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

source code of linux/arch/mips/kvm/mmu.c