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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_TABLE_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(new_pmd);
126 pud_populate(NULL, pud, new_pmd);
127 }
128 pmd = pmd_offset(pud, addr);
129 if (pmd_none(*pmd)) {
130 pte_t *new_pte;
131
132 if (!cache)
133 return NULL;
134 new_pte = kvm_mmu_memory_cache_alloc(cache);
135 clear_page(new_pte);
136 pmd_populate_kernel(NULL, pmd, new_pte);
137 }
138 return pte_offset_kernel(pmd, 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(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(start_gpa);
158 int i_max = pte_index(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(pte[i]))
164 continue;
165
166 set_pte(pte + i, __pte(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(start_gpa);
177 int i_max = pmd_index(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[i]))
183 continue;
184
185 pte = pte_offset_kernel(pmd + i, 0);
186 if (i == i_max)
187 end = end_gpa;
188
189 if (kvm_mips_flush_gpa_pte(pte, start_gpa, end)) {
190 pmd_clear(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(start_gpa);
205 int i_max = pud_index(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[i]))
211 continue;
212
213 pmd = pmd_offset(pud + i, 0);
214 if (i == i_max)
215 end = end_gpa;
216
217 if (kvm_mips_flush_gpa_pmd(pmd, start_gpa, end)) {
218 pud_clear(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[i]))
240 continue;
241
242 p4d = p4d_offset(pgd, 0);
243 pud = pud_offset(p4d + i, 0);
244 if (i == i_max)
245 end = end_gpa;
246
247 if (kvm_mips_flush_gpa_pud(pud, start_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(kvm->arch.gpa_mm.pgd,
273 start_gfn << PAGE_SHIFT,
274 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(kvm->arch.gpa_mm.pgd,
399 start_gfn << PAGE_SHIFT,
400 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(mask);
421
422 kvm_mips_mkclean_gpa_pt(kvm, start, 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(kvm->arch.gpa_mm.pgd,
437 start_gfn << PAGE_SHIFT,
438 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, range->start, range->end);
444 return true;
445}
446
447bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
448{
449 return kvm_mips_mkold_gpa_pt(kvm, range->start, range->end);
450}
451
452bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
453{
454 gpa_t gpa = range->start << PAGE_SHIFT;
455 pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
456
457 if (!gpa_pte)
458 return false;
459 return pte_young(*gpa_pte);
460}
461
462/**
463 * _kvm_mips_map_page_fast() - Fast path GPA fault handler.
464 * @vcpu: VCPU pointer.
465 * @gpa: Guest physical address of fault.
466 * @write_fault: Whether the fault was due to a write.
467 * @out_entry: New PTE for @gpa (written on success unless NULL).
468 * @out_buddy: New PTE for @gpa's buddy (written on success unless
469 * NULL).
470 *
471 * Perform fast path GPA fault handling, doing all that can be done without
472 * calling into KVM. This handles marking old pages young (for idle page
473 * tracking), and dirtying of clean pages (for dirty page logging).
474 *
475 * Returns: 0 on success, in which case we can update derived mappings and
476 * resume guest execution.
477 * -EFAULT on failure due to absent GPA mapping or write to
478 * read-only page, in which case KVM must be consulted.
479 */
480static int _kvm_mips_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa,
481 bool write_fault,
482 pte_t *out_entry, pte_t *out_buddy)
483{
484 struct kvm *kvm = vcpu->kvm;
485 gfn_t gfn = gpa >> PAGE_SHIFT;
486 pte_t *ptep;
487 int ret = 0;
488
489 spin_lock(&kvm->mmu_lock);
490
491 /* Fast path - just check GPA page table for an existing entry */
492 ptep = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
493 if (!ptep || !pte_present(*ptep)) {
494 ret = -EFAULT;
495 goto out;
496 }
497
498 /* Track access to pages marked old */
499 if (!pte_young(*ptep))
500 set_pte(ptep, pte_mkyoung(*ptep));
501
502 if (write_fault && !pte_dirty(*ptep)) {
503 if (!pte_write(*ptep)) {
504 ret = -EFAULT;
505 goto out;
506 }
507
508 /* Track dirtying of writeable pages */
509 set_pte(ptep, pte_mkdirty(*ptep));
510 mark_page_dirty(kvm, gfn);
511 }
512
513 if (out_entry)
514 *out_entry = *ptep;
515 if (out_buddy)
516 *out_buddy = *ptep_buddy(ptep);
517
518out:
519 spin_unlock(&kvm->mmu_lock);
520 return ret;
521}
522
523/**
524 * kvm_mips_map_page() - Map a guest physical page.
525 * @vcpu: VCPU pointer.
526 * @gpa: Guest physical address of fault.
527 * @write_fault: Whether the fault was due to a write.
528 * @out_entry: New PTE for @gpa (written on success unless NULL).
529 * @out_buddy: New PTE for @gpa's buddy (written on success unless
530 * NULL).
531 *
532 * Handle GPA faults by creating a new GPA mapping (or updating an existing
533 * one).
534 *
535 * This takes care of marking pages young or dirty (idle/dirty page tracking),
536 * asking KVM for the corresponding PFN, and creating a mapping in the GPA page
537 * tables. Derived mappings (GVA page tables and TLBs) must be handled by the
538 * caller.
539 *
540 * Returns: 0 on success, in which case the caller may use the @out_entry
541 * and @out_buddy PTEs to update derived mappings and resume guest
542 * execution.
543 * -EFAULT if there is no memory region at @gpa or a write was
544 * attempted to a read-only memory region. This is usually handled
545 * as an MMIO access.
546 */
547static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
548 bool write_fault,
549 pte_t *out_entry, pte_t *out_buddy)
550{
551 struct kvm *kvm = vcpu->kvm;
552 struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
553 gfn_t gfn = gpa >> PAGE_SHIFT;
554 int srcu_idx, err;
555 kvm_pfn_t pfn;
556 pte_t *ptep, entry;
557 bool writeable;
558 unsigned long prot_bits;
559 unsigned long mmu_seq;
560 struct page *page;
561
562 /* Try the fast path to handle old / clean pages */
563 srcu_idx = srcu_read_lock(&kvm->srcu);
564 err = _kvm_mips_map_page_fast(vcpu, gpa, write_fault, out_entry,
565 out_buddy);
566 if (!err)
567 goto out;
568
569 /* We need a minimum of cached pages ready for page table creation */
570 err = kvm_mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES);
571 if (err)
572 goto out;
573
574retry:
575 /*
576 * Used to check for invalidations in progress, of the pfn that is
577 * returned by pfn_to_pfn_prot below.
578 */
579 mmu_seq = kvm->mmu_invalidate_seq;
580 /*
581 * Ensure the read of mmu_invalidate_seq isn't reordered with PTE reads
582 * in kvm_faultin_pfn() (which calls get_user_pages()), so that we don't
583 * risk the page we get a reference to getting unmapped before we have a
584 * chance to grab the mmu_lock without mmu_invalidate_retry() noticing.
585 *
586 * This smp_rmb() pairs with the effective smp_wmb() of the combination
587 * of the pte_unmap_unlock() after the PTE is zapped, and the
588 * spin_lock() in kvm_mmu_notifier_invalidate_<page|range_end>() before
589 * mmu_invalidate_seq is incremented.
590 */
591 smp_rmb();
592
593 /* Slow path - ask KVM core whether we can access this GPA */
594 pfn = kvm_faultin_pfn(vcpu, gfn, write_fault, &writeable, &page);
595 if (is_error_noslot_pfn(pfn)) {
596 err = -EFAULT;
597 goto out;
598 }
599
600 spin_lock(&kvm->mmu_lock);
601 /* Check if an invalidation has taken place since we got pfn */
602 if (mmu_invalidate_retry(kvm, mmu_seq)) {
603 /*
604 * This can happen when mappings are changed asynchronously, but
605 * also synchronously if a COW is triggered by
606 * kvm_faultin_pfn().
607 */
608 spin_unlock(&kvm->mmu_lock);
609 kvm_release_page_unused(page);
610 goto retry;
611 }
612
613 /* Ensure page tables are allocated */
614 ptep = kvm_mips_pte_for_gpa(kvm, memcache, gpa);
615
616 /* Set up the PTE */
617 prot_bits = _PAGE_PRESENT | __READABLE | _page_cachable_default;
618 if (writeable) {
619 prot_bits |= _PAGE_WRITE;
620 if (write_fault) {
621 prot_bits |= __WRITEABLE;
622 mark_page_dirty(kvm, gfn);
623 }
624 }
625 entry = pfn_pte(pfn, __pgprot(prot_bits));
626
627 /* Write the PTE */
628 set_pte(ptep, entry);
629
630 err = 0;
631 if (out_entry)
632 *out_entry = *ptep;
633 if (out_buddy)
634 *out_buddy = *ptep_buddy(ptep);
635
636 kvm_release_faultin_page(kvm, page, false, writeable);
637 spin_unlock(&kvm->mmu_lock);
638out:
639 srcu_read_unlock(&kvm->srcu, srcu_idx);
640 return err;
641}
642
643int kvm_mips_handle_vz_root_tlb_fault(unsigned long badvaddr,
644 struct kvm_vcpu *vcpu,
645 bool write_fault)
646{
647 int ret;
648
649 ret = kvm_mips_map_page(vcpu, badvaddr, write_fault, NULL, NULL);
650 if (ret)
651 return ret;
652
653 /* Invalidate this entry in the TLB */
654 return kvm_vz_host_tlb_inv(vcpu, badvaddr);
655}
656
657/**
658 * kvm_mips_migrate_count() - Migrate timer.
659 * @vcpu: Virtual CPU.
660 *
661 * Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it
662 * if it was running prior to being cancelled.
663 *
664 * Must be called when the VCPU is migrated to a different CPU to ensure that
665 * timer expiry during guest execution interrupts the guest and causes the
666 * interrupt to be delivered in a timely manner.
667 */
668static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu)
669{
670 if (hrtimer_cancel(&vcpu->arch.comparecount_timer))
671 hrtimer_restart(&vcpu->arch.comparecount_timer);
672}
673
674/* Restore ASID once we are scheduled back after preemption */
675void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
676{
677 unsigned long flags;
678
679 kvm_debug("%s: vcpu %p, cpu: %d\n", __func__, vcpu, cpu);
680
681 local_irq_save(flags);
682
683 vcpu->cpu = cpu;
684 if (vcpu->arch.last_sched_cpu != cpu) {
685 kvm_debug("[%d->%d]KVM VCPU[%d] switch\n",
686 vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id);
687 /*
688 * Migrate the timer interrupt to the current CPU so that it
689 * always interrupts the guest and synchronously triggers a
690 * guest timer interrupt.
691 */
692 kvm_mips_migrate_count(vcpu);
693 }
694
695 /* restore guest state to registers */
696 kvm_mips_callbacks->vcpu_load(vcpu, cpu);
697
698 local_irq_restore(flags);
699}
700
701/* ASID can change if another task is scheduled during preemption */
702void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
703{
704 unsigned long flags;
705 int cpu;
706
707 local_irq_save(flags);
708
709 cpu = smp_processor_id();
710 vcpu->arch.last_sched_cpu = cpu;
711 vcpu->cpu = -1;
712
713 /* save guest state in registers */
714 kvm_mips_callbacks->vcpu_put(vcpu, cpu);
715
716 local_irq_restore(flags);
717}