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K. Y. Srinivasan9aa8b502012-11-14 01:09:02 -08001/*
2 * Copyright (c) 2012, Microsoft Corporation.
3 *
4 * Author:
5 * K. Y. Srinivasan <kys@microsoft.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published
9 * by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
14 * NON INFRINGEMENT. See the GNU General Public License for more
15 * details.
16 *
17 */
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/kernel.h>
22#include <linux/mman.h>
23#include <linux/delay.h>
24#include <linux/init.h>
25#include <linux/module.h>
26#include <linux/slab.h>
27#include <linux/kthread.h>
28#include <linux/completion.h>
29#include <linux/memory_hotplug.h>
30#include <linux/memory.h>
31#include <linux/notifier.h>
32#include <linux/mman.h>
33#include <linux/percpu_counter.h>
34
35#include <linux/hyperv.h>
36
37/*
38 * We begin with definitions supporting the Dynamic Memory protocol
39 * with the host.
40 *
41 * Begin protocol definitions.
42 */
43
44
45
46/*
47 * Protocol versions. The low word is the minor version, the high word the major
48 * version.
49 *
50 * History:
51 * Initial version 1.0
52 * Changed to 0.1 on 2009/03/25
53 * Changes to 0.2 on 2009/05/14
54 * Changes to 0.3 on 2009/12/03
55 * Changed to 1.0 on 2011/04/05
56 */
57
58#define DYNMEM_MAKE_VERSION(Major, Minor) ((__u32)(((Major) << 16) | (Minor)))
59#define DYNMEM_MAJOR_VERSION(Version) ((__u32)(Version) >> 16)
60#define DYNMEM_MINOR_VERSION(Version) ((__u32)(Version) & 0xff)
61
62enum {
63 DYNMEM_PROTOCOL_VERSION_1 = DYNMEM_MAKE_VERSION(0, 3),
64 DYNMEM_PROTOCOL_VERSION_2 = DYNMEM_MAKE_VERSION(1, 0),
65
66 DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1,
67 DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2,
68
69 DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN8
70};
71
72
73
74/*
75 * Message Types
76 */
77
78enum dm_message_type {
79 /*
80 * Version 0.3
81 */
82 DM_ERROR = 0,
83 DM_VERSION_REQUEST = 1,
84 DM_VERSION_RESPONSE = 2,
85 DM_CAPABILITIES_REPORT = 3,
86 DM_CAPABILITIES_RESPONSE = 4,
87 DM_STATUS_REPORT = 5,
88 DM_BALLOON_REQUEST = 6,
89 DM_BALLOON_RESPONSE = 7,
90 DM_UNBALLOON_REQUEST = 8,
91 DM_UNBALLOON_RESPONSE = 9,
92 DM_MEM_HOT_ADD_REQUEST = 10,
93 DM_MEM_HOT_ADD_RESPONSE = 11,
94 DM_VERSION_03_MAX = 11,
95 /*
96 * Version 1.0.
97 */
98 DM_INFO_MESSAGE = 12,
99 DM_VERSION_1_MAX = 12
100};
101
102
103/*
104 * Structures defining the dynamic memory management
105 * protocol.
106 */
107
108union dm_version {
109 struct {
110 __u16 minor_version;
111 __u16 major_version;
112 };
113 __u32 version;
114} __packed;
115
116
117union dm_caps {
118 struct {
119 __u64 balloon:1;
120 __u64 hot_add:1;
121 __u64 reservedz:62;
122 } cap_bits;
123 __u64 caps;
124} __packed;
125
126union dm_mem_page_range {
127 struct {
128 /*
129 * The PFN number of the first page in the range.
130 * 40 bits is the architectural limit of a PFN
131 * number for AMD64.
132 */
133 __u64 start_page:40;
134 /*
135 * The number of pages in the range.
136 */
137 __u64 page_cnt:24;
138 } finfo;
139 __u64 page_range;
140} __packed;
141
142
143
144/*
145 * The header for all dynamic memory messages:
146 *
147 * type: Type of the message.
148 * size: Size of the message in bytes; including the header.
149 * trans_id: The guest is responsible for manufacturing this ID.
150 */
151
152struct dm_header {
153 __u16 type;
154 __u16 size;
155 __u32 trans_id;
156} __packed;
157
158/*
159 * A generic message format for dynamic memory.
160 * Specific message formats are defined later in the file.
161 */
162
163struct dm_message {
164 struct dm_header hdr;
165 __u8 data[]; /* enclosed message */
166} __packed;
167
168
169/*
170 * Specific message types supporting the dynamic memory protocol.
171 */
172
173/*
174 * Version negotiation message. Sent from the guest to the host.
175 * The guest is free to try different versions until the host
176 * accepts the version.
177 *
178 * dm_version: The protocol version requested.
179 * is_last_attempt: If TRUE, this is the last version guest will request.
180 * reservedz: Reserved field, set to zero.
181 */
182
183struct dm_version_request {
184 struct dm_header hdr;
185 union dm_version version;
186 __u32 is_last_attempt:1;
187 __u32 reservedz:31;
188} __packed;
189
190/*
191 * Version response message; Host to Guest and indicates
192 * if the host has accepted the version sent by the guest.
193 *
194 * is_accepted: If TRUE, host has accepted the version and the guest
195 * should proceed to the next stage of the protocol. FALSE indicates that
196 * guest should re-try with a different version.
197 *
198 * reservedz: Reserved field, set to zero.
199 */
200
201struct dm_version_response {
202 struct dm_header hdr;
203 __u64 is_accepted:1;
204 __u64 reservedz:63;
205} __packed;
206
207/*
208 * Message reporting capabilities. This is sent from the guest to the
209 * host.
210 */
211
212struct dm_capabilities {
213 struct dm_header hdr;
214 union dm_caps caps;
215 __u64 min_page_cnt;
216 __u64 max_page_number;
217} __packed;
218
219/*
220 * Response to the capabilities message. This is sent from the host to the
221 * guest. This message notifies if the host has accepted the guest's
222 * capabilities. If the host has not accepted, the guest must shutdown
223 * the service.
224 *
225 * is_accepted: Indicates if the host has accepted guest's capabilities.
226 * reservedz: Must be 0.
227 */
228
229struct dm_capabilities_resp_msg {
230 struct dm_header hdr;
231 __u64 is_accepted:1;
232 __u64 reservedz:63;
233} __packed;
234
235/*
236 * This message is used to report memory pressure from the guest.
237 * This message is not part of any transaction and there is no
238 * response to this message.
239 *
240 * num_avail: Available memory in pages.
241 * num_committed: Committed memory in pages.
242 * page_file_size: The accumulated size of all page files
243 * in the system in pages.
244 * zero_free: The nunber of zero and free pages.
245 * page_file_writes: The writes to the page file in pages.
246 * io_diff: An indicator of file cache efficiency or page file activity,
247 * calculated as File Cache Page Fault Count - Page Read Count.
248 * This value is in pages.
249 *
250 * Some of these metrics are Windows specific and fortunately
251 * the algorithm on the host side that computes the guest memory
252 * pressure only uses num_committed value.
253 */
254
255struct dm_status {
256 struct dm_header hdr;
257 __u64 num_avail;
258 __u64 num_committed;
259 __u64 page_file_size;
260 __u64 zero_free;
261 __u32 page_file_writes;
262 __u32 io_diff;
263} __packed;
264
265
266/*
267 * Message to ask the guest to allocate memory - balloon up message.
268 * This message is sent from the host to the guest. The guest may not be
269 * able to allocate as much memory as requested.
270 *
271 * num_pages: number of pages to allocate.
272 */
273
274struct dm_balloon {
275 struct dm_header hdr;
276 __u32 num_pages;
277 __u32 reservedz;
278} __packed;
279
280
281/*
282 * Balloon response message; this message is sent from the guest
283 * to the host in response to the balloon message.
284 *
285 * reservedz: Reserved; must be set to zero.
286 * more_pages: If FALSE, this is the last message of the transaction.
287 * if TRUE there will atleast one more message from the guest.
288 *
289 * range_count: The number of ranges in the range array.
290 *
291 * range_array: An array of page ranges returned to the host.
292 *
293 */
294
295struct dm_balloon_response {
296 struct dm_header hdr;
297 __u32 reservedz;
298 __u32 more_pages:1;
299 __u32 range_count:31;
300 union dm_mem_page_range range_array[];
301} __packed;
302
303/*
304 * Un-balloon message; this message is sent from the host
305 * to the guest to give guest more memory.
306 *
307 * more_pages: If FALSE, this is the last message of the transaction.
308 * if TRUE there will atleast one more message from the guest.
309 *
310 * reservedz: Reserved; must be set to zero.
311 *
312 * range_count: The number of ranges in the range array.
313 *
314 * range_array: An array of page ranges returned to the host.
315 *
316 */
317
318struct dm_unballoon_request {
319 struct dm_header hdr;
320 __u32 more_pages:1;
321 __u32 reservedz:31;
322 __u32 range_count;
323 union dm_mem_page_range range_array[];
324} __packed;
325
326/*
327 * Un-balloon response message; this message is sent from the guest
328 * to the host in response to an unballoon request.
329 *
330 */
331
332struct dm_unballoon_response {
333 struct dm_header hdr;
334} __packed;
335
336
337/*
338 * Hot add request message. Message sent from the host to the guest.
339 *
340 * mem_range: Memory range to hot add.
341 *
342 * On Linux we currently don't support this since we cannot hot add
343 * arbitrary granularity of memory.
344 */
345
346struct dm_hot_add {
347 struct dm_header hdr;
348 union dm_mem_page_range range;
349} __packed;
350
351/*
352 * Hot add response message.
353 * This message is sent by the guest to report the status of a hot add request.
354 * If page_count is less than the requested page count, then the host should
355 * assume all further hot add requests will fail, since this indicates that
356 * the guest has hit an upper physical memory barrier.
357 *
358 * Hot adds may also fail due to low resources; in this case, the guest must
359 * not complete this message until the hot add can succeed, and the host must
360 * not send a new hot add request until the response is sent.
361 * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS
362 * times it fails the request.
363 *
364 *
365 * page_count: number of pages that were successfully hot added.
366 *
367 * result: result of the operation 1: success, 0: failure.
368 *
369 */
370
371struct dm_hot_add_response {
372 struct dm_header hdr;
373 __u32 page_count;
374 __u32 result;
375} __packed;
376
377/*
378 * Types of information sent from host to the guest.
379 */
380
381enum dm_info_type {
382 INFO_TYPE_MAX_PAGE_CNT = 0,
383 MAX_INFO_TYPE
384};
385
386
387/*
388 * Header for the information message.
389 */
390
391struct dm_info_header {
392 enum dm_info_type type;
393 __u32 data_size;
394} __packed;
395
396/*
397 * This message is sent from the host to the guest to pass
398 * some relevant information (win8 addition).
399 *
400 * reserved: no used.
401 * info_size: size of the information blob.
402 * info: information blob.
403 */
404
405struct dm_info_msg {
406 struct dm_info_header header;
407 __u32 reserved;
408 __u32 info_size;
409 __u8 info[];
410};
411
412/*
413 * End protocol definitions.
414 */
415
416static bool hot_add;
417static bool do_hot_add;
418
419module_param(hot_add, bool, (S_IRUGO | S_IWUSR));
420MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add");
421
422static atomic_t trans_id = ATOMIC_INIT(0);
423
424static int dm_ring_size = (5 * PAGE_SIZE);
425
426/*
427 * Driver specific state.
428 */
429
430enum hv_dm_state {
431 DM_INITIALIZING = 0,
432 DM_INITIALIZED,
433 DM_BALLOON_UP,
434 DM_BALLOON_DOWN,
435 DM_HOT_ADD,
436 DM_INIT_ERROR
437};
438
439
440static __u8 recv_buffer[PAGE_SIZE];
441static __u8 *send_buffer;
442#define PAGES_IN_2M 512
443
444struct hv_dynmem_device {
445 struct hv_device *dev;
446 enum hv_dm_state state;
447 struct completion host_event;
448 struct completion config_event;
449
450 /*
451 * Number of pages we have currently ballooned out.
452 */
453 unsigned int num_pages_ballooned;
454
455 /*
456 * This thread handles both balloon/hot-add
457 * requests from the host as well as notifying
458 * the host with regards to memory pressure in
459 * the guest.
460 */
461 struct task_struct *thread;
462
463 /*
464 * We start with the highest version we can support
465 * and downgrade based on the host; we save here the
466 * next version to try.
467 */
468 __u32 next_version;
469};
470
471static struct hv_dynmem_device dm_device;
472
473static void hot_add_req(struct hv_dynmem_device *dm, struct dm_hot_add *msg)
474{
475
476 struct dm_hot_add_response resp;
477
478 if (do_hot_add) {
479
480 pr_info("Memory hot add not supported\n");
481
482 /*
483 * Currently we do not support hot add.
484 * Just fail the request.
485 */
486 }
487
488 memset(&resp, 0, sizeof(struct dm_hot_add_response));
489 resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE;
490 resp.hdr.size = sizeof(struct dm_hot_add_response);
491 resp.hdr.trans_id = atomic_inc_return(&trans_id);
492
493 resp.page_count = 0;
494 resp.result = 0;
495
496 dm->state = DM_INITIALIZED;
497 vmbus_sendpacket(dm->dev->channel, &resp,
498 sizeof(struct dm_hot_add_response),
499 (unsigned long)NULL,
500 VM_PKT_DATA_INBAND, 0);
501
502}
503
504static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg)
505{
506 switch (msg->header.type) {
507 case INFO_TYPE_MAX_PAGE_CNT:
508 pr_info("Received INFO_TYPE_MAX_PAGE_CNT\n");
509 pr_info("Data Size is %d\n", msg->header.data_size);
510 break;
511 default:
512 pr_info("Received Unknown type: %d\n", msg->header.type);
513 }
514}
515
516/*
517 * Post our status as it relates memory pressure to the
518 * host. Host expects the guests to post this status
519 * periodically at 1 second intervals.
520 *
521 * The metrics specified in this protocol are very Windows
522 * specific and so we cook up numbers here to convey our memory
523 * pressure.
524 */
525
526static void post_status(struct hv_dynmem_device *dm)
527{
528 struct dm_status status;
529
530
531 memset(&status, 0, sizeof(struct dm_status));
532 status.hdr.type = DM_STATUS_REPORT;
533 status.hdr.size = sizeof(struct dm_status);
534 status.hdr.trans_id = atomic_inc_return(&trans_id);
535
536
537 status.num_committed = vm_memory_committed();
538
539 vmbus_sendpacket(dm->dev->channel, &status,
540 sizeof(struct dm_status),
541 (unsigned long)NULL,
542 VM_PKT_DATA_INBAND, 0);
543
544}
545
546
547
Greg Kroah-Hartman989623c2012-11-21 12:46:40 -0800548static void free_balloon_pages(struct hv_dynmem_device *dm,
K. Y. Srinivasan9aa8b502012-11-14 01:09:02 -0800549 union dm_mem_page_range *range_array)
550{
551 int num_pages = range_array->finfo.page_cnt;
552 __u64 start_frame = range_array->finfo.start_page;
553 struct page *pg;
554 int i;
555
556 for (i = 0; i < num_pages; i++) {
557 pg = pfn_to_page(i + start_frame);
558 __free_page(pg);
559 dm->num_pages_ballooned--;
560 }
561}
562
563
564
565static int alloc_balloon_pages(struct hv_dynmem_device *dm, int num_pages,
566 struct dm_balloon_response *bl_resp, int alloc_unit,
567 bool *alloc_error)
568{
569 int i = 0;
570 struct page *pg;
571
572 if (num_pages < alloc_unit)
573 return 0;
574
575 for (i = 0; (i * alloc_unit) < num_pages; i++) {
576 if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) >
577 PAGE_SIZE)
578 return i * alloc_unit;
579
580 /*
581 * We execute this code in a thread context. Furthermore,
582 * we don't want the kernel to try too hard.
583 */
584 pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY |
585 __GFP_NOMEMALLOC | __GFP_NOWARN,
586 get_order(alloc_unit << PAGE_SHIFT));
587
588 if (!pg) {
589 *alloc_error = true;
590 return i * alloc_unit;
591 }
592
593
594 dm->num_pages_ballooned += alloc_unit;
595
596 bl_resp->range_count++;
597 bl_resp->range_array[i].finfo.start_page =
598 page_to_pfn(pg);
599 bl_resp->range_array[i].finfo.page_cnt = alloc_unit;
600 bl_resp->hdr.size += sizeof(union dm_mem_page_range);
601
602 }
603
604 return num_pages;
605}
606
607
608
609static void balloon_up(struct hv_dynmem_device *dm, struct dm_balloon *req)
610{
611 int num_pages = req->num_pages;
612 int num_ballooned = 0;
613 struct dm_balloon_response *bl_resp;
614 int alloc_unit;
615 int ret;
616 bool alloc_error = false;
617 bool done = false;
618 int i;
619
620
621 /*
622 * Currently, we only support 4k allocations.
623 */
624 alloc_unit = 1;
625
626 while (!done) {
627 bl_resp = (struct dm_balloon_response *)send_buffer;
628 memset(send_buffer, 0, PAGE_SIZE);
629 bl_resp->hdr.type = DM_BALLOON_RESPONSE;
630 bl_resp->hdr.trans_id = atomic_inc_return(&trans_id);
631 bl_resp->hdr.size = sizeof(struct dm_balloon_response);
632 bl_resp->more_pages = 1;
633
634
635 num_pages -= num_ballooned;
636 num_ballooned = alloc_balloon_pages(dm, num_pages,
637 bl_resp, alloc_unit,
638 &alloc_error);
639
640 if ((alloc_error) || (num_ballooned == num_pages)) {
641 bl_resp->more_pages = 0;
642 done = true;
643 dm->state = DM_INITIALIZED;
644 }
645
646 /*
647 * We are pushing a lot of data through the channel;
648 * deal with transient failures caused because of the
649 * lack of space in the ring buffer.
650 */
651
652 do {
653 ret = vmbus_sendpacket(dm_device.dev->channel,
654 bl_resp,
655 bl_resp->hdr.size,
656 (unsigned long)NULL,
657 VM_PKT_DATA_INBAND, 0);
658
659 if (ret == -EAGAIN)
660 msleep(20);
661
662 } while (ret == -EAGAIN);
663
664 if (ret) {
665 /*
666 * Free up the memory we allocatted.
667 */
668 pr_info("Balloon response failed\n");
669
670 for (i = 0; i < bl_resp->range_count; i++)
671 free_balloon_pages(dm,
672 &bl_resp->range_array[i]);
673
674 done = true;
675 }
676 }
677
678}
679
680static void balloon_down(struct hv_dynmem_device *dm,
681 struct dm_unballoon_request *req)
682{
683 union dm_mem_page_range *range_array = req->range_array;
684 int range_count = req->range_count;
685 struct dm_unballoon_response resp;
686 int i;
687
688 for (i = 0; i < range_count; i++)
689 free_balloon_pages(dm, &range_array[i]);
690
691 if (req->more_pages == 1)
692 return;
693
694 memset(&resp, 0, sizeof(struct dm_unballoon_response));
695 resp.hdr.type = DM_UNBALLOON_RESPONSE;
696 resp.hdr.trans_id = atomic_inc_return(&trans_id);
697 resp.hdr.size = sizeof(struct dm_unballoon_response);
698
699 vmbus_sendpacket(dm_device.dev->channel, &resp,
700 sizeof(struct dm_unballoon_response),
701 (unsigned long)NULL,
702 VM_PKT_DATA_INBAND, 0);
703
704 dm->state = DM_INITIALIZED;
705}
706
707static void balloon_onchannelcallback(void *context);
708
709static int dm_thread_func(void *dm_dev)
710{
711 struct hv_dynmem_device *dm = dm_dev;
712 int t;
713 unsigned long scan_start;
714
715 while (!kthread_should_stop()) {
716 t = wait_for_completion_timeout(&dm_device.config_event, 1*HZ);
717 /*
718 * The host expects us to post information on the memory
719 * pressure every second.
720 */
721
722 if (t == 0)
723 post_status(dm);
724
725 scan_start = jiffies;
726 switch (dm->state) {
727 case DM_BALLOON_UP:
728 balloon_up(dm, (struct dm_balloon *)recv_buffer);
729 break;
730
731 case DM_HOT_ADD:
732 hot_add_req(dm, (struct dm_hot_add *)recv_buffer);
733 break;
734 default:
735 break;
736 }
737
738 if (!time_in_range(jiffies, scan_start, scan_start + HZ))
739 post_status(dm);
740
741 }
742
743 return 0;
744}
745
746
747static void version_resp(struct hv_dynmem_device *dm,
748 struct dm_version_response *vresp)
749{
750 struct dm_version_request version_req;
751 int ret;
752
753 if (vresp->is_accepted) {
754 /*
755 * We are done; wakeup the
756 * context waiting for version
757 * negotiation.
758 */
759 complete(&dm->host_event);
760 return;
761 }
762 /*
763 * If there are more versions to try, continue
764 * with negotiations; if not
765 * shutdown the service since we are not able
766 * to negotiate a suitable version number
767 * with the host.
768 */
769 if (dm->next_version == 0)
770 goto version_error;
771
772 dm->next_version = 0;
773 memset(&version_req, 0, sizeof(struct dm_version_request));
774 version_req.hdr.type = DM_VERSION_REQUEST;
775 version_req.hdr.size = sizeof(struct dm_version_request);
776 version_req.hdr.trans_id = atomic_inc_return(&trans_id);
777 version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN7;
778 version_req.is_last_attempt = 1;
779
780 ret = vmbus_sendpacket(dm->dev->channel, &version_req,
781 sizeof(struct dm_version_request),
782 (unsigned long)NULL,
783 VM_PKT_DATA_INBAND, 0);
784
785 if (ret)
786 goto version_error;
787
788 return;
789
790version_error:
791 dm->state = DM_INIT_ERROR;
792 complete(&dm->host_event);
793}
794
795static void cap_resp(struct hv_dynmem_device *dm,
796 struct dm_capabilities_resp_msg *cap_resp)
797{
798 if (!cap_resp->is_accepted) {
799 pr_info("Capabilities not accepted by host\n");
800 dm->state = DM_INIT_ERROR;
801 }
802 complete(&dm->host_event);
803}
804
805static void balloon_onchannelcallback(void *context)
806{
807 struct hv_device *dev = context;
808 u32 recvlen;
809 u64 requestid;
810 struct dm_message *dm_msg;
811 struct dm_header *dm_hdr;
812 struct hv_dynmem_device *dm = hv_get_drvdata(dev);
813
814 memset(recv_buffer, 0, sizeof(recv_buffer));
815 vmbus_recvpacket(dev->channel, recv_buffer,
816 PAGE_SIZE, &recvlen, &requestid);
817
818 if (recvlen > 0) {
819 dm_msg = (struct dm_message *)recv_buffer;
820 dm_hdr = &dm_msg->hdr;
821
822 switch (dm_hdr->type) {
823 case DM_VERSION_RESPONSE:
824 version_resp(dm,
825 (struct dm_version_response *)dm_msg);
826 break;
827
828 case DM_CAPABILITIES_RESPONSE:
829 cap_resp(dm,
830 (struct dm_capabilities_resp_msg *)dm_msg);
831 break;
832
833 case DM_BALLOON_REQUEST:
834 dm->state = DM_BALLOON_UP;
835 complete(&dm->config_event);
836 break;
837
838 case DM_UNBALLOON_REQUEST:
839 dm->state = DM_BALLOON_DOWN;
840 balloon_down(dm,
841 (struct dm_unballoon_request *)recv_buffer);
842 break;
843
844 case DM_MEM_HOT_ADD_REQUEST:
845 dm->state = DM_HOT_ADD;
846 complete(&dm->config_event);
847 break;
848
849 case DM_INFO_MESSAGE:
850 process_info(dm, (struct dm_info_msg *)dm_msg);
851 break;
852
853 default:
854 pr_err("Unhandled message: type: %d\n", dm_hdr->type);
855
856 }
857 }
858
859}
860
861static int balloon_probe(struct hv_device *dev,
862 const struct hv_vmbus_device_id *dev_id)
863{
864 int ret, t;
865 struct dm_version_request version_req;
866 struct dm_capabilities cap_msg;
867
868 do_hot_add = hot_add;
869
870 /*
871 * First allocate a send buffer.
872 */
873
874 send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
875 if (!send_buffer)
876 return -ENOMEM;
877
878 ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0,
879 balloon_onchannelcallback, dev);
880
881 if (ret)
882 return ret;
883
884 dm_device.dev = dev;
885 dm_device.state = DM_INITIALIZING;
886 dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN7;
887 init_completion(&dm_device.host_event);
888 init_completion(&dm_device.config_event);
889
890 dm_device.thread =
891 kthread_run(dm_thread_func, &dm_device, "hv_balloon");
892 if (IS_ERR(dm_device.thread)) {
893 ret = PTR_ERR(dm_device.thread);
894 goto probe_error0;
895 }
896
897 hv_set_drvdata(dev, &dm_device);
898 /*
899 * Initiate the hand shake with the host and negotiate
900 * a version that the host can support. We start with the
901 * highest version number and go down if the host cannot
902 * support it.
903 */
904 memset(&version_req, 0, sizeof(struct dm_version_request));
905 version_req.hdr.type = DM_VERSION_REQUEST;
906 version_req.hdr.size = sizeof(struct dm_version_request);
907 version_req.hdr.trans_id = atomic_inc_return(&trans_id);
908 version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN8;
909 version_req.is_last_attempt = 0;
910
911 ret = vmbus_sendpacket(dev->channel, &version_req,
912 sizeof(struct dm_version_request),
913 (unsigned long)NULL,
914 VM_PKT_DATA_INBAND,
915 VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
916 if (ret)
917 goto probe_error1;
918
919 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
920 if (t == 0) {
921 ret = -ETIMEDOUT;
922 goto probe_error1;
923 }
924
925 /*
926 * If we could not negotiate a compatible version with the host
927 * fail the probe function.
928 */
929 if (dm_device.state == DM_INIT_ERROR) {
930 ret = -ETIMEDOUT;
931 goto probe_error1;
932 }
933 /*
934 * Now submit our capabilities to the host.
935 */
936 memset(&cap_msg, 0, sizeof(struct dm_capabilities));
937 cap_msg.hdr.type = DM_CAPABILITIES_REPORT;
938 cap_msg.hdr.size = sizeof(struct dm_capabilities);
939 cap_msg.hdr.trans_id = atomic_inc_return(&trans_id);
940
941 cap_msg.caps.cap_bits.balloon = 1;
942 /*
943 * While we currently don't support hot-add,
944 * we still advertise this capability since the
945 * host requires that guests partcipating in the
946 * dynamic memory protocol support hot add.
947 */
948 cap_msg.caps.cap_bits.hot_add = 1;
949
950 /*
951 * Currently the host does not use these
952 * values and we set them to what is done in the
953 * Windows driver.
954 */
955 cap_msg.min_page_cnt = 0;
956 cap_msg.max_page_number = -1;
957
958 ret = vmbus_sendpacket(dev->channel, &cap_msg,
959 sizeof(struct dm_capabilities),
960 (unsigned long)NULL,
961 VM_PKT_DATA_INBAND,
962 VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
963 if (ret)
964 goto probe_error1;
965
966 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
967 if (t == 0) {
968 ret = -ETIMEDOUT;
969 goto probe_error1;
970 }
971
972 /*
973 * If the host does not like our capabilities,
974 * fail the probe function.
975 */
976 if (dm_device.state == DM_INIT_ERROR) {
977 ret = -ETIMEDOUT;
978 goto probe_error1;
979 }
980
981 dm_device.state = DM_INITIALIZED;
982
983 return 0;
984
985probe_error1:
986 kthread_stop(dm_device.thread);
987
988probe_error0:
989 vmbus_close(dev->channel);
990 return ret;
991}
992
993static int balloon_remove(struct hv_device *dev)
994{
995 struct hv_dynmem_device *dm = hv_get_drvdata(dev);
996
997 if (dm->num_pages_ballooned != 0)
998 pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned);
999
1000 vmbus_close(dev->channel);
1001 kthread_stop(dm->thread);
1002
1003 return 0;
1004}
1005
1006static const struct hv_vmbus_device_id id_table[] = {
1007 /* Dynamic Memory Class ID */
1008 /* 525074DC-8985-46e2-8057-A307DC18A502 */
1009 { VMBUS_DEVICE(0xdc, 0x74, 0x50, 0X52, 0x85, 0x89, 0xe2, 0x46,
1010 0x80, 0x57, 0xa3, 0x07, 0xdc, 0x18, 0xa5, 0x02)
1011 },
1012 { },
1013};
1014
1015MODULE_DEVICE_TABLE(vmbus, id_table);
1016
1017static struct hv_driver balloon_drv = {
1018 .name = "hv_balloon",
1019 .id_table = id_table,
1020 .probe = balloon_probe,
1021 .remove = balloon_remove,
1022};
1023
1024static int __init init_balloon_drv(void)
1025{
1026
1027 return vmbus_driver_register(&balloon_drv);
1028}
1029
1030static void exit_balloon_drv(void)
1031{
1032
1033 vmbus_driver_unregister(&balloon_drv);
1034}
1035
1036module_init(init_balloon_drv);
1037module_exit(exit_balloon_drv);
1038
1039MODULE_DESCRIPTION("Hyper-V Balloon");
1040MODULE_VERSION(HV_DRV_VERSION);
1041MODULE_LICENSE("GPL");