Commit | Line | Data |
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1775826c | 1 | /****************************************************************************** |
1775826c JF |
2 | * Xen balloon driver - enables returning/claiming memory to/from Xen. |
3 | * | |
4 | * Copyright (c) 2003, B Dragovic | |
5 | * Copyright (c) 2003-2004, M Williamson, K Fraser | |
6 | * Copyright (c) 2005 Dan M. Smith, IBM Corporation | |
080e2be7 DK |
7 | * Copyright (c) 2010 Daniel Kiper |
8 | * | |
9 | * Memory hotplug support was written by Daniel Kiper. Work on | |
10 | * it was sponsored by Google under Google Summer of Code 2010 | |
11 | * program. Jeremy Fitzhardinge from Citrix was the mentor for | |
12 | * this project. | |
1775826c JF |
13 | * |
14 | * This program is free software; you can redistribute it and/or | |
15 | * modify it under the terms of the GNU General Public License version 2 | |
16 | * as published by the Free Software Foundation; or, when distributed | |
17 | * separately from the Linux kernel or incorporated into other | |
18 | * software packages, subject to the following license: | |
19 | * | |
20 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
21 | * of this source file (the "Software"), to deal in the Software without | |
22 | * restriction, including without limitation the rights to use, copy, modify, | |
23 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, | |
24 | * and to permit persons to whom the Software is furnished to do so, subject to | |
25 | * the following conditions: | |
26 | * | |
27 | * The above copyright notice and this permission notice shall be included in | |
28 | * all copies or substantial portions of the Software. | |
29 | * | |
30 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
31 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
32 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
33 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
34 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
35 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |
36 | * IN THE SOFTWARE. | |
37 | */ | |
38 | ||
283c0972 JP |
39 | #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt |
40 | ||
cd9151e2 | 41 | #include <linux/cpu.h> |
1775826c | 42 | #include <linux/kernel.h> |
1775826c JF |
43 | #include <linux/sched.h> |
44 | #include <linux/errno.h> | |
45 | #include <linux/mm.h> | |
46 | #include <linux/bootmem.h> | |
47 | #include <linux/pagemap.h> | |
48 | #include <linux/highmem.h> | |
49 | #include <linux/mutex.h> | |
1775826c | 50 | #include <linux/list.h> |
5a0e3ad6 | 51 | #include <linux/gfp.h> |
080e2be7 DK |
52 | #include <linux/notifier.h> |
53 | #include <linux/memory.h> | |
54 | #include <linux/memory_hotplug.h> | |
cd9151e2 | 55 | #include <linux/percpu-defs.h> |
55b3da98 | 56 | #include <linux/slab.h> |
1cf6a6c8 | 57 | #include <linux/sysctl.h> |
1775826c | 58 | |
1775826c JF |
59 | #include <asm/page.h> |
60 | #include <asm/pgalloc.h> | |
61 | #include <asm/pgtable.h> | |
1775826c JF |
62 | #include <asm/tlb.h> |
63 | ||
ecbf29cd JF |
64 | #include <asm/xen/hypervisor.h> |
65 | #include <asm/xen/hypercall.h> | |
1ccbf534 JF |
66 | |
67 | #include <xen/xen.h> | |
ecbf29cd | 68 | #include <xen/interface/xen.h> |
1775826c | 69 | #include <xen/interface/memory.h> |
803eb047 | 70 | #include <xen/balloon.h> |
1775826c JF |
71 | #include <xen/features.h> |
72 | #include <xen/page.h> | |
73 | ||
1cf6a6c8 DV |
74 | static int xen_hotplug_unpopulated; |
75 | ||
76 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG | |
77 | ||
78 | static int zero; | |
79 | static int one = 1; | |
80 | ||
81 | static struct ctl_table balloon_table[] = { | |
82 | { | |
83 | .procname = "hotplug_unpopulated", | |
84 | .data = &xen_hotplug_unpopulated, | |
85 | .maxlen = sizeof(int), | |
86 | .mode = 0644, | |
87 | .proc_handler = proc_dointvec_minmax, | |
88 | .extra1 = &zero, | |
89 | .extra2 = &one, | |
90 | }, | |
91 | { } | |
92 | }; | |
93 | ||
94 | static struct ctl_table balloon_root[] = { | |
95 | { | |
96 | .procname = "balloon", | |
97 | .mode = 0555, | |
98 | .child = balloon_table, | |
99 | }, | |
100 | { } | |
101 | }; | |
102 | ||
103 | static struct ctl_table xen_root[] = { | |
104 | { | |
105 | .procname = "xen", | |
106 | .mode = 0555, | |
107 | .child = balloon_root, | |
108 | }, | |
109 | { } | |
110 | }; | |
111 | ||
112 | #endif | |
113 | ||
30756c62 JG |
114 | /* |
115 | * Use one extent per PAGE_SIZE to avoid to break down the page into | |
116 | * multiple frame. | |
117 | */ | |
118 | #define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1) | |
119 | ||
95d2ac4a DK |
120 | /* |
121 | * balloon_process() state: | |
122 | * | |
123 | * BP_DONE: done or nothing to do, | |
b2ac6aa8 | 124 | * BP_WAIT: wait to be rescheduled, |
95d2ac4a DK |
125 | * BP_EAGAIN: error, go to sleep, |
126 | * BP_ECANCELED: error, balloon operation canceled. | |
127 | */ | |
1775826c | 128 | |
95d2ac4a DK |
129 | enum bp_state { |
130 | BP_DONE, | |
b2ac6aa8 | 131 | BP_WAIT, |
95d2ac4a DK |
132 | BP_EAGAIN, |
133 | BP_ECANCELED | |
1775826c JF |
134 | }; |
135 | ||
1775826c | 136 | |
1775826c | 137 | static DEFINE_MUTEX(balloon_mutex); |
1775826c | 138 | |
803eb047 DDG |
139 | struct balloon_stats balloon_stats; |
140 | EXPORT_SYMBOL_GPL(balloon_stats); | |
1775826c JF |
141 | |
142 | /* We increase/decrease in batches which fit in a page */ | |
3990dd27 | 143 | static xen_pfn_t frame_list[PAGE_SIZE / sizeof(xen_pfn_t)]; |
cd9151e2 | 144 | |
1775826c | 145 | |
1775826c JF |
146 | /* List of ballooned pages, threaded through the mem_map array. */ |
147 | static LIST_HEAD(ballooned_pages); | |
1cf6a6c8 | 148 | static DECLARE_WAIT_QUEUE_HEAD(balloon_wq); |
1775826c JF |
149 | |
150 | /* Main work function, always executed in process context. */ | |
151 | static void balloon_process(struct work_struct *work); | |
95170b2e | 152 | static DECLARE_DELAYED_WORK(balloon_worker, balloon_process); |
1775826c JF |
153 | |
154 | /* When ballooning out (allocating memory to return to Xen) we don't really | |
155 | want the kernel to try too hard since that can trigger the oom killer. */ | |
156 | #define GFP_BALLOON \ | |
157 | (GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC) | |
158 | ||
159 | static void scrub_page(struct page *page) | |
160 | { | |
161 | #ifdef CONFIG_XEN_SCRUB_PAGES | |
26a3e991 | 162 | clear_highpage(page); |
1775826c JF |
163 | #endif |
164 | } | |
165 | ||
166 | /* balloon_append: add the given page to the balloon. */ | |
9be4d457 | 167 | static void __balloon_append(struct page *page) |
1775826c JF |
168 | { |
169 | /* Lowmem is re-populated first, so highmem pages go at list tail. */ | |
170 | if (PageHighMem(page)) { | |
171 | list_add_tail(&page->lru, &ballooned_pages); | |
172 | balloon_stats.balloon_high++; | |
1775826c JF |
173 | } else { |
174 | list_add(&page->lru, &ballooned_pages); | |
175 | balloon_stats.balloon_low++; | |
176 | } | |
1cf6a6c8 | 177 | wake_up(&balloon_wq); |
9be4d457 | 178 | } |
3d65c948 | 179 | |
9be4d457 JF |
180 | static void balloon_append(struct page *page) |
181 | { | |
182 | __balloon_append(page); | |
3dcc0571 | 183 | adjust_managed_page_count(page, -1); |
1775826c JF |
184 | } |
185 | ||
186 | /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ | |
81b286e0 | 187 | static struct page *balloon_retrieve(bool require_lowmem) |
1775826c JF |
188 | { |
189 | struct page *page; | |
190 | ||
191 | if (list_empty(&ballooned_pages)) | |
192 | return NULL; | |
193 | ||
81b286e0 DV |
194 | page = list_entry(ballooned_pages.next, struct page, lru); |
195 | if (require_lowmem && PageHighMem(page)) | |
196 | return NULL; | |
1775826c JF |
197 | list_del(&page->lru); |
198 | ||
3dcc0571 | 199 | if (PageHighMem(page)) |
1775826c | 200 | balloon_stats.balloon_high--; |
3dcc0571 | 201 | else |
1775826c JF |
202 | balloon_stats.balloon_low--; |
203 | ||
3dcc0571 | 204 | adjust_managed_page_count(page, 1); |
3d65c948 | 205 | |
1775826c JF |
206 | return page; |
207 | } | |
208 | ||
1775826c JF |
209 | static struct page *balloon_next_page(struct page *page) |
210 | { | |
211 | struct list_head *next = page->lru.next; | |
212 | if (next == &ballooned_pages) | |
213 | return NULL; | |
214 | return list_entry(next, struct page, lru); | |
215 | } | |
216 | ||
95d2ac4a | 217 | static enum bp_state update_schedule(enum bp_state state) |
1775826c | 218 | { |
b2ac6aa8 DV |
219 | if (state == BP_WAIT) |
220 | return BP_WAIT; | |
221 | ||
fd8b7951 BO |
222 | if (state == BP_ECANCELED) |
223 | return BP_ECANCELED; | |
224 | ||
95d2ac4a DK |
225 | if (state == BP_DONE) { |
226 | balloon_stats.schedule_delay = 1; | |
227 | balloon_stats.retry_count = 1; | |
228 | return BP_DONE; | |
229 | } | |
230 | ||
95d2ac4a DK |
231 | ++balloon_stats.retry_count; |
232 | ||
233 | if (balloon_stats.max_retry_count != RETRY_UNLIMITED && | |
234 | balloon_stats.retry_count > balloon_stats.max_retry_count) { | |
95d2ac4a DK |
235 | balloon_stats.schedule_delay = 1; |
236 | balloon_stats.retry_count = 1; | |
237 | return BP_ECANCELED; | |
238 | } | |
239 | ||
240 | balloon_stats.schedule_delay <<= 1; | |
241 | ||
242 | if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay) | |
243 | balloon_stats.schedule_delay = balloon_stats.max_schedule_delay; | |
244 | ||
245 | return BP_EAGAIN; | |
1775826c JF |
246 | } |
247 | ||
080e2be7 | 248 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
55b3da98 DV |
249 | static struct resource *additional_memory_resource(phys_addr_t size) |
250 | { | |
251 | struct resource *res; | |
252 | int ret; | |
253 | ||
254 | res = kzalloc(sizeof(*res), GFP_KERNEL); | |
255 | if (!res) | |
256 | return NULL; | |
257 | ||
258 | res->name = "System RAM"; | |
782b8664 | 259 | res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; |
55b3da98 DV |
260 | |
261 | ret = allocate_resource(&iomem_resource, res, | |
262 | size, 0, -1, | |
263 | PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL); | |
264 | if (ret < 0) { | |
265 | pr_err("Cannot allocate new System RAM resource\n"); | |
266 | kfree(res); | |
267 | return NULL; | |
268 | } | |
269 | ||
270 | return res; | |
271 | } | |
272 | ||
273 | static void release_memory_resource(struct resource *resource) | |
274 | { | |
275 | if (!resource) | |
276 | return; | |
277 | ||
278 | /* | |
279 | * No need to reset region to identity mapped since we now | |
280 | * know that no I/O can be in this region | |
281 | */ | |
282 | release_resource(resource); | |
283 | kfree(resource); | |
284 | } | |
080e2be7 | 285 | |
b2ac6aa8 | 286 | static enum bp_state reserve_additional_memory(void) |
080e2be7 | 287 | { |
b2ac6aa8 | 288 | long credit; |
55b3da98 | 289 | struct resource *resource; |
080e2be7 | 290 | int nid, rc; |
55b3da98 | 291 | unsigned long balloon_hotplug; |
080e2be7 | 292 | |
1cf6a6c8 DV |
293 | credit = balloon_stats.target_pages + balloon_stats.target_unpopulated |
294 | - balloon_stats.total_pages; | |
b2ac6aa8 DV |
295 | |
296 | /* | |
297 | * Already hotplugged enough pages? Wait for them to be | |
298 | * onlined. | |
299 | */ | |
300 | if (credit <= 0) | |
301 | return BP_WAIT; | |
302 | ||
55b3da98 DV |
303 | balloon_hotplug = round_up(credit, PAGES_PER_SECTION); |
304 | ||
305 | resource = additional_memory_resource(balloon_hotplug * PAGE_SIZE); | |
306 | if (!resource) | |
307 | goto err; | |
308 | ||
309 | nid = memory_add_physaddr_to_nid(resource->start); | |
080e2be7 | 310 | |
3c56b3a1 | 311 | #ifdef CONFIG_XEN_HAVE_PVMMU |
30756c62 JG |
312 | /* |
313 | * We don't support PV MMU when Linux and Xen is using | |
314 | * different page granularity. | |
315 | */ | |
316 | BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); | |
317 | ||
3c56b3a1 JG |
318 | /* |
319 | * add_memory() will build page tables for the new memory so | |
320 | * the p2m must contain invalid entries so the correct | |
321 | * non-present PTEs will be written. | |
322 | * | |
323 | * If a failure occurs, the original (identity) p2m entries | |
324 | * are not restored since this region is now known not to | |
325 | * conflict with any devices. | |
326 | */ | |
327 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { | |
328 | unsigned long pfn, i; | |
329 | ||
55b3da98 | 330 | pfn = PFN_DOWN(resource->start); |
3c56b3a1 JG |
331 | for (i = 0; i < balloon_hotplug; i++) { |
332 | if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) { | |
333 | pr_warn("set_phys_to_machine() failed, no memory added\n"); | |
55b3da98 | 334 | goto err; |
3c56b3a1 JG |
335 | } |
336 | } | |
337 | } | |
338 | #endif | |
339 | ||
703fc13a VK |
340 | /* |
341 | * add_memory_resource() will call online_pages() which in its turn | |
342 | * will call xen_online_page() callback causing deadlock if we don't | |
343 | * release balloon_mutex here. Unlocking here is safe because the | |
344 | * callers drop the mutex before trying again. | |
345 | */ | |
346 | mutex_unlock(&balloon_mutex); | |
347 | rc = add_memory_resource(nid, resource, memhp_auto_online); | |
348 | mutex_lock(&balloon_mutex); | |
349 | ||
080e2be7 | 350 | if (rc) { |
3dcf6367 | 351 | pr_warn("Cannot add additional memory (%i)\n", rc); |
55b3da98 | 352 | goto err; |
080e2be7 DK |
353 | } |
354 | ||
de5a77d8 | 355 | balloon_stats.total_pages += balloon_hotplug; |
080e2be7 | 356 | |
b2ac6aa8 | 357 | return BP_WAIT; |
55b3da98 DV |
358 | err: |
359 | release_memory_resource(resource); | |
360 | return BP_ECANCELED; | |
080e2be7 DK |
361 | } |
362 | ||
363 | static void xen_online_page(struct page *page) | |
364 | { | |
365 | __online_page_set_limits(page); | |
366 | ||
367 | mutex_lock(&balloon_mutex); | |
368 | ||
369 | __balloon_append(page); | |
370 | ||
080e2be7 DK |
371 | mutex_unlock(&balloon_mutex); |
372 | } | |
373 | ||
374 | static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v) | |
375 | { | |
376 | if (val == MEM_ONLINE) | |
377 | schedule_delayed_work(&balloon_worker, 0); | |
378 | ||
379 | return NOTIFY_OK; | |
380 | } | |
381 | ||
382 | static struct notifier_block xen_memory_nb = { | |
383 | .notifier_call = xen_memory_notifier, | |
384 | .priority = 0 | |
385 | }; | |
386 | #else | |
b2ac6aa8 | 387 | static enum bp_state reserve_additional_memory(void) |
1775826c | 388 | { |
de5a77d8 | 389 | balloon_stats.target_pages = balloon_stats.current_pages; |
1cf6a6c8 | 390 | return BP_ECANCELED; |
1775826c | 391 | } |
de5a77d8 | 392 | #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */ |
1775826c | 393 | |
de5a77d8 | 394 | static long current_credit(void) |
080e2be7 | 395 | { |
de5a77d8 | 396 | return balloon_stats.target_pages - balloon_stats.current_pages; |
080e2be7 DK |
397 | } |
398 | ||
de5a77d8 | 399 | static bool balloon_is_inflated(void) |
080e2be7 | 400 | { |
de5a77d8 | 401 | return balloon_stats.balloon_low || balloon_stats.balloon_high; |
080e2be7 | 402 | } |
080e2be7 | 403 | |
95d2ac4a | 404 | static enum bp_state increase_reservation(unsigned long nr_pages) |
1775826c | 405 | { |
95d2ac4a | 406 | int rc; |
30756c62 | 407 | unsigned long i; |
1775826c | 408 | struct page *page; |
1775826c JF |
409 | struct xen_memory_reservation reservation = { |
410 | .address_bits = 0, | |
30756c62 | 411 | .extent_order = EXTENT_ORDER, |
1775826c JF |
412 | .domid = DOMID_SELF |
413 | }; | |
414 | ||
415 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
416 | nr_pages = ARRAY_SIZE(frame_list); | |
417 | ||
9346c2a8 | 418 | page = list_first_entry_or_null(&ballooned_pages, struct page, lru); |
1775826c | 419 | for (i = 0; i < nr_pages; i++) { |
95d2ac4a DK |
420 | if (!page) { |
421 | nr_pages = i; | |
422 | break; | |
423 | } | |
30756c62 JG |
424 | |
425 | /* XENMEM_populate_physmap requires a PFN based on Xen | |
426 | * granularity. | |
427 | */ | |
428 | frame_list[i] = page_to_xen_pfn(page); | |
1775826c JF |
429 | page = balloon_next_page(page); |
430 | } | |
431 | ||
a90971eb | 432 | set_xen_guest_handle(reservation.extent_start, frame_list); |
fde28e8f JF |
433 | reservation.nr_extents = nr_pages; |
434 | rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation); | |
40095de1 | 435 | if (rc <= 0) |
95d2ac4a | 436 | return BP_EAGAIN; |
1775826c | 437 | |
bc2c0303 | 438 | for (i = 0; i < rc; i++) { |
b6f30679 | 439 | page = balloon_retrieve(false); |
1775826c JF |
440 | BUG_ON(page == NULL); |
441 | ||
c2374bf5 | 442 | #ifdef CONFIG_XEN_HAVE_PVMMU |
30756c62 JG |
443 | /* |
444 | * We don't support PV MMU when Linux and Xen is using | |
445 | * different page granularity. | |
446 | */ | |
447 | BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); | |
448 | ||
c1d15f5c | 449 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
30756c62 JG |
450 | unsigned long pfn = page_to_pfn(page); |
451 | ||
c1d15f5c SS |
452 | set_phys_to_machine(pfn, frame_list[i]); |
453 | ||
454 | /* Link back into the page tables if not highmem. */ | |
455 | if (!PageHighMem(page)) { | |
456 | int ret; | |
457 | ret = HYPERVISOR_update_va_mapping( | |
458 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
459 | mfn_pte(frame_list[i], PAGE_KERNEL), | |
460 | 0); | |
461 | BUG_ON(ret); | |
462 | } | |
1775826c | 463 | } |
c2374bf5 | 464 | #endif |
1775826c JF |
465 | |
466 | /* Relinquish the page back to the allocator. */ | |
3dcc0571 | 467 | __free_reserved_page(page); |
1775826c JF |
468 | } |
469 | ||
bc2c0303 | 470 | balloon_stats.current_pages += rc; |
1775826c | 471 | |
95d2ac4a | 472 | return BP_DONE; |
1775826c JF |
473 | } |
474 | ||
b6f30679 | 475 | static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) |
1775826c | 476 | { |
95d2ac4a | 477 | enum bp_state state = BP_DONE; |
30756c62 JG |
478 | unsigned long i; |
479 | struct page *page, *tmp; | |
1775826c JF |
480 | int ret; |
481 | struct xen_memory_reservation reservation = { | |
482 | .address_bits = 0, | |
30756c62 | 483 | .extent_order = EXTENT_ORDER, |
1775826c JF |
484 | .domid = DOMID_SELF |
485 | }; | |
30756c62 | 486 | LIST_HEAD(pages); |
1775826c JF |
487 | |
488 | if (nr_pages > ARRAY_SIZE(frame_list)) | |
489 | nr_pages = ARRAY_SIZE(frame_list); | |
490 | ||
491 | for (i = 0; i < nr_pages; i++) { | |
fce92683 LN |
492 | page = alloc_page(gfp); |
493 | if (page == NULL) { | |
1775826c | 494 | nr_pages = i; |
95d2ac4a | 495 | state = BP_EAGAIN; |
1775826c JF |
496 | break; |
497 | } | |
09ed3d5b | 498 | scrub_page(page); |
30756c62 | 499 | list_add(&page->lru, &pages); |
09ed3d5b | 500 | } |
1775826c | 501 | |
09ed3d5b WL |
502 | /* |
503 | * Ensure that ballooned highmem pages don't have kmaps. | |
504 | * | |
505 | * Do this before changing the p2m as kmap_flush_unused() | |
506 | * reads PTEs to obtain pages (and hence needs the original | |
507 | * p2m entry). | |
508 | */ | |
509 | kmap_flush_unused(); | |
510 | ||
30756c62 JG |
511 | /* |
512 | * Setup the frame, update direct mapping, invalidate P2M, | |
513 | * and add to balloon. | |
514 | */ | |
515 | i = 0; | |
516 | list_for_each_entry_safe(page, tmp, &pages, lru) { | |
517 | /* XENMEM_decrease_reservation requires a GFN */ | |
518 | frame_list[i++] = xen_page_to_gfn(page); | |
1058a75f | 519 | |
c1d15f5c | 520 | #ifdef CONFIG_XEN_HAVE_PVMMU |
30756c62 JG |
521 | /* |
522 | * We don't support PV MMU when Linux and Xen is using | |
523 | * different page granularity. | |
524 | */ | |
525 | BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); | |
526 | ||
04660bb5 | 527 | if (!xen_feature(XENFEAT_auto_translated_physmap)) { |
30756c62 JG |
528 | unsigned long pfn = page_to_pfn(page); |
529 | ||
c1d15f5c SS |
530 | if (!PageHighMem(page)) { |
531 | ret = HYPERVISOR_update_va_mapping( | |
532 | (unsigned long)__va(pfn << PAGE_SHIFT), | |
0bb599fd | 533 | __pte_ma(0), 0); |
c1d15f5c | 534 | BUG_ON(ret); |
fb9a0c44 DV |
535 | } |
536 | __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); | |
04660bb5 | 537 | } |
c1d15f5c | 538 | #endif |
30756c62 | 539 | list_del(&page->lru); |
24f69373 | 540 | |
09ed3d5b | 541 | balloon_append(page); |
1775826c JF |
542 | } |
543 | ||
24f69373 | 544 | flush_tlb_all(); |
2bad07ce | 545 | |
a90971eb | 546 | set_xen_guest_handle(reservation.extent_start, frame_list); |
1775826c JF |
547 | reservation.nr_extents = nr_pages; |
548 | ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); | |
549 | BUG_ON(ret != nr_pages); | |
550 | ||
551 | balloon_stats.current_pages -= nr_pages; | |
1775826c | 552 | |
95d2ac4a | 553 | return state; |
1775826c JF |
554 | } |
555 | ||
556 | /* | |
929423fa | 557 | * As this is a work item it is guaranteed to run as a single instance only. |
1775826c JF |
558 | * We may of course race updates of the target counts (which are protected |
559 | * by the balloon lock), or with changes to the Xen hard limit, but we will | |
560 | * recover from these in time. | |
561 | */ | |
562 | static void balloon_process(struct work_struct *work) | |
563 | { | |
95d2ac4a | 564 | enum bp_state state = BP_DONE; |
1775826c JF |
565 | long credit; |
566 | ||
1775826c JF |
567 | |
568 | do { | |
929423fa JG |
569 | mutex_lock(&balloon_mutex); |
570 | ||
83be7e52 | 571 | credit = current_credit(); |
95d2ac4a | 572 | |
080e2be7 DK |
573 | if (credit > 0) { |
574 | if (balloon_is_inflated()) | |
575 | state = increase_reservation(credit); | |
576 | else | |
b2ac6aa8 | 577 | state = reserve_additional_memory(); |
080e2be7 | 578 | } |
95d2ac4a | 579 | |
1775826c | 580 | if (credit < 0) |
b6f30679 | 581 | state = decrease_reservation(-credit, GFP_BALLOON); |
95d2ac4a DK |
582 | |
583 | state = update_schedule(state); | |
1775826c | 584 | |
929423fa JG |
585 | mutex_unlock(&balloon_mutex); |
586 | ||
587 | cond_resched(); | |
588 | ||
95d2ac4a | 589 | } while (credit && state == BP_DONE); |
1775826c JF |
590 | |
591 | /* Schedule more work if there is some still to be done. */ | |
95d2ac4a DK |
592 | if (state == BP_EAGAIN) |
593 | schedule_delayed_work(&balloon_worker, balloon_stats.schedule_delay * HZ); | |
1775826c JF |
594 | } |
595 | ||
596 | /* Resets the Xen limit, sets new target, and kicks off processing. */ | |
803eb047 | 597 | void balloon_set_new_target(unsigned long target) |
1775826c JF |
598 | { |
599 | /* No need for lock. Not read-modify-write updates. */ | |
1775826c | 600 | balloon_stats.target_pages = target; |
95170b2e | 601 | schedule_delayed_work(&balloon_worker, 0); |
1775826c | 602 | } |
803eb047 | 603 | EXPORT_SYMBOL_GPL(balloon_set_new_target); |
1775826c | 604 | |
1cf6a6c8 DV |
605 | static int add_ballooned_pages(int nr_pages) |
606 | { | |
607 | enum bp_state st; | |
608 | ||
609 | if (xen_hotplug_unpopulated) { | |
610 | st = reserve_additional_memory(); | |
611 | if (st != BP_ECANCELED) { | |
612 | mutex_unlock(&balloon_mutex); | |
613 | wait_event(balloon_wq, | |
614 | !list_empty(&ballooned_pages)); | |
615 | mutex_lock(&balloon_mutex); | |
616 | return 0; | |
617 | } | |
618 | } | |
619 | ||
620 | st = decrease_reservation(nr_pages, GFP_USER); | |
621 | if (st != BP_DONE) | |
622 | return -ENOMEM; | |
623 | ||
624 | return 0; | |
625 | } | |
626 | ||
b6f30679 KRW |
627 | /** |
628 | * alloc_xenballooned_pages - get pages that have been ballooned out | |
629 | * @nr_pages: Number of pages to get | |
630 | * @pages: pages returned | |
631 | * @return 0 on success, error otherwise | |
632 | */ | |
81b286e0 | 633 | int alloc_xenballooned_pages(int nr_pages, struct page **pages) |
1775826c | 634 | { |
b6f30679 | 635 | int pgno = 0; |
e882dc9c | 636 | struct page *page; |
1cf6a6c8 DV |
637 | int ret; |
638 | ||
b6f30679 | 639 | mutex_lock(&balloon_mutex); |
1cf6a6c8 DV |
640 | |
641 | balloon_stats.target_unpopulated += nr_pages; | |
642 | ||
b6f30679 | 643 | while (pgno < nr_pages) { |
81b286e0 DV |
644 | page = balloon_retrieve(true); |
645 | if (page) { | |
b6f30679 | 646 | pages[pgno++] = page; |
4a69c909 | 647 | #ifdef CONFIG_XEN_HAVE_PVMMU |
30756c62 JG |
648 | /* |
649 | * We don't support PV MMU when Linux and Xen is using | |
650 | * different page granularity. | |
651 | */ | |
652 | BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); | |
653 | ||
4a69c909 DV |
654 | ret = xen_alloc_p2m_entry(page_to_pfn(page)); |
655 | if (ret < 0) | |
656 | goto out_undo; | |
657 | #endif | |
b6f30679 | 658 | } else { |
1cf6a6c8 DV |
659 | ret = add_ballooned_pages(nr_pages - pgno); |
660 | if (ret < 0) | |
b6f30679 KRW |
661 | goto out_undo; |
662 | } | |
1775826c | 663 | } |
b6f30679 KRW |
664 | mutex_unlock(&balloon_mutex); |
665 | return 0; | |
666 | out_undo: | |
b6f30679 | 667 | mutex_unlock(&balloon_mutex); |
1cf6a6c8 DV |
668 | free_xenballooned_pages(pgno, pages); |
669 | return ret; | |
1775826c | 670 | } |
b6f30679 | 671 | EXPORT_SYMBOL(alloc_xenballooned_pages); |
1775826c | 672 | |
b6f30679 KRW |
673 | /** |
674 | * free_xenballooned_pages - return pages retrieved with get_ballooned_pages | |
675 | * @nr_pages: Number of pages | |
676 | * @pages: pages to return | |
677 | */ | |
e882dc9c | 678 | void free_xenballooned_pages(int nr_pages, struct page **pages) |
1775826c | 679 | { |
b6f30679 | 680 | int i; |
1775826c | 681 | |
b6f30679 | 682 | mutex_lock(&balloon_mutex); |
1775826c | 683 | |
b6f30679 KRW |
684 | for (i = 0; i < nr_pages; i++) { |
685 | if (pages[i]) | |
686 | balloon_append(pages[i]); | |
687 | } | |
688 | ||
1cf6a6c8 DV |
689 | balloon_stats.target_unpopulated -= nr_pages; |
690 | ||
b6f30679 | 691 | /* The balloon may be too large now. Shrink it if needed. */ |
83be7e52 | 692 | if (current_credit()) |
b6f30679 | 693 | schedule_delayed_work(&balloon_worker, 0); |
1775826c | 694 | |
b6f30679 KRW |
695 | mutex_unlock(&balloon_mutex); |
696 | } | |
697 | EXPORT_SYMBOL(free_xenballooned_pages); | |
1775826c | 698 | |
8b5d44a5 DV |
699 | static void __init balloon_add_region(unsigned long start_pfn, |
700 | unsigned long pages) | |
1775826c | 701 | { |
4dfe22f5 | 702 | unsigned long pfn, extra_pfn_end; |
1775826c JF |
703 | struct page *page; |
704 | ||
8b5d44a5 DV |
705 | /* |
706 | * If the amount of usable memory has been limited (e.g., with | |
707 | * the 'mem' command line parameter), don't add pages beyond | |
708 | * this limit. | |
709 | */ | |
710 | extra_pfn_end = min(max_pfn, start_pfn + pages); | |
711 | ||
712 | for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) { | |
713 | page = pfn_to_page(pfn); | |
714 | /* totalram_pages and totalhigh_pages do not | |
715 | include the boot-time balloon extension, so | |
716 | don't subtract from it. */ | |
717 | __balloon_append(page); | |
718 | } | |
de5a77d8 DV |
719 | |
720 | balloon_stats.total_pages += extra_pfn_end - start_pfn; | |
8b5d44a5 DV |
721 | } |
722 | ||
723 | static int __init balloon_init(void) | |
724 | { | |
0bb599fd | 725 | int i; |
8b5d44a5 | 726 | |
53d5522c | 727 | if (!xen_domain()) |
1775826c JF |
728 | return -ENODEV; |
729 | ||
283c0972 | 730 | pr_info("Initialising balloon driver\n"); |
1775826c | 731 | |
aa24411b DV |
732 | balloon_stats.current_pages = xen_pv_domain() |
733 | ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn) | |
c275a57f | 734 | : get_num_physpages(); |
1775826c JF |
735 | balloon_stats.target_pages = balloon_stats.current_pages; |
736 | balloon_stats.balloon_low = 0; | |
737 | balloon_stats.balloon_high = 0; | |
de5a77d8 | 738 | balloon_stats.total_pages = balloon_stats.current_pages; |
1775826c | 739 | |
95d2ac4a DK |
740 | balloon_stats.schedule_delay = 1; |
741 | balloon_stats.max_schedule_delay = 32; | |
742 | balloon_stats.retry_count = 1; | |
40095de1 | 743 | balloon_stats.max_retry_count = RETRY_UNLIMITED; |
1775826c | 744 | |
080e2be7 | 745 | #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
080e2be7 DK |
746 | set_online_page_callback(&xen_online_page); |
747 | register_memory_notifier(&xen_memory_nb); | |
1cf6a6c8 | 748 | register_sysctl_table(xen_root); |
080e2be7 DK |
749 | #endif |
750 | ||
2a4c92fa | 751 | /* |
b1cbf9b1 | 752 | * Initialize the balloon with pages from the extra memory |
8b5d44a5 | 753 | * regions (see arch/x86/xen/setup.c). |
2a4c92fa | 754 | */ |
8b5d44a5 | 755 | for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) |
626d7508 JG |
756 | if (xen_extra_mem[i].n_pfns) |
757 | balloon_add_region(xen_extra_mem[i].start_pfn, | |
758 | xen_extra_mem[i].n_pfns); | |
1775826c | 759 | |
1775826c JF |
760 | return 0; |
761 | } | |
1775826c | 762 | subsys_initcall(balloon_init); |