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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         case 0x2f8:
 48                 return true;
 49         }
 50         return false;
 51 }
 52 
 53 static bool valid_pat_type(unsigned t)
 54 {
 55         return t < 8 && (1 << t) & 0xf3; /* 0, 1, 4, 5, 6, 7 */
 56 }
 57 
 58 static bool valid_mtrr_type(unsigned t)
 59 {
 60         return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */
 61 }
 62 
 63 bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data)
 64 {
 65         int i;
 66         u64 mask;
 67 
 68         if (!msr_mtrr_valid(msr))
 69                 return false;
 70 
 71         if (msr == MSR_IA32_CR_PAT) {
 72                 for (i = 0; i < 8; i++)
 73                         if (!valid_pat_type((data >> (i * 8)) & 0xff))
 74                                 return false;
 75                 return true;
 76         } else if (msr == MSR_MTRRdefType) {
 77                 if (data & ~0xcff)
 78                         return false;
 79                 return valid_mtrr_type(data & 0xff);
 80         } else if (msr >= MSR_MTRRfix64K_00000 && msr <= MSR_MTRRfix4K_F8000) {
 81                 for (i = 0; i < 8 ; i++)
 82                         if (!valid_mtrr_type((data >> (i * 8)) & 0xff))
 83                                 return false;
 84                 return true;
 85         }
 86 
 87         /* variable MTRRs */
 88         WARN_ON(!(msr >= 0x200 && msr < 0x200 + 2 * KVM_NR_VAR_MTRR));
 89 
 90         mask = (~0ULL) << cpuid_maxphyaddr(vcpu);
 91         if ((msr & 1) == 0) {
 92                 /* MTRR base */
 93                 if (!valid_mtrr_type(data & 0xff))
 94                         return false;
 95                 mask |= 0xf00;
 96         } else
 97                 /* MTRR mask */
 98                 mask |= 0x7ff;
 99         if (data & mask) {
100                 kvm_inject_gp(vcpu, 0);
101                 return false;
102         }
103 
104         return true;
105 }
106 EXPORT_SYMBOL_GPL(kvm_mtrr_valid);
107 
108 static bool mtrr_is_enabled(struct kvm_mtrr *mtrr_state)
109 {
110         return !!(mtrr_state->deftype & IA32_MTRR_DEF_TYPE_E);
111 }
112 
113 static bool fixed_mtrr_is_enabled(struct kvm_mtrr *mtrr_state)
114 {
115         return !!(mtrr_state->deftype & IA32_MTRR_DEF_TYPE_FE);
116 }
117 
118 static u8 mtrr_default_type(struct kvm_mtrr *mtrr_state)
119 {
120         return mtrr_state->deftype & IA32_MTRR_DEF_TYPE_TYPE_MASK;
121 }
122 
123 static u8 mtrr_disabled_type(void)
124 {
125         /*
126          * Intel SDM 11.11.2.2: all MTRRs are disabled when
127          * IA32_MTRR_DEF_TYPE.E bit is cleared, and the UC
128          * memory type is applied to all of physical memory.
129          */
130         return MTRR_TYPE_UNCACHABLE;
131 }
132 
133 /*
134 * Three terms are used in the following code:
135 * - segment, it indicates the address segments covered by fixed MTRRs.
136 * - unit, it corresponds to the MSR entry in the segment.
137 * - range, a range is covered in one memory cache type.
138 */
139 struct fixed_mtrr_segment {
140         u64 start;
141         u64 end;
142 
143         int range_shift;
144 
145         /* the start position in kvm_mtrr.fixed_ranges[]. */
146         int range_start;
147 };
148 
149 static struct fixed_mtrr_segment fixed_seg_table[] = {
150         /* MSR_MTRRfix64K_00000, 1 unit. 64K fixed mtrr. */
151         {
152                 .start = 0x0,
153                 .end = 0x80000,
154                 .range_shift = 16, /* 64K */
155                 .range_start = 0,
156         },
157 
158         /*
159          * MSR_MTRRfix16K_80000 ... MSR_MTRRfix16K_A0000, 2 units,
160          * 16K fixed mtrr.
161          */
162         {
163                 .start = 0x80000,
164                 .end = 0xc0000,
165                 .range_shift = 14, /* 16K */
166                 .range_start = 8,
167         },
168 
169         /*
170          * MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000, 8 units,
171          * 4K fixed mtrr.
172          */
173         {
174                 .start = 0xc0000,
175                 .end = 0x100000,
176                 .range_shift = 12, /* 12K */
177                 .range_start = 24,
178         }
179 };
180 
181 /*
182  * The size of unit is covered in one MSR, one MSR entry contains
183  * 8 ranges so that unit size is always 8 * 2^range_shift.
184  */
185 static u64 fixed_mtrr_seg_unit_size(int seg)
186 {
187         return 8 << fixed_seg_table[seg].range_shift;
188 }
189 
190 static bool fixed_msr_to_seg_unit(u32 msr, int *seg, int *unit)
191 {
192         switch (msr) {
193         case MSR_MTRRfix64K_00000:
194                 *seg = 0;
195                 *unit = 0;
196                 break;
197         case MSR_MTRRfix16K_80000 ... MSR_MTRRfix16K_A0000:
198                 *seg = 1;
199                 *unit = msr - MSR_MTRRfix16K_80000;
200                 break;
201         case MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000:
202                 *seg = 2;
203                 *unit = msr - MSR_MTRRfix4K_C0000;
204                 break;
205         default:
206                 return false;
207         }
208 
209         return true;
210 }
211 
212 static void fixed_mtrr_seg_unit_range(int seg, int unit, u64 *start, u64 *end)
213 {
214         struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg];
215         u64 unit_size = fixed_mtrr_seg_unit_size(seg);
216 
217         *start = mtrr_seg->start + unit * unit_size;
218         *end = *start + unit_size;
219         WARN_ON(*end > mtrr_seg->end);
220 }
221 
222 static int fixed_mtrr_seg_unit_range_index(int seg, int unit)
223 {
224         struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg];
225 
226         WARN_ON(mtrr_seg->start + unit * fixed_mtrr_seg_unit_size(seg)
227                 > mtrr_seg->end);
228 
229         /* each unit has 8 ranges. */
230         return mtrr_seg->range_start + 8 * unit;
231 }
232 
233 static int fixed_mtrr_seg_end_range_index(int seg)
234 {
235         struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg];
236         int n;
237 
238         n = (mtrr_seg->end - mtrr_seg->start) >> mtrr_seg->range_shift;
239         return mtrr_seg->range_start + n - 1;
240 }
241 
242 static bool fixed_msr_to_range(u32 msr, u64 *start, u64 *end)
243 {
244         int seg, unit;
245 
246         if (!fixed_msr_to_seg_unit(msr, &seg, &unit))
247                 return false;
248 
249         fixed_mtrr_seg_unit_range(seg, unit, start, end);
250         return true;
251 }
252 
253 static int fixed_msr_to_range_index(u32 msr)
254 {
255         int seg, unit;
256 
257         if (!fixed_msr_to_seg_unit(msr, &seg, &unit))
258                 return -1;
259 
260         return fixed_mtrr_seg_unit_range_index(seg, unit);
261 }
262 
263 static int fixed_mtrr_addr_to_seg(u64 addr)
264 {
265         struct fixed_mtrr_segment *mtrr_seg;
266         int seg, seg_num = ARRAY_SIZE(fixed_seg_table);
267 
268         for (seg = 0; seg < seg_num; seg++) {
269                 mtrr_seg = &fixed_seg_table[seg];
270                 if (mtrr_seg->start >= addr && addr < mtrr_seg->end)
271                         return seg;
272         }
273 
274         return -1;
275 }
276 
277 static int fixed_mtrr_addr_seg_to_range_index(u64 addr, int seg)
278 {
279         struct fixed_mtrr_segment *mtrr_seg;
280         int index;
281 
282         mtrr_seg = &fixed_seg_table[seg];
283         index = mtrr_seg->range_start;
284         index += (addr - mtrr_seg->start) >> mtrr_seg->range_shift;
285         return index;
286 }
287 
288 static u64 fixed_mtrr_range_end_addr(int seg, int index)
289 {
290         struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg];
291         int pos = index - mtrr_seg->range_start;
292 
293         return mtrr_seg->start + ((pos + 1) << mtrr_seg->range_shift);
294 }
295 
296 static void var_mtrr_range(struct kvm_mtrr_range *range, u64 *start, u64 *end)
297 {
298         u64 mask;
299 
300         *start = range->base & PAGE_MASK;
301 
302         mask = range->mask & PAGE_MASK;
303         mask |= ~0ULL << boot_cpu_data.x86_phys_bits;
304 
305         /* This cannot overflow because writing to the reserved bits of
306          * variable MTRRs causes a #GP.
307          */
308         *end = (*start | ~mask) + 1;
309 }
310 
311 static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr)
312 {
313         struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
314         gfn_t start, end;
315         int index;
316 
317         if (msr == MSR_IA32_CR_PAT || !tdp_enabled ||
318               !kvm_arch_has_noncoherent_dma(vcpu->kvm))
319                 return;
320 
321         if (!mtrr_is_enabled(mtrr_state) && msr != MSR_MTRRdefType)
322                 return;
323 
324         /* fixed MTRRs. */
325         if (fixed_msr_to_range(msr, &start, &end)) {
326                 if (!fixed_mtrr_is_enabled(mtrr_state))
327                         return;
328         } else if (msr == MSR_MTRRdefType) {
329                 start = 0x0;
330                 end = ~0ULL;
331         } else {
332                 /* variable range MTRRs. */
333                 index = (msr - 0x200) / 2;
334                 var_mtrr_range(&mtrr_state->var_ranges[index], &start, &end);
335         }
336 
337         kvm_zap_gfn_range(vcpu->kvm, gpa_to_gfn(start), gpa_to_gfn(end));
338 }
339 
340 static bool var_mtrr_range_is_valid(struct kvm_mtrr_range *range)
341 {
342         return (range->mask & (1 << 11)) != 0;
343 }
344 
345 static void set_var_mtrr_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
346 {
347         struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
348         struct kvm_mtrr_range *tmp, *cur;
349         int index, is_mtrr_mask;
350 
351         index = (msr - 0x200) / 2;
352         is_mtrr_mask = msr - 0x200 - 2 * index;
353         cur = &mtrr_state->var_ranges[index];
354 
355         /* remove the entry if it's in the list. */
356         if (var_mtrr_range_is_valid(cur))
357                 list_del(&mtrr_state->var_ranges[index].node);
358 
359         if (!is_mtrr_mask)
360                 cur->base = data;
361         else
362                 cur->mask = data;
363 
364         /* add it to the list if it's enabled. */
365         if (var_mtrr_range_is_valid(cur)) {
366                 list_for_each_entry(tmp, &mtrr_state->head, node)
367                         if (cur->base >= tmp->base)
368                                 break;
369                 list_add_tail(&cur->node, &tmp->node);
370         }
371 }
372 
373 int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
374 {
375         int index;
376 
377         if (!kvm_mtrr_valid(vcpu, msr, data))
378                 return 1;
379 
380         index = fixed_msr_to_range_index(msr);
381         if (index >= 0)
382                 *(u64 *)&vcpu->arch.mtrr_state.fixed_ranges[index] = data;
383         else if (msr == MSR_MTRRdefType)
384                 vcpu->arch.mtrr_state.deftype = data;
385         else if (msr == MSR_IA32_CR_PAT)
386                 vcpu->arch.pat = data;
387         else
388                 set_var_mtrr_msr(vcpu, msr, data);
389 
390         update_mtrr(vcpu, msr);
391         return 0;
392 }
393 
394 int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
395 {
396         int index;
397 
398         /* MSR_MTRRcap is a readonly MSR. */
399         if (msr == MSR_MTRRcap) {
400                 /*
401                  * SMRR = 0
402                  * WC = 1
403                  * FIX = 1
404                  * VCNT = KVM_NR_VAR_MTRR
405                  */
406                 *pdata = 0x500 | KVM_NR_VAR_MTRR;
407                 return 0;
408         }
409 
410         if (!msr_mtrr_valid(msr))
411                 return 1;
412 
413         index = fixed_msr_to_range_index(msr);
414         if (index >= 0)
415                 *pdata = *(u64 *)&vcpu->arch.mtrr_state.fixed_ranges[index];
416         else if (msr == MSR_MTRRdefType)
417                 *pdata = vcpu->arch.mtrr_state.deftype;
418         else if (msr == MSR_IA32_CR_PAT)
419                 *pdata = vcpu->arch.pat;
420         else {  /* Variable MTRRs */
421                 int is_mtrr_mask;
422 
423                 index = (msr - 0x200) / 2;
424                 is_mtrr_mask = msr - 0x200 - 2 * index;
425                 if (!is_mtrr_mask)
426                         *pdata = vcpu->arch.mtrr_state.var_ranges[index].base;
427                 else
428                         *pdata = vcpu->arch.mtrr_state.var_ranges[index].mask;
429         }
430 
431         return 0;
432 }
433 
434 void kvm_vcpu_mtrr_init(struct kvm_vcpu *vcpu)
435 {
436         INIT_LIST_HEAD(&vcpu->arch.mtrr_state.head);
437 }
438 
439 struct mtrr_iter {
440         /* input fields. */
441         struct kvm_mtrr *mtrr_state;
442         u64 start;
443         u64 end;
444 
445         /* output fields. */
446         int mem_type;
447         /* mtrr is completely disabled? */
448         bool mtrr_disabled;
449         /* [start, end) is not fully covered in MTRRs? */
450         bool partial_map;
451 
452         /* private fields. */
453         union {
454                 /* used for fixed MTRRs. */
455                 struct {
456                         int index;
457                         int seg;
458                 };
459 
460                 /* used for var MTRRs. */
461                 struct {
462                         struct kvm_mtrr_range *range;
463                         /* max address has been covered in var MTRRs. */
464                         u64 start_max;
465                 };
466         };
467 
468         bool fixed;
469 };
470 
471 static bool mtrr_lookup_fixed_start(struct mtrr_iter *iter)
472 {
473         int seg, index;
474 
475         if (!fixed_mtrr_is_enabled(iter->mtrr_state))
476                 return false;
477 
478         seg = fixed_mtrr_addr_to_seg(iter->start);
479         if (seg < 0)
480                 return false;
481 
482         iter->fixed = true;
483         index = fixed_mtrr_addr_seg_to_range_index(iter->start, seg);
484         iter->index = index;
485         iter->seg = seg;
486         return true;
487 }
488 
489 static bool match_var_range(struct mtrr_iter *iter,
490                             struct kvm_mtrr_range *range)
491 {
492         u64 start, end;
493 
494         var_mtrr_range(range, &start, &end);
495         if (!(start >= iter->end || end <= iter->start)) {
496                 iter->range = range;
497 
498                 /*
499                  * the function is called when we do kvm_mtrr.head walking.
500                  * Range has the minimum base address which interleaves
501                  * [looker->start_max, looker->end).
502                  */
503                 iter->partial_map |= iter->start_max < start;
504 
505                 /* update the max address has been covered. */
506                 iter->start_max = max(iter->start_max, end);
507                 return true;
508         }
509 
510         return false;
511 }
512 
513 static void __mtrr_lookup_var_next(struct mtrr_iter *iter)
514 {
515         struct kvm_mtrr *mtrr_state = iter->mtrr_state;
516 
517         list_for_each_entry_continue(iter->range, &mtrr_state->head, node)
518                 if (match_var_range(iter, iter->range))
519                         return;
520 
521         iter->range = NULL;
522         iter->partial_map |= iter->start_max < iter->end;
523 }
524 
525 static void mtrr_lookup_var_start(struct mtrr_iter *iter)
526 {
527         struct kvm_mtrr *mtrr_state = iter->mtrr_state;
528 
529         iter->fixed = false;
530         iter->start_max = iter->start;
531         iter->range = list_prepare_entry(iter->range, &mtrr_state->head, node);
532 
533         __mtrr_lookup_var_next(iter);
534 }
535 
536 static void mtrr_lookup_fixed_next(struct mtrr_iter *iter)
537 {
538         /* terminate the lookup. */
539         if (fixed_mtrr_range_end_addr(iter->seg, iter->index) >= iter->end) {
540                 iter->fixed = false;
541                 iter->range = NULL;
542                 return;
543         }
544 
545         iter->index++;
546 
547         /* have looked up for all fixed MTRRs. */
548         if (iter->index >= ARRAY_SIZE(iter->mtrr_state->fixed_ranges))
549                 return mtrr_lookup_var_start(iter);
550 
551         /* switch to next segment. */
552         if (iter->index > fixed_mtrr_seg_end_range_index(iter->seg))
553                 iter->seg++;
554 }
555 
556 static void mtrr_lookup_var_next(struct mtrr_iter *iter)
557 {
558         __mtrr_lookup_var_next(iter);
559 }
560 
561 static void mtrr_lookup_start(struct mtrr_iter *iter)
562 {
563         if (!mtrr_is_enabled(iter->mtrr_state)) {
564                 iter->mtrr_disabled = true;
565                 return;
566         }
567 
568         if (!mtrr_lookup_fixed_start(iter))
569                 mtrr_lookup_var_start(iter);
570 }
571 
572 static void mtrr_lookup_init(struct mtrr_iter *iter,
573                              struct kvm_mtrr *mtrr_state, u64 start, u64 end)
574 {
575         iter->mtrr_state = mtrr_state;
576         iter->start = start;
577         iter->end = end;
578         iter->mtrr_disabled = false;
579         iter->partial_map = false;
580         iter->fixed = false;
581         iter->range = NULL;
582 
583         mtrr_lookup_start(iter);
584 }
585 
586 static bool mtrr_lookup_okay(struct mtrr_iter *iter)
587 {
588         if (iter->fixed) {
589                 iter->mem_type = iter->mtrr_state->fixed_ranges[iter->index];
590                 return true;
591         }
592 
593         if (iter->range) {
594                 iter->mem_type = iter->range->base & 0xff;
595                 return true;
596         }
597 
598         return false;
599 }
600 
601 static void mtrr_lookup_next(struct mtrr_iter *iter)
602 {
603         if (iter->fixed)
604                 mtrr_lookup_fixed_next(iter);
605         else
606                 mtrr_lookup_var_next(iter);
607 }
608 
609 #define mtrr_for_each_mem_type(_iter_, _mtrr_, _gpa_start_, _gpa_end_) \
610         for (mtrr_lookup_init(_iter_, _mtrr_, _gpa_start_, _gpa_end_); \
611              mtrr_lookup_okay(_iter_); mtrr_lookup_next(_iter_))
612 
613 u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
614 {
615         struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
616         struct mtrr_iter iter;
617         u64 start, end;
618         int type = -1;
619         const int wt_wb_mask = (1 << MTRR_TYPE_WRBACK)
620                                | (1 << MTRR_TYPE_WRTHROUGH);
621 
622         start = gfn_to_gpa(gfn);
623         end = start + PAGE_SIZE;
624 
625         mtrr_for_each_mem_type(&iter, mtrr_state, start, end) {
626                 int curr_type = iter.mem_type;
627 
628                 /*
629                  * Please refer to Intel SDM Volume 3: 11.11.4.1 MTRR
630                  * Precedences.
631                  */
632 
633                 if (type == -1) {
634                         type = curr_type;
635                         continue;
636                 }
637 
638                 /*
639                  * If two or more variable memory ranges match and the
640                  * memory types are identical, then that memory type is
641                  * used.
642                  */
643                 if (type == curr_type)
644                         continue;
645 
646                 /*
647                  * If two or more variable memory ranges match and one of
648                  * the memory types is UC, the UC memory type used.
649                  */
650                 if (curr_type == MTRR_TYPE_UNCACHABLE)
651                         return MTRR_TYPE_UNCACHABLE;
652 
653                 /*
654                  * If two or more variable memory ranges match and the
655                  * memory types are WT and WB, the WT memory type is used.
656                  */
657                 if (((1 << type) & wt_wb_mask) &&
658                       ((1 << curr_type) & wt_wb_mask)) {
659                         type = MTRR_TYPE_WRTHROUGH;
660                         continue;
661                 }
662 
663                 /*
664                  * For overlaps not defined by the above rules, processor
665                  * behavior is undefined.
666                  */
667 
668                 /* We use WB for this undefined behavior. :( */
669                 return MTRR_TYPE_WRBACK;
670         }
671 
672         if (iter.mtrr_disabled)
673                 return mtrr_disabled_type();
674 
675         /* not contained in any MTRRs. */
676         if (type == -1)
677                 return mtrr_default_type(mtrr_state);
678 
679         /*
680          * We just check one page, partially covered by MTRRs is
681          * impossible.
682          */
683         WARN_ON(iter.partial_map);
684 
685         return type;
686 }
687 EXPORT_SYMBOL_GPL(kvm_mtrr_get_guest_memory_type);
688 
689 bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn,
690                                           int page_num)
691 {
692         struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
693         struct mtrr_iter iter;
694         u64 start, end;
695         int type = -1;
696 
697         start = gfn_to_gpa(gfn);
698         end = gfn_to_gpa(gfn + page_num);
699         mtrr_for_each_mem_type(&iter, mtrr_state, start, end) {
700                 if (type == -1) {
701                         type = iter.mem_type;
702                         continue;
703                 }
704 
705                 if (type != iter.mem_type)
706                         return false;
707         }
708 
709         if (iter.mtrr_disabled)
710                 return true;
711 
712         if (!iter.partial_map)
713                 return true;
714 
715         if (type == -1)
716                 return true;
717 
718         return type == mtrr_default_type(mtrr_state);
719 }
720 

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