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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 /* do we need a gpadl body msg */
326 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
327 sizeof(struct vmbus_channel_gpadl_header) -
328 sizeof(struct gpa_range);
329 pfncount = pfnsize / sizeof(u64);
330
331 if (pagecount > pfncount) {
332 /* we need a gpadl body */
333 /* fill in the header */
334 msgsize = sizeof(struct vmbus_channel_msginfo) +
335 sizeof(struct vmbus_channel_gpadl_header) +
336 sizeof(struct gpa_range) + pfncount * sizeof(u64);
337 msgheader = kzalloc(msgsize, GFP_KERNEL);
338 if (!msgheader)
339 goto nomem;
340
341 INIT_LIST_HEAD(&msgheader->submsglist);
342 msgheader->msgsize = msgsize;
343
344 gpadl_header = (struct vmbus_channel_gpadl_header *)
345 msgheader->msg;
346 gpadl_header->rangecount = 1;
347 gpadl_header->range_buflen = sizeof(struct gpa_range) +
348 pagecount * sizeof(u64);
349 gpadl_header->range[0].byte_offset = 0;
350 gpadl_header->range[0].byte_count = hv_gpadl_size(type, size);
351 for (i = 0; i < pfncount; i++)
352 gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn(
353 type, kbuffer, size, send_offset, i);
354 *msginfo = msgheader;
355
356 pfnsum = pfncount;
357 pfnleft = pagecount - pfncount;
358
359 /* how many pfns can we fit */
360 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
361 sizeof(struct vmbus_channel_gpadl_body);
362 pfncount = pfnsize / sizeof(u64);
363
364 /* fill in the body */
365 while (pfnleft) {
366 if (pfnleft > pfncount)
367 pfncurr = pfncount;
368 else
369 pfncurr = pfnleft;
370
371 msgsize = sizeof(struct vmbus_channel_msginfo) +
372 sizeof(struct vmbus_channel_gpadl_body) +
373 pfncurr * sizeof(u64);
374 msgbody = kzalloc(msgsize, GFP_KERNEL);
375
376 if (!msgbody) {
377 struct vmbus_channel_msginfo *pos = NULL;
378 struct vmbus_channel_msginfo *tmp = NULL;
379 /*
380 * Free up all the allocated messages.
381 */
382 list_for_each_entry_safe(pos, tmp,
383 &msgheader->submsglist,
384 msglistentry) {
385
386 list_del(&pos->msglistentry);
387 kfree(pos);
388 }
389
390 goto nomem;
391 }
392
393 msgbody->msgsize = msgsize;
394 gpadl_body =
395 (struct vmbus_channel_gpadl_body *)msgbody->msg;
396
397 /*
398 * Gpadl is u32 and we are using a pointer which could
399 * be 64-bit
400 * This is governed by the guest/host protocol and
401 * so the hypervisor guarantees that this is ok.
402 */
403 for (i = 0; i < pfncurr; i++)
404 gpadl_body->pfn[i] = hv_gpadl_hvpfn(type,
405 kbuffer, size, send_offset, pfnsum + i);
406
407 /* add to msg header */
408 list_add_tail(&msgbody->msglistentry,
409 &msgheader->submsglist);
410 pfnsum += pfncurr;
411 pfnleft -= pfncurr;
412 }
413 } else {
414 /* everything fits in a header */
415 msgsize = sizeof(struct vmbus_channel_msginfo) +
416 sizeof(struct vmbus_channel_gpadl_header) +
417 sizeof(struct gpa_range) + pagecount * sizeof(u64);
418 msgheader = kzalloc(msgsize, GFP_KERNEL);
419 if (msgheader == NULL)
420 goto nomem;
421
422 INIT_LIST_HEAD(&msgheader->submsglist);
423 msgheader->msgsize = msgsize;
424
425 gpadl_header = (struct vmbus_channel_gpadl_header *)
426 msgheader->msg;
427 gpadl_header->rangecount = 1;
428 gpadl_header->range_buflen = sizeof(struct gpa_range) +
429 pagecount * sizeof(u64);
430 gpadl_header->range[0].byte_offset = 0;
431 gpadl_header->range[0].byte_count = hv_gpadl_size(type, size);
432 for (i = 0; i < pagecount; i++)
433 gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn(
434 type, kbuffer, size, send_offset, i);
435
436 *msginfo = msgheader;
437 }
438
439 return 0;
440nomem:
441 kfree(msgheader);
442 kfree(msgbody);
443 return -ENOMEM;
444}
445
446/*
447 * __vmbus_establish_gpadl - Establish a GPADL for a buffer or ringbuffer
448 *
449 * @channel: a channel
450 * @type: the type of the corresponding GPADL, only meaningful for the guest.
451 * @kbuffer: from kmalloc or vmalloc
452 * @size: page-size multiple
453 * @send_offset: the offset (in bytes) where the send ring buffer starts,
454 * should be 0 for BUFFER type gpadl
455 * @gpadl_handle: some funky thing
456 */
457static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
458 enum hv_gpadl_type type, void *kbuffer,
459 u32 size, u32 send_offset,
460 struct vmbus_gpadl *gpadl)
461{
462 struct vmbus_channel_gpadl_header *gpadlmsg;
463 struct vmbus_channel_gpadl_body *gpadl_body;
464 struct vmbus_channel_msginfo *msginfo = NULL;
465 struct vmbus_channel_msginfo *submsginfo, *tmp;
466 struct list_head *curr;
467 u32 next_gpadl_handle;
468 unsigned long flags;
469 int ret = 0;
470
471 next_gpadl_handle =
472 (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
473
474 ret = create_gpadl_header(type, kbuffer, size, send_offset, &msginfo);
475 if (ret)
476 return ret;
477
478 ret = set_memory_decrypted((unsigned long)kbuffer,
479 PFN_UP(size));
480 if (ret) {
481 dev_warn(&channel->device_obj->device,
482 "Failed to set host visibility for new GPADL %d.\n",
483 ret);
484 return ret;
485 }
486
487 init_completion(&msginfo->waitevent);
488 msginfo->waiting_channel = channel;
489
490 gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
491 gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
492 gpadlmsg->child_relid = channel->offermsg.child_relid;
493 gpadlmsg->gpadl = next_gpadl_handle;
494
495
496 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
497 list_add_tail(&msginfo->msglistentry,
498 &vmbus_connection.chn_msg_list);
499
500 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
501
502 if (channel->rescind) {
503 ret = -ENODEV;
504 goto cleanup;
505 }
506
507 ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
508 sizeof(*msginfo), true);
509
510 trace_vmbus_establish_gpadl_header(gpadlmsg, ret);
511
512 if (ret != 0)
513 goto cleanup;
514
515 list_for_each(curr, &msginfo->submsglist) {
516 submsginfo = (struct vmbus_channel_msginfo *)curr;
517 gpadl_body =
518 (struct vmbus_channel_gpadl_body *)submsginfo->msg;
519
520 gpadl_body->header.msgtype =
521 CHANNELMSG_GPADL_BODY;
522 gpadl_body->gpadl = next_gpadl_handle;
523
524 ret = vmbus_post_msg(gpadl_body,
525 submsginfo->msgsize - sizeof(*submsginfo),
526 true);
527
528 trace_vmbus_establish_gpadl_body(gpadl_body, ret);
529
530 if (ret != 0)
531 goto cleanup;
532
533 }
534 wait_for_completion(&msginfo->waitevent);
535
536 if (msginfo->response.gpadl_created.creation_status != 0) {
537 pr_err("Failed to establish GPADL: err = 0x%x\n",
538 msginfo->response.gpadl_created.creation_status);
539
540 ret = -EDQUOT;
541 goto cleanup;
542 }
543
544 if (channel->rescind) {
545 ret = -ENODEV;
546 goto cleanup;
547 }
548
549 /* At this point, we received the gpadl created msg */
550 gpadl->gpadl_handle = gpadlmsg->gpadl;
551 gpadl->buffer = kbuffer;
552 gpadl->size = size;
553
554
555cleanup:
556 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
557 list_del(&msginfo->msglistentry);
558 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
559 list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
560 msglistentry) {
561 kfree(submsginfo);
562 }
563
564 kfree(msginfo);
565
566 if (ret)
567 set_memory_encrypted((unsigned long)kbuffer,
568 PFN_UP(size));
569
570 return ret;
571}
572
573/*
574 * vmbus_establish_gpadl - Establish a GPADL for the specified buffer
575 *
576 * @channel: a channel
577 * @kbuffer: from kmalloc or vmalloc
578 * @size: page-size multiple
579 * @gpadl_handle: some funky thing
580 */
581int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
582 u32 size, struct vmbus_gpadl *gpadl)
583{
584 return __vmbus_establish_gpadl(channel, HV_GPADL_BUFFER, kbuffer, size,
585 0U, gpadl);
586}
587EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
588
589/**
590 * request_arr_init - Allocates memory for the requestor array. Each slot
591 * keeps track of the next available slot in the array. Initially, each
592 * slot points to the next one (as in a Linked List). The last slot
593 * does not point to anything, so its value is U64_MAX by default.
594 * @size The size of the array
595 */
596static u64 *request_arr_init(u32 size)
597{
598 int i;
599 u64 *req_arr;
600
601 req_arr = kcalloc(size, sizeof(u64), GFP_KERNEL);
602 if (!req_arr)
603 return NULL;
604
605 for (i = 0; i < size - 1; i++)
606 req_arr[i] = i + 1;
607
608 /* Last slot (no more available slots) */
609 req_arr[i] = U64_MAX;
610
611 return req_arr;
612}
613
614/*
615 * vmbus_alloc_requestor - Initializes @rqstor's fields.
616 * Index 0 is the first free slot
617 * @size: Size of the requestor array
618 */
619static int vmbus_alloc_requestor(struct vmbus_requestor *rqstor, u32 size)
620{
621 u64 *rqst_arr;
622 unsigned long *bitmap;
623
624 rqst_arr = request_arr_init(size);
625 if (!rqst_arr)
626 return -ENOMEM;
627
628 bitmap = bitmap_zalloc(size, GFP_KERNEL);
629 if (!bitmap) {
630 kfree(rqst_arr);
631 return -ENOMEM;
632 }
633
634 rqstor->req_arr = rqst_arr;
635 rqstor->req_bitmap = bitmap;
636 rqstor->size = size;
637 rqstor->next_request_id = 0;
638 spin_lock_init(&rqstor->req_lock);
639
640 return 0;
641}
642
643/*
644 * vmbus_free_requestor - Frees memory allocated for @rqstor
645 * @rqstor: Pointer to the requestor struct
646 */
647static void vmbus_free_requestor(struct vmbus_requestor *rqstor)
648{
649 kfree(rqstor->req_arr);
650 bitmap_free(rqstor->req_bitmap);
651}
652
653static int __vmbus_open(struct vmbus_channel *newchannel,
654 void *userdata, u32 userdatalen,
655 void (*onchannelcallback)(void *context), void *context)
656{
657 struct vmbus_channel_open_channel *open_msg;
658 struct vmbus_channel_msginfo *open_info = NULL;
659 struct page *page = newchannel->ringbuffer_page;
660 u32 send_pages, recv_pages;
661 unsigned long flags;
662 int err;
663
664 if (userdatalen > MAX_USER_DEFINED_BYTES)
665 return -EINVAL;
666
667 send_pages = newchannel->ringbuffer_send_offset;
668 recv_pages = newchannel->ringbuffer_pagecount - send_pages;
669
670 if (newchannel->state != CHANNEL_OPEN_STATE)
671 return -EINVAL;
672
673 /* Create and init requestor */
674 if (newchannel->rqstor_size) {
675 if (vmbus_alloc_requestor(&newchannel->requestor, newchannel->rqstor_size))
676 return -ENOMEM;
677 }
678
679 newchannel->state = CHANNEL_OPENING_STATE;
680 newchannel->onchannel_callback = onchannelcallback;
681 newchannel->channel_callback_context = context;
682
683 if (!newchannel->max_pkt_size)
684 newchannel->max_pkt_size = VMBUS_DEFAULT_MAX_PKT_SIZE;
685
686 /* Establish the gpadl for the ring buffer */
687 newchannel->ringbuffer_gpadlhandle.gpadl_handle = 0;
688
689 err = __vmbus_establish_gpadl(newchannel, HV_GPADL_RING,
690 page_address(newchannel->ringbuffer_page),
691 (send_pages + recv_pages) << PAGE_SHIFT,
692 newchannel->ringbuffer_send_offset << PAGE_SHIFT,
693 &newchannel->ringbuffer_gpadlhandle);
694 if (err)
695 goto error_clean_ring;
696
697 err = hv_ringbuffer_init(&newchannel->outbound,
698 page, send_pages, 0);
699 if (err)
700 goto error_free_gpadl;
701
702 err = hv_ringbuffer_init(&newchannel->inbound, &page[send_pages],
703 recv_pages, newchannel->max_pkt_size);
704 if (err)
705 goto error_free_gpadl;
706
707 /* Create and init the channel open message */
708 open_info = kzalloc(sizeof(*open_info) +
709 sizeof(struct vmbus_channel_open_channel),
710 GFP_KERNEL);
711 if (!open_info) {
712 err = -ENOMEM;
713 goto error_free_gpadl;
714 }
715
716 init_completion(&open_info->waitevent);
717 open_info->waiting_channel = newchannel;
718
719 open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
720 open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
721 open_msg->openid = newchannel->offermsg.child_relid;
722 open_msg->child_relid = newchannel->offermsg.child_relid;
723 open_msg->ringbuffer_gpadlhandle
724 = newchannel->ringbuffer_gpadlhandle.gpadl_handle;
725 /*
726 * The unit of ->downstream_ringbuffer_pageoffset is HV_HYP_PAGE and
727 * the unit of ->ringbuffer_send_offset (i.e. send_pages) is PAGE, so
728 * here we calculate it into HV_HYP_PAGE.
729 */
730 open_msg->downstream_ringbuffer_pageoffset =
731 hv_ring_gpadl_send_hvpgoffset(send_pages << PAGE_SHIFT);
732 open_msg->target_vp = hv_cpu_number_to_vp_number(newchannel->target_cpu);
733
734 if (userdatalen)
735 memcpy(open_msg->userdata, userdata, userdatalen);
736
737 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
738 list_add_tail(&open_info->msglistentry,
739 &vmbus_connection.chn_msg_list);
740 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
741
742 if (newchannel->rescind) {
743 err = -ENODEV;
744 goto error_clean_msglist;
745 }
746
747 err = vmbus_post_msg(open_msg,
748 sizeof(struct vmbus_channel_open_channel), true);
749
750 trace_vmbus_open(open_msg, err);
751
752 if (err != 0)
753 goto error_clean_msglist;
754
755 wait_for_completion(&open_info->waitevent);
756
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
761 if (newchannel->rescind) {
762 err = -ENODEV;
763 goto error_free_info;
764 }
765
766 if (open_info->response.open_result.status) {
767 err = -EAGAIN;
768 goto error_free_info;
769 }
770
771 newchannel->state = CHANNEL_OPENED_STATE;
772 kfree(open_info);
773 return 0;
774
775error_clean_msglist:
776 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
777 list_del(&open_info->msglistentry);
778 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
779error_free_info:
780 kfree(open_info);
781error_free_gpadl:
782 vmbus_teardown_gpadl(newchannel, &newchannel->ringbuffer_gpadlhandle);
783error_clean_ring:
784 hv_ringbuffer_cleanup(&newchannel->outbound);
785 hv_ringbuffer_cleanup(&newchannel->inbound);
786 vmbus_free_requestor(&newchannel->requestor);
787 newchannel->state = CHANNEL_OPEN_STATE;
788 return err;
789}
790
791/*
792 * vmbus_connect_ring - Open the channel but reuse ring buffer
793 */
794int vmbus_connect_ring(struct vmbus_channel *newchannel,
795 void (*onchannelcallback)(void *context), void *context)
796{
797 return __vmbus_open(newchannel, NULL, 0, onchannelcallback, context);
798}
799EXPORT_SYMBOL_GPL(vmbus_connect_ring);
800
801/*
802 * vmbus_open - Open the specified channel.
803 */
804int vmbus_open(struct vmbus_channel *newchannel,
805 u32 send_ringbuffer_size, u32 recv_ringbuffer_size,
806 void *userdata, u32 userdatalen,
807 void (*onchannelcallback)(void *context), void *context)
808{
809 int err;
810
811 err = vmbus_alloc_ring(newchannel, send_ringbuffer_size,
812 recv_ringbuffer_size);
813 if (err)
814 return err;
815
816 err = __vmbus_open(newchannel, userdata, userdatalen,
817 onchannelcallback, context);
818 if (err)
819 vmbus_free_ring(newchannel);
820
821 return err;
822}
823EXPORT_SYMBOL_GPL(vmbus_open);
824
825/*
826 * vmbus_teardown_gpadl -Teardown the specified GPADL handle
827 */
828int vmbus_teardown_gpadl(struct vmbus_channel *channel, struct vmbus_gpadl *gpadl)
829{
830 struct vmbus_channel_gpadl_teardown *msg;
831 struct vmbus_channel_msginfo *info;
832 unsigned long flags;
833 int ret;
834
835 info = kzalloc(sizeof(*info) +
836 sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
837 if (!info)
838 return -ENOMEM;
839
840 init_completion(&info->waitevent);
841 info->waiting_channel = channel;
842
843 msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
844
845 msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
846 msg->child_relid = channel->offermsg.child_relid;
847 msg->gpadl = gpadl->gpadl_handle;
848
849 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
850 list_add_tail(&info->msglistentry,
851 &vmbus_connection.chn_msg_list);
852 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
853
854 if (channel->rescind)
855 goto post_msg_err;
856
857 ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown),
858 true);
859
860 trace_vmbus_teardown_gpadl(msg, ret);
861
862 if (ret)
863 goto post_msg_err;
864
865 wait_for_completion(&info->waitevent);
866
867 gpadl->gpadl_handle = 0;
868
869post_msg_err:
870 /*
871 * If the channel has been rescinded;
872 * we will be awakened by the rescind
873 * handler; set the error code to zero so we don't leak memory.
874 */
875 if (channel->rescind)
876 ret = 0;
877
878 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
879 list_del(&info->msglistentry);
880 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
881
882 kfree(info);
883
884 ret = set_memory_encrypted((unsigned long)gpadl->buffer,
885 PFN_UP(gpadl->size));
886 if (ret)
887 pr_warn("Fail to set mem host visibility in GPADL teardown %d.\n", ret);
888
889 return ret;
890}
891EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
892
893void vmbus_reset_channel_cb(struct vmbus_channel *channel)
894{
895 unsigned long flags;
896
897 /*
898 * vmbus_on_event(), running in the per-channel tasklet, can race
899 * with vmbus_close_internal() in the case of SMP guest, e.g., when
900 * the former is accessing channel->inbound.ring_buffer, the latter
901 * could be freeing the ring_buffer pages, so here we must stop it
902 * first.
903 *
904 * vmbus_chan_sched() might call the netvsc driver callback function
905 * that ends up scheduling NAPI work that accesses the ring buffer.
906 * At this point, we have to ensure that any such work is completed
907 * and that the channel ring buffer is no longer being accessed, cf.
908 * the calls to napi_disable() in netvsc_device_remove().
909 */
910 tasklet_disable(&channel->callback_event);
911
912 /* See the inline comments in vmbus_chan_sched(). */
913 spin_lock_irqsave(&channel->sched_lock, flags);
914 channel->onchannel_callback = NULL;
915 spin_unlock_irqrestore(&channel->sched_lock, flags);
916
917 channel->sc_creation_callback = NULL;
918
919 /* Re-enable tasklet for use on re-open */
920 tasklet_enable(&channel->callback_event);
921}
922
923static int vmbus_close_internal(struct vmbus_channel *channel)
924{
925 struct vmbus_channel_close_channel *msg;
926 int ret;
927
928 vmbus_reset_channel_cb(channel);
929
930 /*
931 * In case a device driver's probe() fails (e.g.,
932 * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
933 * rescinded later (e.g., we dynamically disable an Integrated Service
934 * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
935 * here we should skip most of the below cleanup work.
936 */
937 if (channel->state != CHANNEL_OPENED_STATE)
938 return -EINVAL;
939
940 channel->state = CHANNEL_OPEN_STATE;
941
942 /* Send a closing message */
943
944 msg = &channel->close_msg.msg;
945
946 msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
947 msg->child_relid = channel->offermsg.child_relid;
948
949 ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel),
950 true);
951
952 trace_vmbus_close_internal(msg, ret);
953
954 if (ret) {
955 pr_err("Close failed: close post msg return is %d\n", ret);
956 /*
957 * If we failed to post the close msg,
958 * it is perhaps better to leak memory.
959 */
960 }
961
962 /* Tear down the gpadl for the channel's ring buffer */
963 else if (channel->ringbuffer_gpadlhandle.gpadl_handle) {
964 ret = vmbus_teardown_gpadl(channel, &channel->ringbuffer_gpadlhandle);
965 if (ret) {
966 pr_err("Close failed: teardown gpadl return %d\n", ret);
967 /*
968 * If we failed to teardown gpadl,
969 * it is perhaps better to leak memory.
970 */
971 }
972 }
973
974 if (!ret)
975 vmbus_free_requestor(&channel->requestor);
976
977 return ret;
978}
979
980/* disconnect ring - close all channels */
981int vmbus_disconnect_ring(struct vmbus_channel *channel)
982{
983 struct vmbus_channel *cur_channel, *tmp;
984 int ret;
985
986 if (channel->primary_channel != NULL)
987 return -EINVAL;
988
989 list_for_each_entry_safe(cur_channel, tmp, &channel->sc_list, sc_list) {
990 if (cur_channel->rescind)
991 wait_for_completion(&cur_channel->rescind_event);
992
993 mutex_lock(&vmbus_connection.channel_mutex);
994 if (vmbus_close_internal(cur_channel) == 0) {
995 vmbus_free_ring(cur_channel);
996
997 if (cur_channel->rescind)
998 hv_process_channel_removal(cur_channel);
999 }
1000 mutex_unlock(&vmbus_connection.channel_mutex);
1001 }
1002
1003 /*
1004 * Now close the primary.
1005 */
1006 mutex_lock(&vmbus_connection.channel_mutex);
1007 ret = vmbus_close_internal(channel);
1008 mutex_unlock(&vmbus_connection.channel_mutex);
1009
1010 return ret;
1011}
1012EXPORT_SYMBOL_GPL(vmbus_disconnect_ring);
1013
1014/*
1015 * vmbus_close - Close the specified channel
1016 */
1017void vmbus_close(struct vmbus_channel *channel)
1018{
1019 if (vmbus_disconnect_ring(channel) == 0)
1020 vmbus_free_ring(channel);
1021}
1022EXPORT_SYMBOL_GPL(vmbus_close);
1023
1024/**
1025 * vmbus_sendpacket_getid() - Send the specified buffer on the given channel
1026 * @channel: Pointer to vmbus_channel structure
1027 * @buffer: Pointer to the buffer you want to send the data from.
1028 * @bufferlen: Maximum size of what the buffer holds.
1029 * @requestid: Identifier of the request
1030 * @trans_id: Identifier of the transaction associated to this request, if
1031 * the send is successful; undefined, otherwise.
1032 * @type: Type of packet that is being sent e.g. negotiate, time
1033 * packet etc.
1034 * @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
1035 *
1036 * Sends data in @buffer directly to Hyper-V via the vmbus.
1037 * This will send the data unparsed to Hyper-V.
1038 *
1039 * Mainly used by Hyper-V drivers.
1040 */
1041int vmbus_sendpacket_getid(struct vmbus_channel *channel, void *buffer,
1042 u32 bufferlen, u64 requestid, u64 *trans_id,
1043 enum vmbus_packet_type type, u32 flags)
1044{
1045 struct vmpacket_descriptor desc;
1046 u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
1047 u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
1048 struct kvec bufferlist[3];
1049 u64 aligned_data = 0;
1050 int num_vecs = ((bufferlen != 0) ? 3 : 1);
1051
1052
1053 /* Setup the descriptor */
1054 desc.type = type; /* VmbusPacketTypeDataInBand; */
1055 desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
1056 /* in 8-bytes granularity */
1057 desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
1058 desc.len8 = (u16)(packetlen_aligned >> 3);
1059 desc.trans_id = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
1060
1061 bufferlist[0].iov_base = &desc;
1062 bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
1063 bufferlist[1].iov_base = buffer;
1064 bufferlist[1].iov_len = bufferlen;
1065 bufferlist[2].iov_base = &aligned_data;
1066 bufferlist[2].iov_len = (packetlen_aligned - packetlen);
1067
1068 return hv_ringbuffer_write(channel, bufferlist, num_vecs, requestid, trans_id);
1069}
1070EXPORT_SYMBOL(vmbus_sendpacket_getid);
1071
1072/**
1073 * vmbus_sendpacket() - Send the specified buffer on the given channel
1074 * @channel: Pointer to vmbus_channel structure
1075 * @buffer: Pointer to the buffer you want to send the data from.
1076 * @bufferlen: Maximum size of what the buffer holds.
1077 * @requestid: Identifier of the request
1078 * @type: Type of packet that is being sent e.g. negotiate, time
1079 * packet etc.
1080 * @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
1081 *
1082 * Sends data in @buffer directly to Hyper-V via the vmbus.
1083 * This will send the data unparsed to Hyper-V.
1084 *
1085 * Mainly used by Hyper-V drivers.
1086 */
1087int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
1088 u32 bufferlen, u64 requestid,
1089 enum vmbus_packet_type type, u32 flags)
1090{
1091 return vmbus_sendpacket_getid(channel, buffer, bufferlen,
1092 requestid, NULL, type, flags);
1093}
1094EXPORT_SYMBOL(vmbus_sendpacket);
1095
1096/*
1097 * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
1098 * packets using a GPADL Direct packet type. This interface allows you
1099 * to control notifying the host. This will be useful for sending
1100 * batched data. Also the sender can control the send flags
1101 * explicitly.
1102 */
1103int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
1104 struct hv_page_buffer pagebuffers[],
1105 u32 pagecount, void *buffer, u32 bufferlen,
1106 u64 requestid)
1107{
1108 int i;
1109 struct vmbus_channel_packet_page_buffer desc;
1110 u32 descsize;
1111 u32 packetlen;
1112 u32 packetlen_aligned;
1113 struct kvec bufferlist[3];
1114 u64 aligned_data = 0;
1115
1116 if (pagecount > MAX_PAGE_BUFFER_COUNT)
1117 return -EINVAL;
1118
1119 /*
1120 * Adjust the size down since vmbus_channel_packet_page_buffer is the
1121 * largest size we support
1122 */
1123 descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
1124 ((MAX_PAGE_BUFFER_COUNT - pagecount) *
1125 sizeof(struct hv_page_buffer));
1126 packetlen = descsize + bufferlen;
1127 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
1128
1129 /* Setup the descriptor */
1130 desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
1131 desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
1132 desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
1133 desc.length8 = (u16)(packetlen_aligned >> 3);
1134 desc.transactionid = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
1135 desc.reserved = 0;
1136 desc.rangecount = pagecount;
1137
1138 for (i = 0; i < pagecount; i++) {
1139 desc.range[i].len = pagebuffers[i].len;
1140 desc.range[i].offset = pagebuffers[i].offset;
1141 desc.range[i].pfn = pagebuffers[i].pfn;
1142 }
1143
1144 bufferlist[0].iov_base = &desc;
1145 bufferlist[0].iov_len = descsize;
1146 bufferlist[1].iov_base = buffer;
1147 bufferlist[1].iov_len = bufferlen;
1148 bufferlist[2].iov_base = &aligned_data;
1149 bufferlist[2].iov_len = (packetlen_aligned - packetlen);
1150
1151 return hv_ringbuffer_write(channel, bufferlist, 3, requestid, NULL);
1152}
1153EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
1154
1155/*
1156 * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
1157 * using a GPADL Direct packet type.
1158 * The buffer includes the vmbus descriptor.
1159 */
1160int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
1161 struct vmbus_packet_mpb_array *desc,
1162 u32 desc_size,
1163 void *buffer, u32 bufferlen, u64 requestid)
1164{
1165 u32 packetlen;
1166 u32 packetlen_aligned;
1167 struct kvec bufferlist[3];
1168 u64 aligned_data = 0;
1169
1170 packetlen = desc_size + bufferlen;
1171 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
1172
1173 /* Setup the descriptor */
1174 desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
1175 desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
1176 desc->dataoffset8 = desc_size >> 3; /* in 8-bytes granularity */
1177 desc->length8 = (u16)(packetlen_aligned >> 3);
1178 desc->transactionid = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
1179 desc->reserved = 0;
1180 desc->rangecount = 1;
1181
1182 bufferlist[0].iov_base = desc;
1183 bufferlist[0].iov_len = desc_size;
1184 bufferlist[1].iov_base = buffer;
1185 bufferlist[1].iov_len = bufferlen;
1186 bufferlist[2].iov_base = &aligned_data;
1187 bufferlist[2].iov_len = (packetlen_aligned - packetlen);
1188
1189 return hv_ringbuffer_write(channel, bufferlist, 3, requestid, NULL);
1190}
1191EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
1192
1193/**
1194 * __vmbus_recvpacket() - Retrieve the user packet on the specified channel
1195 * @channel: Pointer to vmbus_channel structure
1196 * @buffer: Pointer to the buffer you want to receive the data into.
1197 * @bufferlen: Maximum size of what the buffer can hold.
1198 * @buffer_actual_len: The actual size of the data after it was received.
1199 * @requestid: Identifier of the request
1200 * @raw: true means keep the vmpacket_descriptor header in the received data.
1201 *
1202 * Receives directly from the hyper-v vmbus and puts the data it received
1203 * into Buffer. This will receive the data unparsed from hyper-v.
1204 *
1205 * Mainly used by Hyper-V drivers.
1206 */
1207static inline int
1208__vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
1209 u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
1210 bool raw)
1211{
1212 return hv_ringbuffer_read(channel, buffer, bufferlen,
1213 buffer_actual_len, requestid, raw);
1214
1215}
1216
1217int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
1218 u32 bufferlen, u32 *buffer_actual_len,
1219 u64 *requestid)
1220{
1221 return __vmbus_recvpacket(channel, buffer, bufferlen,
1222 buffer_actual_len, requestid, false);
1223}
1224EXPORT_SYMBOL(vmbus_recvpacket);
1225
1226/*
1227 * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
1228 */
1229int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
1230 u32 bufferlen, u32 *buffer_actual_len,
1231 u64 *requestid)
1232{
1233 return __vmbus_recvpacket(channel, buffer, bufferlen,
1234 buffer_actual_len, requestid, true);
1235}
1236EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
1237
1238/*
1239 * vmbus_next_request_id - Returns a new request id. It is also
1240 * the index at which the guest memory address is stored.
1241 * Uses a spin lock to avoid race conditions.
1242 * @channel: Pointer to the VMbus channel struct
1243 * @rqst_add: Guest memory address to be stored in the array
1244 */
1245u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
1246{
1247 struct vmbus_requestor *rqstor = &channel->requestor;
1248 unsigned long flags;
1249 u64 current_id;
1250
1251 /* Check rqstor has been initialized */
1252 if (!channel->rqstor_size)
1253 return VMBUS_NO_RQSTOR;
1254
1255 lock_requestor(channel, flags);
1256 current_id = rqstor->next_request_id;
1257
1258 /* Requestor array is full */
1259 if (current_id >= rqstor->size) {
1260 unlock_requestor(channel, flags);
1261 return VMBUS_RQST_ERROR;
1262 }
1263
1264 rqstor->next_request_id = rqstor->req_arr[current_id];
1265 rqstor->req_arr[current_id] = rqst_addr;
1266
1267 /* The already held spin lock provides atomicity */
1268 bitmap_set(rqstor->req_bitmap, current_id, 1);
1269
1270 unlock_requestor(channel, flags);
1271
1272 /*
1273 * Cannot return an ID of 0, which is reserved for an unsolicited
1274 * message from Hyper-V; Hyper-V does not acknowledge (respond to)
1275 * VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED requests with ID of
1276 * 0 sent by the guest.
1277 */
1278 return current_id + 1;
1279}
1280EXPORT_SYMBOL_GPL(vmbus_next_request_id);
1281
1282/* As in vmbus_request_addr_match() but without the requestor lock */
1283u64 __vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id,
1284 u64 rqst_addr)
1285{
1286 struct vmbus_requestor *rqstor = &channel->requestor;
1287 u64 req_addr;
1288
1289 /* Check rqstor has been initialized */
1290 if (!channel->rqstor_size)
1291 return VMBUS_NO_RQSTOR;
1292
1293 /* Hyper-V can send an unsolicited message with ID of 0 */
1294 if (!trans_id)
1295 return VMBUS_RQST_ERROR;
1296
1297 /* Data corresponding to trans_id is stored at trans_id - 1 */
1298 trans_id--;
1299
1300 /* Invalid trans_id */
1301 if (trans_id >= rqstor->size || !test_bit(trans_id, rqstor->req_bitmap))
1302 return VMBUS_RQST_ERROR;
1303
1304 req_addr = rqstor->req_arr[trans_id];
1305 if (rqst_addr == VMBUS_RQST_ADDR_ANY || req_addr == rqst_addr) {
1306 rqstor->req_arr[trans_id] = rqstor->next_request_id;
1307 rqstor->next_request_id = trans_id;
1308
1309 /* The already held spin lock provides atomicity */
1310 bitmap_clear(rqstor->req_bitmap, trans_id, 1);
1311 }
1312
1313 return req_addr;
1314}
1315EXPORT_SYMBOL_GPL(__vmbus_request_addr_match);
1316
1317/*
1318 * vmbus_request_addr_match - Clears/removes @trans_id from the @channel's
1319 * requestor, provided the memory address stored at @trans_id equals @rqst_addr
1320 * (or provided @rqst_addr matches the sentinel value VMBUS_RQST_ADDR_ANY).
1321 *
1322 * Returns the memory address stored at @trans_id, or VMBUS_RQST_ERROR if
1323 * @trans_id is not contained in the requestor.
1324 *
1325 * Acquires and releases the requestor spin lock.
1326 */
1327u64 vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id,
1328 u64 rqst_addr)
1329{
1330 unsigned long flags;
1331 u64 req_addr;
1332
1333 lock_requestor(channel, flags);
1334 req_addr = __vmbus_request_addr_match(channel, trans_id, rqst_addr);
1335 unlock_requestor(channel, flags);
1336
1337 return req_addr;
1338}
1339EXPORT_SYMBOL_GPL(vmbus_request_addr_match);
1340
1341/*
1342 * vmbus_request_addr - Returns the memory address stored at @trans_id
1343 * in @rqstor. Uses a spin lock to avoid race conditions.
1344 * @channel: Pointer to the VMbus channel struct
1345 * @trans_id: Request id sent back from Hyper-V. Becomes the requestor's
1346 * next request id.
1347 */
1348u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id)
1349{
1350 return vmbus_request_addr_match(channel, trans_id, VMBUS_RQST_ADDR_ANY);
1351}
1352EXPORT_SYMBOL_GPL(vmbus_request_addr);