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