GNU Linux-libre 4.4.289-gnu1
[releases.git] / drivers / hv / channel.c
1 /*
2  * Copyright (c) 2009, Microsoft Corporation.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15  * Place - Suite 330, Boston, MA 02111-1307 USA.
16  *
17  * Authors:
18  *   Haiyang Zhang <haiyangz@microsoft.com>
19  *   Hank Janssen  <hjanssen@microsoft.com>
20  */
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
23 #include <linux/kernel.h>
24 #include <linux/sched.h>
25 #include <linux/wait.h>
26 #include <linux/mm.h>
27 #include <linux/slab.h>
28 #include <linux/module.h>
29 #include <linux/hyperv.h>
30 #include <linux/uio.h>
31 #include <linux/interrupt.h>
32
33 #include "hyperv_vmbus.h"
34
35 #define NUM_PAGES_SPANNED(addr, len) \
36 ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
37
38 /*
39  * vmbus_setevent- Trigger an event notification on the specified
40  * channel.
41  */
42 static void vmbus_setevent(struct vmbus_channel *channel)
43 {
44         struct hv_monitor_page *monitorpage;
45
46         if (channel->offermsg.monitor_allocated) {
47                 /* Each u32 represents 32 channels */
48                 sync_set_bit(channel->offermsg.child_relid & 31,
49                         (unsigned long *) vmbus_connection.send_int_page +
50                         (channel->offermsg.child_relid >> 5));
51
52                 /* Get the child to parent monitor page */
53                 monitorpage = vmbus_connection.monitor_pages[1];
54
55                 sync_set_bit(channel->monitor_bit,
56                         (unsigned long *)&monitorpage->trigger_group
57                                         [channel->monitor_grp].pending);
58
59         } else {
60                 vmbus_set_event(channel);
61         }
62 }
63
64 /*
65  * vmbus_open - Open the specified channel.
66  */
67 int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
68                      u32 recv_ringbuffer_size, void *userdata, u32 userdatalen,
69                      void (*onchannelcallback)(void *context), void *context)
70 {
71         struct vmbus_channel_open_channel *open_msg;
72         struct vmbus_channel_msginfo *open_info = NULL;
73         void *in, *out;
74         unsigned long flags;
75         int ret, err = 0;
76         struct page *page;
77
78         spin_lock_irqsave(&newchannel->lock, flags);
79         if (newchannel->state == CHANNEL_OPEN_STATE) {
80                 newchannel->state = CHANNEL_OPENING_STATE;
81         } else {
82                 spin_unlock_irqrestore(&newchannel->lock, flags);
83                 return -EINVAL;
84         }
85         spin_unlock_irqrestore(&newchannel->lock, flags);
86
87         newchannel->onchannel_callback = onchannelcallback;
88         newchannel->channel_callback_context = context;
89
90         /* Allocate the ring buffer */
91         page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
92                                 GFP_KERNEL|__GFP_ZERO,
93                                 get_order(send_ringbuffer_size +
94                                 recv_ringbuffer_size));
95
96         if (!page)
97                 out = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
98                                                get_order(send_ringbuffer_size +
99                                                recv_ringbuffer_size));
100         else
101                 out = (void *)page_address(page);
102
103         if (!out) {
104                 err = -ENOMEM;
105                 goto error0;
106         }
107
108         in = (void *)((unsigned long)out + send_ringbuffer_size);
109
110         newchannel->ringbuffer_pages = out;
111         newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
112                                            recv_ringbuffer_size) >> PAGE_SHIFT;
113
114         ret = hv_ringbuffer_init(
115                 &newchannel->outbound, out, send_ringbuffer_size);
116
117         if (ret != 0) {
118                 err = ret;
119                 goto error0;
120         }
121
122         ret = hv_ringbuffer_init(
123                 &newchannel->inbound, in, recv_ringbuffer_size);
124         if (ret != 0) {
125                 err = ret;
126                 goto error0;
127         }
128
129
130         /* Establish the gpadl for the ring buffer */
131         newchannel->ringbuffer_gpadlhandle = 0;
132
133         ret = vmbus_establish_gpadl(newchannel,
134                                          newchannel->outbound.ring_buffer,
135                                          send_ringbuffer_size +
136                                          recv_ringbuffer_size,
137                                          &newchannel->ringbuffer_gpadlhandle);
138
139         if (ret != 0) {
140                 err = ret;
141                 goto error0;
142         }
143
144         /* Create and init the channel open message */
145         open_info = kmalloc(sizeof(*open_info) +
146                            sizeof(struct vmbus_channel_open_channel),
147                            GFP_KERNEL);
148         if (!open_info) {
149                 err = -ENOMEM;
150                 goto error_gpadl;
151         }
152
153         init_completion(&open_info->waitevent);
154
155         open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
156         open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
157         open_msg->openid = newchannel->offermsg.child_relid;
158         open_msg->child_relid = newchannel->offermsg.child_relid;
159         open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
160         open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
161                                                   PAGE_SHIFT;
162         open_msg->target_vp = newchannel->target_vp;
163
164         if (userdatalen > MAX_USER_DEFINED_BYTES) {
165                 err = -EINVAL;
166                 goto error_gpadl;
167         }
168
169         if (userdatalen)
170                 memcpy(open_msg->userdata, userdata, userdatalen);
171
172         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
173         list_add_tail(&open_info->msglistentry,
174                       &vmbus_connection.chn_msg_list);
175         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
176
177         ret = vmbus_post_msg(open_msg,
178                                sizeof(struct vmbus_channel_open_channel));
179
180         if (ret != 0) {
181                 err = ret;
182                 goto error1;
183         }
184
185         wait_for_completion(&open_info->waitevent);
186
187         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
188         list_del(&open_info->msglistentry);
189         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
190
191         if (open_info->response.open_result.status) {
192                 err = -EAGAIN;
193                 goto error_gpadl;
194         }
195
196         newchannel->state = CHANNEL_OPENED_STATE;
197         kfree(open_info);
198         return 0;
199
200 error1:
201         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
202         list_del(&open_info->msglistentry);
203         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
204
205 error_gpadl:
206         vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
207
208 error0:
209         free_pages((unsigned long)out,
210                 get_order(send_ringbuffer_size + recv_ringbuffer_size));
211         kfree(open_info);
212         newchannel->state = CHANNEL_OPEN_STATE;
213         return err;
214 }
215 EXPORT_SYMBOL_GPL(vmbus_open);
216
217 /*
218  * create_gpadl_header - Creates a gpadl for the specified buffer
219  */
220 static int create_gpadl_header(void *kbuffer, u32 size,
221                                          struct vmbus_channel_msginfo **msginfo,
222                                          u32 *messagecount)
223 {
224         int i;
225         int pagecount;
226         struct vmbus_channel_gpadl_header *gpadl_header;
227         struct vmbus_channel_gpadl_body *gpadl_body;
228         struct vmbus_channel_msginfo *msgheader;
229         struct vmbus_channel_msginfo *msgbody = NULL;
230         u32 msgsize;
231
232         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
233
234         pagecount = size >> PAGE_SHIFT;
235
236         /* do we need a gpadl body msg */
237         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
238                   sizeof(struct vmbus_channel_gpadl_header) -
239                   sizeof(struct gpa_range);
240         pfncount = pfnsize / sizeof(u64);
241
242         if (pagecount > pfncount) {
243                 /* we need a gpadl body */
244                 /* fill in the header */
245                 msgsize = sizeof(struct vmbus_channel_msginfo) +
246                           sizeof(struct vmbus_channel_gpadl_header) +
247                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
248                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
249                 if (!msgheader)
250                         goto nomem;
251
252                 INIT_LIST_HEAD(&msgheader->submsglist);
253                 msgheader->msgsize = msgsize;
254
255                 gpadl_header = (struct vmbus_channel_gpadl_header *)
256                         msgheader->msg;
257                 gpadl_header->rangecount = 1;
258                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
259                                          pagecount * sizeof(u64);
260                 gpadl_header->range[0].byte_offset = 0;
261                 gpadl_header->range[0].byte_count = size;
262                 for (i = 0; i < pfncount; i++)
263                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
264                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
265                 *msginfo = msgheader;
266                 *messagecount = 1;
267
268                 pfnsum = pfncount;
269                 pfnleft = pagecount - pfncount;
270
271                 /* how many pfns can we fit */
272                 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
273                           sizeof(struct vmbus_channel_gpadl_body);
274                 pfncount = pfnsize / sizeof(u64);
275
276                 /* fill in the body */
277                 while (pfnleft) {
278                         if (pfnleft > pfncount)
279                                 pfncurr = pfncount;
280                         else
281                                 pfncurr = pfnleft;
282
283                         msgsize = sizeof(struct vmbus_channel_msginfo) +
284                                   sizeof(struct vmbus_channel_gpadl_body) +
285                                   pfncurr * sizeof(u64);
286                         msgbody = kzalloc(msgsize, GFP_KERNEL);
287
288                         if (!msgbody) {
289                                 struct vmbus_channel_msginfo *pos = NULL;
290                                 struct vmbus_channel_msginfo *tmp = NULL;
291                                 /*
292                                  * Free up all the allocated messages.
293                                  */
294                                 list_for_each_entry_safe(pos, tmp,
295                                         &msgheader->submsglist,
296                                         msglistentry) {
297
298                                         list_del(&pos->msglistentry);
299                                         kfree(pos);
300                                 }
301
302                                 goto nomem;
303                         }
304
305                         msgbody->msgsize = msgsize;
306                         (*messagecount)++;
307                         gpadl_body =
308                                 (struct vmbus_channel_gpadl_body *)msgbody->msg;
309
310                         /*
311                          * Gpadl is u32 and we are using a pointer which could
312                          * be 64-bit
313                          * This is governed by the guest/host protocol and
314                          * so the hypervisor gurantees that this is ok.
315                          */
316                         for (i = 0; i < pfncurr; i++)
317                                 gpadl_body->pfn[i] = slow_virt_to_phys(
318                                         kbuffer + PAGE_SIZE * (pfnsum + i)) >>
319                                         PAGE_SHIFT;
320
321                         /* add to msg header */
322                         list_add_tail(&msgbody->msglistentry,
323                                       &msgheader->submsglist);
324                         pfnsum += pfncurr;
325                         pfnleft -= pfncurr;
326                 }
327         } else {
328                 /* everything fits in a header */
329                 msgsize = sizeof(struct vmbus_channel_msginfo) +
330                           sizeof(struct vmbus_channel_gpadl_header) +
331                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
332                 msgheader = kzalloc(msgsize, GFP_KERNEL);
333                 if (msgheader == NULL)
334                         goto nomem;
335                 msgheader->msgsize = msgsize;
336
337                 gpadl_header = (struct vmbus_channel_gpadl_header *)
338                         msgheader->msg;
339                 gpadl_header->rangecount = 1;
340                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
341                                          pagecount * sizeof(u64);
342                 gpadl_header->range[0].byte_offset = 0;
343                 gpadl_header->range[0].byte_count = size;
344                 for (i = 0; i < pagecount; i++)
345                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
346                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
347
348                 *msginfo = msgheader;
349                 *messagecount = 1;
350         }
351
352         return 0;
353 nomem:
354         kfree(msgheader);
355         kfree(msgbody);
356         return -ENOMEM;
357 }
358
359 /*
360  * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
361  *
362  * @channel: a channel
363  * @kbuffer: from kmalloc or vmalloc
364  * @size: page-size multiple
365  * @gpadl_handle: some funky thing
366  */
367 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
368                                u32 size, u32 *gpadl_handle)
369 {
370         struct vmbus_channel_gpadl_header *gpadlmsg;
371         struct vmbus_channel_gpadl_body *gpadl_body;
372         struct vmbus_channel_msginfo *msginfo = NULL;
373         struct vmbus_channel_msginfo *submsginfo, *tmp;
374         u32 msgcount;
375         struct list_head *curr;
376         u32 next_gpadl_handle;
377         unsigned long flags;
378         int ret = 0;
379
380         next_gpadl_handle =
381                 (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
382
383         ret = create_gpadl_header(kbuffer, size, &msginfo, &msgcount);
384         if (ret)
385                 return ret;
386
387         init_completion(&msginfo->waitevent);
388
389         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
390         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
391         gpadlmsg->child_relid = channel->offermsg.child_relid;
392         gpadlmsg->gpadl = next_gpadl_handle;
393
394
395         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
396         list_add_tail(&msginfo->msglistentry,
397                       &vmbus_connection.chn_msg_list);
398
399         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
400
401         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
402                                sizeof(*msginfo));
403         if (ret != 0)
404                 goto cleanup;
405
406         if (msgcount > 1) {
407                 list_for_each(curr, &msginfo->submsglist) {
408
409                         submsginfo = (struct vmbus_channel_msginfo *)curr;
410                         gpadl_body =
411                              (struct vmbus_channel_gpadl_body *)submsginfo->msg;
412
413                         gpadl_body->header.msgtype =
414                                 CHANNELMSG_GPADL_BODY;
415                         gpadl_body->gpadl = next_gpadl_handle;
416
417                         ret = vmbus_post_msg(gpadl_body,
418                                                submsginfo->msgsize -
419                                                sizeof(*submsginfo));
420                         if (ret != 0)
421                                 goto cleanup;
422
423                 }
424         }
425         wait_for_completion(&msginfo->waitevent);
426
427         /* At this point, we received the gpadl created msg */
428         *gpadl_handle = gpadlmsg->gpadl;
429
430 cleanup:
431         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
432         list_del(&msginfo->msglistentry);
433         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
434
435         if (msgcount > 1) {
436                 list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
437                          msglistentry) {
438                         kfree(submsginfo);
439                 }
440         }
441
442         kfree(msginfo);
443         return ret;
444 }
445 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
446
447 /*
448  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
449  */
450 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
451 {
452         struct vmbus_channel_gpadl_teardown *msg;
453         struct vmbus_channel_msginfo *info;
454         unsigned long flags;
455         int ret;
456
457         info = kmalloc(sizeof(*info) +
458                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
459         if (!info)
460                 return -ENOMEM;
461
462         init_completion(&info->waitevent);
463
464         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
465
466         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
467         msg->child_relid = channel->offermsg.child_relid;
468         msg->gpadl = gpadl_handle;
469
470         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
471         list_add_tail(&info->msglistentry,
472                       &vmbus_connection.chn_msg_list);
473         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
474         ret = vmbus_post_msg(msg,
475                                sizeof(struct vmbus_channel_gpadl_teardown));
476
477         if (ret)
478                 goto post_msg_err;
479
480         wait_for_completion(&info->waitevent);
481
482 post_msg_err:
483         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
484         list_del(&info->msglistentry);
485         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
486
487         kfree(info);
488         return ret;
489 }
490 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
491
492 static void reset_channel_cb(void *arg)
493 {
494         struct vmbus_channel *channel = arg;
495
496         channel->onchannel_callback = NULL;
497 }
498
499 static int vmbus_close_internal(struct vmbus_channel *channel)
500 {
501         struct vmbus_channel_close_channel *msg;
502         struct tasklet_struct *tasklet;
503         int ret;
504
505         /*
506          * process_chn_event(), running in the tasklet, can race
507          * with vmbus_close_internal() in the case of SMP guest, e.g., when
508          * the former is accessing channel->inbound.ring_buffer, the latter
509          * could be freeing the ring_buffer pages.
510          *
511          * To resolve the race, we can serialize them by disabling the
512          * tasklet when the latter is running here.
513          */
514         tasklet = hv_context.event_dpc[channel->target_cpu];
515         tasklet_disable(tasklet);
516
517         channel->state = CHANNEL_OPEN_STATE;
518         channel->sc_creation_callback = NULL;
519         /* Stop callback and cancel the timer asap */
520         if (channel->target_cpu != get_cpu()) {
521                 put_cpu();
522                 smp_call_function_single(channel->target_cpu, reset_channel_cb,
523                                          channel, true);
524         } else {
525                 reset_channel_cb(channel);
526                 put_cpu();
527         }
528
529         /* Send a closing message */
530
531         msg = &channel->close_msg.msg;
532
533         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
534         msg->child_relid = channel->offermsg.child_relid;
535
536         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel));
537
538         if (ret) {
539                 pr_err("Close failed: close post msg return is %d\n", ret);
540                 /*
541                  * If we failed to post the close msg,
542                  * it is perhaps better to leak memory.
543                  */
544                 goto out;
545         }
546
547         /* Tear down the gpadl for the channel's ring buffer */
548         if (channel->ringbuffer_gpadlhandle) {
549                 ret = vmbus_teardown_gpadl(channel,
550                                            channel->ringbuffer_gpadlhandle);
551                 if (ret) {
552                         pr_err("Close failed: teardown gpadl return %d\n", ret);
553                         /*
554                          * If we failed to teardown gpadl,
555                          * it is perhaps better to leak memory.
556                          */
557                         goto out;
558                 }
559         }
560
561         /* Cleanup the ring buffers for this channel */
562         hv_ringbuffer_cleanup(&channel->outbound);
563         hv_ringbuffer_cleanup(&channel->inbound);
564
565         free_pages((unsigned long)channel->ringbuffer_pages,
566                 get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
567
568 out:
569         tasklet_enable(tasklet);
570
571         return ret;
572 }
573
574 /*
575  * vmbus_close - Close the specified channel
576  */
577 void vmbus_close(struct vmbus_channel *channel)
578 {
579         struct list_head *cur, *tmp;
580         struct vmbus_channel *cur_channel;
581
582         if (channel->primary_channel != NULL) {
583                 /*
584                  * We will only close sub-channels when
585                  * the primary is closed.
586                  */
587                 return;
588         }
589         /*
590          * Close all the sub-channels first and then close the
591          * primary channel.
592          */
593         list_for_each_safe(cur, tmp, &channel->sc_list) {
594                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
595                 if (cur_channel->state != CHANNEL_OPENED_STATE)
596                         continue;
597                 vmbus_close_internal(cur_channel);
598         }
599         /*
600          * Now close the primary.
601          */
602         vmbus_close_internal(channel);
603 }
604 EXPORT_SYMBOL_GPL(vmbus_close);
605
606 int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
607                            u32 bufferlen, u64 requestid,
608                            enum vmbus_packet_type type, u32 flags, bool kick_q)
609 {
610         struct vmpacket_descriptor desc;
611         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
612         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
613         struct kvec bufferlist[3];
614         u64 aligned_data = 0;
615         int ret;
616         bool signal = false;
617         int num_vecs = ((bufferlen != 0) ? 3 : 1);
618
619
620         /* Setup the descriptor */
621         desc.type = type; /* VmbusPacketTypeDataInBand; */
622         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
623         /* in 8-bytes granularity */
624         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
625         desc.len8 = (u16)(packetlen_aligned >> 3);
626         desc.trans_id = requestid;
627
628         bufferlist[0].iov_base = &desc;
629         bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
630         bufferlist[1].iov_base = buffer;
631         bufferlist[1].iov_len = bufferlen;
632         bufferlist[2].iov_base = &aligned_data;
633         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
634
635         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, num_vecs,
636                                   &signal);
637
638         /*
639          * Signalling the host is conditional on many factors:
640          * 1. The ring state changed from being empty to non-empty.
641          *    This is tracked by the variable "signal".
642          * 2. The variable kick_q tracks if more data will be placed
643          *    on the ring. We will not signal if more data is
644          *    to be placed.
645          *
646          * Based on the channel signal state, we will decide
647          * which signaling policy will be applied.
648          *
649          * If we cannot write to the ring-buffer; signal the host
650          * even if we may not have written anything. This is a rare
651          * enough condition that it should not matter.
652          */
653
654         if (channel->signal_policy)
655                 signal = true;
656         else
657                 kick_q = true;
658
659         if (((ret == 0) && kick_q && signal) || (ret))
660                 vmbus_setevent(channel);
661
662         return ret;
663 }
664 EXPORT_SYMBOL(vmbus_sendpacket_ctl);
665
666 /**
667  * vmbus_sendpacket() - Send the specified buffer on the given channel
668  * @channel: Pointer to vmbus_channel structure.
669  * @buffer: Pointer to the buffer you want to receive the data into.
670  * @bufferlen: Maximum size of what the the buffer will hold
671  * @requestid: Identifier of the request
672  * @type: Type of packet that is being send e.g. negotiate, time
673  * packet etc.
674  *
675  * Sends data in @buffer directly to hyper-v via the vmbus
676  * This will send the data unparsed to hyper-v.
677  *
678  * Mainly used by Hyper-V drivers.
679  */
680 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
681                            u32 bufferlen, u64 requestid,
682                            enum vmbus_packet_type type, u32 flags)
683 {
684         return vmbus_sendpacket_ctl(channel, buffer, bufferlen, requestid,
685                                     type, flags, true);
686 }
687 EXPORT_SYMBOL(vmbus_sendpacket);
688
689 /*
690  * vmbus_sendpacket_pagebuffer_ctl - Send a range of single-page buffer
691  * packets using a GPADL Direct packet type. This interface allows you
692  * to control notifying the host. This will be useful for sending
693  * batched data. Also the sender can control the send flags
694  * explicitly.
695  */
696 int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
697                                      struct hv_page_buffer pagebuffers[],
698                                      u32 pagecount, void *buffer, u32 bufferlen,
699                                      u64 requestid,
700                                      u32 flags,
701                                      bool kick_q)
702 {
703         int ret;
704         int i;
705         struct vmbus_channel_packet_page_buffer desc;
706         u32 descsize;
707         u32 packetlen;
708         u32 packetlen_aligned;
709         struct kvec bufferlist[3];
710         u64 aligned_data = 0;
711         bool signal = false;
712
713         if (pagecount > MAX_PAGE_BUFFER_COUNT)
714                 return -EINVAL;
715
716
717         /*
718          * Adjust the size down since vmbus_channel_packet_page_buffer is the
719          * largest size we support
720          */
721         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
722                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
723                           sizeof(struct hv_page_buffer));
724         packetlen = descsize + bufferlen;
725         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
726
727         /* Setup the descriptor */
728         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
729         desc.flags = flags;
730         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
731         desc.length8 = (u16)(packetlen_aligned >> 3);
732         desc.transactionid = requestid;
733         desc.rangecount = pagecount;
734
735         for (i = 0; i < pagecount; i++) {
736                 desc.range[i].len = pagebuffers[i].len;
737                 desc.range[i].offset = pagebuffers[i].offset;
738                 desc.range[i].pfn        = pagebuffers[i].pfn;
739         }
740
741         bufferlist[0].iov_base = &desc;
742         bufferlist[0].iov_len = descsize;
743         bufferlist[1].iov_base = buffer;
744         bufferlist[1].iov_len = bufferlen;
745         bufferlist[2].iov_base = &aligned_data;
746         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
747
748         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
749
750         /*
751          * Signalling the host is conditional on many factors:
752          * 1. The ring state changed from being empty to non-empty.
753          *    This is tracked by the variable "signal".
754          * 2. The variable kick_q tracks if more data will be placed
755          *    on the ring. We will not signal if more data is
756          *    to be placed.
757          *
758          * Based on the channel signal state, we will decide
759          * which signaling policy will be applied.
760          *
761          * If we cannot write to the ring-buffer; signal the host
762          * even if we may not have written anything. This is a rare
763          * enough condition that it should not matter.
764          */
765
766         if (channel->signal_policy)
767                 signal = true;
768         else
769                 kick_q = true;
770
771         if (((ret == 0) && kick_q && signal) || (ret))
772                 vmbus_setevent(channel);
773
774         return ret;
775 }
776 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer_ctl);
777
778 /*
779  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
780  * packets using a GPADL Direct packet type.
781  */
782 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
783                                      struct hv_page_buffer pagebuffers[],
784                                      u32 pagecount, void *buffer, u32 bufferlen,
785                                      u64 requestid)
786 {
787         u32 flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
788         return vmbus_sendpacket_pagebuffer_ctl(channel, pagebuffers, pagecount,
789                                                buffer, bufferlen, requestid,
790                                                flags, true);
791
792 }
793 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
794
795 /*
796  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
797  * using a GPADL Direct packet type.
798  * The buffer includes the vmbus descriptor.
799  */
800 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
801                               struct vmbus_packet_mpb_array *desc,
802                               u32 desc_size,
803                               void *buffer, u32 bufferlen, u64 requestid)
804 {
805         int ret;
806         u32 packetlen;
807         u32 packetlen_aligned;
808         struct kvec bufferlist[3];
809         u64 aligned_data = 0;
810         bool signal = false;
811
812         packetlen = desc_size + bufferlen;
813         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
814
815         /* Setup the descriptor */
816         desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
817         desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
818         desc->dataoffset8 = desc_size >> 3; /* in 8-bytes grandularity */
819         desc->length8 = (u16)(packetlen_aligned >> 3);
820         desc->transactionid = requestid;
821         desc->rangecount = 1;
822
823         bufferlist[0].iov_base = desc;
824         bufferlist[0].iov_len = desc_size;
825         bufferlist[1].iov_base = buffer;
826         bufferlist[1].iov_len = bufferlen;
827         bufferlist[2].iov_base = &aligned_data;
828         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
829
830         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
831
832         if (ret == 0 && signal)
833                 vmbus_setevent(channel);
834
835         return ret;
836 }
837 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
838
839 /*
840  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
841  * using a GPADL Direct packet type.
842  */
843 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
844                                 struct hv_multipage_buffer *multi_pagebuffer,
845                                 void *buffer, u32 bufferlen, u64 requestid)
846 {
847         int ret;
848         struct vmbus_channel_packet_multipage_buffer desc;
849         u32 descsize;
850         u32 packetlen;
851         u32 packetlen_aligned;
852         struct kvec bufferlist[3];
853         u64 aligned_data = 0;
854         bool signal = false;
855         u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
856                                          multi_pagebuffer->len);
857
858         if (pfncount > MAX_MULTIPAGE_BUFFER_COUNT)
859                 return -EINVAL;
860
861         /*
862          * Adjust the size down since vmbus_channel_packet_multipage_buffer is
863          * the largest size we support
864          */
865         descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) -
866                           ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
867                           sizeof(u64));
868         packetlen = descsize + bufferlen;
869         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
870
871
872         /* Setup the descriptor */
873         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
874         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
875         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
876         desc.length8 = (u16)(packetlen_aligned >> 3);
877         desc.transactionid = requestid;
878         desc.rangecount = 1;
879
880         desc.range.len = multi_pagebuffer->len;
881         desc.range.offset = multi_pagebuffer->offset;
882
883         memcpy(desc.range.pfn_array, multi_pagebuffer->pfn_array,
884                pfncount * sizeof(u64));
885
886         bufferlist[0].iov_base = &desc;
887         bufferlist[0].iov_len = descsize;
888         bufferlist[1].iov_base = buffer;
889         bufferlist[1].iov_len = bufferlen;
890         bufferlist[2].iov_base = &aligned_data;
891         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
892
893         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
894
895         if (ret == 0 && signal)
896                 vmbus_setevent(channel);
897
898         return ret;
899 }
900 EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
901
902 /**
903  * vmbus_recvpacket() - Retrieve the user packet on the specified channel
904  * @channel: Pointer to vmbus_channel structure.
905  * @buffer: Pointer to the buffer you want to receive the data into.
906  * @bufferlen: Maximum size of what the the buffer will hold
907  * @buffer_actual_len: The actual size of the data after it was received
908  * @requestid: Identifier of the request
909  *
910  * Receives directly from the hyper-v vmbus and puts the data it received
911  * into Buffer. This will receive the data unparsed from hyper-v.
912  *
913  * Mainly used by Hyper-V drivers.
914  */
915 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
916                         u32 bufferlen, u32 *buffer_actual_len, u64 *requestid)
917 {
918         struct vmpacket_descriptor desc;
919         u32 packetlen;
920         u32 userlen;
921         int ret;
922         bool signal = false;
923
924         *buffer_actual_len = 0;
925         *requestid = 0;
926
927
928         ret = hv_ringbuffer_peek(&channel->inbound, &desc,
929                              sizeof(struct vmpacket_descriptor));
930         if (ret != 0)
931                 return 0;
932
933         packetlen = desc.len8 << 3;
934         userlen = packetlen - (desc.offset8 << 3);
935
936         *buffer_actual_len = userlen;
937
938         if (userlen > bufferlen) {
939
940                 pr_err("Buffer too small - got %d needs %d\n",
941                            bufferlen, userlen);
942                 return -ETOOSMALL;
943         }
944
945         *requestid = desc.trans_id;
946
947         /* Copy over the packet to the user buffer */
948         ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
949                              (desc.offset8 << 3), &signal);
950
951         if (signal)
952                 vmbus_setevent(channel);
953
954         return 0;
955 }
956 EXPORT_SYMBOL(vmbus_recvpacket);
957
958 /*
959  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
960  */
961 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
962                               u32 bufferlen, u32 *buffer_actual_len,
963                               u64 *requestid)
964 {
965         struct vmpacket_descriptor desc;
966         u32 packetlen;
967         int ret;
968         bool signal = false;
969
970         *buffer_actual_len = 0;
971         *requestid = 0;
972
973
974         ret = hv_ringbuffer_peek(&channel->inbound, &desc,
975                              sizeof(struct vmpacket_descriptor));
976         if (ret != 0)
977                 return 0;
978
979
980         packetlen = desc.len8 << 3;
981
982         *buffer_actual_len = packetlen;
983
984         if (packetlen > bufferlen)
985                 return -ENOBUFS;
986
987         *requestid = desc.trans_id;
988
989         /* Copy over the entire packet to the user buffer */
990         ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0,
991                                  &signal);
992
993         if (signal)
994                 vmbus_setevent(channel);
995
996         return ret;
997 }
998 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);