GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / hv / channel.c
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  */
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  */
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  */
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  */
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 */
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                 __free_pages(channel->ringbuffer_page,
157                              get_order(channel->ringbuffer_pagecount
158                                        << PAGE_SHIFT));
159                 channel->ringbuffer_page = NULL;
160         }
161 }
162 EXPORT_SYMBOL_GPL(vmbus_free_ring);
163
164 /* vmbus_alloc_ring - allocate and map pages for ring buffer */
165 int 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 }
191 EXPORT_SYMBOL_GPL(vmbus_alloc_ring);
192
193 /* Used for Hyper-V Socket: a guest client's connect() to the host */
194 int 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 }
211 EXPORT_SYMBOL_GPL(vmbus_send_tl_connect_request);
212
213 static 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
229 static 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
281 free_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  */
298 int 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 }
304 EXPORT_SYMBOL_GPL(vmbus_send_modifychannel);
305
306 /*
307  * create_gpadl_header - Creates a gpadl for the specified buffer
308  */
309 static 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;
440 nomem:
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  */
457 static 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
555 cleanup:
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  */
581 int 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 }
587 EXPORT_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  */
596 static 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  */
619 static 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  */
647 static void vmbus_free_requestor(struct vmbus_requestor *rqstor)
648 {
649         kfree(rqstor->req_arr);
650         bitmap_free(rqstor->req_bitmap);
651 }
652
653 static 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
775 error_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);
779 error_free_info:
780         kfree(open_info);
781 error_free_gpadl:
782         vmbus_teardown_gpadl(newchannel, &newchannel->ringbuffer_gpadlhandle);
783 error_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  */
794 int 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 }
799 EXPORT_SYMBOL_GPL(vmbus_connect_ring);
800
801 /*
802  * vmbus_open - Open the specified channel.
803  */
804 int 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 }
823 EXPORT_SYMBOL_GPL(vmbus_open);
824
825 /*
826  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
827  */
828 int 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
869 post_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 }
891 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
892
893 void 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
923 static 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 */
981 int 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 }
1012 EXPORT_SYMBOL_GPL(vmbus_disconnect_ring);
1013
1014 /*
1015  * vmbus_close - Close the specified channel
1016  */
1017 void vmbus_close(struct vmbus_channel *channel)
1018 {
1019         if (vmbus_disconnect_ring(channel) == 0)
1020                 vmbus_free_ring(channel);
1021 }
1022 EXPORT_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  */
1041 int 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 }
1070 EXPORT_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  */
1087 int 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 }
1094 EXPORT_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  */
1103 int 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 }
1153 EXPORT_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  */
1160 int 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 }
1191 EXPORT_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  */
1207 static 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
1217 int 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 }
1224 EXPORT_SYMBOL(vmbus_recvpacket);
1225
1226 /*
1227  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
1228  */
1229 int 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 }
1236 EXPORT_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  */
1245 u64 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 }
1280 EXPORT_SYMBOL_GPL(vmbus_next_request_id);
1281
1282 /* As in vmbus_request_addr_match() but without the requestor lock */
1283 u64 __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 }
1315 EXPORT_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  */
1327 u64 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 }
1339 EXPORT_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  */
1348 u64 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 }
1352 EXPORT_SYMBOL_GPL(vmbus_request_addr);