KVM: MTRR: introduce fixed_mtrr_segment table
[deliverable/linux.git] / 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
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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
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29static 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
53static bool valid_pat_type(unsigned t)
54{
55 return t < 8 && (1 << t) & 0xf3; /* 0, 1, 4, 5, 6, 7 */
56}
57
58static bool valid_mtrr_type(unsigned t)
59{
60 return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */
61}
62
63bool 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}
106EXPORT_SYMBOL_GPL(kvm_mtrr_valid);
107
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108static bool mtrr_is_enabled(struct kvm_mtrr *mtrr_state)
109{
110 return !!(mtrr_state->deftype & IA32_MTRR_DEF_TYPE_E);
111}
112
113static bool fixed_mtrr_is_enabled(struct kvm_mtrr *mtrr_state)
114{
115 return !!(mtrr_state->deftype & IA32_MTRR_DEF_TYPE_FE);
116}
117
118static u8 mtrr_default_type(struct kvm_mtrr *mtrr_state)
119{
120 return mtrr_state->deftype & IA32_MTRR_DEF_TYPE_TYPE_MASK;
121}
122
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123/*
124* Three terms are used in the following code:
125* - segment, it indicates the address segments covered by fixed MTRRs.
126* - unit, it corresponds to the MSR entry in the segment.
127* - range, a range is covered in one memory cache type.
128*/
129struct fixed_mtrr_segment {
130 u64 start;
131 u64 end;
132
133 int range_shift;
134
135 /* the start position in kvm_mtrr.fixed_ranges[]. */
136 int range_start;
137};
138
139static struct fixed_mtrr_segment fixed_seg_table[] = {
140 /* MSR_MTRRfix64K_00000, 1 unit. 64K fixed mtrr. */
141 {
142 .start = 0x0,
143 .end = 0x80000,
144 .range_shift = 16, /* 64K */
145 .range_start = 0,
146 },
147
148 /*
149 * MSR_MTRRfix16K_80000 ... MSR_MTRRfix16K_A0000, 2 units,
150 * 16K fixed mtrr.
151 */
152 {
153 .start = 0x80000,
154 .end = 0xc0000,
155 .range_shift = 14, /* 16K */
156 .range_start = 8,
157 },
158
159 /*
160 * MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000, 8 units,
161 * 4K fixed mtrr.
162 */
163 {
164 .start = 0xc0000,
165 .end = 0x100000,
166 .range_shift = 12, /* 12K */
167 .range_start = 24,
168 }
169};
170
171/*
172 * The size of unit is covered in one MSR, one MSR entry contains
173 * 8 ranges so that unit size is always 8 * 2^range_shift.
174 */
175static u64 fixed_mtrr_seg_unit_size(int seg)
176{
177 return 8 << fixed_seg_table[seg].range_shift;
178}
179
180static bool fixed_msr_to_seg_unit(u32 msr, int *seg, int *unit)
181{
182 switch (msr) {
183 case MSR_MTRRfix64K_00000:
184 *seg = 0;
185 *unit = 0;
186 break;
187 case MSR_MTRRfix16K_80000 ... MSR_MTRRfix16K_A0000:
188 *seg = 1;
189 *unit = msr - MSR_MTRRfix16K_80000;
190 break;
191 case MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000:
192 *seg = 2;
193 *unit = msr - MSR_MTRRfix4K_C0000;
194 break;
195 default:
196 return false;
197 }
198
199 return true;
200}
201
202static void fixed_mtrr_seg_unit_range(int seg, int unit, u64 *start, u64 *end)
203{
204 struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg];
205 u64 unit_size = fixed_mtrr_seg_unit_size(seg);
206
207 *start = mtrr_seg->start + unit * unit_size;
208 *end = *start + unit_size;
209 WARN_ON(*end > mtrr_seg->end);
210}
211
212static int fixed_mtrr_seg_unit_range_index(int seg, int unit)
213{
214 struct fixed_mtrr_segment *mtrr_seg = &fixed_seg_table[seg];
215
216 WARN_ON(mtrr_seg->start + unit * fixed_mtrr_seg_unit_size(seg)
217 > mtrr_seg->end);
218
219 /* each unit has 8 ranges. */
220 return mtrr_seg->range_start + 8 * unit;
221}
222
223static bool fixed_msr_to_range(u32 msr, u64 *start, u64 *end)
224{
225 int seg, unit;
226
227 if (!fixed_msr_to_seg_unit(msr, &seg, &unit))
228 return false;
229
230 fixed_mtrr_seg_unit_range(seg, unit, start, end);
231 return true;
232}
233
234static int fixed_msr_to_range_index(u32 msr)
235{
236 int seg, unit;
237
238 if (!fixed_msr_to_seg_unit(msr, &seg, &unit))
239 return -1;
240
241 return fixed_mtrr_seg_unit_range_index(seg, unit);
242}
243
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244static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr)
245{
70109e7d 246 struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
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247 gfn_t start, end, mask;
248 int index;
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249
250 if (msr == MSR_IA32_CR_PAT || !tdp_enabled ||
251 !kvm_arch_has_noncoherent_dma(vcpu->kvm))
252 return;
253
10fac2dc 254 if (!mtrr_is_enabled(mtrr_state) && msr != MSR_MTRRdefType)
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255 return;
256
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257 /* fixed MTRRs. */
258 if (fixed_msr_to_range(msr, &start, &end)) {
259 if (!fixed_mtrr_is_enabled(mtrr_state))
260 return;
261 } else if (msr == MSR_MTRRdefType) {
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262 start = 0x0;
263 end = ~0ULL;
de9aef5e 264 } else {
ff53604b 265 /* variable range MTRRs. */
ff53604b 266 index = (msr - 0x200) / 2;
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267 start = mtrr_state->var_ranges[index].base & PAGE_MASK;
268 mask = mtrr_state->var_ranges[index].mask & PAGE_MASK;
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269 mask |= ~0ULL << cpuid_maxphyaddr(vcpu);
270
271 end = ((start & mask) | ~mask) + 1;
272 }
273
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274 kvm_zap_gfn_range(vcpu->kvm, gpa_to_gfn(start), gpa_to_gfn(end));
275}
276
277int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
278{
de9aef5e 279 int index;
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280
281 if (!kvm_mtrr_valid(vcpu, msr, data))
282 return 1;
283
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284 index = fixed_msr_to_range_index(msr);
285 if (index >= 0)
286 *(u64 *)&vcpu->arch.mtrr_state.fixed_ranges[index] = data;
287 else if (msr == MSR_MTRRdefType)
10fac2dc 288 vcpu->arch.mtrr_state.deftype = data;
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289 else if (msr == MSR_IA32_CR_PAT)
290 vcpu->arch.pat = data;
291 else { /* Variable MTRRs */
de9aef5e 292 int is_mtrr_mask;
ff53604b 293
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294 index = (msr - 0x200) / 2;
295 is_mtrr_mask = msr - 0x200 - 2 * index;
ff53604b 296 if (!is_mtrr_mask)
de9aef5e 297 vcpu->arch.mtrr_state.var_ranges[index].base = data;
ff53604b 298 else
de9aef5e 299 vcpu->arch.mtrr_state.var_ranges[index].mask = data;
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300 }
301
302 update_mtrr(vcpu, msr);
303 return 0;
304}
305
306int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
307{
de9aef5e 308 int index;
ff53604b 309
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310 /* MSR_MTRRcap is a readonly MSR. */
311 if (msr == MSR_MTRRcap) {
312 /*
313 * SMRR = 0
314 * WC = 1
315 * FIX = 1
316 * VCNT = KVM_NR_VAR_MTRR
317 */
318 *pdata = 0x500 | KVM_NR_VAR_MTRR;
319 return 0;
320 }
321
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322 if (!msr_mtrr_valid(msr))
323 return 1;
324
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325 index = fixed_msr_to_range_index(msr);
326 if (index >= 0)
327 *pdata = *(u64 *)&vcpu->arch.mtrr_state.fixed_ranges[index];
328 else if (msr == MSR_MTRRdefType)
10fac2dc 329 *pdata = vcpu->arch.mtrr_state.deftype;
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330 else if (msr == MSR_IA32_CR_PAT)
331 *pdata = vcpu->arch.pat;
332 else { /* Variable MTRRs */
de9aef5e 333 int is_mtrr_mask;
ff53604b 334
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335 index = (msr - 0x200) / 2;
336 is_mtrr_mask = msr - 0x200 - 2 * index;
ff53604b 337 if (!is_mtrr_mask)
de9aef5e 338 *pdata = vcpu->arch.mtrr_state.var_ranges[index].base;
ff53604b 339 else
de9aef5e 340 *pdata = vcpu->arch.mtrr_state.var_ranges[index].mask;
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341 }
342
343 return 0;
344}
345
3f3f78b6 346u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
ff53604b 347{
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348 struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
349 u64 base, mask, start;
350 int i, num_var_ranges, type;
351 const int wt_wb_mask = (1 << MTRR_TYPE_WRBACK)
352 | (1 << MTRR_TYPE_WRTHROUGH);
353
354 start = gfn_to_gpa(gfn);
355 num_var_ranges = KVM_NR_VAR_MTRR;
356 type = -1;
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357
358 /* MTRR is completely disabled, use UC for all of physical memory. */
10fac2dc 359 if (!mtrr_is_enabled(mtrr_state))
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360 return MTRR_TYPE_UNCACHABLE;
361
ff53604b 362 /* Look in fixed ranges. Just return the type as per start */
10fac2dc 363 if (fixed_mtrr_is_enabled(mtrr_state) && (start < 0x100000)) {
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364 int idx;
365
366 if (start < 0x80000) {
367 idx = 0;
368 idx += (start >> 16);
369 return mtrr_state->fixed_ranges[idx];
370 } else if (start < 0xC0000) {
371 idx = 1 * 8;
372 idx += ((start - 0x80000) >> 14);
373 return mtrr_state->fixed_ranges[idx];
374 } else if (start < 0x1000000) {
375 idx = 3 * 8;
376 idx += ((start - 0xC0000) >> 12);
377 return mtrr_state->fixed_ranges[idx];
378 }
379 }
380
381 /*
382 * Look in variable ranges
383 * Look of multiple ranges matching this address and pick type
384 * as per MTRR precedence
385 */
ff53604b 386 for (i = 0; i < num_var_ranges; ++i) {
3f3f78b6 387 int curr_type;
ff53604b 388
86fd5270 389 if (!(mtrr_state->var_ranges[i].mask & (1 << 11)))
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390 continue;
391
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392 base = mtrr_state->var_ranges[i].base & PAGE_MASK;
393 mask = mtrr_state->var_ranges[i].mask & PAGE_MASK;
ff53604b 394
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395 if ((start & mask) != (base & mask))
396 continue;
397
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398 /*
399 * Please refer to Intel SDM Volume 3: 11.11.4.1 MTRR
400 * Precedences.
401 */
402
403 curr_type = mtrr_state->var_ranges[i].base & 0xff;
404 if (type == -1) {
405 type = curr_type;
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406 continue;
407 }
408
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409 /*
410 * If two or more variable memory ranges match and the
411 * memory types are identical, then that memory type is
412 * used.
413 */
414 if (type == curr_type)
415 continue;
416
417 /*
418 * If two or more variable memory ranges match and one of
419 * the memory types is UC, the UC memory type used.
420 */
421 if (curr_type == MTRR_TYPE_UNCACHABLE)
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422 return MTRR_TYPE_UNCACHABLE;
423
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424 /*
425 * If two or more variable memory ranges match and the
426 * memory types are WT and WB, the WT memory type is used.
427 */
428 if (((1 << type) & wt_wb_mask) &&
429 ((1 << curr_type) & wt_wb_mask)) {
430 type = MTRR_TYPE_WRTHROUGH;
431 continue;
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432 }
433
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434 /*
435 * For overlaps not defined by the above rules, processor
436 * behavior is undefined.
437 */
438
439 /* We use WB for this undefined behavior. :( */
440 return MTRR_TYPE_WRBACK;
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441 }
442
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443 if (type != -1)
444 return type;
ff53604b 445
10fac2dc 446 return mtrr_default_type(mtrr_state);
ff53604b 447}
ff53604b 448EXPORT_SYMBOL_GPL(kvm_mtrr_get_guest_memory_type);
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