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-rw-r--r--arch/x86/xen/mmu.c365
1 files changed, 0 insertions, 365 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 44924e551fde..7575e55cd52e 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -173,371 +173,6 @@ DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */
173 */ 173 */
174#define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK) 174#define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
175 175
176/*
177 * Xen leaves the responsibility for maintaining p2m mappings to the
178 * guests themselves, but it must also access and update the p2m array
179 * during suspend/resume when all the pages are reallocated.
180 *
181 * The p2m table is logically a flat array, but we implement it as a
182 * three-level tree to allow the address space to be sparse.
183 *
184 * Xen
185 * |
186 * p2m_top p2m_top_mfn
187 * / \ / \
188 * p2m_mid p2m_mid p2m_mid_mfn p2m_mid_mfn
189 * / \ / \ / /
190 * p2m p2m p2m p2m p2m p2m p2m ...
191 *
192 * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
193 *
194 * The p2m_top and p2m_top_mfn levels are limited to 1 page, so the
195 * maximum representable pseudo-physical address space is:
196 * P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages
197 *
198 * P2M_PER_PAGE depends on the architecture, as a mfn is always
199 * unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to
200 * 512 and 1024 entries respectively.
201 */
202
203unsigned long xen_max_p2m_pfn __read_mostly;
204
205#define P2M_PER_PAGE (PAGE_SIZE / sizeof(unsigned long))
206#define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *))
207#define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **))
208
209#define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
210
211/* Placeholders for holes in the address space */
212static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE);
213static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE);
214static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE);
215
216static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE);
217static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE);
218static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE);
219
220RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
221RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
222
223static inline unsigned p2m_top_index(unsigned long pfn)
224{
225 BUG_ON(pfn >= MAX_P2M_PFN);
226 return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE);
227}
228
229static inline unsigned p2m_mid_index(unsigned long pfn)
230{
231 return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE;
232}
233
234static inline unsigned p2m_index(unsigned long pfn)
235{
236 return pfn % P2M_PER_PAGE;
237}
238
239static void p2m_top_init(unsigned long ***top)
240{
241 unsigned i;
242
243 for (i = 0; i < P2M_TOP_PER_PAGE; i++)
244 top[i] = p2m_mid_missing;
245}
246
247static void p2m_top_mfn_init(unsigned long *top)
248{
249 unsigned i;
250
251 for (i = 0; i < P2M_TOP_PER_PAGE; i++)
252 top[i] = virt_to_mfn(p2m_mid_missing_mfn);
253}
254
255static void p2m_top_mfn_p_init(unsigned long **top)
256{
257 unsigned i;
258
259 for (i = 0; i < P2M_TOP_PER_PAGE; i++)
260 top[i] = p2m_mid_missing_mfn;
261}
262
263static void p2m_mid_init(unsigned long **mid)
264{
265 unsigned i;
266
267 for (i = 0; i < P2M_MID_PER_PAGE; i++)
268 mid[i] = p2m_missing;
269}
270
271static void p2m_mid_mfn_init(unsigned long *mid)
272{
273 unsigned i;
274
275 for (i = 0; i < P2M_MID_PER_PAGE; i++)
276 mid[i] = virt_to_mfn(p2m_missing);
277}
278
279static void p2m_init(unsigned long *p2m)
280{
281 unsigned i;
282
283 for (i = 0; i < P2M_MID_PER_PAGE; i++)
284 p2m[i] = INVALID_P2M_ENTRY;
285}
286
287/*
288 * Build the parallel p2m_top_mfn and p2m_mid_mfn structures
289 *
290 * This is called both at boot time, and after resuming from suspend:
291 * - At boot time we're called very early, and must use extend_brk()
292 * to allocate memory.
293 *
294 * - After resume we're called from within stop_machine, but the mfn
295 * tree should alreay be completely allocated.
296 */
297void xen_build_mfn_list_list(void)
298{
299 unsigned long pfn;
300
301 /* Pre-initialize p2m_top_mfn to be completely missing */
302 if (p2m_top_mfn == NULL) {
303 p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
304 p2m_mid_mfn_init(p2m_mid_missing_mfn);
305
306 p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
307 p2m_top_mfn_p_init(p2m_top_mfn_p);
308
309 p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
310 p2m_top_mfn_init(p2m_top_mfn);
311 } else {
312 /* Reinitialise, mfn's all change after migration */
313 p2m_mid_mfn_init(p2m_mid_missing_mfn);
314 }
315
316 for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) {
317 unsigned topidx = p2m_top_index(pfn);
318 unsigned mididx = p2m_mid_index(pfn);
319 unsigned long **mid;
320 unsigned long *mid_mfn_p;
321
322 mid = p2m_top[topidx];
323 mid_mfn_p = p2m_top_mfn_p[topidx];
324
325 /* Don't bother allocating any mfn mid levels if
326 * they're just missing, just update the stored mfn,
327 * since all could have changed over a migrate.
328 */
329 if (mid == p2m_mid_missing) {
330 BUG_ON(mididx);
331 BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
332 p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
333 pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
334 continue;
335 }
336
337 if (mid_mfn_p == p2m_mid_missing_mfn) {
338 /*
339 * XXX boot-time only! We should never find
340 * missing parts of the mfn tree after
341 * runtime. extend_brk() will BUG if we call
342 * it too late.
343 */
344 mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
345 p2m_mid_mfn_init(mid_mfn_p);
346
347 p2m_top_mfn_p[topidx] = mid_mfn_p;
348 }
349
350 p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
351 mid_mfn_p[mididx] = virt_to_mfn(mid[mididx]);
352 }
353}
354
355void xen_setup_mfn_list_list(void)
356{
357 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
358
359 HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
360 virt_to_mfn(p2m_top_mfn);
361 HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
362}
363
364/* Set up p2m_top to point to the domain-builder provided p2m pages */
365void __init xen_build_dynamic_phys_to_machine(void)
366{
367 unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
368 unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
369 unsigned long pfn;
370
371 xen_max_p2m_pfn = max_pfn;
372
373 p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
374 p2m_init(p2m_missing);
375
376 p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
377 p2m_mid_init(p2m_mid_missing);
378
379 p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE);
380 p2m_top_init(p2m_top);
381
382 /*
383 * The domain builder gives us a pre-constructed p2m array in
384 * mfn_list for all the pages initially given to us, so we just
385 * need to graft that into our tree structure.
386 */
387 for (pfn = 0; pfn < max_pfn; pfn += P2M_PER_PAGE) {
388 unsigned topidx = p2m_top_index(pfn);
389 unsigned mididx = p2m_mid_index(pfn);
390
391 if (p2m_top[topidx] == p2m_mid_missing) {
392 unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
393 p2m_mid_init(mid);
394
395 p2m_top[topidx] = mid;
396 }
397
398 p2m_top[topidx][mididx] = &mfn_list[pfn];
399 }
400}
401
402unsigned long get_phys_to_machine(unsigned long pfn)
403{
404 unsigned topidx, mididx, idx;
405
406 if (unlikely(pfn >= MAX_P2M_PFN))
407 return INVALID_P2M_ENTRY;
408
409 topidx = p2m_top_index(pfn);
410 mididx = p2m_mid_index(pfn);
411 idx = p2m_index(pfn);
412
413 return p2m_top[topidx][mididx][idx];
414}
415EXPORT_SYMBOL_GPL(get_phys_to_machine);
416
417static void *alloc_p2m_page(void)
418{
419 return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
420}
421
422static void free_p2m_page(void *p)
423{
424 free_page((unsigned long)p);
425}
426
427/*
428 * Fully allocate the p2m structure for a given pfn. We need to check
429 * that both the top and mid levels are allocated, and make sure the
430 * parallel mfn tree is kept in sync. We may race with other cpus, so
431 * the new pages are installed with cmpxchg; if we lose the race then
432 * simply free the page we allocated and use the one that's there.
433 */
434static bool alloc_p2m(unsigned long pfn)
435{
436 unsigned topidx, mididx;
437 unsigned long ***top_p, **mid;
438 unsigned long *top_mfn_p, *mid_mfn;
439
440 topidx = p2m_top_index(pfn);
441 mididx = p2m_mid_index(pfn);
442
443 top_p = &p2m_top[topidx];
444 mid = *top_p;
445
446 if (mid == p2m_mid_missing) {
447 /* Mid level is missing, allocate a new one */
448 mid = alloc_p2m_page();
449 if (!mid)
450 return false;
451
452 p2m_mid_init(mid);
453
454 if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing)
455 free_p2m_page(mid);
456 }
457
458 top_mfn_p = &p2m_top_mfn[topidx];
459 mid_mfn = p2m_top_mfn_p[topidx];
460
461 BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
462
463 if (mid_mfn == p2m_mid_missing_mfn) {
464 /* Separately check the mid mfn level */
465 unsigned long missing_mfn;
466 unsigned long mid_mfn_mfn;
467
468 mid_mfn = alloc_p2m_page();
469 if (!mid_mfn)
470 return false;
471
472 p2m_mid_mfn_init(mid_mfn);
473
474 missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
475 mid_mfn_mfn = virt_to_mfn(mid_mfn);
476 if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn)
477 free_p2m_page(mid_mfn);
478 else
479 p2m_top_mfn_p[topidx] = mid_mfn;
480 }
481
482 if (p2m_top[topidx][mididx] == p2m_missing) {
483 /* p2m leaf page is missing */
484 unsigned long *p2m;
485
486 p2m = alloc_p2m_page();
487 if (!p2m)
488 return false;
489
490 p2m_init(p2m);
491
492 if (cmpxchg(&mid[mididx], p2m_missing, p2m) != p2m_missing)
493 free_p2m_page(p2m);
494 else
495 mid_mfn[mididx] = virt_to_mfn(p2m);
496 }
497
498 return true;
499}
500
501/* Try to install p2m mapping; fail if intermediate bits missing */
502bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
503{
504 unsigned topidx, mididx, idx;
505
506 if (unlikely(pfn >= MAX_P2M_PFN)) {
507 BUG_ON(mfn != INVALID_P2M_ENTRY);
508 return true;
509 }
510
511 topidx = p2m_top_index(pfn);
512 mididx = p2m_mid_index(pfn);
513 idx = p2m_index(pfn);
514
515 if (p2m_top[topidx][mididx] == p2m_missing)
516 return mfn == INVALID_P2M_ENTRY;
517
518 p2m_top[topidx][mididx][idx] = mfn;
519
520 return true;
521}
522
523bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
524{
525 if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
526 BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
527 return true;
528 }
529
530 if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
531 if (!alloc_p2m(pfn))
532 return false;
533
534 if (!__set_phys_to_machine(pfn, mfn))
535 return false;
536 }
537
538 return true;
539}
540
541unsigned long arbitrary_virt_to_mfn(void *vaddr) 176unsigned long arbitrary_virt_to_mfn(void *vaddr)
542{ 177{
543 xmaddr_t maddr = arbitrary_virt_to_machine(vaddr); 178 xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);
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