Root/
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/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/percpu_counter.h> |
33 | |
34 | #include <linux/hyperv.h> |
35 | |
36 | /* |
37 | * We begin with definitions supporting the Dynamic Memory protocol |
38 | * with the host. |
39 | * |
40 | * Begin protocol definitions. |
41 | */ |
42 | |
43 | |
44 | |
45 | /* |
46 | * Protocol versions. The low word is the minor version, the high word the major |
47 | * version. |
48 | * |
49 | * History: |
50 | * Initial version 1.0 |
51 | * Changed to 0.1 on 2009/03/25 |
52 | * Changes to 0.2 on 2009/05/14 |
53 | * Changes to 0.3 on 2009/12/03 |
54 | * Changed to 1.0 on 2011/04/05 |
55 | */ |
56 | |
57 | #define DYNMEM_MAKE_VERSION(Major, Minor) ((__u32)(((Major) << 16) | (Minor))) |
58 | #define DYNMEM_MAJOR_VERSION(Version) ((__u32)(Version) >> 16) |
59 | #define DYNMEM_MINOR_VERSION(Version) ((__u32)(Version) & 0xff) |
60 | |
61 | enum { |
62 | DYNMEM_PROTOCOL_VERSION_1 = DYNMEM_MAKE_VERSION(0, 3), |
63 | DYNMEM_PROTOCOL_VERSION_2 = DYNMEM_MAKE_VERSION(1, 0), |
64 | |
65 | DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1, |
66 | DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2, |
67 | |
68 | DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN8 |
69 | }; |
70 | |
71 | |
72 | |
73 | /* |
74 | * Message Types |
75 | */ |
76 | |
77 | enum dm_message_type { |
78 | /* |
79 | * Version 0.3 |
80 | */ |
81 | DM_ERROR = 0, |
82 | DM_VERSION_REQUEST = 1, |
83 | DM_VERSION_RESPONSE = 2, |
84 | DM_CAPABILITIES_REPORT = 3, |
85 | DM_CAPABILITIES_RESPONSE = 4, |
86 | DM_STATUS_REPORT = 5, |
87 | DM_BALLOON_REQUEST = 6, |
88 | DM_BALLOON_RESPONSE = 7, |
89 | DM_UNBALLOON_REQUEST = 8, |
90 | DM_UNBALLOON_RESPONSE = 9, |
91 | DM_MEM_HOT_ADD_REQUEST = 10, |
92 | DM_MEM_HOT_ADD_RESPONSE = 11, |
93 | DM_VERSION_03_MAX = 11, |
94 | /* |
95 | * Version 1.0. |
96 | */ |
97 | DM_INFO_MESSAGE = 12, |
98 | DM_VERSION_1_MAX = 12 |
99 | }; |
100 | |
101 | |
102 | /* |
103 | * Structures defining the dynamic memory management |
104 | * protocol. |
105 | */ |
106 | |
107 | union dm_version { |
108 | struct { |
109 | __u16 minor_version; |
110 | __u16 major_version; |
111 | }; |
112 | __u32 version; |
113 | } __packed; |
114 | |
115 | |
116 | union dm_caps { |
117 | struct { |
118 | __u64 balloon:1; |
119 | __u64 hot_add:1; |
120 | __u64 reservedz:62; |
121 | } cap_bits; |
122 | __u64 caps; |
123 | } __packed; |
124 | |
125 | union dm_mem_page_range { |
126 | struct { |
127 | /* |
128 | * The PFN number of the first page in the range. |
129 | * 40 bits is the architectural limit of a PFN |
130 | * number for AMD64. |
131 | */ |
132 | __u64 start_page:40; |
133 | /* |
134 | * The number of pages in the range. |
135 | */ |
136 | __u64 page_cnt:24; |
137 | } finfo; |
138 | __u64 page_range; |
139 | } __packed; |
140 | |
141 | |
142 | |
143 | /* |
144 | * The header for all dynamic memory messages: |
145 | * |
146 | * type: Type of the message. |
147 | * size: Size of the message in bytes; including the header. |
148 | * trans_id: The guest is responsible for manufacturing this ID. |
149 | */ |
150 | |
151 | struct dm_header { |
152 | __u16 type; |
153 | __u16 size; |
154 | __u32 trans_id; |
155 | } __packed; |
156 | |
157 | /* |
158 | * A generic message format for dynamic memory. |
159 | * Specific message formats are defined later in the file. |
160 | */ |
161 | |
162 | struct dm_message { |
163 | struct dm_header hdr; |
164 | __u8 data[]; /* enclosed message */ |
165 | } __packed; |
166 | |
167 | |
168 | /* |
169 | * Specific message types supporting the dynamic memory protocol. |
170 | */ |
171 | |
172 | /* |
173 | * Version negotiation message. Sent from the guest to the host. |
174 | * The guest is free to try different versions until the host |
175 | * accepts the version. |
176 | * |
177 | * dm_version: The protocol version requested. |
178 | * is_last_attempt: If TRUE, this is the last version guest will request. |
179 | * reservedz: Reserved field, set to zero. |
180 | */ |
181 | |
182 | struct dm_version_request { |
183 | struct dm_header hdr; |
184 | union dm_version version; |
185 | __u32 is_last_attempt:1; |
186 | __u32 reservedz:31; |
187 | } __packed; |
188 | |
189 | /* |
190 | * Version response message; Host to Guest and indicates |
191 | * if the host has accepted the version sent by the guest. |
192 | * |
193 | * is_accepted: If TRUE, host has accepted the version and the guest |
194 | * should proceed to the next stage of the protocol. FALSE indicates that |
195 | * guest should re-try with a different version. |
196 | * |
197 | * reservedz: Reserved field, set to zero. |
198 | */ |
199 | |
200 | struct dm_version_response { |
201 | struct dm_header hdr; |
202 | __u64 is_accepted:1; |
203 | __u64 reservedz:63; |
204 | } __packed; |
205 | |
206 | /* |
207 | * Message reporting capabilities. This is sent from the guest to the |
208 | * host. |
209 | */ |
210 | |
211 | struct dm_capabilities { |
212 | struct dm_header hdr; |
213 | union dm_caps caps; |
214 | __u64 min_page_cnt; |
215 | __u64 max_page_number; |
216 | } __packed; |
217 | |
218 | /* |
219 | * Response to the capabilities message. This is sent from the host to the |
220 | * guest. This message notifies if the host has accepted the guest's |
221 | * capabilities. If the host has not accepted, the guest must shutdown |
222 | * the service. |
223 | * |
224 | * is_accepted: Indicates if the host has accepted guest's capabilities. |
225 | * reservedz: Must be 0. |
226 | */ |
227 | |
228 | struct dm_capabilities_resp_msg { |
229 | struct dm_header hdr; |
230 | __u64 is_accepted:1; |
231 | __u64 reservedz:63; |
232 | } __packed; |
233 | |
234 | /* |
235 | * This message is used to report memory pressure from the guest. |
236 | * This message is not part of any transaction and there is no |
237 | * response to this message. |
238 | * |
239 | * num_avail: Available memory in pages. |
240 | * num_committed: Committed memory in pages. |
241 | * page_file_size: The accumulated size of all page files |
242 | * in the system in pages. |
243 | * zero_free: The nunber of zero and free pages. |
244 | * page_file_writes: The writes to the page file in pages. |
245 | * io_diff: An indicator of file cache efficiency or page file activity, |
246 | * calculated as File Cache Page Fault Count - Page Read Count. |
247 | * This value is in pages. |
248 | * |
249 | * Some of these metrics are Windows specific and fortunately |
250 | * the algorithm on the host side that computes the guest memory |
251 | * pressure only uses num_committed value. |
252 | */ |
253 | |
254 | struct dm_status { |
255 | struct dm_header hdr; |
256 | __u64 num_avail; |
257 | __u64 num_committed; |
258 | __u64 page_file_size; |
259 | __u64 zero_free; |
260 | __u32 page_file_writes; |
261 | __u32 io_diff; |
262 | } __packed; |
263 | |
264 | |
265 | /* |
266 | * Message to ask the guest to allocate memory - balloon up message. |
267 | * This message is sent from the host to the guest. The guest may not be |
268 | * able to allocate as much memory as requested. |
269 | * |
270 | * num_pages: number of pages to allocate. |
271 | */ |
272 | |
273 | struct dm_balloon { |
274 | struct dm_header hdr; |
275 | __u32 num_pages; |
276 | __u32 reservedz; |
277 | } __packed; |
278 | |
279 | |
280 | /* |
281 | * Balloon response message; this message is sent from the guest |
282 | * to the host in response to the balloon message. |
283 | * |
284 | * reservedz: Reserved; must be set to zero. |
285 | * more_pages: If FALSE, this is the last message of the transaction. |
286 | * if TRUE there will atleast one more message from the guest. |
287 | * |
288 | * range_count: The number of ranges in the range array. |
289 | * |
290 | * range_array: An array of page ranges returned to the host. |
291 | * |
292 | */ |
293 | |
294 | struct dm_balloon_response { |
295 | struct dm_header hdr; |
296 | __u32 reservedz; |
297 | __u32 more_pages:1; |
298 | __u32 range_count:31; |
299 | union dm_mem_page_range range_array[]; |
300 | } __packed; |
301 | |
302 | /* |
303 | * Un-balloon message; this message is sent from the host |
304 | * to the guest to give guest more memory. |
305 | * |
306 | * more_pages: If FALSE, this is the last message of the transaction. |
307 | * if TRUE there will atleast one more message from the guest. |
308 | * |
309 | * reservedz: Reserved; must be set to zero. |
310 | * |
311 | * range_count: The number of ranges in the range array. |
312 | * |
313 | * range_array: An array of page ranges returned to the host. |
314 | * |
315 | */ |
316 | |
317 | struct dm_unballoon_request { |
318 | struct dm_header hdr; |
319 | __u32 more_pages:1; |
320 | __u32 reservedz:31; |
321 | __u32 range_count; |
322 | union dm_mem_page_range range_array[]; |
323 | } __packed; |
324 | |
325 | /* |
326 | * Un-balloon response message; this message is sent from the guest |
327 | * to the host in response to an unballoon request. |
328 | * |
329 | */ |
330 | |
331 | struct dm_unballoon_response { |
332 | struct dm_header hdr; |
333 | } __packed; |
334 | |
335 | |
336 | /* |
337 | * Hot add request message. Message sent from the host to the guest. |
338 | * |
339 | * mem_range: Memory range to hot add. |
340 | * |
341 | * On Linux we currently don't support this since we cannot hot add |
342 | * arbitrary granularity of memory. |
343 | */ |
344 | |
345 | struct dm_hot_add { |
346 | struct dm_header hdr; |
347 | union dm_mem_page_range range; |
348 | } __packed; |
349 | |
350 | /* |
351 | * Hot add response message. |
352 | * This message is sent by the guest to report the status of a hot add request. |
353 | * If page_count is less than the requested page count, then the host should |
354 | * assume all further hot add requests will fail, since this indicates that |
355 | * the guest has hit an upper physical memory barrier. |
356 | * |
357 | * Hot adds may also fail due to low resources; in this case, the guest must |
358 | * not complete this message until the hot add can succeed, and the host must |
359 | * not send a new hot add request until the response is sent. |
360 | * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS |
361 | * times it fails the request. |
362 | * |
363 | * |
364 | * page_count: number of pages that were successfully hot added. |
365 | * |
366 | * result: result of the operation 1: success, 0: failure. |
367 | * |
368 | */ |
369 | |
370 | struct dm_hot_add_response { |
371 | struct dm_header hdr; |
372 | __u32 page_count; |
373 | __u32 result; |
374 | } __packed; |
375 | |
376 | /* |
377 | * Types of information sent from host to the guest. |
378 | */ |
379 | |
380 | enum dm_info_type { |
381 | INFO_TYPE_MAX_PAGE_CNT = 0, |
382 | MAX_INFO_TYPE |
383 | }; |
384 | |
385 | |
386 | /* |
387 | * Header for the information message. |
388 | */ |
389 | |
390 | struct dm_info_header { |
391 | enum dm_info_type type; |
392 | __u32 data_size; |
393 | } __packed; |
394 | |
395 | /* |
396 | * This message is sent from the host to the guest to pass |
397 | * some relevant information (win8 addition). |
398 | * |
399 | * reserved: no used. |
400 | * info_size: size of the information blob. |
401 | * info: information blob. |
402 | */ |
403 | |
404 | struct dm_info_msg { |
405 | struct dm_header hdr; |
406 | __u32 reserved; |
407 | __u32 info_size; |
408 | __u8 info[]; |
409 | }; |
410 | |
411 | /* |
412 | * End protocol definitions. |
413 | */ |
414 | |
415 | static bool hot_add; |
416 | static bool do_hot_add; |
417 | /* |
418 | * Delay reporting memory pressure by |
419 | * the specified number of seconds. |
420 | */ |
421 | static uint pressure_report_delay = 30; |
422 | |
423 | module_param(hot_add, bool, (S_IRUGO | S_IWUSR)); |
424 | MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add"); |
425 | |
426 | module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR)); |
427 | MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure"); |
428 | static atomic_t trans_id = ATOMIC_INIT(0); |
429 | |
430 | static int dm_ring_size = (5 * PAGE_SIZE); |
431 | |
432 | /* |
433 | * Driver specific state. |
434 | */ |
435 | |
436 | enum hv_dm_state { |
437 | DM_INITIALIZING = 0, |
438 | DM_INITIALIZED, |
439 | DM_BALLOON_UP, |
440 | DM_BALLOON_DOWN, |
441 | DM_HOT_ADD, |
442 | DM_INIT_ERROR |
443 | }; |
444 | |
445 | |
446 | static __u8 recv_buffer[PAGE_SIZE]; |
447 | static __u8 *send_buffer; |
448 | #define PAGES_IN_2M 512 |
449 | |
450 | struct hv_dynmem_device { |
451 | struct hv_device *dev; |
452 | enum hv_dm_state state; |
453 | struct completion host_event; |
454 | struct completion config_event; |
455 | |
456 | /* |
457 | * Number of pages we have currently ballooned out. |
458 | */ |
459 | unsigned int num_pages_ballooned; |
460 | |
461 | /* |
462 | * This thread handles both balloon/hot-add |
463 | * requests from the host as well as notifying |
464 | * the host with regards to memory pressure in |
465 | * the guest. |
466 | */ |
467 | struct task_struct *thread; |
468 | |
469 | /* |
470 | * We start with the highest version we can support |
471 | * and downgrade based on the host; we save here the |
472 | * next version to try. |
473 | */ |
474 | __u32 next_version; |
475 | }; |
476 | |
477 | static struct hv_dynmem_device dm_device; |
478 | |
479 | static void hot_add_req(struct hv_dynmem_device *dm, struct dm_hot_add *msg) |
480 | { |
481 | |
482 | struct dm_hot_add_response resp; |
483 | |
484 | if (do_hot_add) { |
485 | |
486 | pr_info("Memory hot add not supported\n"); |
487 | |
488 | /* |
489 | * Currently we do not support hot add. |
490 | * Just fail the request. |
491 | */ |
492 | } |
493 | |
494 | memset(&resp, 0, sizeof(struct dm_hot_add_response)); |
495 | resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE; |
496 | resp.hdr.size = sizeof(struct dm_hot_add_response); |
497 | resp.hdr.trans_id = atomic_inc_return(&trans_id); |
498 | |
499 | resp.page_count = 0; |
500 | resp.result = 0; |
501 | |
502 | dm->state = DM_INITIALIZED; |
503 | vmbus_sendpacket(dm->dev->channel, &resp, |
504 | sizeof(struct dm_hot_add_response), |
505 | (unsigned long)NULL, |
506 | VM_PKT_DATA_INBAND, 0); |
507 | |
508 | } |
509 | |
510 | static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg) |
511 | { |
512 | struct dm_info_header *info_hdr; |
513 | |
514 | info_hdr = (struct dm_info_header *)msg->info; |
515 | |
516 | switch (info_hdr->type) { |
517 | case INFO_TYPE_MAX_PAGE_CNT: |
518 | pr_info("Received INFO_TYPE_MAX_PAGE_CNT\n"); |
519 | pr_info("Data Size is %d\n", info_hdr->data_size); |
520 | break; |
521 | default: |
522 | pr_info("Received Unknown type: %d\n", info_hdr->type); |
523 | } |
524 | } |
525 | |
526 | unsigned long compute_balloon_floor(void) |
527 | { |
528 | unsigned long min_pages; |
529 | #define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT)) |
530 | /* Simple continuous piecewiese linear function: |
531 | * max MiB -> min MiB gradient |
532 | * 0 0 |
533 | * 16 16 |
534 | * 32 24 |
535 | * 128 72 (1/2) |
536 | * 512 168 (1/4) |
537 | * 2048 360 (1/8) |
538 | * 8192 552 (1/32) |
539 | * 32768 1320 |
540 | * 131072 4392 |
541 | */ |
542 | if (totalram_pages < MB2PAGES(128)) |
543 | min_pages = MB2PAGES(8) + (totalram_pages >> 1); |
544 | else if (totalram_pages < MB2PAGES(512)) |
545 | min_pages = MB2PAGES(40) + (totalram_pages >> 2); |
546 | else if (totalram_pages < MB2PAGES(2048)) |
547 | min_pages = MB2PAGES(104) + (totalram_pages >> 3); |
548 | else |
549 | min_pages = MB2PAGES(296) + (totalram_pages >> 5); |
550 | #undef MB2PAGES |
551 | return min_pages; |
552 | } |
553 | |
554 | /* |
555 | * Post our status as it relates memory pressure to the |
556 | * host. Host expects the guests to post this status |
557 | * periodically at 1 second intervals. |
558 | * |
559 | * The metrics specified in this protocol are very Windows |
560 | * specific and so we cook up numbers here to convey our memory |
561 | * pressure. |
562 | */ |
563 | |
564 | static void post_status(struct hv_dynmem_device *dm) |
565 | { |
566 | struct dm_status status; |
567 | struct sysinfo val; |
568 | |
569 | if (pressure_report_delay > 0) { |
570 | --pressure_report_delay; |
571 | return; |
572 | } |
573 | si_meminfo(&val); |
574 | memset(&status, 0, sizeof(struct dm_status)); |
575 | status.hdr.type = DM_STATUS_REPORT; |
576 | status.hdr.size = sizeof(struct dm_status); |
577 | status.hdr.trans_id = atomic_inc_return(&trans_id); |
578 | |
579 | /* |
580 | * The host expects the guest to report free memory. |
581 | * Further, the host expects the pressure information to |
582 | * include the ballooned out pages. |
583 | * For a given amount of memory that we are managing, we |
584 | * need to compute a floor below which we should not balloon. |
585 | * Compute this and add it to the pressure report. |
586 | */ |
587 | status.num_avail = val.freeram; |
588 | status.num_committed = vm_memory_committed() + |
589 | dm->num_pages_ballooned + |
590 | compute_balloon_floor(); |
591 | |
592 | vmbus_sendpacket(dm->dev->channel, &status, |
593 | sizeof(struct dm_status), |
594 | (unsigned long)NULL, |
595 | VM_PKT_DATA_INBAND, 0); |
596 | |
597 | } |
598 | |
599 | static void free_balloon_pages(struct hv_dynmem_device *dm, |
600 | union dm_mem_page_range *range_array) |
601 | { |
602 | int num_pages = range_array->finfo.page_cnt; |
603 | __u64 start_frame = range_array->finfo.start_page; |
604 | struct page *pg; |
605 | int i; |
606 | |
607 | for (i = 0; i < num_pages; i++) { |
608 | pg = pfn_to_page(i + start_frame); |
609 | __free_page(pg); |
610 | dm->num_pages_ballooned--; |
611 | } |
612 | } |
613 | |
614 | |
615 | |
616 | static int alloc_balloon_pages(struct hv_dynmem_device *dm, int num_pages, |
617 | struct dm_balloon_response *bl_resp, int alloc_unit, |
618 | bool *alloc_error) |
619 | { |
620 | int i = 0; |
621 | struct page *pg; |
622 | |
623 | if (num_pages < alloc_unit) |
624 | return 0; |
625 | |
626 | for (i = 0; (i * alloc_unit) < num_pages; i++) { |
627 | if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) > |
628 | PAGE_SIZE) |
629 | return i * alloc_unit; |
630 | |
631 | /* |
632 | * We execute this code in a thread context. Furthermore, |
633 | * we don't want the kernel to try too hard. |
634 | */ |
635 | pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY | |
636 | __GFP_NOMEMALLOC | __GFP_NOWARN, |
637 | get_order(alloc_unit << PAGE_SHIFT)); |
638 | |
639 | if (!pg) { |
640 | *alloc_error = true; |
641 | return i * alloc_unit; |
642 | } |
643 | |
644 | |
645 | dm->num_pages_ballooned += alloc_unit; |
646 | |
647 | bl_resp->range_count++; |
648 | bl_resp->range_array[i].finfo.start_page = |
649 | page_to_pfn(pg); |
650 | bl_resp->range_array[i].finfo.page_cnt = alloc_unit; |
651 | bl_resp->hdr.size += sizeof(union dm_mem_page_range); |
652 | |
653 | } |
654 | |
655 | return num_pages; |
656 | } |
657 | |
658 | |
659 | |
660 | static void balloon_up(struct hv_dynmem_device *dm, struct dm_balloon *req) |
661 | { |
662 | int num_pages = req->num_pages; |
663 | int num_ballooned = 0; |
664 | struct dm_balloon_response *bl_resp; |
665 | int alloc_unit; |
666 | int ret; |
667 | bool alloc_error = false; |
668 | bool done = false; |
669 | int i; |
670 | |
671 | |
672 | /* |
673 | * Currently, we only support 4k allocations. |
674 | */ |
675 | alloc_unit = 1; |
676 | |
677 | while (!done) { |
678 | bl_resp = (struct dm_balloon_response *)send_buffer; |
679 | memset(send_buffer, 0, PAGE_SIZE); |
680 | bl_resp->hdr.type = DM_BALLOON_RESPONSE; |
681 | bl_resp->hdr.trans_id = atomic_inc_return(&trans_id); |
682 | bl_resp->hdr.size = sizeof(struct dm_balloon_response); |
683 | bl_resp->more_pages = 1; |
684 | |
685 | |
686 | num_pages -= num_ballooned; |
687 | num_ballooned = alloc_balloon_pages(dm, num_pages, |
688 | bl_resp, alloc_unit, |
689 | &alloc_error); |
690 | |
691 | if ((alloc_error) || (num_ballooned == num_pages)) { |
692 | bl_resp->more_pages = 0; |
693 | done = true; |
694 | dm->state = DM_INITIALIZED; |
695 | } |
696 | |
697 | /* |
698 | * We are pushing a lot of data through the channel; |
699 | * deal with transient failures caused because of the |
700 | * lack of space in the ring buffer. |
701 | */ |
702 | |
703 | do { |
704 | ret = vmbus_sendpacket(dm_device.dev->channel, |
705 | bl_resp, |
706 | bl_resp->hdr.size, |
707 | (unsigned long)NULL, |
708 | VM_PKT_DATA_INBAND, 0); |
709 | |
710 | if (ret == -EAGAIN) |
711 | msleep(20); |
712 | |
713 | } while (ret == -EAGAIN); |
714 | |
715 | if (ret) { |
716 | /* |
717 | * Free up the memory we allocatted. |
718 | */ |
719 | pr_info("Balloon response failed\n"); |
720 | |
721 | for (i = 0; i < bl_resp->range_count; i++) |
722 | free_balloon_pages(dm, |
723 | &bl_resp->range_array[i]); |
724 | |
725 | done = true; |
726 | } |
727 | } |
728 | |
729 | } |
730 | |
731 | static void balloon_down(struct hv_dynmem_device *dm, |
732 | struct dm_unballoon_request *req) |
733 | { |
734 | union dm_mem_page_range *range_array = req->range_array; |
735 | int range_count = req->range_count; |
736 | struct dm_unballoon_response resp; |
737 | int i; |
738 | |
739 | for (i = 0; i < range_count; i++) |
740 | free_balloon_pages(dm, &range_array[i]); |
741 | |
742 | if (req->more_pages == 1) |
743 | return; |
744 | |
745 | memset(&resp, 0, sizeof(struct dm_unballoon_response)); |
746 | resp.hdr.type = DM_UNBALLOON_RESPONSE; |
747 | resp.hdr.trans_id = atomic_inc_return(&trans_id); |
748 | resp.hdr.size = sizeof(struct dm_unballoon_response); |
749 | |
750 | vmbus_sendpacket(dm_device.dev->channel, &resp, |
751 | sizeof(struct dm_unballoon_response), |
752 | (unsigned long)NULL, |
753 | VM_PKT_DATA_INBAND, 0); |
754 | |
755 | dm->state = DM_INITIALIZED; |
756 | } |
757 | |
758 | static void balloon_onchannelcallback(void *context); |
759 | |
760 | static int dm_thread_func(void *dm_dev) |
761 | { |
762 | struct hv_dynmem_device *dm = dm_dev; |
763 | int t; |
764 | unsigned long scan_start; |
765 | |
766 | while (!kthread_should_stop()) { |
767 | t = wait_for_completion_timeout(&dm_device.config_event, 1*HZ); |
768 | /* |
769 | * The host expects us to post information on the memory |
770 | * pressure every second. |
771 | */ |
772 | |
773 | if (t == 0) |
774 | post_status(dm); |
775 | |
776 | scan_start = jiffies; |
777 | switch (dm->state) { |
778 | case DM_BALLOON_UP: |
779 | balloon_up(dm, (struct dm_balloon *)recv_buffer); |
780 | break; |
781 | |
782 | case DM_HOT_ADD: |
783 | hot_add_req(dm, (struct dm_hot_add *)recv_buffer); |
784 | break; |
785 | default: |
786 | break; |
787 | } |
788 | |
789 | if (!time_in_range(jiffies, scan_start, scan_start + HZ)) |
790 | post_status(dm); |
791 | |
792 | } |
793 | |
794 | return 0; |
795 | } |
796 | |
797 | |
798 | static void version_resp(struct hv_dynmem_device *dm, |
799 | struct dm_version_response *vresp) |
800 | { |
801 | struct dm_version_request version_req; |
802 | int ret; |
803 | |
804 | if (vresp->is_accepted) { |
805 | /* |
806 | * We are done; wakeup the |
807 | * context waiting for version |
808 | * negotiation. |
809 | */ |
810 | complete(&dm->host_event); |
811 | return; |
812 | } |
813 | /* |
814 | * If there are more versions to try, continue |
815 | * with negotiations; if not |
816 | * shutdown the service since we are not able |
817 | * to negotiate a suitable version number |
818 | * with the host. |
819 | */ |
820 | if (dm->next_version == 0) |
821 | goto version_error; |
822 | |
823 | dm->next_version = 0; |
824 | memset(&version_req, 0, sizeof(struct dm_version_request)); |
825 | version_req.hdr.type = DM_VERSION_REQUEST; |
826 | version_req.hdr.size = sizeof(struct dm_version_request); |
827 | version_req.hdr.trans_id = atomic_inc_return(&trans_id); |
828 | version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN7; |
829 | version_req.is_last_attempt = 1; |
830 | |
831 | ret = vmbus_sendpacket(dm->dev->channel, &version_req, |
832 | sizeof(struct dm_version_request), |
833 | (unsigned long)NULL, |
834 | VM_PKT_DATA_INBAND, 0); |
835 | |
836 | if (ret) |
837 | goto version_error; |
838 | |
839 | return; |
840 | |
841 | version_error: |
842 | dm->state = DM_INIT_ERROR; |
843 | complete(&dm->host_event); |
844 | } |
845 | |
846 | static void cap_resp(struct hv_dynmem_device *dm, |
847 | struct dm_capabilities_resp_msg *cap_resp) |
848 | { |
849 | if (!cap_resp->is_accepted) { |
850 | pr_info("Capabilities not accepted by host\n"); |
851 | dm->state = DM_INIT_ERROR; |
852 | } |
853 | complete(&dm->host_event); |
854 | } |
855 | |
856 | static void balloon_onchannelcallback(void *context) |
857 | { |
858 | struct hv_device *dev = context; |
859 | u32 recvlen; |
860 | u64 requestid; |
861 | struct dm_message *dm_msg; |
862 | struct dm_header *dm_hdr; |
863 | struct hv_dynmem_device *dm = hv_get_drvdata(dev); |
864 | |
865 | memset(recv_buffer, 0, sizeof(recv_buffer)); |
866 | vmbus_recvpacket(dev->channel, recv_buffer, |
867 | PAGE_SIZE, &recvlen, &requestid); |
868 | |
869 | if (recvlen > 0) { |
870 | dm_msg = (struct dm_message *)recv_buffer; |
871 | dm_hdr = &dm_msg->hdr; |
872 | |
873 | switch (dm_hdr->type) { |
874 | case DM_VERSION_RESPONSE: |
875 | version_resp(dm, |
876 | (struct dm_version_response *)dm_msg); |
877 | break; |
878 | |
879 | case DM_CAPABILITIES_RESPONSE: |
880 | cap_resp(dm, |
881 | (struct dm_capabilities_resp_msg *)dm_msg); |
882 | break; |
883 | |
884 | case DM_BALLOON_REQUEST: |
885 | dm->state = DM_BALLOON_UP; |
886 | complete(&dm->config_event); |
887 | break; |
888 | |
889 | case DM_UNBALLOON_REQUEST: |
890 | dm->state = DM_BALLOON_DOWN; |
891 | balloon_down(dm, |
892 | (struct dm_unballoon_request *)recv_buffer); |
893 | break; |
894 | |
895 | case DM_MEM_HOT_ADD_REQUEST: |
896 | dm->state = DM_HOT_ADD; |
897 | complete(&dm->config_event); |
898 | break; |
899 | |
900 | case DM_INFO_MESSAGE: |
901 | process_info(dm, (struct dm_info_msg *)dm_msg); |
902 | break; |
903 | |
904 | default: |
905 | pr_err("Unhandled message: type: %d\n", dm_hdr->type); |
906 | |
907 | } |
908 | } |
909 | |
910 | } |
911 | |
912 | static int balloon_probe(struct hv_device *dev, |
913 | const struct hv_vmbus_device_id *dev_id) |
914 | { |
915 | int ret, t; |
916 | struct dm_version_request version_req; |
917 | struct dm_capabilities cap_msg; |
918 | |
919 | do_hot_add = hot_add; |
920 | |
921 | /* |
922 | * First allocate a send buffer. |
923 | */ |
924 | |
925 | send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); |
926 | if (!send_buffer) |
927 | return -ENOMEM; |
928 | |
929 | ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0, |
930 | balloon_onchannelcallback, dev); |
931 | |
932 | if (ret) |
933 | goto probe_error0; |
934 | |
935 | dm_device.dev = dev; |
936 | dm_device.state = DM_INITIALIZING; |
937 | dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN7; |
938 | init_completion(&dm_device.host_event); |
939 | init_completion(&dm_device.config_event); |
940 | |
941 | dm_device.thread = |
942 | kthread_run(dm_thread_func, &dm_device, "hv_balloon"); |
943 | if (IS_ERR(dm_device.thread)) { |
944 | ret = PTR_ERR(dm_device.thread); |
945 | goto probe_error1; |
946 | } |
947 | |
948 | hv_set_drvdata(dev, &dm_device); |
949 | /* |
950 | * Initiate the hand shake with the host and negotiate |
951 | * a version that the host can support. We start with the |
952 | * highest version number and go down if the host cannot |
953 | * support it. |
954 | */ |
955 | memset(&version_req, 0, sizeof(struct dm_version_request)); |
956 | version_req.hdr.type = DM_VERSION_REQUEST; |
957 | version_req.hdr.size = sizeof(struct dm_version_request); |
958 | version_req.hdr.trans_id = atomic_inc_return(&trans_id); |
959 | version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN8; |
960 | version_req.is_last_attempt = 0; |
961 | |
962 | ret = vmbus_sendpacket(dev->channel, &version_req, |
963 | sizeof(struct dm_version_request), |
964 | (unsigned long)NULL, |
965 | VM_PKT_DATA_INBAND, |
966 | VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); |
967 | if (ret) |
968 | goto probe_error2; |
969 | |
970 | t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); |
971 | if (t == 0) { |
972 | ret = -ETIMEDOUT; |
973 | goto probe_error2; |
974 | } |
975 | |
976 | /* |
977 | * If we could not negotiate a compatible version with the host |
978 | * fail the probe function. |
979 | */ |
980 | if (dm_device.state == DM_INIT_ERROR) { |
981 | ret = -ETIMEDOUT; |
982 | goto probe_error2; |
983 | } |
984 | /* |
985 | * Now submit our capabilities to the host. |
986 | */ |
987 | memset(&cap_msg, 0, sizeof(struct dm_capabilities)); |
988 | cap_msg.hdr.type = DM_CAPABILITIES_REPORT; |
989 | cap_msg.hdr.size = sizeof(struct dm_capabilities); |
990 | cap_msg.hdr.trans_id = atomic_inc_return(&trans_id); |
991 | |
992 | cap_msg.caps.cap_bits.balloon = 1; |
993 | /* |
994 | * While we currently don't support hot-add, |
995 | * we still advertise this capability since the |
996 | * host requires that guests partcipating in the |
997 | * dynamic memory protocol support hot add. |
998 | */ |
999 | cap_msg.caps.cap_bits.hot_add = 1; |
1000 | |
1001 | /* |
1002 | * Currently the host does not use these |
1003 | * values and we set them to what is done in the |
1004 | * Windows driver. |
1005 | */ |
1006 | cap_msg.min_page_cnt = 0; |
1007 | cap_msg.max_page_number = -1; |
1008 | |
1009 | ret = vmbus_sendpacket(dev->channel, &cap_msg, |
1010 | sizeof(struct dm_capabilities), |
1011 | (unsigned long)NULL, |
1012 | VM_PKT_DATA_INBAND, |
1013 | VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); |
1014 | if (ret) |
1015 | goto probe_error2; |
1016 | |
1017 | t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); |
1018 | if (t == 0) { |
1019 | ret = -ETIMEDOUT; |
1020 | goto probe_error2; |
1021 | } |
1022 | |
1023 | /* |
1024 | * If the host does not like our capabilities, |
1025 | * fail the probe function. |
1026 | */ |
1027 | if (dm_device.state == DM_INIT_ERROR) { |
1028 | ret = -ETIMEDOUT; |
1029 | goto probe_error2; |
1030 | } |
1031 | |
1032 | dm_device.state = DM_INITIALIZED; |
1033 | |
1034 | return 0; |
1035 | |
1036 | probe_error2: |
1037 | kthread_stop(dm_device.thread); |
1038 | |
1039 | probe_error1: |
1040 | vmbus_close(dev->channel); |
1041 | probe_error0: |
1042 | kfree(send_buffer); |
1043 | return ret; |
1044 | } |
1045 | |
1046 | static int balloon_remove(struct hv_device *dev) |
1047 | { |
1048 | struct hv_dynmem_device *dm = hv_get_drvdata(dev); |
1049 | |
1050 | if (dm->num_pages_ballooned != 0) |
1051 | pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned); |
1052 | |
1053 | vmbus_close(dev->channel); |
1054 | kthread_stop(dm->thread); |
1055 | kfree(send_buffer); |
1056 | |
1057 | return 0; |
1058 | } |
1059 | |
1060 | static const struct hv_vmbus_device_id id_table[] = { |
1061 | /* Dynamic Memory Class ID */ |
1062 | /* 525074DC-8985-46e2-8057-A307DC18A502 */ |
1063 | { HV_DM_GUID, }, |
1064 | { }, |
1065 | }; |
1066 | |
1067 | MODULE_DEVICE_TABLE(vmbus, id_table); |
1068 | |
1069 | static struct hv_driver balloon_drv = { |
1070 | .name = "hv_balloon", |
1071 | .id_table = id_table, |
1072 | .probe = balloon_probe, |
1073 | .remove = balloon_remove, |
1074 | }; |
1075 | |
1076 | static int __init init_balloon_drv(void) |
1077 | { |
1078 | |
1079 | return vmbus_driver_register(&balloon_drv); |
1080 | } |
1081 | |
1082 | static void exit_balloon_drv(void) |
1083 | { |
1084 | |
1085 | vmbus_driver_unregister(&balloon_drv); |
1086 | } |
1087 | |
1088 | module_init(init_balloon_drv); |
1089 | module_exit(exit_balloon_drv); |
1090 | |
1091 | MODULE_DESCRIPTION("Hyper-V Balloon"); |
1092 | MODULE_VERSION(HV_DRV_VERSION); |
1093 | MODULE_LICENSE("GPL"); |
1094 |
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