source: src/linux/universal/linux-3.18/drivers/hv/hv_balloon.c @ 31885

Last change on this file since 31885 was 31885, checked in by brainslayer, 3 months ago

update

File size: 36.7 KB
Line 
1/*
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/jiffies.h>
23#include <linux/mman.h>
24#include <linux/delay.h>
25#include <linux/init.h>
26#include <linux/module.h>
27#include <linux/slab.h>
28#include <linux/kthread.h>
29#include <linux/completion.h>
30#include <linux/memory_hotplug.h>
31#include <linux/memory.h>
32#include <linux/notifier.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                /*
122                 * To support guests that may have alignment
123                 * limitations on hot-add, the guest can specify
124                 * its alignment requirements; a value of n
125                 * represents an alignment of 2^n in mega bytes.
126                 */
127                __u64 hot_add_alignment:4;
128                __u64 reservedz:58;
129        } cap_bits;
130        __u64 caps;
131} __packed;
132
133union dm_mem_page_range {
134        struct  {
135                /*
136                 * The PFN number of the first page in the range.
137                 * 40 bits is the architectural limit of a PFN
138                 * number for AMD64.
139                 */
140                __u64 start_page:40;
141                /*
142                 * The number of pages in the range.
143                 */
144                __u64 page_cnt:24;
145        } finfo;
146        __u64  page_range;
147} __packed;
148
149
150
151/*
152 * The header for all dynamic memory messages:
153 *
154 * type: Type of the message.
155 * size: Size of the message in bytes; including the header.
156 * trans_id: The guest is responsible for manufacturing this ID.
157 */
158
159struct dm_header {
160        __u16 type;
161        __u16 size;
162        __u32 trans_id;
163} __packed;
164
165/*
166 * A generic message format for dynamic memory.
167 * Specific message formats are defined later in the file.
168 */
169
170struct dm_message {
171        struct dm_header hdr;
172        __u8 data[]; /* enclosed message */
173} __packed;
174
175
176/*
177 * Specific message types supporting the dynamic memory protocol.
178 */
179
180/*
181 * Version negotiation message. Sent from the guest to the host.
182 * The guest is free to try different versions until the host
183 * accepts the version.
184 *
185 * dm_version: The protocol version requested.
186 * is_last_attempt: If TRUE, this is the last version guest will request.
187 * reservedz: Reserved field, set to zero.
188 */
189
190struct dm_version_request {
191        struct dm_header hdr;
192        union dm_version version;
193        __u32 is_last_attempt:1;
194        __u32 reservedz:31;
195} __packed;
196
197/*
198 * Version response message; Host to Guest and indicates
199 * if the host has accepted the version sent by the guest.
200 *
201 * is_accepted: If TRUE, host has accepted the version and the guest
202 * should proceed to the next stage of the protocol. FALSE indicates that
203 * guest should re-try with a different version.
204 *
205 * reservedz: Reserved field, set to zero.
206 */
207
208struct dm_version_response {
209        struct dm_header hdr;
210        __u64 is_accepted:1;
211        __u64 reservedz:63;
212} __packed;
213
214/*
215 * Message reporting capabilities. This is sent from the guest to the
216 * host.
217 */
218
219struct dm_capabilities {
220        struct dm_header hdr;
221        union dm_caps caps;
222        __u64 min_page_cnt;
223        __u64 max_page_number;
224} __packed;
225
226/*
227 * Response to the capabilities message. This is sent from the host to the
228 * guest. This message notifies if the host has accepted the guest's
229 * capabilities. If the host has not accepted, the guest must shutdown
230 * the service.
231 *
232 * is_accepted: Indicates if the host has accepted guest's capabilities.
233 * reservedz: Must be 0.
234 */
235
236struct dm_capabilities_resp_msg {
237        struct dm_header hdr;
238        __u64 is_accepted:1;
239        __u64 reservedz:63;
240} __packed;
241
242/*
243 * This message is used to report memory pressure from the guest.
244 * This message is not part of any transaction and there is no
245 * response to this message.
246 *
247 * num_avail: Available memory in pages.
248 * num_committed: Committed memory in pages.
249 * page_file_size: The accumulated size of all page files
250 *                 in the system in pages.
251 * zero_free: The nunber of zero and free pages.
252 * page_file_writes: The writes to the page file in pages.
253 * io_diff: An indicator of file cache efficiency or page file activity,
254 *          calculated as File Cache Page Fault Count - Page Read Count.
255 *          This value is in pages.
256 *
257 * Some of these metrics are Windows specific and fortunately
258 * the algorithm on the host side that computes the guest memory
259 * pressure only uses num_committed value.
260 */
261
262struct dm_status {
263        struct dm_header hdr;
264        __u64 num_avail;
265        __u64 num_committed;
266        __u64 page_file_size;
267        __u64 zero_free;
268        __u32 page_file_writes;
269        __u32 io_diff;
270} __packed;
271
272
273/*
274 * Message to ask the guest to allocate memory - balloon up message.
275 * This message is sent from the host to the guest. The guest may not be
276 * able to allocate as much memory as requested.
277 *
278 * num_pages: number of pages to allocate.
279 */
280
281struct dm_balloon {
282        struct dm_header hdr;
283        __u32 num_pages;
284        __u32 reservedz;
285} __packed;
286
287
288/*
289 * Balloon response message; this message is sent from the guest
290 * to the host in response to the balloon message.
291 *
292 * reservedz: Reserved; must be set to zero.
293 * more_pages: If FALSE, this is the last message of the transaction.
294 * if TRUE there will atleast one more message from the guest.
295 *
296 * range_count: The number of ranges in the range array.
297 *
298 * range_array: An array of page ranges returned to the host.
299 *
300 */
301
302struct dm_balloon_response {
303        struct dm_header hdr;
304        __u32 reservedz;
305        __u32 more_pages:1;
306        __u32 range_count:31;
307        union dm_mem_page_range range_array[];
308} __packed;
309
310/*
311 * Un-balloon message; this message is sent from the host
312 * to the guest to give guest more memory.
313 *
314 * more_pages: If FALSE, this is the last message of the transaction.
315 * if TRUE there will atleast one more message from the guest.
316 *
317 * reservedz: Reserved; must be set to zero.
318 *
319 * range_count: The number of ranges in the range array.
320 *
321 * range_array: An array of page ranges returned to the host.
322 *
323 */
324
325struct dm_unballoon_request {
326        struct dm_header hdr;
327        __u32 more_pages:1;
328        __u32 reservedz:31;
329        __u32 range_count;
330        union dm_mem_page_range range_array[];
331} __packed;
332
333/*
334 * Un-balloon response message; this message is sent from the guest
335 * to the host in response to an unballoon request.
336 *
337 */
338
339struct dm_unballoon_response {
340        struct dm_header hdr;
341} __packed;
342
343
344/*
345 * Hot add request message. Message sent from the host to the guest.
346 *
347 * mem_range: Memory range to hot add.
348 *
349 * On Linux we currently don't support this since we cannot hot add
350 * arbitrary granularity of memory.
351 */
352
353struct dm_hot_add {
354        struct dm_header hdr;
355        union dm_mem_page_range range;
356} __packed;
357
358/*
359 * Hot add response message.
360 * This message is sent by the guest to report the status of a hot add request.
361 * If page_count is less than the requested page count, then the host should
362 * assume all further hot add requests will fail, since this indicates that
363 * the guest has hit an upper physical memory barrier.
364 *
365 * Hot adds may also fail due to low resources; in this case, the guest must
366 * not complete this message until the hot add can succeed, and the host must
367 * not send a new hot add request until the response is sent.
368 * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS
369 * times it fails the request.
370 *
371 *
372 * page_count: number of pages that were successfully hot added.
373 *
374 * result: result of the operation 1: success, 0: failure.
375 *
376 */
377
378struct dm_hot_add_response {
379        struct dm_header hdr;
380        __u32 page_count;
381        __u32 result;
382} __packed;
383
384/*
385 * Types of information sent from host to the guest.
386 */
387
388enum dm_info_type {
389        INFO_TYPE_MAX_PAGE_CNT = 0,
390        MAX_INFO_TYPE
391};
392
393
394/*
395 * Header for the information message.
396 */
397
398struct dm_info_header {
399        enum dm_info_type type;
400        __u32 data_size;
401} __packed;
402
403/*
404 * This message is sent from the host to the guest to pass
405 * some relevant information (win8 addition).
406 *
407 * reserved: no used.
408 * info_size: size of the information blob.
409 * info: information blob.
410 */
411
412struct dm_info_msg {
413        struct dm_header hdr;
414        __u32 reserved;
415        __u32 info_size;
416        __u8  info[];
417};
418
419/*
420 * End protocol definitions.
421 */
422
423/*
424 * State to manage hot adding memory into the guest.
425 * The range start_pfn : end_pfn specifies the range
426 * that the host has asked us to hot add. The range
427 * start_pfn : ha_end_pfn specifies the range that we have
428 * currently hot added. We hot add in multiples of 128M
429 * chunks; it is possible that we may not be able to bring
430 * online all the pages in the region. The range
431 * covered_start_pfn : covered_end_pfn defines the pages that can
432 * be brough online.
433 */
434
435struct hv_hotadd_state {
436        struct list_head list;
437        unsigned long start_pfn;
438        unsigned long covered_start_pfn;
439        unsigned long covered_end_pfn;
440        unsigned long ha_end_pfn;
441        unsigned long end_pfn;
442};
443
444struct balloon_state {
445        __u32 num_pages;
446        struct work_struct wrk;
447};
448
449struct hot_add_wrk {
450        union dm_mem_page_range ha_page_range;
451        union dm_mem_page_range ha_region_range;
452        struct work_struct wrk;
453};
454
455static bool hot_add = true;
456static bool do_hot_add;
457/*
458 * Delay reporting memory pressure by
459 * the specified number of seconds.
460 */
461static uint pressure_report_delay = 45;
462
463/*
464 * The last time we posted a pressure report to host.
465 */
466static unsigned long last_post_time;
467
468module_param(hot_add, bool, (S_IRUGO | S_IWUSR));
469MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add");
470
471module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR));
472MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure");
473static atomic_t trans_id = ATOMIC_INIT(0);
474
475static int dm_ring_size = (5 * PAGE_SIZE);
476
477/*
478 * Driver specific state.
479 */
480
481enum hv_dm_state {
482        DM_INITIALIZING = 0,
483        DM_INITIALIZED,
484        DM_BALLOON_UP,
485        DM_BALLOON_DOWN,
486        DM_HOT_ADD,
487        DM_INIT_ERROR
488};
489
490
491static __u8 recv_buffer[PAGE_SIZE];
492static __u8 *send_buffer;
493#define PAGES_IN_2M     512
494#define HA_CHUNK (32 * 1024)
495
496struct hv_dynmem_device {
497        struct hv_device *dev;
498        enum hv_dm_state state;
499        struct completion host_event;
500        struct completion config_event;
501
502        /*
503         * Number of pages we have currently ballooned out.
504         */
505        unsigned int num_pages_ballooned;
506
507        /*
508         * State to manage the ballooning (up) operation.
509         */
510        struct balloon_state balloon_wrk;
511
512        /*
513         * State to execute the "hot-add" operation.
514         */
515        struct hot_add_wrk ha_wrk;
516
517        /*
518         * This state tracks if the host has specified a hot-add
519         * region.
520         */
521        bool host_specified_ha_region;
522
523        /*
524         * State to synchronize hot-add.
525         */
526        struct completion  ol_waitevent;
527        bool ha_waiting;
528        /*
529         * This thread handles hot-add
530         * requests from the host as well as notifying
531         * the host with regards to memory pressure in
532         * the guest.
533         */
534        struct task_struct *thread;
535
536        /*
537         * A list of hot-add regions.
538         */
539        struct list_head ha_region_list;
540
541        /*
542         * We start with the highest version we can support
543         * and downgrade based on the host; we save here the
544         * next version to try.
545         */
546        __u32 next_version;
547};
548
549static struct hv_dynmem_device dm_device;
550
551static void post_status(struct hv_dynmem_device *dm);
552#ifdef CONFIG_MEMORY_HOTPLUG
553
554static void hv_bring_pgs_online(unsigned long start_pfn, unsigned long size)
555{
556        int i;
557
558        for (i = 0; i < size; i++) {
559                struct page *pg;
560                pg = pfn_to_page(start_pfn + i);
561                __online_page_set_limits(pg);
562                __online_page_increment_counters(pg);
563                __online_page_free(pg);
564        }
565}
566
567static void hv_mem_hot_add(unsigned long start, unsigned long size,
568                                unsigned long pfn_count,
569                                struct hv_hotadd_state *has)
570{
571        int ret = 0;
572        int i, nid;
573        unsigned long start_pfn;
574        unsigned long processed_pfn;
575        unsigned long total_pfn = pfn_count;
576
577        for (i = 0; i < (size/HA_CHUNK); i++) {
578                start_pfn = start + (i * HA_CHUNK);
579                has->ha_end_pfn +=  HA_CHUNK;
580
581                if (total_pfn > HA_CHUNK) {
582                        processed_pfn = HA_CHUNK;
583                        total_pfn -= HA_CHUNK;
584                } else {
585                        processed_pfn = total_pfn;
586                        total_pfn = 0;
587                }
588
589                has->covered_end_pfn +=  processed_pfn;
590
591                init_completion(&dm_device.ol_waitevent);
592                dm_device.ha_waiting = true;
593
594                nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));
595                ret = add_memory(nid, PFN_PHYS((start_pfn)),
596                                (HA_CHUNK << PAGE_SHIFT));
597
598                if (ret) {
599                        pr_info("hot_add memory failed error is %d\n", ret);
600                        if (ret == -EEXIST) {
601                                /*
602                                 * This error indicates that the error
603                                 * is not a transient failure. This is the
604                                 * case where the guest's physical address map
605                                 * precludes hot adding memory. Stop all further
606                                 * memory hot-add.
607                                 */
608                                do_hot_add = false;
609                        }
610                        has->ha_end_pfn -= HA_CHUNK;
611                        has->covered_end_pfn -=  processed_pfn;
612                        break;
613                }
614
615                /*
616                 * Wait for the memory block to be onlined.
617                 * Since the hot add has succeeded, it is ok to
618                 * proceed even if the pages in the hot added region
619                 * have not been "onlined" within the allowed time.
620                 */
621                wait_for_completion_timeout(&dm_device.ol_waitevent, 5*HZ);
622                post_status(&dm_device);
623        }
624
625        return;
626}
627
628static void hv_online_page(struct page *pg)
629{
630        struct list_head *cur;
631        struct hv_hotadd_state *has;
632        unsigned long cur_start_pgp;
633        unsigned long cur_end_pgp;
634
635        if (dm_device.ha_waiting) {
636                dm_device.ha_waiting = false;
637                complete(&dm_device.ol_waitevent);
638        }
639
640        list_for_each(cur, &dm_device.ha_region_list) {
641                has = list_entry(cur, struct hv_hotadd_state, list);
642                cur_start_pgp = (unsigned long)
643                                pfn_to_page(has->covered_start_pfn);
644                cur_end_pgp = (unsigned long)pfn_to_page(has->covered_end_pfn);
645
646                if (((unsigned long)pg >= cur_start_pgp) &&
647                        ((unsigned long)pg < cur_end_pgp)) {
648                        /*
649                         * This frame is currently backed; online the
650                         * page.
651                         */
652                        __online_page_set_limits(pg);
653                        __online_page_increment_counters(pg);
654                        __online_page_free(pg);
655                        has->covered_start_pfn++;
656                }
657        }
658}
659
660static bool pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
661{
662        struct list_head *cur;
663        struct hv_hotadd_state *has;
664        unsigned long residual, new_inc;
665
666        if (list_empty(&dm_device.ha_region_list))
667                return false;
668
669        list_for_each(cur, &dm_device.ha_region_list) {
670                has = list_entry(cur, struct hv_hotadd_state, list);
671
672                /*
673                 * If the pfn range we are dealing with is not in the current
674                 * "hot add block", move on.
675                 */
676                if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)
677                        continue;
678                /*
679                 * If the current hot add-request extends beyond
680                 * our current limit; extend it.
681                 */
682                if ((start_pfn + pfn_cnt) > has->end_pfn) {
683                        residual = (start_pfn + pfn_cnt - has->end_pfn);
684                        /*
685                         * Extend the region by multiples of HA_CHUNK.
686                         */
687                        new_inc = (residual / HA_CHUNK) * HA_CHUNK;
688                        if (residual % HA_CHUNK)
689                                new_inc += HA_CHUNK;
690
691                        has->end_pfn += new_inc;
692                }
693
694                /*
695                 * If the current start pfn is not where the covered_end
696                 * is, update it.
697                 */
698
699                if (has->covered_end_pfn != start_pfn) {
700                        has->covered_end_pfn = start_pfn;
701                        has->covered_start_pfn = start_pfn;
702                }
703                return true;
704
705        }
706
707        return false;
708}
709
710static unsigned long handle_pg_range(unsigned long pg_start,
711                                        unsigned long pg_count)
712{
713        unsigned long start_pfn = pg_start;
714        unsigned long pfn_cnt = pg_count;
715        unsigned long size;
716        struct list_head *cur;
717        struct hv_hotadd_state *has;
718        unsigned long pgs_ol = 0;
719        unsigned long old_covered_state;
720
721        if (list_empty(&dm_device.ha_region_list))
722                return 0;
723
724        list_for_each(cur, &dm_device.ha_region_list) {
725                has = list_entry(cur, struct hv_hotadd_state, list);
726
727                /*
728                 * If the pfn range we are dealing with is not in the current
729                 * "hot add block", move on.
730                 */
731                if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)
732                        continue;
733
734                old_covered_state = has->covered_end_pfn;
735
736                if (start_pfn < has->ha_end_pfn) {
737                        /*
738                         * This is the case where we are backing pages
739                         * in an already hot added region. Bring
740                         * these pages online first.
741                         */
742                        pgs_ol = has->ha_end_pfn - start_pfn;
743                        if (pgs_ol > pfn_cnt)
744                                pgs_ol = pfn_cnt;
745                        hv_bring_pgs_online(start_pfn, pgs_ol);
746                        has->covered_end_pfn +=  pgs_ol;
747                        has->covered_start_pfn +=  pgs_ol;
748                        pfn_cnt -= pgs_ol;
749                }
750
751                if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) {
752                        /*
753                         * We have some residual hot add range
754                         * that needs to be hot added; hot add
755                         * it now. Hot add a multiple of
756                         * of HA_CHUNK that fully covers the pages
757                         * we have.
758                         */
759                        size = (has->end_pfn - has->ha_end_pfn);
760                        if (pfn_cnt <= size) {
761                                size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK);
762                                if (pfn_cnt % HA_CHUNK)
763                                        size += HA_CHUNK;
764                        } else {
765                                pfn_cnt = size;
766                        }
767                        hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has);
768                }
769                /*
770                 * If we managed to online any pages that were given to us,
771                 * we declare success.
772                 */
773                return has->covered_end_pfn - old_covered_state;
774
775        }
776
777        return 0;
778}
779
780static unsigned long process_hot_add(unsigned long pg_start,
781                                        unsigned long pfn_cnt,
782                                        unsigned long rg_start,
783                                        unsigned long rg_size)
784{
785        struct hv_hotadd_state *ha_region = NULL;
786
787        if (pfn_cnt == 0)
788                return 0;
789
790        if (!dm_device.host_specified_ha_region)
791                if (pfn_covered(pg_start, pfn_cnt))
792                        goto do_pg_range;
793
794        /*
795         * If the host has specified a hot-add range; deal with it first.
796         */
797
798        if (rg_size != 0) {
799                ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL);
800                if (!ha_region)
801                        return 0;
802
803                INIT_LIST_HEAD(&ha_region->list);
804
805                list_add_tail(&ha_region->list, &dm_device.ha_region_list);
806                ha_region->start_pfn = rg_start;
807                ha_region->ha_end_pfn = rg_start;
808                ha_region->covered_start_pfn = pg_start;
809                ha_region->covered_end_pfn = pg_start;
810                ha_region->end_pfn = rg_start + rg_size;
811        }
812
813do_pg_range:
814        /*
815         * Process the page range specified; bringing them
816         * online if possible.
817         */
818        return handle_pg_range(pg_start, pfn_cnt);
819}
820
821#endif
822
823static void hot_add_req(struct work_struct *dummy)
824{
825        struct dm_hot_add_response resp;
826#ifdef CONFIG_MEMORY_HOTPLUG
827        unsigned long pg_start, pfn_cnt;
828        unsigned long rg_start, rg_sz;
829#endif
830        struct hv_dynmem_device *dm = &dm_device;
831
832        memset(&resp, 0, sizeof(struct dm_hot_add_response));
833        resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE;
834        resp.hdr.size = sizeof(struct dm_hot_add_response);
835
836#ifdef CONFIG_MEMORY_HOTPLUG
837        pg_start = dm->ha_wrk.ha_page_range.finfo.start_page;
838        pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt;
839
840        rg_start = dm->ha_wrk.ha_region_range.finfo.start_page;
841        rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt;
842
843        if ((rg_start == 0) && (!dm->host_specified_ha_region)) {
844                unsigned long region_size;
845                unsigned long region_start;
846
847                /*
848                 * The host has not specified the hot-add region.
849                 * Based on the hot-add page range being specified,
850                 * compute a hot-add region that can cover the pages
851                 * that need to be hot-added while ensuring the alignment
852                 * and size requirements of Linux as it relates to hot-add.
853                 */
854                region_start = pg_start;
855                region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK;
856                if (pfn_cnt % HA_CHUNK)
857                        region_size += HA_CHUNK;
858
859                region_start = (pg_start / HA_CHUNK) * HA_CHUNK;
860
861                rg_start = region_start;
862                rg_sz = region_size;
863        }
864
865        if (do_hot_add)
866                resp.page_count = process_hot_add(pg_start, pfn_cnt,
867                                                rg_start, rg_sz);
868#endif
869        /*
870         * The result field of the response structure has the
871         * following semantics:
872         *
873         * 1. If all or some pages hot-added: Guest should return success.
874         *
875         * 2. If no pages could be hot-added:
876         *
877         * If the guest returns success, then the host
878         * will not attempt any further hot-add operations. This
879         * signifies a permanent failure.
880         *
881         * If the guest returns failure, then this failure will be
882         * treated as a transient failure and the host may retry the
883         * hot-add operation after some delay.
884         */
885        if (resp.page_count > 0)
886                resp.result = 1;
887        else if (!do_hot_add)
888                resp.result = 1;
889        else
890                resp.result = 0;
891
892        if (!do_hot_add || (resp.page_count == 0))
893                pr_info("Memory hot add failed\n");
894
895        dm->state = DM_INITIALIZED;
896        resp.hdr.trans_id = atomic_inc_return(&trans_id);
897        vmbus_sendpacket(dm->dev->channel, &resp,
898                        sizeof(struct dm_hot_add_response),
899                        (unsigned long)NULL,
900                        VM_PKT_DATA_INBAND, 0);
901}
902
903static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg)
904{
905        struct dm_info_header *info_hdr;
906
907        info_hdr = (struct dm_info_header *)msg->info;
908
909        switch (info_hdr->type) {
910        case INFO_TYPE_MAX_PAGE_CNT:
911                pr_info("Received INFO_TYPE_MAX_PAGE_CNT\n");
912                pr_info("Data Size is %d\n", info_hdr->data_size);
913                break;
914        default:
915                pr_info("Received Unknown type: %d\n", info_hdr->type);
916        }
917}
918
919static unsigned long compute_balloon_floor(void)
920{
921        unsigned long min_pages;
922#define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT))
923        /* Simple continuous piecewiese linear function:
924         *  max MiB -> min MiB  gradient
925         *       0         0
926         *      16        16
927         *      32        24
928         *     128        72    (1/2)
929         *     512       168    (1/4)
930         *    2048       360    (1/8)
931         *    8192       552    (1/32)
932         *   32768      1320
933         *  131072      4392
934         */
935        if (totalram_pages < MB2PAGES(128))
936                min_pages = MB2PAGES(8) + (totalram_pages >> 1);
937        else if (totalram_pages < MB2PAGES(512))
938                min_pages = MB2PAGES(40) + (totalram_pages >> 2);
939        else if (totalram_pages < MB2PAGES(2048))
940                min_pages = MB2PAGES(104) + (totalram_pages >> 3);
941        else
942                min_pages = MB2PAGES(296) + (totalram_pages >> 5);
943#undef MB2PAGES
944        return min_pages;
945}
946
947/*
948 * Post our status as it relates memory pressure to the
949 * host. Host expects the guests to post this status
950 * periodically at 1 second intervals.
951 *
952 * The metrics specified in this protocol are very Windows
953 * specific and so we cook up numbers here to convey our memory
954 * pressure.
955 */
956
957static void post_status(struct hv_dynmem_device *dm)
958{
959        struct dm_status status;
960        struct sysinfo val;
961        unsigned long now = jiffies;
962        unsigned long last_post = last_post_time;
963
964        if (pressure_report_delay > 0) {
965                --pressure_report_delay;
966                return;
967        }
968
969        if (!time_after(now, (last_post_time + HZ)))
970                return;
971
972        si_meminfo(&val);
973        memset(&status, 0, sizeof(struct dm_status));
974        status.hdr.type = DM_STATUS_REPORT;
975        status.hdr.size = sizeof(struct dm_status);
976        status.hdr.trans_id = atomic_inc_return(&trans_id);
977
978        /*
979         * The host expects the guest to report free memory.
980         * Further, the host expects the pressure information to
981         * include the ballooned out pages.
982         * For a given amount of memory that we are managing, we
983         * need to compute a floor below which we should not balloon.
984         * Compute this and add it to the pressure report.
985         */
986        status.num_avail = val.freeram;
987        status.num_committed = vm_memory_committed() +
988                                dm->num_pages_ballooned +
989                                compute_balloon_floor();
990
991        /*
992         * If our transaction ID is no longer current, just don't
993         * send the status. This can happen if we were interrupted
994         * after we picked our transaction ID.
995         */
996        if (status.hdr.trans_id != atomic_read(&trans_id))
997                return;
998
999        /*
1000         * If the last post time that we sampled has changed,
1001         * we have raced, don't post the status.
1002         */
1003        if (last_post != last_post_time)
1004                return;
1005
1006        last_post_time = jiffies;
1007        vmbus_sendpacket(dm->dev->channel, &status,
1008                                sizeof(struct dm_status),
1009                                (unsigned long)NULL,
1010                                VM_PKT_DATA_INBAND, 0);
1011
1012}
1013
1014static void free_balloon_pages(struct hv_dynmem_device *dm,
1015                         union dm_mem_page_range *range_array)
1016{
1017        int num_pages = range_array->finfo.page_cnt;
1018        __u64 start_frame = range_array->finfo.start_page;
1019        struct page *pg;
1020        int i;
1021
1022        for (i = 0; i < num_pages; i++) {
1023                pg = pfn_to_page(i + start_frame);
1024                __free_page(pg);
1025                dm->num_pages_ballooned--;
1026        }
1027}
1028
1029
1030
1031static int  alloc_balloon_pages(struct hv_dynmem_device *dm, int num_pages,
1032                         struct dm_balloon_response *bl_resp, int alloc_unit,
1033                         bool *alloc_error)
1034{
1035        int i = 0;
1036        struct page *pg;
1037
1038        if (num_pages < alloc_unit)
1039                return 0;
1040
1041        for (i = 0; (i * alloc_unit) < num_pages; i++) {
1042                if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) >
1043                        PAGE_SIZE)
1044                        return i * alloc_unit;
1045
1046                /*
1047                 * We execute this code in a thread context. Furthermore,
1048                 * we don't want the kernel to try too hard.
1049                 */
1050                pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY |
1051                                __GFP_NOMEMALLOC | __GFP_NOWARN,
1052                                get_order(alloc_unit << PAGE_SHIFT));
1053
1054                if (!pg) {
1055                        *alloc_error = true;
1056                        return i * alloc_unit;
1057                }
1058
1059
1060                dm->num_pages_ballooned += alloc_unit;
1061
1062                /*
1063                 * If we allocatted 2M pages; split them so we
1064                 * can free them in any order we get.
1065                 */
1066
1067                if (alloc_unit != 1)
1068                        split_page(pg, get_order(alloc_unit << PAGE_SHIFT));
1069
1070                bl_resp->range_count++;
1071                bl_resp->range_array[i].finfo.start_page =
1072                        page_to_pfn(pg);
1073                bl_resp->range_array[i].finfo.page_cnt = alloc_unit;
1074                bl_resp->hdr.size += sizeof(union dm_mem_page_range);
1075
1076        }
1077
1078        return num_pages;
1079}
1080
1081
1082
1083static void balloon_up(struct work_struct *dummy)
1084{
1085        int num_pages = dm_device.balloon_wrk.num_pages;
1086        int num_ballooned = 0;
1087        struct dm_balloon_response *bl_resp;
1088        int alloc_unit;
1089        int ret;
1090        bool alloc_error = false;
1091        bool done = false;
1092        int i;
1093
1094
1095        /*
1096         * We will attempt 2M allocations. However, if we fail to
1097         * allocate 2M chunks, we will go back to 4k allocations.
1098         */
1099        alloc_unit = 512;
1100
1101        while (!done) {
1102                bl_resp = (struct dm_balloon_response *)send_buffer;
1103                memset(send_buffer, 0, PAGE_SIZE);
1104                bl_resp->hdr.type = DM_BALLOON_RESPONSE;
1105                bl_resp->hdr.size = sizeof(struct dm_balloon_response);
1106                bl_resp->more_pages = 1;
1107
1108
1109                num_pages -= num_ballooned;
1110                num_ballooned = alloc_balloon_pages(&dm_device, num_pages,
1111                                                bl_resp, alloc_unit,
1112                                                 &alloc_error);
1113
1114                if ((alloc_error) && (alloc_unit != 1)) {
1115                        alloc_unit = 1;
1116                        continue;
1117                }
1118
1119                if ((alloc_error) || (num_ballooned == num_pages)) {
1120                        bl_resp->more_pages = 0;
1121                        done = true;
1122                        dm_device.state = DM_INITIALIZED;
1123                }
1124
1125                /*
1126                 * We are pushing a lot of data through the channel;
1127                 * deal with transient failures caused because of the
1128                 * lack of space in the ring buffer.
1129                 */
1130
1131                do {
1132                        bl_resp->hdr.trans_id = atomic_inc_return(&trans_id);
1133                        ret = vmbus_sendpacket(dm_device.dev->channel,
1134                                                bl_resp,
1135                                                bl_resp->hdr.size,
1136                                                (unsigned long)NULL,
1137                                                VM_PKT_DATA_INBAND, 0);
1138
1139                        if (ret == -EAGAIN)
1140                                msleep(20);
1141                        post_status(&dm_device);
1142                } while (ret == -EAGAIN);
1143
1144                if (ret) {
1145                        /*
1146                         * Free up the memory we allocatted.
1147                         */
1148                        pr_info("Balloon response failed\n");
1149
1150                        for (i = 0; i < bl_resp->range_count; i++)
1151                                free_balloon_pages(&dm_device,
1152                                                 &bl_resp->range_array[i]);
1153
1154                        done = true;
1155                }
1156        }
1157
1158}
1159
1160static void balloon_down(struct hv_dynmem_device *dm,
1161                        struct dm_unballoon_request *req)
1162{
1163        union dm_mem_page_range *range_array = req->range_array;
1164        int range_count = req->range_count;
1165        struct dm_unballoon_response resp;
1166        int i;
1167
1168        for (i = 0; i < range_count; i++) {
1169                free_balloon_pages(dm, &range_array[i]);
1170                post_status(&dm_device);
1171        }
1172
1173        if (req->more_pages == 1)
1174                return;
1175
1176        memset(&resp, 0, sizeof(struct dm_unballoon_response));
1177        resp.hdr.type = DM_UNBALLOON_RESPONSE;
1178        resp.hdr.trans_id = atomic_inc_return(&trans_id);
1179        resp.hdr.size = sizeof(struct dm_unballoon_response);
1180
1181        vmbus_sendpacket(dm_device.dev->channel, &resp,
1182                                sizeof(struct dm_unballoon_response),
1183                                (unsigned long)NULL,
1184                                VM_PKT_DATA_INBAND, 0);
1185
1186        dm->state = DM_INITIALIZED;
1187}
1188
1189static void balloon_onchannelcallback(void *context);
1190
1191static int dm_thread_func(void *dm_dev)
1192{
1193        struct hv_dynmem_device *dm = dm_dev;
1194        int t;
1195
1196        while (!kthread_should_stop()) {
1197                t = wait_for_completion_interruptible_timeout(
1198                                                &dm_device.config_event, 1*HZ);
1199                /*
1200                 * The host expects us to post information on the memory
1201                 * pressure every second.
1202                 */
1203
1204                if (t == 0)
1205                        post_status(dm);
1206
1207        }
1208
1209        return 0;
1210}
1211
1212
1213static void version_resp(struct hv_dynmem_device *dm,
1214                        struct dm_version_response *vresp)
1215{
1216        struct dm_version_request version_req;
1217        int ret;
1218
1219        if (vresp->is_accepted) {
1220                /*
1221                 * We are done; wakeup the
1222                 * context waiting for version
1223                 * negotiation.
1224                 */
1225                complete(&dm->host_event);
1226                return;
1227        }
1228        /*
1229         * If there are more versions to try, continue
1230         * with negotiations; if not
1231         * shutdown the service since we are not able
1232         * to negotiate a suitable version number
1233         * with the host.
1234         */
1235        if (dm->next_version == 0)
1236                goto version_error;
1237
1238        dm->next_version = 0;
1239        memset(&version_req, 0, sizeof(struct dm_version_request));
1240        version_req.hdr.type = DM_VERSION_REQUEST;
1241        version_req.hdr.size = sizeof(struct dm_version_request);
1242        version_req.hdr.trans_id = atomic_inc_return(&trans_id);
1243        version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN7;
1244        version_req.is_last_attempt = 1;
1245
1246        ret = vmbus_sendpacket(dm->dev->channel, &version_req,
1247                                sizeof(struct dm_version_request),
1248                                (unsigned long)NULL,
1249                                VM_PKT_DATA_INBAND, 0);
1250
1251        if (ret)
1252                goto version_error;
1253
1254        return;
1255
1256version_error:
1257        dm->state = DM_INIT_ERROR;
1258        complete(&dm->host_event);
1259}
1260
1261static void cap_resp(struct hv_dynmem_device *dm,
1262                        struct dm_capabilities_resp_msg *cap_resp)
1263{
1264        if (!cap_resp->is_accepted) {
1265                pr_info("Capabilities not accepted by host\n");
1266                dm->state = DM_INIT_ERROR;
1267        }
1268        complete(&dm->host_event);
1269}
1270
1271static void balloon_onchannelcallback(void *context)
1272{
1273        struct hv_device *dev = context;
1274        u32 recvlen;
1275        u64 requestid;
1276        struct dm_message *dm_msg;
1277        struct dm_header *dm_hdr;
1278        struct hv_dynmem_device *dm = hv_get_drvdata(dev);
1279        struct dm_balloon *bal_msg;
1280        struct dm_hot_add *ha_msg;
1281        union dm_mem_page_range *ha_pg_range;
1282        union dm_mem_page_range *ha_region;
1283
1284        memset(recv_buffer, 0, sizeof(recv_buffer));
1285        vmbus_recvpacket(dev->channel, recv_buffer,
1286                         PAGE_SIZE, &recvlen, &requestid);
1287
1288        if (recvlen > 0) {
1289                dm_msg = (struct dm_message *)recv_buffer;
1290                dm_hdr = &dm_msg->hdr;
1291
1292                switch (dm_hdr->type) {
1293                case DM_VERSION_RESPONSE:
1294                        version_resp(dm,
1295                                 (struct dm_version_response *)dm_msg);
1296                        break;
1297
1298                case DM_CAPABILITIES_RESPONSE:
1299                        cap_resp(dm,
1300                                 (struct dm_capabilities_resp_msg *)dm_msg);
1301                        break;
1302
1303                case DM_BALLOON_REQUEST:
1304                        if (dm->state == DM_BALLOON_UP)
1305                                pr_warn("Currently ballooning\n");
1306                        bal_msg = (struct dm_balloon *)recv_buffer;
1307                        dm->state = DM_BALLOON_UP;
1308                        dm_device.balloon_wrk.num_pages = bal_msg->num_pages;
1309                        schedule_work(&dm_device.balloon_wrk.wrk);
1310                        break;
1311
1312                case DM_UNBALLOON_REQUEST:
1313                        dm->state = DM_BALLOON_DOWN;
1314                        balloon_down(dm,
1315                                 (struct dm_unballoon_request *)recv_buffer);
1316                        break;
1317
1318                case DM_MEM_HOT_ADD_REQUEST:
1319                        if (dm->state == DM_HOT_ADD)
1320                                pr_warn("Currently hot-adding\n");
1321                        dm->state = DM_HOT_ADD;
1322                        ha_msg = (struct dm_hot_add *)recv_buffer;
1323                        if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) {
1324                                /*
1325                                 * This is a normal hot-add request specifying
1326                                 * hot-add memory.
1327                                 */
1328                                ha_pg_range = &ha_msg->range;
1329                                dm->ha_wrk.ha_page_range = *ha_pg_range;
1330                                dm->ha_wrk.ha_region_range.page_range = 0;
1331                        } else {
1332                                /*
1333                                 * Host is specifying that we first hot-add
1334                                 * a region and then partially populate this
1335                                 * region.
1336                                 */
1337                                dm->host_specified_ha_region = true;
1338                                ha_pg_range = &ha_msg->range;
1339                                ha_region = &ha_pg_range[1];
1340                                dm->ha_wrk.ha_page_range = *ha_pg_range;
1341                                dm->ha_wrk.ha_region_range = *ha_region;
1342                        }
1343                        schedule_work(&dm_device.ha_wrk.wrk);
1344                        break;
1345
1346                case DM_INFO_MESSAGE:
1347                        process_info(dm, (struct dm_info_msg *)dm_msg);
1348                        break;
1349
1350                default:
1351                        pr_err("Unhandled message: type: %d\n", dm_hdr->type);
1352
1353                }
1354        }
1355
1356}
1357
1358static int balloon_probe(struct hv_device *dev,
1359                        const struct hv_vmbus_device_id *dev_id)
1360{
1361        int ret, t;
1362        struct dm_version_request version_req;
1363        struct dm_capabilities cap_msg;
1364
1365        do_hot_add = hot_add;
1366
1367        /*
1368         * First allocate a send buffer.
1369         */
1370
1371        send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
1372        if (!send_buffer)
1373                return -ENOMEM;
1374
1375        ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0,
1376                        balloon_onchannelcallback, dev);
1377
1378        if (ret)
1379                goto probe_error0;
1380
1381        dm_device.dev = dev;
1382        dm_device.state = DM_INITIALIZING;
1383        dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN7;
1384        init_completion(&dm_device.host_event);
1385        init_completion(&dm_device.config_event);
1386        INIT_LIST_HEAD(&dm_device.ha_region_list);
1387        INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up);
1388        INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req);
1389        dm_device.host_specified_ha_region = false;
1390
1391        dm_device.thread =
1392                 kthread_run(dm_thread_func, &dm_device, "hv_balloon");
1393        if (IS_ERR(dm_device.thread)) {
1394                ret = PTR_ERR(dm_device.thread);
1395                goto probe_error1;
1396        }
1397
1398#ifdef CONFIG_MEMORY_HOTPLUG
1399        set_online_page_callback(&hv_online_page);
1400#endif
1401
1402        hv_set_drvdata(dev, &dm_device);
1403        /*
1404         * Initiate the hand shake with the host and negotiate
1405         * a version that the host can support. We start with the
1406         * highest version number and go down if the host cannot
1407         * support it.
1408         */
1409        memset(&version_req, 0, sizeof(struct dm_version_request));
1410        version_req.hdr.type = DM_VERSION_REQUEST;
1411        version_req.hdr.size = sizeof(struct dm_version_request);
1412        version_req.hdr.trans_id = atomic_inc_return(&trans_id);
1413        version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN8;
1414        version_req.is_last_attempt = 0;
1415
1416        ret = vmbus_sendpacket(dev->channel, &version_req,
1417                                sizeof(struct dm_version_request),
1418                                (unsigned long)NULL,
1419                                VM_PKT_DATA_INBAND, 0);
1420        if (ret)
1421                goto probe_error2;
1422
1423        t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
1424        if (t == 0) {
1425                ret = -ETIMEDOUT;
1426                goto probe_error2;
1427        }
1428
1429        /*
1430         * If we could not negotiate a compatible version with the host
1431         * fail the probe function.
1432         */
1433        if (dm_device.state == DM_INIT_ERROR) {
1434                ret = -ETIMEDOUT;
1435                goto probe_error2;
1436        }
1437        /*
1438         * Now submit our capabilities to the host.
1439         */
1440        memset(&cap_msg, 0, sizeof(struct dm_capabilities));
1441        cap_msg.hdr.type = DM_CAPABILITIES_REPORT;
1442        cap_msg.hdr.size = sizeof(struct dm_capabilities);
1443        cap_msg.hdr.trans_id = atomic_inc_return(&trans_id);
1444
1445        cap_msg.caps.cap_bits.balloon = 1;
1446        cap_msg.caps.cap_bits.hot_add = 1;
1447
1448        /*
1449         * Specify our alignment requirements as it relates
1450         * memory hot-add. Specify 128MB alignment.
1451         */
1452        cap_msg.caps.cap_bits.hot_add_alignment = 7;
1453
1454        /*
1455         * Currently the host does not use these
1456         * values and we set them to what is done in the
1457         * Windows driver.
1458         */
1459        cap_msg.min_page_cnt = 0;
1460        cap_msg.max_page_number = -1;
1461
1462        ret = vmbus_sendpacket(dev->channel, &cap_msg,
1463                                sizeof(struct dm_capabilities),
1464                                (unsigned long)NULL,
1465                                VM_PKT_DATA_INBAND, 0);
1466        if (ret)
1467                goto probe_error2;
1468
1469        t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
1470        if (t == 0) {
1471                ret = -ETIMEDOUT;
1472                goto probe_error2;
1473        }
1474
1475        /*
1476         * If the host does not like our capabilities,
1477         * fail the probe function.
1478         */
1479        if (dm_device.state == DM_INIT_ERROR) {
1480                ret = -ETIMEDOUT;
1481                goto probe_error2;
1482        }
1483
1484        dm_device.state = DM_INITIALIZED;
1485
1486        return 0;
1487
1488probe_error2:
1489#ifdef CONFIG_MEMORY_HOTPLUG
1490        restore_online_page_callback(&hv_online_page);
1491#endif
1492        kthread_stop(dm_device.thread);
1493
1494probe_error1:
1495        vmbus_close(dev->channel);
1496probe_error0:
1497        kfree(send_buffer);
1498        return ret;
1499}
1500
1501static int balloon_remove(struct hv_device *dev)
1502{
1503        struct hv_dynmem_device *dm = hv_get_drvdata(dev);
1504        struct list_head *cur, *tmp;
1505        struct hv_hotadd_state *has;
1506
1507        if (dm->num_pages_ballooned != 0)
1508                pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned);
1509
1510        cancel_work_sync(&dm->balloon_wrk.wrk);
1511        cancel_work_sync(&dm->ha_wrk.wrk);
1512
1513        vmbus_close(dev->channel);
1514        kthread_stop(dm->thread);
1515        kfree(send_buffer);
1516#ifdef CONFIG_MEMORY_HOTPLUG
1517        restore_online_page_callback(&hv_online_page);
1518#endif
1519        list_for_each_safe(cur, tmp, &dm->ha_region_list) {
1520                has = list_entry(cur, struct hv_hotadd_state, list);
1521                list_del(&has->list);
1522                kfree(has);
1523        }
1524
1525        return 0;
1526}
1527
1528static const struct hv_vmbus_device_id id_table[] = {
1529        /* Dynamic Memory Class ID */
1530        /* 525074DC-8985-46e2-8057-A307DC18A502 */
1531        { HV_DM_GUID, },
1532        { },
1533};
1534
1535MODULE_DEVICE_TABLE(vmbus, id_table);
1536
1537static  struct hv_driver balloon_drv = {
1538        .name = "hv_balloon",
1539        .id_table = id_table,
1540        .probe =  balloon_probe,
1541        .remove =  balloon_remove,
1542};
1543
1544static int __init init_balloon_drv(void)
1545{
1546
1547        return vmbus_driver_register(&balloon_drv);
1548}
1549
1550module_init(init_balloon_drv);
1551
1552MODULE_DESCRIPTION("Hyper-V Balloon");
1553MODULE_LICENSE("GPL");
Note: See TracBrowser for help on using the repository browser.