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TOMOYO Linux Cross Reference
Linux/arch/x86/kvm/mtrr.c

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  1 /*
  2  * vMTRR implementation
  3  *
  4  * Copyright (C) 2006 Qumranet, Inc.
  5  * Copyright 2010 Red Hat, Inc. and/or its affiliates.
  6  * Copyright(C) 2015 Intel Corporation.
  7  *
  8  * Authors:
  9  *   Yaniv Kamay  <yaniv@qumranet.com>
 10  *   Avi Kivity   <avi@qumranet.com>
 11  *   Marcelo Tosatti <mtosatti@redhat.com>
 12  *   Paolo Bonzini <pbonzini@redhat.com>
 13  *   Xiao Guangrong <guangrong.xiao@linux.intel.com>
 14  *
 15  * This work is licensed under the terms of the GNU GPL, version 2.  See
 16  * the COPYING file in the top-level directory.
 17  */
 18 
 19 #include <linux/kvm_host.h>
 20 #include <asm/mtrr.h>
 21 
 22 #include "cpuid.h"
 23 #include "mmu.h"
 24 
 25 #define IA32_MTRR_DEF_TYPE_E            (1ULL << 11)
 26 #define IA32_MTRR_DEF_TYPE_FE           (1ULL << 10)
 27 #define IA32_MTRR_DEF_TYPE_TYPE_MASK    (0xff)
 28 
 29 static bool msr_mtrr_valid(unsigned msr)
 30 {
 31         switch (msr) {
 32         case 0x200 ... 0x200 + 2 * KVM_NR_VAR_MTRR - 1:
 33         case MSR_MTRRfix64K_00000:
 34         case MSR_MTRRfix16K_80000:
 35         case MSR_MTRRfix16K_A0000:
 36         case MSR_MTRRfix4K_C0000:
 37         case MSR_MTRRfix4K_C8000:
 38         case MSR_MTRRfix4K_D0000:
 39         case MSR_MTRRfix4K_D8000:
 40         case MSR_MTRRfix4K_E0000:
 41         case MSR_MTRRfix4K_E8000:
 42         case MSR_MTRRfix4K_F0000:
 43         case MSR_MTRRfix4K_F8000:
 44         case MSR_MTRRdefType:
 45         case MSR_IA32_CR_PAT:
 46                 return true;
 47         }
 48         return false;
 49 }
 50 
 51 static bool valid_pat_type(unsigned t)
 52 {
 53         return t < 8 && (1 << t) & 0xf3; /* 0, 1, 4, 5, 6, 7 */
 54 }
 55 
 56 static bool valid_mtrr_type(unsigned t)
 57 {
 58         return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */
 59 }
 60 
 61 bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data)
 62 {
 63         int i;
 64         u64 mask;
 65 
 66         if (!msr_mtrr_valid(msr))
 67                 return false;
 68 
 69         if (msr == MSR_IA32_CR_PAT) {
 70                 for (i = 0; i < 8; i++)
 71                         if (!valid_pat_type((data >> (i * 8)) & 0xff))
 72                                 return false;
 73                 return true;
 74         } else if (msr == MSR_MTRRdefType) {
 75                 if (data & ~0xcff)
 76                         return false;
 77                 return valid_mtrr_type(data & 0xff);
 78         } else if (msr >= MSR_MTRRfix64K_00000 && msr <= MSR_MTRRfix4K_F8000) {
 79                 for (i = 0; i < 8 ; i++)
 80                         if (!valid_mtrr_type((data >> (i * 8)) & 0xff))
 81                                 return false;
 82                 return true;
 83         }
 84 
 85         /* variable MTRRs */
 86         WARN_ON(!(msr >= 0x200 && msr < 0x200 + 2 * KVM_NR_VAR_MTRR));
 87 
 88         mask = (~0ULL) << cpuid_maxphyaddr(vcpu);
 89         if ((msr & 1) == 0) {
 90                 /* MTRR base */
 91                 if (!valid_mtrr_type(data & 0xff))
 92                         return false;
 93                 mask |= 0xf00;
 94         } else
 95                 /* MTRR mask */
 96                 mask |= 0x7ff;
 97         if (data & mask) {
 98                 kvm_inject_gp(vcpu, 0);
 99                 return false;
100         }
101 
102         return true;
103 }
104 EXPORT_SYMBOL_GPL(kvm_mtrr_valid);
105 
106 static bool mtrr_is_enabled(struct kvm_mtrr *mtrr_state)
107 {
108         return !!(mtrr_state->deftype & IA32_MTRR_DEF_TYPE_E);
109 }
110 
111 static bool fixed_mtrr_is_enabled(struct kvm_mtrr *mtrr_state)
112 {
113         return !!(mtrr_state->deftype & IA32_MTRR_DEF_TYPE_FE);
114 }
115 
116 static u8 mtrr_default_type(struct kvm_mtrr *mtrr_state)
117 {
118         return mtrr_state->deftype & IA32_MTRR_DEF_TYPE_TYPE_MASK;
119 }
120 
121 static u8 mtrr_disabled_type(struct kvm_vcpu *vcpu)
122 {
123         /*
124          * Intel SDM 11.11.2.2: all MTRRs are disabled when
125          * IA32_MTRR_DEF_TYPE.E bit is cleared, and the UC
126          * memory type is applied to all of physical memory.
127          *
128          * However, virtual machines can be run with CPUID such that
129          * there are no MTRRs.  In that case, the firmware will never
130          * enable MTRRs and it is obviously undesirable to run the
131          * guest entirely with UC memory and we use WB.
132          */
133         if (guest_cpuid_has(vcpu, X86_FEATURE_MTRR))
134                 return MTRR_TYPE_UNCACHABLE;
135         else
136                 return MTRR_TYPE_WRBACK;
137 }
138 
139 /*
140 * Three terms are used in the following code:
141 * - segment, it indicates the address segments covered by fixed MTRRs.
142 * - unit, it corresponds to the MSR entry in the segment.
143 * - range, a range is covered in one memory cache type.
144 */
145 struct fixed_mtrr_segment {
146         u64 start;
147         u64 end;
148 
149         int range_shift;
150 
151         /* the start position in kvm_mtrr.fixed_ranges[]. */
152         int range_start;
153 };
154 
155 static struct fixed_mtrr_segment fixed_seg_table[] = {
156         /* MSR_MTRRfix64K_00000, 1 unit. 64K fixed mtrr. */
157         {
158                 .start = 0x0,
159                 .end = 0x80000,
160                 .range_shift = 16, /* 64K */
161                 .range_start = 0,
162         },
163 
164         /*
165          * MSR_MTRRfix16K_80000 ... MSR_MTRRfix16K_A0000, 2 units,
166          * 16K fixed mtrr.
167          */
168         {
169                 .start = 0x80000,
170                 .end = 0xc0000,
171                 .range_shift = 14, /* 16K */
172                 .range_start = 8,
173         },
174 
175         /*
176          * MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000, 8 units,
177          * 4K fixed mtrr.
178          */
179         {
180                 .start = 0xc0000,
181                 .end = 0x100000,
182                 .range_shift = 12, /* 12K */
183                 .range_start = 24,
184         }
185 };
186 
187 /*
188  * The size of unit is covered in one MSR, one MSR entry contains
189  * 8 ranges so that unit size is always 8 * 2^range_shift.
190  */
191 static u64 fixed_mtrr_seg_unit_size(int seg)
192 {
193         return 8 << fixed_seg_table[seg].range_shift;
194 }
195 
196 static bool fixed_msr_to_seg_unit(u32 msr, int *seg, int *unit)
197 {
198         switch (msr) {
199         case MSR_MTRRfix64K_00000:
200                 *seg = 0;
201                 *unit = 0;
202                 break;
203         case MSR_MTRRfix16K_80000 ... MSR_MTRRfix16K_A0000:
204                 *seg = 1;
205                 *unit = msr - MSR_MTRRfix16K_80000;
206                 break;
207         case MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000:
208                 *seg = 2;
209                 *unit = msr - MSR_MTRRfix4K_C0000;
210                 break;
211         default:
212                 return false;
213         }
214 
215         return true;
216 }
217 
218 static void fixed_mtrr_seg_unit_range(int seg, int unit, u64 *start, u64 *end)
219 {
220         struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg];
221         u64 unit_size = fixed_mtrr_seg_unit_size(seg);
222 
223         *start = mtrr_seg->start + unit * unit_size;
224         *end = *start + unit_size;
225         WARN_ON(*end > mtrr_seg->end);
226 }
227 
228 static int fixed_mtrr_seg_unit_range_index(int seg, int unit)
229 {
230         struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg];
231 
232         WARN_ON(mtrr_seg->start + unit * fixed_mtrr_seg_unit_size(seg)
233                 > mtrr_seg->end);
234 
235         /* each unit has 8 ranges. */
236         return mtrr_seg->range_start + 8 * unit;
237 }
238 
239 static int fixed_mtrr_seg_end_range_index(int seg)
240 {
241         struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg];
242         int n;
243 
244         n = (mtrr_seg->end - mtrr_seg->start) >> mtrr_seg->range_shift;
245         return mtrr_seg->range_start + n - 1;
246 }
247 
248 static bool fixed_msr_to_range(u32 msr, u64 *start, u64 *end)
249 {
250         int seg, unit;
251 
252         if (!fixed_msr_to_seg_unit(msr, &seg, &unit))
253                 return false;
254 
255         fixed_mtrr_seg_unit_range(seg, unit, start, end);
256         return true;
257 }
258 
259 static int fixed_msr_to_range_index(u32 msr)
260 {
261         int seg, unit;
262 
263         if (!fixed_msr_to_seg_unit(msr, &seg, &unit))
264                 return -1;
265 
266         return fixed_mtrr_seg_unit_range_index(seg, unit);
267 }
268 
269 static int fixed_mtrr_addr_to_seg(u64 addr)
270 {
271         struct fixed_mtrr_segment *mtrr_seg;
272         int seg, seg_num = ARRAY_SIZE(fixed_seg_table);
273 
274         for (seg = 0; seg < seg_num; seg++) {
275                 mtrr_seg = &fixed_seg_table[seg];
276                 if (mtrr_seg->start <= addr && addr < mtrr_seg->end)
277                         return seg;
278         }
279 
280         return -1;
281 }
282 
283 static int fixed_mtrr_addr_seg_to_range_index(u64 addr, int seg)
284 {
285         struct fixed_mtrr_segment *mtrr_seg;
286         int index;
287 
288         mtrr_seg = &fixed_seg_table[seg];
289         index = mtrr_seg->range_start;
290         index += (addr - mtrr_seg->start) >> mtrr_seg->range_shift;
291         return index;
292 }
293 
294 static u64 fixed_mtrr_range_end_addr(int seg, int index)
295 {
296         struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg];
297         int pos = index - mtrr_seg->range_start;
298 
299         return mtrr_seg->start + ((pos + 1) << mtrr_seg->range_shift);
300 }
301 
302 static void var_mtrr_range(struct kvm_mtrr_range *range, u64 *start, u64 *end)
303 {
304         u64 mask;
305 
306         *start = range->base & PAGE_MASK;
307 
308         mask = range->mask & PAGE_MASK;
309 
310         /* This cannot overflow because writing to the reserved bits of
311          * variable MTRRs causes a #GP.
312          */
313         *end = (*start | ~mask) + 1;
314 }
315 
316 static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr)
317 {
318         struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
319         gfn_t start, end;
320         int index;
321 
322         if (msr == MSR_IA32_CR_PAT || !tdp_enabled ||
323               !kvm_arch_has_noncoherent_dma(vcpu->kvm))
324                 return;
325 
326         if (!mtrr_is_enabled(mtrr_state) && msr != MSR_MTRRdefType)
327                 return;
328 
329         /* fixed MTRRs. */
330         if (fixed_msr_to_range(msr, &start, &end)) {
331                 if (!fixed_mtrr_is_enabled(mtrr_state))
332                         return;
333         } else if (msr == MSR_MTRRdefType) {
334                 start = 0x0;
335                 end = ~0ULL;
336         } else {
337                 /* variable range MTRRs. */
338                 index = (msr - 0x200) / 2;
339                 var_mtrr_range(&mtrr_state->var_ranges[index], &start, &end);
340         }
341 
342         kvm_zap_gfn_range(vcpu->kvm, gpa_to_gfn(start), gpa_to_gfn(end));
343 }
344 
345 static bool var_mtrr_range_is_valid(struct kvm_mtrr_range *range)
346 {
347         return (range->mask & (1 << 11)) != 0;
348 }
349 
350 static void set_var_mtrr_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
351 {
352         struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
353         struct kvm_mtrr_range *tmp, *cur;
354         int index, is_mtrr_mask;
355 
356         index = (msr - 0x200) / 2;
357         is_mtrr_mask = msr - 0x200 - 2 * index;
358         cur = &mtrr_state->var_ranges[index];
359 
360         /* remove the entry if it's in the list. */
361         if (var_mtrr_range_is_valid(cur))
362                 list_del(&mtrr_state->var_ranges[index].node);
363 
364         /* Extend the mask with all 1 bits to the left, since those
365          * bits must implicitly be 0.  The bits are then cleared
366          * when reading them.
367          */
368         if (!is_mtrr_mask)
369                 cur->base = data;
370         else
371                 cur->mask = data | (-1LL << cpuid_maxphyaddr(vcpu));
372 
373         /* add it to the list if it's enabled. */
374         if (var_mtrr_range_is_valid(cur)) {
375                 list_for_each_entry(tmp, &mtrr_state->head, node)
376                         if (cur->base >= tmp->base)
377                                 break;
378                 list_add_tail(&cur->node, &tmp->node);
379         }
380 }
381 
382 int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
383 {
384         int index;
385 
386         if (!kvm_mtrr_valid(vcpu, msr, data))
387                 return 1;
388 
389         index = fixed_msr_to_range_index(msr);
390         if (index >= 0)
391                 *(u64 *)&vcpu->arch.mtrr_state.fixed_ranges[index] = data;
392         else if (msr == MSR_MTRRdefType)
393                 vcpu->arch.mtrr_state.deftype = data;
394         else if (msr == MSR_IA32_CR_PAT)
395                 vcpu->arch.pat = data;
396         else
397                 set_var_mtrr_msr(vcpu, msr, data);
398 
399         update_mtrr(vcpu, msr);
400         return 0;
401 }
402 
403 int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
404 {
405         int index;
406 
407         /* MSR_MTRRcap is a readonly MSR. */
408         if (msr == MSR_MTRRcap) {
409                 /*
410                  * SMRR = 0
411                  * WC = 1
412                  * FIX = 1
413                  * VCNT = KVM_NR_VAR_MTRR
414                  */
415                 *pdata = 0x500 | KVM_NR_VAR_MTRR;
416                 return 0;
417         }
418 
419         if (!msr_mtrr_valid(msr))
420                 return 1;
421 
422         index = fixed_msr_to_range_index(msr);
423         if (index >= 0)
424                 *pdata = *(u64 *)&vcpu->arch.mtrr_state.fixed_ranges[index];
425         else if (msr == MSR_MTRRdefType)
426                 *pdata = vcpu->arch.mtrr_state.deftype;
427         else if (msr == MSR_IA32_CR_PAT)
428                 *pdata = vcpu->arch.pat;
429         else {  /* Variable MTRRs */
430                 int is_mtrr_mask;
431 
432                 index = (msr - 0x200) / 2;
433                 is_mtrr_mask = msr - 0x200 - 2 * index;
434                 if (!is_mtrr_mask)
435                         *pdata = vcpu->arch.mtrr_state.var_ranges[index].base;
436                 else
437                         *pdata = vcpu->arch.mtrr_state.var_ranges[index].mask;
438 
439                 *pdata &= (1ULL << cpuid_maxphyaddr(vcpu)) - 1;
440         }
441 
442         return 0;
443 }
444 
445 void kvm_vcpu_mtrr_init(struct kvm_vcpu *vcpu)
446 {
447         INIT_LIST_HEAD(&vcpu->arch.mtrr_state.head);
448 }
449 
450 struct mtrr_iter {
451         /* input fields. */
452         struct kvm_mtrr *mtrr_state;
453         u64 start;
454         u64 end;
455 
456         /* output fields. */
457         int mem_type;
458         /* mtrr is completely disabled? */
459         bool mtrr_disabled;
460         /* [start, end) is not fully covered in MTRRs? */
461         bool partial_map;
462 
463         /* private fields. */
464         union {
465                 /* used for fixed MTRRs. */
466                 struct {
467                         int index;
468                         int seg;
469                 };
470 
471                 /* used for var MTRRs. */
472                 struct {
473                         struct kvm_mtrr_range *range;
474                         /* max address has been covered in var MTRRs. */
475                         u64 start_max;
476                 };
477         };
478 
479         bool fixed;
480 };
481 
482 static bool mtrr_lookup_fixed_start(struct mtrr_iter *iter)
483 {
484         int seg, index;
485 
486         if (!fixed_mtrr_is_enabled(iter->mtrr_state))
487                 return false;
488 
489         seg = fixed_mtrr_addr_to_seg(iter->start);
490         if (seg < 0)
491                 return false;
492 
493         iter->fixed = true;
494         index = fixed_mtrr_addr_seg_to_range_index(iter->start, seg);
495         iter->index = index;
496         iter->seg = seg;
497         return true;
498 }
499 
500 static bool match_var_range(struct mtrr_iter *iter,
501                             struct kvm_mtrr_range *range)
502 {
503         u64 start, end;
504 
505         var_mtrr_range(range, &start, &end);
506         if (!(start >= iter->end || end <= iter->start)) {
507                 iter->range = range;
508 
509                 /*
510                  * the function is called when we do kvm_mtrr.head walking.
511                  * Range has the minimum base address which interleaves
512                  * [looker->start_max, looker->end).
513                  */
514                 iter->partial_map |= iter->start_max < start;
515 
516                 /* update the max address has been covered. */
517                 iter->start_max = max(iter->start_max, end);
518                 return true;
519         }
520 
521         return false;
522 }
523 
524 static void __mtrr_lookup_var_next(struct mtrr_iter *iter)
525 {
526         struct kvm_mtrr *mtrr_state = iter->mtrr_state;
527 
528         list_for_each_entry_continue(iter->range, &mtrr_state->head, node)
529                 if (match_var_range(iter, iter->range))
530                         return;
531 
532         iter->range = NULL;
533         iter->partial_map |= iter->start_max < iter->end;
534 }
535 
536 static void mtrr_lookup_var_start(struct mtrr_iter *iter)
537 {
538         struct kvm_mtrr *mtrr_state = iter->mtrr_state;
539 
540         iter->fixed = false;
541         iter->start_max = iter->start;
542         iter->range = NULL;
543         iter->range = list_prepare_entry(iter->range, &mtrr_state->head, node);
544 
545         __mtrr_lookup_var_next(iter);
546 }
547 
548 static void mtrr_lookup_fixed_next(struct mtrr_iter *iter)
549 {
550         /* terminate the lookup. */
551         if (fixed_mtrr_range_end_addr(iter->seg, iter->index) >= iter->end) {
552                 iter->fixed = false;
553                 iter->range = NULL;
554                 return;
555         }
556 
557         iter->index++;
558 
559         /* have looked up for all fixed MTRRs. */
560         if (iter->index >= ARRAY_SIZE(iter->mtrr_state->fixed_ranges))
561                 return mtrr_lookup_var_start(iter);
562 
563         /* switch to next segment. */
564         if (iter->index > fixed_mtrr_seg_end_range_index(iter->seg))
565                 iter->seg++;
566 }
567 
568 static void mtrr_lookup_var_next(struct mtrr_iter *iter)
569 {
570         __mtrr_lookup_var_next(iter);
571 }
572 
573 static void mtrr_lookup_start(struct mtrr_iter *iter)
574 {
575         if (!mtrr_is_enabled(iter->mtrr_state)) {
576                 iter->mtrr_disabled = true;
577                 return;
578         }
579 
580         if (!mtrr_lookup_fixed_start(iter))
581                 mtrr_lookup_var_start(iter);
582 }
583 
584 static void mtrr_lookup_init(struct mtrr_iter *iter,
585                              struct kvm_mtrr *mtrr_state, u64 start, u64 end)
586 {
587         iter->mtrr_state = mtrr_state;
588         iter->start = start;
589         iter->end = end;
590         iter->mtrr_disabled = false;
591         iter->partial_map = false;
592         iter->fixed = false;
593         iter->range = NULL;
594 
595         mtrr_lookup_start(iter);
596 }
597 
598 static bool mtrr_lookup_okay(struct mtrr_iter *iter)
599 {
600         if (iter->fixed) {
601                 iter->mem_type = iter->mtrr_state->fixed_ranges[iter->index];
602                 return true;
603         }
604 
605         if (iter->range) {
606                 iter->mem_type = iter->range->base & 0xff;
607                 return true;
608         }
609 
610         return false;
611 }
612 
613 static void mtrr_lookup_next(struct mtrr_iter *iter)
614 {
615         if (iter->fixed)
616                 mtrr_lookup_fixed_next(iter);
617         else
618                 mtrr_lookup_var_next(iter);
619 }
620 
621 #define mtrr_for_each_mem_type(_iter_, _mtrr_, _gpa_start_, _gpa_end_) \
622         for (mtrr_lookup_init(_iter_, _mtrr_, _gpa_start_, _gpa_end_); \
623              mtrr_lookup_okay(_iter_); mtrr_lookup_next(_iter_))
624 
625 u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
626 {
627         struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
628         struct mtrr_iter iter;
629         u64 start, end;
630         int type = -1;
631         const int wt_wb_mask = (1 << MTRR_TYPE_WRBACK)
632                                | (1 << MTRR_TYPE_WRTHROUGH);
633 
634         start = gfn_to_gpa(gfn);
635         end = start + PAGE_SIZE;
636 
637         mtrr_for_each_mem_type(&iter, mtrr_state, start, end) {
638                 int curr_type = iter.mem_type;
639 
640                 /*
641                  * Please refer to Intel SDM Volume 3: 11.11.4.1 MTRR
642                  * Precedences.
643                  */
644 
645                 if (type == -1) {
646                         type = curr_type;
647                         continue;
648                 }
649 
650                 /*
651                  * If two or more variable memory ranges match and the
652                  * memory types are identical, then that memory type is
653                  * used.
654                  */
655                 if (type == curr_type)
656                         continue;
657 
658                 /*
659                  * If two or more variable memory ranges match and one of
660                  * the memory types is UC, the UC memory type used.
661                  */
662                 if (curr_type == MTRR_TYPE_UNCACHABLE)
663                         return MTRR_TYPE_UNCACHABLE;
664 
665                 /*
666                  * If two or more variable memory ranges match and the
667                  * memory types are WT and WB, the WT memory type is used.
668                  */
669                 if (((1 << type) & wt_wb_mask) &&
670                       ((1 << curr_type) & wt_wb_mask)) {
671                         type = MTRR_TYPE_WRTHROUGH;
672                         continue;
673                 }
674 
675                 /*
676                  * For overlaps not defined by the above rules, processor
677                  * behavior is undefined.
678                  */
679 
680                 /* We use WB for this undefined behavior. :( */
681                 return MTRR_TYPE_WRBACK;
682         }
683 
684         if (iter.mtrr_disabled)
685                 return mtrr_disabled_type(vcpu);
686 
687         /* not contained in any MTRRs. */
688         if (type == -1)
689                 return mtrr_default_type(mtrr_state);
690 
691         /*
692          * We just check one page, partially covered by MTRRs is
693          * impossible.
694          */
695         WARN_ON(iter.partial_map);
696 
697         return type;
698 }
699 EXPORT_SYMBOL_GPL(kvm_mtrr_get_guest_memory_type);
700 
701 bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn,
702                                           int page_num)
703 {
704         struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
705         struct mtrr_iter iter;
706         u64 start, end;
707         int type = -1;
708 
709         start = gfn_to_gpa(gfn);
710         end = gfn_to_gpa(gfn + page_num);
711         mtrr_for_each_mem_type(&iter, mtrr_state, start, end) {
712                 if (type == -1) {
713                         type = iter.mem_type;
714                         continue;
715                 }
716 
717                 if (type != iter.mem_type)
718                         return false;
719         }
720 
721         if (iter.mtrr_disabled)
722                 return true;
723 
724         if (!iter.partial_map)
725                 return true;
726 
727         if (type == -1)
728                 return true;
729 
730         return type == mtrr_default_type(mtrr_state);
731 }
732 

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