		return -ENOMEM;
608 
609 	bitmap = bitmap_zalloc(size, GFP_KERNEL);
610 	if (!bitmap) {
611 		kfree(rqst_arr);
612 		return -ENOMEM;
613 	}
614 
615 	rqstor->req_arr = rqst_arr;
616 	rqstor->req_bitmap = bitmap;
617 	rqstor->size = size;
618 	rqstor->next_request_id = 0;
619 	spin_lock_init(&rqstor->req_lock);
620 
621 	return 0;
622 }
623 
624 /*
625  * vmbus_free_requestor - Frees memory allocated for @rqstor
626  * @rqstor: Pointer to the requestor struct
627  */
vmbus_free_requestor(struct vmbus_requestor * rqstor)628 static void vmbus_free_requestor(struct vmbus_requestor *rqstor)
629 {
630 	kfree(rqstor->req_arr);
631 	bitmap_free(rqstor->req_bitmap);
632 }
633 
__vmbus_open(struct vmbus_channel * newchannel,void * userdata,u32 userdatalen,void (* onchannelcallback)(void * context),void * context)634 static int __vmbus_open(struct vmbus_channel *newchannel,
635 		       void *userdata, u32 userdatalen,
636 		       void (*onchannelcallback)(void *context), void *context)
637 {
638 	struct vmbus_channel_open_channel *open_msg;
639 	struct vmbus_channel_msginfo *open_info = NULL;
640 	struct page *page = newchannel->ringbuffer_page;
641 	u32 send_pages, recv_pages;
642 	unsigned long flags;
643 	int err;
644 
645 	if (userdatalen > MAX_USER_DEFINED_BYTES)
646 		return -EINVAL;
647 
648 	send_pages = newchannel->ringbuffer_send_offset;
649 	recv_pages = newchannel->ringbuffer_pagecount - send_pages;
650 
651 	if (newchannel->state != CHANNEL_OPEN_STATE)
652 		return -EINVAL;
653 
654 	/* Create and init requestor */
655 	if (newchannel->rqstor_size) {
656 		if (vmbus_alloc_requestor(&newchannel->requestor, newchannel->rqstor_size))
657 			return -ENOMEM;
658 	}
659 
660 	newchannel->state = CHANNEL_OPENING_STATE;
661 	newchannel->onchannel_callback = onchannelcallback;
662 	newchannel->channel_callback_context = context;
663 
664 	if (!newchannel->max_pkt_size)
665 		newchannel->max_pkt_size = VMBUS_DEFAULT_MAX_PKT_SIZE;
666 
667 	/* Establish the gpadl for the ring buffer */
668 	newchannel->ringbuffer_gpadlhandle.gpadl_handle = 0;
669 
670 	err = __vmbus_establish_gpadl(newchannel, HV_GPADL_RING,
671 				      page_address(newchannel->ringbuffer_page),
672 				      (send_pages + recv_pages) << PAGE_SHIFT,
673 				      newchannel->ringbuffer_send_offset << PAGE_SHIFT,
674 				      &newchannel->ringbuffer_gpadlhandle);
675 	if (err)
676 		goto error_clean_ring;
677 
678 	err = hv_ringbuffer_init(&newchannel->outbound,
679 				 page, send_pages, 0);
680 	if (err)
681 		goto error_free_gpadl;
682 
683 	err = hv_ringbuffer_init(&newchannel->inbound, &page[send_pages],
684 				 recv_pages, newchannel->max_pkt_size);
685 	if (err)
686 		goto error_free_gpadl;
687 
688 	/* Create and init the channel open message */
689 	open_info = kzalloc(sizeof(*open_info) +
690 			   sizeof(struct vmbus_channel_open_channel),
691 			   GFP_KERNEL);
692 	if (!open_info) {
693 		err = -ENOMEM;
694 		goto error_free_gpadl;
695 	}
696 
697 	init_completion(&open_info->waitevent);
698 	open_info->waiting_channel = newchannel;
699 
700 	open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
701 	open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
702 	open_msg->openid = newchannel->offermsg.child_relid;
703 	open_msg->child_relid = newchannel->offermsg.child_relid;
704 	open_msg->ringbuffer_gpadlhandle
705 		= newchannel->ringbuffer_gpadlhandle.gpadl_handle;
706 	/*
707 	 * The unit of ->downstream_ringbuffer_pageoffset is HV_HYP_PAGE and
708 	 * the unit of ->ringbuffer_send_offset (i.e. send_pages) is PAGE, so
709 	 * here we calculate it into HV_HYP_PAGE.
710 	 */
711 	open_msg->downstream_ringbuffer_pageoffset =
712 		hv_ring_gpadl_send_hvpgoffset(send_pages << PAGE_SHIFT);
713 	open_msg->target_vp = hv_cpu_number_to_vp_number(newchannel->target_cpu);
714 
715 	if (userdatalen)
716 		memcpy(open_msg->userdata, userdata, userdatalen);
717 
718 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
719 	list_add_tail(&open_info->msglistentry,
720 		      &vmbus_connection.chn_msg_list);
721 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
722 
723 	if (newchannel->rescind) {
724 		err = -ENODEV;
725 		goto error_clean_msglist;
726 	}
727 
728 	err = vmbus_post_msg(open_msg,
729 			     sizeof(struct vmbus_channel_open_channel), true);
730 
731 	trace_vmbus_open(open_msg, err);
732 
733 	if (err != 0)
734 		goto error_clean_msglist;
735 
736 	wait_for_completion(&open_info->waitevent);
737 
738 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
739 	list_del(&open_info->msglistentry);
740 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
741 
742 	if (newchannel->rescind) {
743 		err = -ENODEV;
744 		goto error_free_info;
745 	}
746 
747 	if (open_info->response.open_result.status) {
748 		err = -EAGAIN;
749 		goto error_free_info;
750 	}
751 
752 	newchannel->state = CHANNEL_OPENED_STATE;
753 	kfree(open_info);
754 	return 0;
755 
756 error_clean_msglist:
757 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
758 	list_del(&open_info->msglistentry);
759 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
760 error_free_info:
761 	kfree(open_info);
762 error_free_gpadl:
763 	vmbus_teardown_gpadl(newchannel, &newchannel->ringbuffer_gpadlhandle);
764 error_clean_ring:
765 	hv_ringbuffer_cleanup(&newchannel->outbound);
766 	hv_ringbuffer_cleanup(&newchannel->inbound);
767 	vmbus_free_requestor(&newchannel->requestor);
768 	newchannel->state = CHANNEL_OPEN_STATE;
769 	return err;
770 }
771 
772 /*
773  * vmbus_connect_ring - Open the channel but reuse ring buffer
774  */
vmbus_connect_ring(struct vmbus_channel * newchannel,void (* onchannelcallback)(void * context),void * context)775 int vmbus_connect_ring(struct vmbus_channel *newchannel,
776 		       void (*onchannelcallback)(void *context), void *context)
777 {
778 	return  __vmbus_open(newchannel, NULL, 0, onchannelcallback, context);
779 }
780 EXPORT_SYMBOL_GPL(vmbus_connect_ring);
781 
782 /*
783  * vmbus_open - Open the specified channel.
784  */
vmbus_open(struct vmbus_channel * newchannel,u32 send_ringbuffer_size,u32 recv_ringbuffer_size,void * userdata,u32 userdatalen,void (* onchannelcallback)(void * context),void * context)785 int vmbus_open(struct vmbus_channel *newchannel,
786 	       u32 send_ringbuffer_size, u32 recv_ringbuffer_size,
787 	       void *userdata, u32 userdatalen,
788 	       void (*onchannelcallback)(void *context), void *context)
789 {
790 	int err;
791 
792 	err = vmbus_alloc_ring(newchannel, send_ringbuffer_size,
793 			       recv_ringbuffer_size);
794 	if (err)
795 		return err;
796 
797 	err = __vmbus_open(newchannel, userdata, userdatalen,
798 			   onchannelcallback, context);
799 	if (err)
800 		vmbus_free_ring(newchannel);
801 
802 	return err;
803 }
804 EXPORT_SYMBOL_GPL(vmbus_open);
805 
806 /*
807  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
808  */
vmbus_teardown_gpadl(struct vmbus_channel * channel,struct vmbus_gpadl * gpadl)809 int vmbus_teardown_gpadl(struct vmbus_channel *channel, struct vmbus_gpadl *gpadl)
810 {
811 	struct vmbus_channel_gpadl_teardown *msg;
812 	struct vmbus_channel_msginfo *info;
813 	unsigned long flags;
814 	int ret;
815 
816 	info = kzalloc(sizeof(*info) +
817 		       sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
818 	if (!info)
819 		return -ENOMEM;
820 
821 	init_completion(&info->waitevent);
822 	info->waiting_channel = channel;
823 
824 	msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
825 
826 	msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
827 	msg->child_relid = channel->offermsg.child_relid;
828 	msg->gpadl = gpadl->gpadl_handle;
829 
830 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
831 	list_add_tail(&info->msglistentry,
832 		      &vmbus_connection.chn_msg_list);
833 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
834 
835 	if (channel->rescind)
836 		goto post_msg_err;
837 
838 	ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown),
839 			     true);
840 
841 	trace_vmbus_teardown_gpadl(msg, ret);
842 
843 	if (ret)
844 		goto post_msg_err;
845 
846 	wait_for_completion(&info->waitevent);
847 
848 	gpadl->gpadl_handle = 0;
849 
850 post_msg_err:
851 	/*
852 	 * If the channel has been rescinded;
853 	 * we will be awakened by the rescind
854 	 * handler; set the error code to zero so we don't leak memory.
855 	 */
856 	if (channel->rescind)
857 		ret = 0;
858 
859 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
860 	list_del(&info->msglistentry);
861 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
862 
863 	kfree(info);
864 
865 	ret = set_memory_encrypted((unsigned long)gpadl->buffer,
866 				   PFN_UP(gpadl->size));
867 	if (ret)
868 		pr_warn("Fail to set mem host visibility in GPADL teardown %d.\n", ret);
869 
870 	gpadl->decrypted = ret;
871 
872 	return ret;
873 }
874 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
875 
vmbus_reset_channel_cb(struct vmbus_channel * channel)876 void vmbus_reset_channel_cb(struct vmbus_channel *channel)
877 {
878 	unsigned long flags;
879 
880 	/*
881 	 * vmbus_on_event(), running in the per-channel tasklet, can race
882 	 * with vmbus_close_internal() in the case of SMP guest, e.g., when
883 	 * the former is accessing channel->inbound.ring_buffer, the latter
884 	 * could be freeing the ring_buffer pages, so here we must stop it
885 	 * first.
886 	 *
887 	 * vmbus_chan_sched() might call the netvsc driver callback function
888 	 * that ends up scheduling NAPI work that accesses the ring buffer.
889 	 * At this point, we have to ensure that any such work is completed
890 	 * and that the channel ring buffer is no longer being accessed, cf.
891 	 * the calls to napi_disable() in netvsc_device_remove().
892 	 */
893 	tasklet_disable(&channel->callback_event);
894 
895 	/* See the inline comments in vmbus_chan_sched(). */
896 	spin_lock_irqsave(&channel->sched_lock, flags);
897 	channel->onchannel_callback = NULL;
898 	spin_unlock_irqrestore(&channel->sched_lock, flags);
899 
900 	channel->sc_creation_callback = NULL;
901 
902 	/* Re-enable tasklet for use on re-open */
903 	tasklet_enable(&channel->callback_event);
904 }
905 
vmbus_close_internal(struct vmbus_channel * channel)906 static int vmbus_close_internal(struct vmbus_channel *channel)
907 {
908 	struct vmbus_channel_close_channel *msg;
909 	int ret;
910 
911 	vmbus_reset_channel_cb(channel);
912 
913 	/*
914 	 * In case a device driver's probe() fails (e.g.,
915 	 * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
916 	 * rescinded later (e.g., we dynamically disable an Integrated Service
917 	 * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
918 	 * here we should skip most of the below cleanup work.
919 	 */
920 	if (channel->state != CHANNEL_OPENED_STATE)
921 		return -EINVAL;
922 
923 	channel->state = CHANNEL_OPEN_STATE;
924 
925 	/* Send a closing message */
926 
927 	msg = &channel->close_msg.msg;
928 
929 	msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
930 	msg->child_relid = channel->offermsg.child_relid;
931 
932 	ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel),
933 			     true);
934 
935 	trace_vmbus_close_internal(msg, ret);
936 
937 	if (ret) {
938 		pr_err("Close failed: close post msg return is %d\n", ret);
939 		/*
940 		 * If we failed to post the close msg,
941 		 * it is perhaps better to leak memory.
942 		 */
943 	}
944 
945 	/* Tear down the gpadl for the channel's ring buffer */
946 	else if (channel->ringbuffer_gpadlhandle.gpadl_handle) {
947 		ret = vmbus_teardown_gpadl(channel, &channel->ringbuffer_gpadlhandle);
948 		if (ret) {
949 			pr_err("Close failed: teardown gpadl return %d\n", ret);
950 			/*
951 			 * If we failed to teardown gpadl,
952 			 * it is perhaps better to leak memory.
953 			 */
954 		}
955 	}
956 
957 	if (!ret)
958 		vmbus_free_requestor(&channel->requestor);
959 
960 	return ret;
961 }
962 
963 /* disconnect ring - close all channels */
vmbus_disconnect_ring(struct vmbus_channel * channel)964 int vmbus_disconnect_ring(struct vmbus_channel *channel)
965 {
966 	struct vmbus_channel *cur_channel, *tmp;
967 	int ret;
968 
969 	if (channel->primary_channel != NULL)
970 		return -EINVAL;
971 
972 	list_for_each_entry_safe(cur_channel, tmp, &channel->sc_list, sc_list) {
973 		if (cur_channel->rescind)
974 			wait_for_completion(&cur_channel->rescind_event);
975 
976 		mutex_lock(&vmbus_connection.channel_mutex);
977 		if (vmbus_close_internal(cur_channel) == 0) {
978 			vmbus_free_ring(cur_channel);
979 
980 			if (cur_channel->rescind)
981 				hv_process_channel_removal(cur_channel);
982 		}
983 		mutex_unlock(&vmbus_connection.channel_mutex);
984 	}
985 
986 	/*
987 	 * Now close the primary.
988 	 */
989 	mutex_lock(&vmbus_connection.channel_mutex);
990 	ret = vmbus_close_internal(channel);
991 	mutex_unlock(&vmbus_connection.channel_mutex);
992 
993 	return ret;
994 }
995 EXPORT_SYMBOL_GPL(vmbus_disconnect_ring);
996 
997 /*
998  * vmbus_close - Close the specified channel
999  */
vmbus_close(struct vmbus_channel * channel)1000 void vmbus_close(struct vmbus_channel *channel)
1001 {
1002 	if (vmbus_disconnect_ring(channel) == 0)
1003 		vmbus_free_ring(channel);
1004 }
1005 EXPORT_SYMBOL_GPL(vmbus_close);
1006 
1007 /**
1008  * vmbus_sendpacket_getid() - Send the specified buffer on the given channel
1009  * @channel: Pointer to vmbus_channel structure
1010  * @buffer: Pointer to the buffer you want to send the data from.
1011  * @bufferlen: Maximum size of what the buffer holds.
1012  * @requestid: Identifier of the request
1013  * @trans_id: Identifier of the transaction associated to this request, if
1014  *            the send is successful; undefined, otherwise.
1015  * @type: Type of packet that is being sent e.g. negotiate, time
1016  *	  packet etc.
1017  * @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
1018  *
1019  * Sends data in @buffer directly to Hyper-V via the vmbus.
1020  * This will send the data unparsed to Hyper-V.
1021  *
1022  * Mainly used by Hyper-V drivers.
1023  */
vmbus_sendpacket_getid(struct vmbus_channel * channel,void * buffer,u32 bufferlen,u64 requestid,u64 * trans_id,enum vmbus_packet_type type,u32 flags)1024 int vmbus_sendpacket_getid(struct vmbus_channel *channel, void *buffer,
1025 			   u32 bufferlen, u64 requestid, u64 *trans_id,
1026 			   enum vmbus_packet_type type, u32 flags)
1027 {
1028 	struct vmpacket_descriptor desc;
1029 	u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
1030 	u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
1031 	struct kvec bufferlist[3];
1032 	u64 aligned_data = 0;
1033 	int num_vecs = ((bufferlen != 0) ? 3 : 1);
1034 
1035 
1036 	/* Setup the descriptor */
1037 	desc.type = type; /* VmbusPacketTypeDataInBand; */
1038 	desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
1039 	/* in 8-bytes granularity */
1040 	desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
1041 	desc.len8 = (u16)(packetlen_aligned >> 3);
1042 	desc.trans_id = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
1043 
1044 	bufferlist[0].iov_base = &desc;
1045 	bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
1046 	bufferlist[1].iov_base = buffer;
1047 	bufferlist[1].iov_len = bufferlen;
1048 	bufferlist[2].iov_base = &aligned_data;
1049 	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
1050 
1051 	return hv_ringbuffer_write(channel, bufferlist, num_vecs, requestid, trans_id);
1052 }
1053 EXPORT_SYMBOL(vmbus_sendpacket_getid);
1054 
1055 /**
1056  * vmbus_sendpacket() - Send the specified buffer on the given channel
1057  * @channel: Pointer to vmbus_channel structure
1058  * @buffer: Pointer to the buffer you want to send the data from.
1059  * @bufferlen: Maximum size of what the buffer holds.
1060  * @requestid: Identifier of the request
1061  * @type: Type of packet that is being sent e.g. negotiate, time
1062  *	  packet etc.
1063  * @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
1064  *
1065  * Sends data in @buffer directly to Hyper-V via the vmbus.
1066  * This will send the data unparsed to Hyper-V.
1067  *
1068  * Mainly used by Hyper-V drivers.
1069  */
vmbus_sendpacket(struct vmbus_channel * channel,void * buffer,u32 bufferlen,u64 requestid,enum vmbus_packet_type type,u32 flags)1070 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
1071 		     u32 bufferlen, u64 requestid,
1072 		     enum vmbus_packet_type type, u32 flags)
1073 {
1074 	return vmbus_sendpacket_getid(channel, buffer, bufferlen,
1075 				      requestid, NULL, type, flags);
1076 }
1077 EXPORT_SYMBOL(vmbus_sendpacket);
1078 
1079 /*
1080  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
1081  * packets using a GPADL Direct packet type. This interface allows you
1082  * to control notifying the host. This will be useful for sending
1083  * batched data. Also the sender can control the send flags
1084  * explicitly.
1085  */
vmbus_sendpacket_pagebuffer(struct vmbus_channel * channel,struct hv_page_buffer pagebuffers[],u32 pagecount,void * buffer,u32 bufferlen,u64 requestid)1086 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
1087 				struct hv_page_buffer pagebuffers[],
1088 				u32 pagecount, void *buffer, u32 bufferlen,
1089 				u64 requestid)
1090 {
1091 	int i;
1092 	struct vmbus_channel_packet_page_buffer desc;
1093 	u32 descsize;
1094 	u32 packetlen;
1095 	u32 packetlen_aligned;
1096 	struct kvec bufferlist[3];
1097 	u64 aligned_data = 0;
1098 
1099 	if (pagecount > MAX_PAGE_BUFFER_COUNT)
1100 		return -EINVAL;
1101 
1102 	/*
1103 	 * Adjust the size down since vmbus_channel_packet_page_buffer is the
1104 	 * largest size we support
1105 	 */
1106 	descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
1107 			  ((MAX_PAGE_BUFFER_COUNT - pagecount) *
1108 			  sizeof(struct hv_page_buffer));
1109 	packetlen = descsize + bufferlen;
1110 	packetlen_aligned = ALIGN(packetlen, sizeof(u64));
1111 
1112 	/* Setup the descriptor */
1113 	desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
1114 	desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
1115 	desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
1116 	desc.length8 = (u16)(packetlen_aligned >> 3);
1117 	desc.transactionid = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
1118 	desc.reserved = 0;
1119 	desc.rangecount = pagecount;
1120 
1121 	for (i = 0; i < pagecount; i++) {
1122 		desc.range[i].len = pagebuffers[i].len;
1123 		desc.range[i].offset = pagebuffers[i].offset;
1124 		desc.range[i].pfn	 = pagebuffers[i].pfn;
1125 	}
1126 
1127 	bufferlist[0].iov_base = &desc;
1128 	bufferlist[0].iov_len = descsize;
1129 	bufferlist[1].iov_base = buffer;
1130 	bufferlist[1].iov_len = bufferlen;
1131 	bufferlist[2].iov_base = &aligned_data;
1132 	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
1133 
1134 	return hv_ringbuffer_write(channel, bufferlist, 3, requestid, NULL);
1135 }
1136 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
1137 
1138 /*
1139  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
1140  * using a GPADL Direct packet type.
1141  * The buffer includes the vmbus descriptor.
1142  */
vmbus_sendpacket_mpb_desc(struct vmbus_channel * channel,struct vmbus_packet_mpb_array * desc,u32 desc_size,void * buffer,u32 bufferlen,u64 requestid)1143 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
1144 			      struct vmbus_packet_mpb_array *desc,
1145 			      u32 desc_size,
1146 			      void *buffer, u32 bufferlen, u64 requestid)
1147 {
1148 	u32 packetlen;
1149 	u32 packetlen_aligned;
1150 	struct kvec bufferlist[3];
1151 	u64 aligned_data = 0;
1152 
1153 	packetlen = desc_size + bufferlen;
1154 	packetlen_aligned = ALIGN(packetlen, sizeof(u64));
1155 
1156 	/* Setup the descriptor */
1157 	desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
1158 	desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
1159 	desc->dataoffset8 = desc_size >> 3; /* in 8-bytes granularity */
1160 	desc->length8 = (u16)(packetlen_aligned >> 3);
1161 	desc->transactionid = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
1162 	desc->reserved = 0;
1163 	desc->rangecount = 1;
1164 
1165 	bufferlist[0].iov_base = desc;
1166 	bufferlist[0].iov_len = desc_size;
1167 	bufferlist[1].iov_base = buffer;
1168 	bufferlist[1].iov_len = bufferlen;
1169 	bufferlist[2].iov_base = &aligned_data;
1170 	bufferlist[2].iov_len = (packetlen_aligned - packetlen);
1171 
1172 	return hv_ringbuffer_write(channel, bufferlist, 3, requestid, NULL);
1173 }
1174 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
1175 
1176 /**
1177  * __vmbus_recvpacket() - Retrieve the user packet on the specified channel
1178  * @channel: Pointer to vmbus_channel structure
1179  * @buffer: Pointer to the buffer you want to receive the data into.
1180  * @bufferlen: Maximum size of what the buffer can hold.
1181  * @buffer_actual_len: The actual size of the data after it was received.
1182  * @requestid: Identifier of the request
1183  * @raw: true means keep the vmpacket_descriptor header in the received data.
1184  *
1185  * Receives directly from the hyper-v vmbus and puts the data it received
1186  * into Buffer. This will receive the data unparsed from hyper-v.
1187  *
1188  * Mainly used by Hyper-V drivers.
1189  */
1190 static inline int
__vmbus_recvpacket(struct vmbus_channel * channel,void * buffer,u32 bufferlen,u32 * buffer_actual_len,u64 * requestid,bool raw)1191 __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
1192 		   u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
1193 		   bool raw)
1194 {
1195 	return hv_ringbuffer_read(channel, buffer, bufferlen,
1196 				  buffer_actual_len, requestid, raw);
1197 
1198 }
1199 
vmbus_recvpacket(struct vmbus_channel * channel,void * buffer,u32 bufferlen,u32 * buffer_actual_len,u64 * requestid)1200 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
1201 		     u32 bufferlen, u32 *buffer_actual_len,
1202 		     u64 *requestid)
1203 {
1204 	return __vmbus_recvpacket(channel, buffer, bufferlen,
1205 				  buffer_actual_len, requestid, false);
1206 }
1207 EXPORT_SYMBOL(vmbus_recvpacket);
1208 
1209 /*
1210  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
1211  */
vmbus_recvpacket_raw(struct vmbus_channel * channel,void * buffer,u32 bufferlen,u32 * buffer_actual_len,u64 * requestid)1212 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
1213 			      u32 bufferlen, u32 *buffer_actual_len,
1214 			      u64 *requestid)
1215 {
1216 	return __vmbus_recvpacket(channel, buffer, bufferlen,
1217 				  buffer_actual_len, requestid, true);
1218 }
1219 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
1220 
1221 /*
1222  * vmbus_next_request_id - Returns a new request id. It is also
1223  * the index at which the guest memory address is stored.
1224  * Uses a spin lock to avoid race conditions.
1225  * @channel: Pointer to the VMbus channel struct
1226  * @rqst_add: Guest memory address to be stored in the array
1227  */
vmbus_next_request_id(struct vmbus_channel * channel,u64 rqst_addr)1228 u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
1229 {
1230 	struct vmbus_requestor *rqstor = &channel->requestor;
1231 	unsigned long flags;
1232 	u64 current_id;
1233 
1234 	/* Check rqstor has been initialized */
1235 	if (!channel->rqstor_size)
1236 		return VMBUS_NO_RQSTOR;
1237 
1238 	lock_requestor(channel, flags);
1239 	current_id = rqstor->next_request_id;
1240 
1241 	/* Requestor array is full */
1242 	if (current_id >= rqstor->size) {
1243 		unlock_requestor(channel, flags);
1244 		return VMBUS_RQST_ERROR;
1245 	}
1246 
1247 	rqstor->next_request_id = rqstor->req_arr[current_id];
1248 	rqstor->req_arr[current_id] = rqst_addr;
1249 
1250 	/* The already held spin lock provides atomicity */
1251 	bitmap_set(rqstor->req_bitmap, current_id, 1);
1252 
1253 	unlock_requestor(channel, flags);
1254 
1255 	/*
1256 	 * Cannot return an ID of 0, which is reserved for an unsolicited
1257 	 * message from Hyper-V; Hyper-V does not acknowledge (respond to)
1258 	 * VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED requests with ID of
1259 	 * 0 sent by the guest.
1260 	 */
1261 	return current_id + 1;
1262 }
1263 EXPORT_SYMBOL_GPL(vmbus_next_request_id);
1264 
1265 /* As in vmbus_request_addr_match() but without the requestor lock */
__vmbus_request_addr_match(struct vmbus_channel * channel,u64 trans_id,u64 rqst_addr)1266 u64 __vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id,
1267 			       u64 rqst_addr)
1268 {
1269 	struct vmbus_requestor *rqstor = &channel->requestor;
1270 	u64 req_addr;
1271 
1272 	/* Check rqstor has been initialized */
1273 	if (!channel->rqstor_size)
1274 		return VMBUS_NO_RQSTOR;
1275 
1276 	/* Hyper-V can send an unsolicited message with ID of 0 */
1277 	if (!trans_id)
1278 		return VMBUS_RQST_ERROR;
1279 
1280 	/* Data corresponding to trans_id is stored at trans_id - 1 */
1281 	trans_id--;
1282 
1283 	/* Invalid trans_id */
1284 	if (trans_id >= rqstor->size || !test_bit(trans_id, rqstor->req_bitmap))
1285 		return VMBUS_RQST_ERROR;
1286 
1287 	req_addr = rqstor->req_arr[trans_id];
1288 	if (rqst_addr == VMBUS_RQST_ADDR_ANY || req_addr == rqst_addr) {
1289 		rqstor->req_arr[trans_id] = rqstor->next_request_id;
1290 		rqstor->next_request_id = trans_id;
1291 
1292 		/* The already held spin lock provides atomicity */
1293 		bitmap_clear(rqstor->req_bitmap, trans_id, 1);
1294 	}
1295 
1296 	return req_addr;
1297 }
1298 EXPORT_SYMBOL_GPL(__vmbus_request_addr_match);
1299 
1300 /*
1301  * vmbus_request_addr_match - Clears/removes @trans_id from the @channel's
1302  * requestor, provided the memory address stored at @trans_id equals @rqst_addr
1303  * (or provided @rqst_addr matches the sentinel value VMBUS_RQST_ADDR_ANY).
1304  *
1305  * Returns the memory address stored at @trans_id, or VMBUS_RQST_ERROR if
1306  * @trans_id is not contained in the requestor.
1307  *
1308  * Acquires and releases the requestor spin lock.
1309  */
vmbus_request_addr_match(struct vmbus_channel * channel,u64 trans_id,u64 rqst_addr)1310 u64 vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id,
1311 			     u64 rqst_addr)
1312 {
1313 	unsigned long flags;
1314 	u64 req_addr;
1315 
1316 	lock_requestor(channel, flags);
1317 	req_addr = __vmbus_request_addr_match(channel, trans_id, rqst_addr);
1318 	unlock_requestor(channel, flags);
1319 
1320 	return req_addr;
1321 }
1322 EXPORT_SYMBOL_GPL(vmbus_request_addr_match);
1323 
1324 /*
1325  * vmbus_request_addr - Returns the memory address stored at @trans_id
1326  * in @rqstor. Uses a spin lock to avoid race conditions.
1327  * @channel: Pointer to the VMbus channel struct
1328  * @trans_id: Request id sent back from Hyper-V. Becomes the requestor's
1329  * next request id.
1330  */
vmbus_request_addr(struct vmbus_channel * channel,u64 trans_id)1331 u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id)
1332 {
1333 	return vmbus_request_addr_match(channel, trans_id, VMBUS_RQST_ADDR_ANY);
1334 }
1335 EXPORT_SYMBOL_GPL(vmbus_request_addr);
1336