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1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * KVM/MIPS MMU handling in the KVM module.
7 *
8 * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
9 * Authors: Sanjay Lal <sanjayl@kymasys.com>
10 */
11
12#include <linux/highmem.h>
13#include <linux/kvm_host.h>
14#include <linux/uaccess.h>
15#include <asm/mmu_context.h>
16#include <asm/pgalloc.h>
17
18/*
19 * KVM_MMU_CACHE_MIN_PAGES is the number of GPA page table translation levels
20 * for which pages need to be cached.
21 */
22#if defined(__PAGETABLE_PMD_FOLDED)
23#define KVM_MMU_CACHE_MIN_PAGES 1
24#else
25#define KVM_MMU_CACHE_MIN_PAGES 2
26#endif
27
28void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
29{
30 kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
31}
32
33/**
34 * kvm_pgd_init() - Initialise KVM GPA page directory.
35 * @page: Pointer to page directory (PGD) for KVM GPA.
36 *
37 * Initialise a KVM GPA page directory with pointers to the invalid table, i.e.
38 * representing no mappings. This is similar to pgd_init(), however it
39 * initialises all the page directory pointers, not just the ones corresponding
40 * to the userland address space (since it is for the guest physical address
41 * space rather than a virtual address space).
42 */
43static void kvm_pgd_init(void *page)
44{
45 unsigned long *p, *end;
46 unsigned long entry;
47
48#ifdef __PAGETABLE_PMD_FOLDED
49 entry = (unsigned long)invalid_pte_table;
50#else
51 entry = (unsigned long)invalid_pmd_table;
52#endif
53
54 p = (unsigned long *)page;
55 end = p + PTRS_PER_PGD;
56
57 do {
58 p[0] = entry;
59 p[1] = entry;
60 p[2] = entry;
61 p[3] = entry;
62 p[4] = entry;
63 p += 8;
64 p[-3] = entry;
65 p[-2] = entry;
66 p[-1] = entry;
67 } while (p != end);
68}
69
70/**
71 * kvm_pgd_alloc() - Allocate and initialise a KVM GPA page directory.
72 *
73 * Allocate a blank KVM GPA page directory (PGD) for representing guest physical
74 * to host physical page mappings.
75 *
76 * Returns: Pointer to new KVM GPA page directory.
77 * NULL on allocation failure.
78 */
79pgd_t *kvm_pgd_alloc(void)
80{
81 pgd_t *ret;
82
83 ret = (pgd_t *)__get_free_pages(GFP_KERNEL, PGD_ORDER);
84 if (ret)
85 kvm_pgd_init(ret);
86
87 return ret;
88}
89
90/**
91 * kvm_mips_walk_pgd() - Walk page table with optional allocation.
92 * @pgd: Page directory pointer.
93 * @addr: Address to index page table using.
94 * @cache: MMU page cache to allocate new page tables from, or NULL.
95 *
96 * Walk the page tables pointed to by @pgd to find the PTE corresponding to the
97 * address @addr. If page tables don't exist for @addr, they will be created
98 * from the MMU cache if @cache is not NULL.
99 *
100 * Returns: Pointer to pte_t corresponding to @addr.
101 * NULL if a page table doesn't exist for @addr and !@cache.
102 * NULL if a page table allocation failed.
103 */
104static pte_t *kvm_mips_walk_pgd(pgd_t *pgd, struct kvm_mmu_memory_cache *cache,
105 unsigned long addr)
106{
107 p4d_t *p4d;
108 pud_t *pud;
109 pmd_t *pmd;
110
111 pgd += pgd_index(addr);
112 if (pgd_none(*pgd)) {
113 /* Not used on MIPS yet */
114 BUG();
115 return NULL;
116 }
117 p4d = p4d_offset(pgd, addr);
118 pud = pud_offset(p4d, addr);
119 if (pud_none(*pud)) {
120 pmd_t *new_pmd;
121
122 if (!cache)
123 return NULL;
124 new_pmd = kvm_mmu_memory_cache_alloc(cache);
125 pmd_init((unsigned long)new_pmd,
126 (unsigned long)invalid_pte_table);
127 pud_populate(NULL, pud, new_pmd);
128 }
129 pmd = pmd_offset(pud, addr);
130 if (pmd_none(*pmd)) {
131 pte_t *new_pte;
132
133 if (!cache)
134 return NULL;
135 new_pte = kvm_mmu_memory_cache_alloc(cache);
136 clear_page(new_pte);
137 pmd_populate_kernel(NULL, pmd, new_pte);
138 }
139 return pte_offset_kernel(pmd, addr);
140}
141
142/* Caller must hold kvm->mm_lock */
143static pte_t *kvm_mips_pte_for_gpa(struct kvm *kvm,
144 struct kvm_mmu_memory_cache *cache,
145 unsigned long addr)
146{
147 return kvm_mips_walk_pgd(kvm->arch.gpa_mm.pgd, cache, addr);
148}
149
150/*
151 * kvm_mips_flush_gpa_{pte,pmd,pud,pgd,pt}.
152 * Flush a range of guest physical address space from the VM's GPA page tables.
153 */
154
155static bool kvm_mips_flush_gpa_pte(pte_t *pte, unsigned long start_gpa,
156 unsigned long end_gpa)
157{
158 int i_min = pte_index(start_gpa);
159 int i_max = pte_index(end_gpa);
160 bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PTE - 1);
161 int i;
162
163 for (i = i_min; i <= i_max; ++i) {
164 if (!pte_present(pte[i]))
165 continue;
166
167 set_pte(pte + i, __pte(0));
168 }
169 return safe_to_remove;
170}
171
172static bool kvm_mips_flush_gpa_pmd(pmd_t *pmd, unsigned long start_gpa,
173 unsigned long end_gpa)
174{
175 pte_t *pte;
176 unsigned long end = ~0ul;
177 int i_min = pmd_index(start_gpa);
178 int i_max = pmd_index(end_gpa);
179 bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PMD - 1);
180 int i;
181
182 for (i = i_min; i <= i_max; ++i, start_gpa = 0) {
183 if (!pmd_present(pmd[i]))
184 continue;
185
186 pte = pte_offset_kernel(pmd + i, 0);
187 if (i == i_max)
188 end = end_gpa;
189
190 if (kvm_mips_flush_gpa_pte(pte, start_gpa, end)) {
191 pmd_clear(pmd + i);
192 pte_free_kernel(NULL, pte);
193 } else {
194 safe_to_remove = false;
195 }
196 }
197 return safe_to_remove;
198}
199
200static bool kvm_mips_flush_gpa_pud(pud_t *pud, unsigned long start_gpa,
201 unsigned long end_gpa)
202{
203 pmd_t *pmd;
204 unsigned long end = ~0ul;
205 int i_min = pud_index(start_gpa);
206 int i_max = pud_index(end_gpa);
207 bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PUD - 1);
208 int i;
209
210 for (i = i_min; i <= i_max; ++i, start_gpa = 0) {
211 if (!pud_present(pud[i]))
212 continue;
213
214 pmd = pmd_offset(pud + i, 0);
215 if (i == i_max)
216 end = end_gpa;
217
218 if (kvm_mips_flush_gpa_pmd(pmd, start_gpa, end)) {
219 pud_clear(pud + i);
220 pmd_free(NULL, pmd);
221 } else {
222 safe_to_remove = false;
223 }
224 }
225 return safe_to_remove;
226}
227
228static bool kvm_mips_flush_gpa_pgd(pgd_t *pgd, unsigned long start_gpa,
229 unsigned long end_gpa)
230{
231 p4d_t *p4d;
232 pud_t *pud;
233 unsigned long end = ~0ul;
234 int i_min = pgd_index(start_gpa);
235 int i_max = pgd_index(end_gpa);
236 bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PGD - 1);
237 int i;
238
239 for (i = i_min; i <= i_max; ++i, start_gpa = 0) {
240 if (!pgd_present(pgd[i]))
241 continue;
242
243 p4d = p4d_offset(pgd, 0);
244 pud = pud_offset(p4d + i, 0);
245 if (i == i_max)
246 end = end_gpa;
247
248 if (kvm_mips_flush_gpa_pud(pud, start_gpa, end)) {
249 pgd_clear(pgd + i);
250 pud_free(NULL, pud);
251 } else {
252 safe_to_remove = false;
253 }
254 }
255 return safe_to_remove;
256}
257
258/**
259 * kvm_mips_flush_gpa_pt() - Flush a range of guest physical addresses.
260 * @kvm: KVM pointer.
261 * @start_gfn: Guest frame number of first page in GPA range to flush.
262 * @end_gfn: Guest frame number of last page in GPA range to flush.
263 *
264 * Flushes a range of GPA mappings from the GPA page tables.
265 *
266 * The caller must hold the @kvm->mmu_lock spinlock.
267 *
268 * Returns: Whether its safe to remove the top level page directory because
269 * all lower levels have been removed.
270 */
271bool kvm_mips_flush_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn)
272{
273 return kvm_mips_flush_gpa_pgd(kvm->arch.gpa_mm.pgd,
274 start_gfn << PAGE_SHIFT,
275 end_gfn << PAGE_SHIFT);
276}
277
278#define BUILD_PTE_RANGE_OP(name, op) \
279static int kvm_mips_##name##_pte(pte_t *pte, unsigned long start, \
280 unsigned long end) \
281{ \
282 int ret = 0; \
283 int i_min = pte_index(start); \
284 int i_max = pte_index(end); \
285 int i; \
286 pte_t old, new; \
287 \
288 for (i = i_min; i <= i_max; ++i) { \
289 if (!pte_present(pte[i])) \
290 continue; \
291 \
292 old = pte[i]; \
293 new = op(old); \
294 if (pte_val(new) == pte_val(old)) \
295 continue; \
296 set_pte(pte + i, new); \
297 ret = 1; \
298 } \
299 return ret; \
300} \
301 \
302/* returns true if anything was done */ \
303static int kvm_mips_##name##_pmd(pmd_t *pmd, unsigned long start, \
304 unsigned long end) \
305{ \
306 int ret = 0; \
307 pte_t *pte; \
308 unsigned long cur_end = ~0ul; \
309 int i_min = pmd_index(start); \
310 int i_max = pmd_index(end); \
311 int i; \
312 \
313 for (i = i_min; i <= i_max; ++i, start = 0) { \
314 if (!pmd_present(pmd[i])) \
315 continue; \
316 \
317 pte = pte_offset_kernel(pmd + i, 0); \
318 if (i == i_max) \
319 cur_end = end; \
320 \
321 ret |= kvm_mips_##name##_pte(pte, start, cur_end); \
322 } \
323 return ret; \
324} \
325 \
326static int kvm_mips_##name##_pud(pud_t *pud, unsigned long start, \
327 unsigned long end) \
328{ \
329 int ret = 0; \
330 pmd_t *pmd; \
331 unsigned long cur_end = ~0ul; \
332 int i_min = pud_index(start); \
333 int i_max = pud_index(end); \
334 int i; \
335 \
336 for (i = i_min; i <= i_max; ++i, start = 0) { \
337 if (!pud_present(pud[i])) \
338 continue; \
339 \
340 pmd = pmd_offset(pud + i, 0); \
341 if (i == i_max) \
342 cur_end = end; \
343 \
344 ret |= kvm_mips_##name##_pmd(pmd, start, cur_end); \
345 } \
346 return ret; \
347} \
348 \
349static int kvm_mips_##name##_pgd(pgd_t *pgd, unsigned long start, \
350 unsigned long end) \
351{ \
352 int ret = 0; \
353 p4d_t *p4d; \
354 pud_t *pud; \
355 unsigned long cur_end = ~0ul; \
356 int i_min = pgd_index(start); \
357 int i_max = pgd_index(end); \
358 int i; \
359 \
360 for (i = i_min; i <= i_max; ++i, start = 0) { \
361 if (!pgd_present(pgd[i])) \
362 continue; \
363 \
364 p4d = p4d_offset(pgd, 0); \
365 pud = pud_offset(p4d + i, 0); \
366 if (i == i_max) \
367 cur_end = end; \
368 \
369 ret |= kvm_mips_##name##_pud(pud, start, cur_end); \
370 } \
371 return ret; \
372}
373
374/*
375 * kvm_mips_mkclean_gpa_pt.
376 * Mark a range of guest physical address space clean (writes fault) in the VM's
377 * GPA page table to allow dirty page tracking.
378 */
379
380BUILD_PTE_RANGE_OP(mkclean, pte_mkclean)
381
382/**
383 * kvm_mips_mkclean_gpa_pt() - Make a range of guest physical addresses clean.
384 * @kvm: KVM pointer.
385 * @start_gfn: Guest frame number of first page in GPA range to flush.
386 * @end_gfn: Guest frame number of last page in GPA range to flush.
387 *
388 * Make a range of GPA mappings clean so that guest writes will fault and
389 * trigger dirty page logging.
390 *
391 * The caller must hold the @kvm->mmu_lock spinlock.
392 *
393 * Returns: Whether any GPA mappings were modified, which would require
394 * derived mappings (GVA page tables & TLB enties) to be
395 * invalidated.
396 */
397int kvm_mips_mkclean_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn)
398{
399 return kvm_mips_mkclean_pgd(kvm->arch.gpa_mm.pgd,
400 start_gfn << PAGE_SHIFT,
401 end_gfn << PAGE_SHIFT);
402}
403
404/**
405 * kvm_arch_mmu_enable_log_dirty_pt_masked() - write protect dirty pages
406 * @kvm: The KVM pointer
407 * @slot: The memory slot associated with mask
408 * @gfn_offset: The gfn offset in memory slot
409 * @mask: The mask of dirty pages at offset 'gfn_offset' in this memory
410 * slot to be write protected
411 *
412 * Walks bits set in mask write protects the associated pte's. Caller must
413 * acquire @kvm->mmu_lock.
414 */
415void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
416 struct kvm_memory_slot *slot,
417 gfn_t gfn_offset, unsigned long mask)
418{
419 gfn_t base_gfn = slot->base_gfn + gfn_offset;
420 gfn_t start = base_gfn + __ffs(mask);
421 gfn_t end = base_gfn + __fls(mask);
422
423 kvm_mips_mkclean_gpa_pt(kvm, start, end);
424}
425
426/*
427 * kvm_mips_mkold_gpa_pt.
428 * Mark a range of guest physical address space old (all accesses fault) in the
429 * VM's GPA page table to allow detection of commonly used pages.
430 */
431
432BUILD_PTE_RANGE_OP(mkold, pte_mkold)
433
434static int kvm_mips_mkold_gpa_pt(struct kvm *kvm, gfn_t start_gfn,
435 gfn_t end_gfn)
436{
437 return kvm_mips_mkold_pgd(kvm->arch.gpa_mm.pgd,
438 start_gfn << PAGE_SHIFT,
439 end_gfn << PAGE_SHIFT);
440}
441
442bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
443{
444 kvm_mips_flush_gpa_pt(kvm, range->start, range->end);
445 return 1;
446}
447
448bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
449{
450 gpa_t gpa = range->start << PAGE_SHIFT;
451 pte_t hva_pte = range->pte;
452 pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
453 pte_t old_pte;
454
455 if (!gpa_pte)
456 return false;
457
458 /* Mapping may need adjusting depending on memslot flags */
459 old_pte = *gpa_pte;
460 if (range->slot->flags & KVM_MEM_LOG_DIRTY_PAGES && !pte_dirty(old_pte))
461 hva_pte = pte_mkclean(hva_pte);
462 else if (range->slot->flags & KVM_MEM_READONLY)
463 hva_pte = pte_wrprotect(hva_pte);
464
465 set_pte(gpa_pte, hva_pte);
466
467 /* Replacing an absent or old page doesn't need flushes */
468 if (!pte_present(old_pte) || !pte_young(old_pte))
469 return false;
470
471 /* Pages swapped, aged, moved, or cleaned require flushes */
472 return !pte_present(hva_pte) ||
473 !pte_young(hva_pte) ||
474 pte_pfn(old_pte) != pte_pfn(hva_pte) ||
475 (pte_dirty(old_pte) && !pte_dirty(hva_pte));
476}
477
478bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
479{
480 return kvm_mips_mkold_gpa_pt(kvm, range->start, range->end);
481}
482
483bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
484{
485 gpa_t gpa = range->start << PAGE_SHIFT;
486 pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
487
488 if (!gpa_pte)
489 return 0;
490 return pte_young(*gpa_pte);
491}
492
493/**
494 * _kvm_mips_map_page_fast() - Fast path GPA fault handler.
495 * @vcpu: VCPU pointer.
496 * @gpa: Guest physical address of fault.
497 * @write_fault: Whether the fault was due to a write.
498 * @out_entry: New PTE for @gpa (written on success unless NULL).
499 * @out_buddy: New PTE for @gpa's buddy (written on success unless
500 * NULL).
501 *
502 * Perform fast path GPA fault handling, doing all that can be done without
503 * calling into KVM. This handles marking old pages young (for idle page
504 * tracking), and dirtying of clean pages (for dirty page logging).
505 *
506 * Returns: 0 on success, in which case we can update derived mappings and
507 * resume guest execution.
508 * -EFAULT on failure due to absent GPA mapping or write to
509 * read-only page, in which case KVM must be consulted.
510 */
511static int _kvm_mips_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa,
512 bool write_fault,
513 pte_t *out_entry, pte_t *out_buddy)
514{
515 struct kvm *kvm = vcpu->kvm;
516 gfn_t gfn = gpa >> PAGE_SHIFT;
517 pte_t *ptep;
518 kvm_pfn_t pfn = 0; /* silence bogus GCC warning */
519 bool pfn_valid = false;
520 int ret = 0;
521
522 spin_lock(&kvm->mmu_lock);
523
524 /* Fast path - just check GPA page table for an existing entry */
525 ptep = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
526 if (!ptep || !pte_present(*ptep)) {
527 ret = -EFAULT;
528 goto out;
529 }
530
531 /* Track access to pages marked old */
532 if (!pte_young(*ptep)) {
533 set_pte(ptep, pte_mkyoung(*ptep));
534 pfn = pte_pfn(*ptep);
535 pfn_valid = true;
536 /* call kvm_set_pfn_accessed() after unlock */
537 }
538 if (write_fault && !pte_dirty(*ptep)) {
539 if (!pte_write(*ptep)) {
540 ret = -EFAULT;
541 goto out;
542 }
543
544 /* Track dirtying of writeable pages */
545 set_pte(ptep, pte_mkdirty(*ptep));
546 pfn = pte_pfn(*ptep);
547 mark_page_dirty(kvm, gfn);
548 kvm_set_pfn_dirty(pfn);
549 }
550
551 if (out_entry)
552 *out_entry = *ptep;
553 if (out_buddy)
554 *out_buddy = *ptep_buddy(ptep);
555
556out:
557 spin_unlock(&kvm->mmu_lock);
558 if (pfn_valid)
559 kvm_set_pfn_accessed(pfn);
560 return ret;
561}
562
563/**
564 * kvm_mips_map_page() - Map a guest physical page.
565 * @vcpu: VCPU pointer.
566 * @gpa: Guest physical address of fault.
567 * @write_fault: Whether the fault was due to a write.
568 * @out_entry: New PTE for @gpa (written on success unless NULL).
569 * @out_buddy: New PTE for @gpa's buddy (written on success unless
570 * NULL).
571 *
572 * Handle GPA faults by creating a new GPA mapping (or updating an existing
573 * one).
574 *
575 * This takes care of marking pages young or dirty (idle/dirty page tracking),
576 * asking KVM for the corresponding PFN, and creating a mapping in the GPA page
577 * tables. Derived mappings (GVA page tables and TLBs) must be handled by the
578 * caller.
579 *
580 * Returns: 0 on success, in which case the caller may use the @out_entry
581 * and @out_buddy PTEs to update derived mappings and resume guest
582 * execution.
583 * -EFAULT if there is no memory region at @gpa or a write was
584 * attempted to a read-only memory region. This is usually handled
585 * as an MMIO access.
586 */
587static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
588 bool write_fault,
589 pte_t *out_entry, pte_t *out_buddy)
590{
591 struct kvm *kvm = vcpu->kvm;
592 struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
593 gfn_t gfn = gpa >> PAGE_SHIFT;
594 int srcu_idx, err;
595 kvm_pfn_t pfn;
596 pte_t *ptep, entry, old_pte;
597 bool writeable;
598 unsigned long prot_bits;
599 unsigned long mmu_seq;
600
601 /* Try the fast path to handle old / clean pages */
602 srcu_idx = srcu_read_lock(&kvm->srcu);
603 err = _kvm_mips_map_page_fast(vcpu, gpa, write_fault, out_entry,
604 out_buddy);
605 if (!err)
606 goto out;
607
608 /* We need a minimum of cached pages ready for page table creation */
609 err = kvm_mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES);
610 if (err)
611 goto out;
612
613retry:
614 /*
615 * Used to check for invalidations in progress, of the pfn that is
616 * returned by pfn_to_pfn_prot below.
617 */
618 mmu_seq = kvm->mmu_notifier_seq;
619 /*
620 * Ensure the read of mmu_notifier_seq isn't reordered with PTE reads in
621 * gfn_to_pfn_prot() (which calls get_user_pages()), so that we don't
622 * risk the page we get a reference to getting unmapped before we have a
623 * chance to grab the mmu_lock without mmu_notifier_retry() noticing.
624 *
625 * This smp_rmb() pairs with the effective smp_wmb() of the combination
626 * of the pte_unmap_unlock() after the PTE is zapped, and the
627 * spin_lock() in kvm_mmu_notifier_invalidate_<page|range_end>() before
628 * mmu_notifier_seq is incremented.
629 */
630 smp_rmb();
631
632 /* Slow path - ask KVM core whether we can access this GPA */
633 pfn = gfn_to_pfn_prot(kvm, gfn, write_fault, &writeable);
634 if (is_error_noslot_pfn(pfn)) {
635 err = -EFAULT;
636 goto out;
637 }
638
639 spin_lock(&kvm->mmu_lock);
640 /* Check if an invalidation has taken place since we got pfn */
641 if (mmu_notifier_retry(kvm, mmu_seq)) {
642 /*
643 * This can happen when mappings are changed asynchronously, but
644 * also synchronously if a COW is triggered by
645 * gfn_to_pfn_prot().
646 */
647 spin_unlock(&kvm->mmu_lock);
648 kvm_release_pfn_clean(pfn);
649 goto retry;
650 }
651
652 /* Ensure page tables are allocated */
653 ptep = kvm_mips_pte_for_gpa(kvm, memcache, gpa);
654
655 /* Set up the PTE */
656 prot_bits = _PAGE_PRESENT | __READABLE | _page_cachable_default;
657 if (writeable) {
658 prot_bits |= _PAGE_WRITE;
659 if (write_fault) {
660 prot_bits |= __WRITEABLE;
661 mark_page_dirty(kvm, gfn);
662 kvm_set_pfn_dirty(pfn);
663 }
664 }
665 entry = pfn_pte(pfn, __pgprot(prot_bits));
666
667 /* Write the PTE */
668 old_pte = *ptep;
669 set_pte(ptep, entry);
670
671 err = 0;
672 if (out_entry)
673 *out_entry = *ptep;
674 if (out_buddy)
675 *out_buddy = *ptep_buddy(ptep);
676
677 spin_unlock(&kvm->mmu_lock);
678 kvm_release_pfn_clean(pfn);
679 kvm_set_pfn_accessed(pfn);
680out:
681 srcu_read_unlock(&kvm->srcu, srcu_idx);
682 return err;
683}
684
685int kvm_mips_handle_vz_root_tlb_fault(unsigned long badvaddr,
686 struct kvm_vcpu *vcpu,
687 bool write_fault)
688{
689 int ret;
690
691 ret = kvm_mips_map_page(vcpu, badvaddr, write_fault, NULL, NULL);
692 if (ret)
693 return ret;
694
695 /* Invalidate this entry in the TLB */
696 return kvm_vz_host_tlb_inv(vcpu, badvaddr);
697}
698
699/**
700 * kvm_mips_migrate_count() - Migrate timer.
701 * @vcpu: Virtual CPU.
702 *
703 * Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it
704 * if it was running prior to being cancelled.
705 *
706 * Must be called when the VCPU is migrated to a different CPU to ensure that
707 * timer expiry during guest execution interrupts the guest and causes the
708 * interrupt to be delivered in a timely manner.
709 */
710static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu)
711{
712 if (hrtimer_cancel(&vcpu->arch.comparecount_timer))
713 hrtimer_restart(&vcpu->arch.comparecount_timer);
714}
715
716/* Restore ASID once we are scheduled back after preemption */
717void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
718{
719 unsigned long flags;
720
721 kvm_debug("%s: vcpu %p, cpu: %d\n", __func__, vcpu, cpu);
722
723 local_irq_save(flags);
724
725 vcpu->cpu = cpu;
726 if (vcpu->arch.last_sched_cpu != cpu) {
727 kvm_debug("[%d->%d]KVM VCPU[%d] switch\n",
728 vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id);
729 /*
730 * Migrate the timer interrupt to the current CPU so that it
731 * always interrupts the guest and synchronously triggers a
732 * guest timer interrupt.
733 */
734 kvm_mips_migrate_count(vcpu);
735 }
736
737 /* restore guest state to registers */
738 kvm_mips_callbacks->vcpu_load(vcpu, cpu);
739
740 local_irq_restore(flags);
741}
742
743/* ASID can change if another task is scheduled during preemption */
744void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
745{
746 unsigned long flags;
747 int cpu;
748
749 local_irq_save(flags);
750
751 cpu = smp_processor_id();
752 vcpu->arch.last_sched_cpu = cpu;
753 vcpu->cpu = -1;
754
755 /* save guest state in registers */
756 kvm_mips_callbacks->vcpu_put(vcpu, cpu);
757
758 local_irq_restore(flags);
759}