2 * MTRR (Memory Type Range Register) cleanup
4 * Copyright (C) 2009 Yinghai Lu
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the Free
18 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #include <linux/module.h>
21 #include <linux/init.h>
22 #include <linux/pci.h>
23 #include <linux/smp.h>
24 #include <linux/cpu.h>
25 #include <linux/sort.h>
26 #include <linux/mutex.h>
27 #include <linux/uaccess.h>
28 #include <linux/kvm_para.h>
30 #include <asm/processor.h>
42 struct var_mtrr_range_state {
43 unsigned long base_pfn;
44 unsigned long size_pfn;
48 struct var_mtrr_state {
49 unsigned long range_startk;
50 unsigned long range_sizek;
51 unsigned long chunk_sizek;
52 unsigned long gran_sizek;
56 /* Should be related to MTRR_VAR_RANGES nums */
59 static struct res_range __initdata range[RANGE_NUM];
60 static int __initdata nr_range;
62 static struct var_mtrr_range_state __initdata range_state[RANGE_NUM];
64 static int __initdata debug_print;
65 #define Dprintk(x...) do { if (debug_print) printk(KERN_DEBUG x); } while (0)
69 add_range(struct res_range *range, int nr_range,
70 unsigned long start, unsigned long end)
73 if (nr_range >= RANGE_NUM)
76 range[nr_range].start = start;
77 range[nr_range].end = end;
85 add_range_with_merge(struct res_range *range, int nr_range,
86 unsigned long start, unsigned long end)
90 /* Try to merge it with old one: */
91 for (i = 0; i < nr_range; i++) {
92 unsigned long final_start, final_end;
93 unsigned long common_start, common_end;
98 common_start = max(range[i].start, start);
99 common_end = min(range[i].end, end);
100 if (common_start > common_end + 1)
103 final_start = min(range[i].start, start);
104 final_end = max(range[i].end, end);
106 range[i].start = final_start;
107 range[i].end = final_end;
111 /* Need to add it: */
112 return add_range(range, nr_range, start, end);
116 subtract_range(struct res_range *range, unsigned long start, unsigned long end)
120 for (j = 0; j < RANGE_NUM; j++) {
124 if (start <= range[j].start && end >= range[j].end) {
130 if (start <= range[j].start && end < range[j].end &&
131 range[j].start < end + 1) {
132 range[j].start = end + 1;
137 if (start > range[j].start && end >= range[j].end &&
138 range[j].end > start - 1) {
139 range[j].end = start - 1;
143 if (start > range[j].start && end < range[j].end) {
144 /* Find the new spare: */
145 for (i = 0; i < RANGE_NUM; i++) {
146 if (range[i].end == 0)
150 range[i].end = range[j].end;
151 range[i].start = end + 1;
153 printk(KERN_ERR "run of slot in ranges\n");
155 range[j].end = start - 1;
161 static int __init cmp_range(const void *x1, const void *x2)
163 const struct res_range *r1 = x1;
164 const struct res_range *r2 = x2;
170 return start1 - start2;
173 static int __init clean_sort_range(struct res_range *range, int az)
175 int i, j, k = az - 1, nr_range = 0;
177 for (i = 0; i < k; i++) {
180 for (j = k; j > i; j--) {
188 range[i].start = range[k].start;
189 range[i].end = range[k].end;
195 for (i = 0; i < az; i++) {
203 sort(range, nr_range, sizeof(struct res_range), cmp_range, NULL);
208 #define BIOS_BUG_MSG KERN_WARNING \
209 "WARNING: BIOS bug: VAR MTRR %d contains strange UC entry under 1M, check with your system vendor!\n"
212 x86_get_mtrr_mem_range(struct res_range *range, int nr_range,
213 unsigned long extra_remove_base,
214 unsigned long extra_remove_size)
216 unsigned long base, size;
220 for (i = 0; i < num_var_ranges; i++) {
221 type = range_state[i].type;
222 if (type != MTRR_TYPE_WRBACK)
224 base = range_state[i].base_pfn;
225 size = range_state[i].size_pfn;
226 nr_range = add_range_with_merge(range, nr_range, base,
230 printk(KERN_DEBUG "After WB checking\n");
231 for (i = 0; i < nr_range; i++)
232 printk(KERN_DEBUG "MTRR MAP PFN: %016lx - %016lx\n",
233 range[i].start, range[i].end + 1);
236 /* Take out UC ranges: */
237 for (i = 0; i < num_var_ranges; i++) {
238 type = range_state[i].type;
239 if (type != MTRR_TYPE_UNCACHABLE &&
240 type != MTRR_TYPE_WRPROT)
242 size = range_state[i].size_pfn;
245 base = range_state[i].base_pfn;
246 if (base < (1<<(20-PAGE_SHIFT)) && mtrr_state.have_fixed &&
247 (mtrr_state.enabled & 1)) {
248 /* Var MTRR contains UC entry below 1M? Skip it: */
249 printk(BIOS_BUG_MSG, i);
250 if (base + size <= (1<<(20-PAGE_SHIFT)))
252 size -= (1<<(20-PAGE_SHIFT)) - base;
253 base = 1<<(20-PAGE_SHIFT);
255 subtract_range(range, base, base + size - 1);
257 if (extra_remove_size)
258 subtract_range(range, extra_remove_base,
259 extra_remove_base + extra_remove_size - 1);
262 printk(KERN_DEBUG "After UC checking\n");
263 for (i = 0; i < RANGE_NUM; i++) {
266 printk(KERN_DEBUG "MTRR MAP PFN: %016lx - %016lx\n",
267 range[i].start, range[i].end + 1);
271 /* sort the ranges */
272 nr_range = clean_sort_range(range, RANGE_NUM);
274 printk(KERN_DEBUG "After sorting\n");
275 for (i = 0; i < nr_range; i++)
276 printk(KERN_DEBUG "MTRR MAP PFN: %016lx - %016lx\n",
277 range[i].start, range[i].end + 1);
280 /* clear those is not used */
281 for (i = nr_range; i < RANGE_NUM; i++)
282 memset(&range[i], 0, sizeof(range[i]));
287 #ifdef CONFIG_MTRR_SANITIZER
289 static unsigned long __init sum_ranges(struct res_range *range, int nr_range)
291 unsigned long sum = 0;
294 for (i = 0; i < nr_range; i++)
295 sum += range[i].end + 1 - range[i].start;
300 static int enable_mtrr_cleanup __initdata =
301 CONFIG_MTRR_SANITIZER_ENABLE_DEFAULT;
303 static int __init disable_mtrr_cleanup_setup(char *str)
305 enable_mtrr_cleanup = 0;
308 early_param("disable_mtrr_cleanup", disable_mtrr_cleanup_setup);
310 static int __init enable_mtrr_cleanup_setup(char *str)
312 enable_mtrr_cleanup = 1;
315 early_param("enable_mtrr_cleanup", enable_mtrr_cleanup_setup);
317 static int __init mtrr_cleanup_debug_setup(char *str)
322 early_param("mtrr_cleanup_debug", mtrr_cleanup_debug_setup);
325 set_var_mtrr(unsigned int reg, unsigned long basek, unsigned long sizek,
326 unsigned char type, unsigned int address_bits)
328 u32 base_lo, base_hi, mask_lo, mask_hi;
332 fill_mtrr_var_range(reg, 0, 0, 0, 0);
336 mask = (1ULL << address_bits) - 1;
337 mask &= ~((((u64)sizek) << 10) - 1);
339 base = ((u64)basek) << 10;
344 base_lo = base & ((1ULL<<32) - 1);
345 base_hi = base >> 32;
347 mask_lo = mask & ((1ULL<<32) - 1);
348 mask_hi = mask >> 32;
350 fill_mtrr_var_range(reg, base_lo, base_hi, mask_lo, mask_hi);
354 save_var_mtrr(unsigned int reg, unsigned long basek, unsigned long sizek,
357 range_state[reg].base_pfn = basek >> (PAGE_SHIFT - 10);
358 range_state[reg].size_pfn = sizek >> (PAGE_SHIFT - 10);
359 range_state[reg].type = type;
362 static void __init set_var_mtrr_all(unsigned int address_bits)
364 unsigned long basek, sizek;
368 for (reg = 0; reg < num_var_ranges; reg++) {
369 basek = range_state[reg].base_pfn << (PAGE_SHIFT - 10);
370 sizek = range_state[reg].size_pfn << (PAGE_SHIFT - 10);
371 type = range_state[reg].type;
373 set_var_mtrr(reg, basek, sizek, type, address_bits);
377 static unsigned long to_size_factor(unsigned long sizek, char *factorp)
379 unsigned long base = sizek;
382 if (base & ((1<<10) - 1)) {
383 /* Not MB-aligned: */
385 } else if (base & ((1<<20) - 1)) {
398 static unsigned int __init
399 range_to_mtrr(unsigned int reg, unsigned long range_startk,
400 unsigned long range_sizek, unsigned char type)
402 if (!range_sizek || (reg >= num_var_ranges))
405 while (range_sizek) {
406 unsigned long max_align, align;
409 /* Compute the maximum size with which we can make a range: */
411 max_align = ffs(range_startk) - 1;
415 align = fls(range_sizek) - 1;
416 if (align > max_align)
421 char start_factor = 'K', size_factor = 'K';
422 unsigned long start_base, size_base;
424 start_base = to_size_factor(range_startk, &start_factor);
425 size_base = to_size_factor(sizek, &size_factor);
427 Dprintk("Setting variable MTRR %d, "
428 "base: %ld%cB, range: %ld%cB, type %s\n",
429 reg, start_base, start_factor,
430 size_base, size_factor,
431 (type == MTRR_TYPE_UNCACHABLE) ? "UC" :
432 ((type == MTRR_TYPE_WRBACK) ? "WB" : "Other")
435 save_var_mtrr(reg++, range_startk, sizek, type);
436 range_startk += sizek;
437 range_sizek -= sizek;
438 if (reg >= num_var_ranges)
444 static unsigned __init
445 range_to_mtrr_with_hole(struct var_mtrr_state *state, unsigned long basek,
448 unsigned long hole_basek, hole_sizek;
449 unsigned long second_basek, second_sizek;
450 unsigned long range0_basek, range0_sizek;
451 unsigned long range_basek, range_sizek;
452 unsigned long chunk_sizek;
453 unsigned long gran_sizek;
459 chunk_sizek = state->chunk_sizek;
460 gran_sizek = state->gran_sizek;
462 /* Align with gran size, prevent small block used up MTRRs: */
463 range_basek = ALIGN(state->range_startk, gran_sizek);
464 if ((range_basek > basek) && basek)
467 state->range_sizek -= (range_basek - state->range_startk);
468 range_sizek = ALIGN(state->range_sizek, gran_sizek);
470 while (range_sizek > state->range_sizek) {
471 range_sizek -= gran_sizek;
475 state->range_sizek = range_sizek;
477 /* Try to append some small hole: */
478 range0_basek = state->range_startk;
479 range0_sizek = ALIGN(state->range_sizek, chunk_sizek);
482 if (range0_sizek == state->range_sizek) {
483 Dprintk("rangeX: %016lx - %016lx\n",
485 (range0_basek + state->range_sizek)<<10);
486 state->reg = range_to_mtrr(state->reg, range0_basek,
487 state->range_sizek, MTRR_TYPE_WRBACK);
491 /* Only cut back when it is not the last: */
493 while (range0_basek + range0_sizek > (basek + sizek)) {
494 if (range0_sizek >= chunk_sizek)
495 range0_sizek -= chunk_sizek;
505 range_basek = range0_basek + range0_sizek;
507 /* One hole in the middle: */
508 if (range_basek > basek && range_basek <= (basek + sizek))
509 second_sizek = range_basek - basek;
511 if (range0_sizek > state->range_sizek) {
513 /* One hole in middle or at the end: */
514 hole_sizek = range0_sizek - state->range_sizek - second_sizek;
516 /* Hole size should be less than half of range0 size: */
517 if (hole_sizek >= (range0_sizek >> 1) &&
518 range0_sizek >= chunk_sizek) {
519 range0_sizek -= chunk_sizek;
528 Dprintk("range0: %016lx - %016lx\n",
530 (range0_basek + range0_sizek)<<10);
531 state->reg = range_to_mtrr(state->reg, range0_basek,
532 range0_sizek, MTRR_TYPE_WRBACK);
535 if (range0_sizek < state->range_sizek) {
536 /* Need to handle left over range: */
537 range_sizek = state->range_sizek - range0_sizek;
539 Dprintk("range: %016lx - %016lx\n",
541 (range_basek + range_sizek)<<10);
543 state->reg = range_to_mtrr(state->reg, range_basek,
544 range_sizek, MTRR_TYPE_WRBACK);
548 hole_basek = range_basek - hole_sizek - second_sizek;
549 Dprintk("hole: %016lx - %016lx\n",
551 (hole_basek + hole_sizek)<<10);
552 state->reg = range_to_mtrr(state->reg, hole_basek,
553 hole_sizek, MTRR_TYPE_UNCACHABLE);
560 set_var_mtrr_range(struct var_mtrr_state *state, unsigned long base_pfn,
561 unsigned long size_pfn)
563 unsigned long basek, sizek;
564 unsigned long second_sizek = 0;
566 if (state->reg >= num_var_ranges)
569 basek = base_pfn << (PAGE_SHIFT - 10);
570 sizek = size_pfn << (PAGE_SHIFT - 10);
572 /* See if I can merge with the last range: */
573 if ((basek <= 1024) ||
574 (state->range_startk + state->range_sizek == basek)) {
575 unsigned long endk = basek + sizek;
576 state->range_sizek = endk - state->range_startk;
579 /* Write the range mtrrs: */
580 if (state->range_sizek != 0)
581 second_sizek = range_to_mtrr_with_hole(state, basek, sizek);
583 /* Allocate an msr: */
584 state->range_startk = basek + second_sizek;
585 state->range_sizek = sizek - second_sizek;
588 /* Mininum size of mtrr block that can take hole: */
589 static u64 mtrr_chunk_size __initdata = (256ULL<<20);
591 static int __init parse_mtrr_chunk_size_opt(char *p)
595 mtrr_chunk_size = memparse(p, &p);
598 early_param("mtrr_chunk_size", parse_mtrr_chunk_size_opt);
600 /* Granularity of mtrr of block: */
601 static u64 mtrr_gran_size __initdata;
603 static int __init parse_mtrr_gran_size_opt(char *p)
607 mtrr_gran_size = memparse(p, &p);
610 early_param("mtrr_gran_size", parse_mtrr_gran_size_opt);
612 static unsigned long nr_mtrr_spare_reg __initdata =
613 CONFIG_MTRR_SANITIZER_SPARE_REG_NR_DEFAULT;
615 static int __init parse_mtrr_spare_reg(char *arg)
618 nr_mtrr_spare_reg = simple_strtoul(arg, NULL, 0);
621 early_param("mtrr_spare_reg_nr", parse_mtrr_spare_reg);
624 x86_setup_var_mtrrs(struct res_range *range, int nr_range,
625 u64 chunk_size, u64 gran_size)
627 struct var_mtrr_state var_state;
631 var_state.range_startk = 0;
632 var_state.range_sizek = 0;
634 var_state.chunk_sizek = chunk_size >> 10;
635 var_state.gran_sizek = gran_size >> 10;
637 memset(range_state, 0, sizeof(range_state));
639 /* Write the range: */
640 for (i = 0; i < nr_range; i++) {
641 set_var_mtrr_range(&var_state, range[i].start,
642 range[i].end - range[i].start + 1);
645 /* Write the last range: */
646 if (var_state.range_sizek != 0)
647 range_to_mtrr_with_hole(&var_state, 0, 0);
649 num_reg = var_state.reg;
650 /* Clear out the extra MTRR's: */
651 while (var_state.reg < num_var_ranges) {
652 save_var_mtrr(var_state.reg, 0, 0, 0);
659 struct mtrr_cleanup_result {
660 unsigned long gran_sizek;
661 unsigned long chunk_sizek;
662 unsigned long lose_cover_sizek;
663 unsigned int num_reg;
668 * gran_size: 64K, 128K, 256K, 512K, 1M, 2M, ..., 2G
669 * chunk size: gran_size, ..., 2G
670 * so we need (1+16)*8
672 #define NUM_RESULT 136
673 #define PSHIFT (PAGE_SHIFT - 10)
675 static struct mtrr_cleanup_result __initdata result[NUM_RESULT];
676 static unsigned long __initdata min_loss_pfn[RANGE_NUM];
678 static void __init print_out_mtrr_range_state(void)
680 char start_factor = 'K', size_factor = 'K';
681 unsigned long start_base, size_base;
685 for (i = 0; i < num_var_ranges; i++) {
687 size_base = range_state[i].size_pfn << (PAGE_SHIFT - 10);
691 size_base = to_size_factor(size_base, &size_factor),
692 start_base = range_state[i].base_pfn << (PAGE_SHIFT - 10);
693 start_base = to_size_factor(start_base, &start_factor),
694 type = range_state[i].type;
696 printk(KERN_DEBUG "reg %d, base: %ld%cB, range: %ld%cB, type %s\n",
697 i, start_base, start_factor,
698 size_base, size_factor,
699 (type == MTRR_TYPE_UNCACHABLE) ? "UC" :
700 ((type == MTRR_TYPE_WRPROT) ? "WP" :
701 ((type == MTRR_TYPE_WRBACK) ? "WB" : "Other"))
706 static int __init mtrr_need_cleanup(void)
711 /* Extra one for all 0: */
712 int num[MTRR_NUM_TYPES + 1];
714 /* Check entries number: */
715 memset(num, 0, sizeof(num));
716 for (i = 0; i < num_var_ranges; i++) {
717 type = range_state[i].type;
718 size = range_state[i].size_pfn;
719 if (type >= MTRR_NUM_TYPES)
722 type = MTRR_NUM_TYPES;
726 /* Check if we got UC entries: */
727 if (!num[MTRR_TYPE_UNCACHABLE])
730 /* Check if we only had WB and UC */
731 if (num[MTRR_TYPE_WRBACK] + num[MTRR_TYPE_UNCACHABLE] !=
732 num_var_ranges - num[MTRR_NUM_TYPES])
738 static unsigned long __initdata range_sums;
741 mtrr_calc_range_state(u64 chunk_size, u64 gran_size,
742 unsigned long x_remove_base,
743 unsigned long x_remove_size, int i)
745 static struct res_range range_new[RANGE_NUM];
746 unsigned long range_sums_new;
747 static int nr_range_new;
750 /* Convert ranges to var ranges state: */
751 num_reg = x86_setup_var_mtrrs(range, nr_range, chunk_size, gran_size);
753 /* We got new setting in range_state, check it: */
754 memset(range_new, 0, sizeof(range_new));
755 nr_range_new = x86_get_mtrr_mem_range(range_new, 0,
756 x_remove_base, x_remove_size);
757 range_sums_new = sum_ranges(range_new, nr_range_new);
759 result[i].chunk_sizek = chunk_size >> 10;
760 result[i].gran_sizek = gran_size >> 10;
761 result[i].num_reg = num_reg;
763 if (range_sums < range_sums_new) {
764 result[i].lose_cover_sizek = (range_sums_new - range_sums) << PSHIFT;
767 result[i].lose_cover_sizek = (range_sums - range_sums_new) << PSHIFT;
770 /* Double check it: */
771 if (!result[i].bad && !result[i].lose_cover_sizek) {
772 if (nr_range_new != nr_range || memcmp(range, range_new, sizeof(range)))
776 if (!result[i].bad && (range_sums - range_sums_new < min_loss_pfn[num_reg]))
777 min_loss_pfn[num_reg] = range_sums - range_sums_new;
780 static void __init mtrr_print_out_one_result(int i)
782 unsigned long gran_base, chunk_base, lose_base;
783 char gran_factor, chunk_factor, lose_factor;
785 gran_base = to_size_factor(result[i].gran_sizek, &gran_factor),
786 chunk_base = to_size_factor(result[i].chunk_sizek, &chunk_factor),
787 lose_base = to_size_factor(result[i].lose_cover_sizek, &lose_factor),
789 pr_info("%sgran_size: %ld%c \tchunk_size: %ld%c \t",
790 result[i].bad ? "*BAD*" : " ",
791 gran_base, gran_factor, chunk_base, chunk_factor);
792 pr_cont("num_reg: %d \tlose cover RAM: %s%ld%c\n",
793 result[i].num_reg, result[i].bad ? "-" : "",
794 lose_base, lose_factor);
797 static int __init mtrr_search_optimal_index(void)
803 if (nr_mtrr_spare_reg >= num_var_ranges)
804 nr_mtrr_spare_reg = num_var_ranges - 1;
807 for (i = num_var_ranges - nr_mtrr_spare_reg; i > 0; i--) {
808 if (!min_loss_pfn[i])
813 if (num_reg_good != -1) {
814 for (i = 0; i < NUM_RESULT; i++) {
815 if (!result[i].bad &&
816 result[i].num_reg == num_reg_good &&
817 !result[i].lose_cover_sizek) {
827 int __init mtrr_cleanup(unsigned address_bits)
829 unsigned long x_remove_base, x_remove_size;
830 unsigned long base, size, def, dummy;
831 u64 chunk_size, gran_size;
836 if (!is_cpu(INTEL) || enable_mtrr_cleanup < 1)
839 rdmsr(MSR_MTRRdefType, def, dummy);
841 if (def != MTRR_TYPE_UNCACHABLE)
844 /* Get it and store it aside: */
845 memset(range_state, 0, sizeof(range_state));
846 for (i = 0; i < num_var_ranges; i++) {
847 mtrr_if->get(i, &base, &size, &type);
848 range_state[i].base_pfn = base;
849 range_state[i].size_pfn = size;
850 range_state[i].type = type;
853 /* Check if we need handle it and can handle it: */
854 if (!mtrr_need_cleanup())
857 /* Print original var MTRRs at first, for debugging: */
858 printk(KERN_DEBUG "original variable MTRRs\n");
859 print_out_mtrr_range_state();
861 memset(range, 0, sizeof(range));
863 x_remove_base = 1 << (32 - PAGE_SHIFT);
865 x_remove_size = (mtrr_tom2 >> PAGE_SHIFT) - x_remove_base;
867 nr_range = x86_get_mtrr_mem_range(range, 0, x_remove_base, x_remove_size);
869 * [0, 1M) should always be covered by var mtrr with WB
870 * and fixed mtrrs should take effect before var mtrr for it:
872 nr_range = add_range_with_merge(range, nr_range, 0,
873 (1ULL<<(20 - PAGE_SHIFT)) - 1);
874 /* Sort the ranges: */
875 sort(range, nr_range, sizeof(struct res_range), cmp_range, NULL);
877 range_sums = sum_ranges(range, nr_range);
878 printk(KERN_INFO "total RAM covered: %ldM\n",
879 range_sums >> (20 - PAGE_SHIFT));
881 if (mtrr_chunk_size && mtrr_gran_size) {
883 mtrr_calc_range_state(mtrr_chunk_size, mtrr_gran_size,
884 x_remove_base, x_remove_size, i);
886 mtrr_print_out_one_result(i);
888 if (!result[i].bad) {
889 set_var_mtrr_all(address_bits);
890 printk(KERN_DEBUG "New variable MTRRs\n");
891 print_out_mtrr_range_state();
894 printk(KERN_INFO "invalid mtrr_gran_size or mtrr_chunk_size, "
895 "will find optimal one\n");
899 memset(min_loss_pfn, 0xff, sizeof(min_loss_pfn));
900 memset(result, 0, sizeof(result));
901 for (gran_size = (1ULL<<16); gran_size < (1ULL<<32); gran_size <<= 1) {
903 for (chunk_size = gran_size; chunk_size < (1ULL<<32);
909 mtrr_calc_range_state(chunk_size, gran_size,
910 x_remove_base, x_remove_size, i);
912 mtrr_print_out_one_result(i);
913 printk(KERN_INFO "\n");
920 /* Try to find the optimal index: */
921 index_good = mtrr_search_optimal_index();
923 if (index_good != -1) {
924 printk(KERN_INFO "Found optimal setting for mtrr clean up\n");
926 mtrr_print_out_one_result(i);
928 /* Convert ranges to var ranges state: */
929 chunk_size = result[i].chunk_sizek;
931 gran_size = result[i].gran_sizek;
933 x86_setup_var_mtrrs(range, nr_range, chunk_size, gran_size);
934 set_var_mtrr_all(address_bits);
935 printk(KERN_DEBUG "New variable MTRRs\n");
936 print_out_mtrr_range_state();
940 for (i = 0; i < NUM_RESULT; i++)
941 mtrr_print_out_one_result(i);
944 printk(KERN_INFO "mtrr_cleanup: can not find optimal value\n");
945 printk(KERN_INFO "please specify mtrr_gran_size/mtrr_chunk_size\n");
950 int __init mtrr_cleanup(unsigned address_bits)
956 static int disable_mtrr_trim;
958 static int __init disable_mtrr_trim_setup(char *str)
960 disable_mtrr_trim = 1;
963 early_param("disable_mtrr_trim", disable_mtrr_trim_setup);
966 * Newer AMD K8s and later CPUs have a special magic MSR way to force WB
967 * for memory >4GB. Check for that here.
968 * Note this won't check if the MTRRs < 4GB where the magic bit doesn't
969 * apply to are wrong, but so far we don't know of any such case in the wild.
971 #define Tom2Enabled (1U << 21)
972 #define Tom2ForceMemTypeWB (1U << 22)
974 int __init amd_special_default_mtrr(void)
978 if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
980 if (boot_cpu_data.x86 < 0xf || boot_cpu_data.x86 > 0x11)
982 /* In case some hypervisor doesn't pass SYSCFG through: */
983 if (rdmsr_safe(MSR_K8_SYSCFG, &l, &h) < 0)
986 * Memory between 4GB and top of mem is forced WB by this magic bit.
987 * Reserved before K8RevF, but should be zero there.
989 if ((l & (Tom2Enabled | Tom2ForceMemTypeWB)) ==
990 (Tom2Enabled | Tom2ForceMemTypeWB))
996 real_trim_memory(unsigned long start_pfn, unsigned long limit_pfn)
998 u64 trim_start, trim_size;
1000 trim_start = start_pfn;
1001 trim_start <<= PAGE_SHIFT;
1003 trim_size = limit_pfn;
1004 trim_size <<= PAGE_SHIFT;
1005 trim_size -= trim_start;
1007 return e820_update_range(trim_start, trim_size, E820_RAM, E820_RESERVED);
1011 * mtrr_trim_uncached_memory - trim RAM not covered by MTRRs
1012 * @end_pfn: ending page frame number
1014 * Some buggy BIOSes don't setup the MTRRs properly for systems with certain
1015 * memory configurations. This routine checks that the highest MTRR matches
1016 * the end of memory, to make sure the MTRRs having a write back type cover
1017 * all of the memory the kernel is intending to use. If not, it'll trim any
1018 * memory off the end by adjusting end_pfn, removing it from the kernel's
1019 * allocation pools, warning the user with an obnoxious message.
1021 int __init mtrr_trim_uncached_memory(unsigned long end_pfn)
1023 unsigned long i, base, size, highest_pfn = 0, def, dummy;
1025 u64 total_trim_size;
1026 /* extra one for all 0 */
1027 int num[MTRR_NUM_TYPES + 1];
1030 * Make sure we only trim uncachable memory on machines that
1031 * support the Intel MTRR architecture:
1033 if (!is_cpu(INTEL) || disable_mtrr_trim)
1036 rdmsr(MSR_MTRRdefType, def, dummy);
1038 if (def != MTRR_TYPE_UNCACHABLE)
1041 /* Get it and store it aside: */
1042 memset(range_state, 0, sizeof(range_state));
1043 for (i = 0; i < num_var_ranges; i++) {
1044 mtrr_if->get(i, &base, &size, &type);
1045 range_state[i].base_pfn = base;
1046 range_state[i].size_pfn = size;
1047 range_state[i].type = type;
1050 /* Find highest cached pfn: */
1051 for (i = 0; i < num_var_ranges; i++) {
1052 type = range_state[i].type;
1053 if (type != MTRR_TYPE_WRBACK)
1055 base = range_state[i].base_pfn;
1056 size = range_state[i].size_pfn;
1057 if (highest_pfn < base + size)
1058 highest_pfn = base + size;
1061 /* kvm/qemu doesn't have mtrr set right, don't trim them all: */
1063 printk(KERN_INFO "CPU MTRRs all blank - virtualized system.\n");
1067 /* Check entries number: */
1068 memset(num, 0, sizeof(num));
1069 for (i = 0; i < num_var_ranges; i++) {
1070 type = range_state[i].type;
1071 if (type >= MTRR_NUM_TYPES)
1073 size = range_state[i].size_pfn;
1075 type = MTRR_NUM_TYPES;
1079 /* No entry for WB? */
1080 if (!num[MTRR_TYPE_WRBACK])
1083 /* Check if we only had WB and UC: */
1084 if (num[MTRR_TYPE_WRBACK] + num[MTRR_TYPE_UNCACHABLE] !=
1085 num_var_ranges - num[MTRR_NUM_TYPES])
1088 memset(range, 0, sizeof(range));
1091 range[nr_range].start = (1ULL<<(32 - PAGE_SHIFT));
1092 range[nr_range].end = (mtrr_tom2 >> PAGE_SHIFT) - 1;
1093 if (highest_pfn < range[nr_range].end + 1)
1094 highest_pfn = range[nr_range].end + 1;
1097 nr_range = x86_get_mtrr_mem_range(range, nr_range, 0, 0);
1099 /* Check the head: */
1100 total_trim_size = 0;
1102 total_trim_size += real_trim_memory(0, range[0].start);
1104 /* Check the holes: */
1105 for (i = 0; i < nr_range - 1; i++) {
1106 if (range[i].end + 1 < range[i+1].start)
1107 total_trim_size += real_trim_memory(range[i].end + 1,
1111 /* Check the top: */
1113 if (range[i].end + 1 < end_pfn)
1114 total_trim_size += real_trim_memory(range[i].end + 1,
1117 if (total_trim_size) {
1118 pr_warning("WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing %lluMB of RAM.\n", total_trim_size >> 20);
1120 if (!changed_by_mtrr_cleanup)
1123 pr_info("update e820 for mtrr\n");