1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * vMTRR implementation
4 *
5 * Copyright (C) 2006 Qumranet, Inc.
6 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
7 * Copyright(C) 2015 Intel Corporation.
8 *
9 * Authors:
10 * Yaniv Kamay <yaniv@qumranet.com>
11 * Avi Kivity <avi@qumranet.com>
12 * Marcelo Tosatti <mtosatti@redhat.com>
13 * Paolo Bonzini <pbonzini@redhat.com>
14 * Xiao Guangrong <guangrong.xiao@linux.intel.com>
15 */
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18 #include <linux/kvm_host.h>
19 #include <asm/mtrr.h>
20
21 #include "cpuid.h"
22
23 static u64 *find_mtrr(struct kvm_vcpu *vcpu, unsigned int msr)
24 {
25 int index;
26
27 switch (msr) {
28 case MTRRphysBase_MSR(0) ... MTRRphysMask_MSR(KVM_NR_VAR_MTRR - 1):
29 index = msr - MTRRphysBase_MSR(0);
30 return &vcpu->arch.mtrr_state.var[index];
31 case MSR_MTRRfix64K_00000:
32 return &vcpu->arch.mtrr_state.fixed_64k;
33 case MSR_MTRRfix16K_80000:
34 case MSR_MTRRfix16K_A0000:
35 index = msr - MSR_MTRRfix16K_80000;
36 return &vcpu->arch.mtrr_state.fixed_16k[index];
37 case MSR_MTRRfix4K_C0000:
38 case MSR_MTRRfix4K_C8000:
39 case MSR_MTRRfix4K_D0000:
40 case MSR_MTRRfix4K_D8000:
41 case MSR_MTRRfix4K_E0000:
42 case MSR_MTRRfix4K_E8000:
43 case MSR_MTRRfix4K_F0000:
44 case MSR_MTRRfix4K_F8000:
45 index = msr - MSR_MTRRfix4K_C0000;
46 return &vcpu->arch.mtrr_state.fixed_4k[index];
47 case MSR_MTRRdefType:
48 return &vcpu->arch.mtrr_state.deftype;
49 default:
50 break;
51 }
52 return NULL;
53 }
54
55 static bool valid_mtrr_type(unsigned t)
56 {
57 return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */
58 }
59
60 static bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data)
61 {
62 int i;
63 u64 mask;
64
65 if (msr == MSR_MTRRdefType) {
66 if (data & ~0xcff)
67 return false;
68 return valid_mtrr_type(data & 0xff);
69 } else if (msr >= MSR_MTRRfix64K_00000 && msr <= MSR_MTRRfix4K_F8000) {
70 for (i = 0; i < 8 ; i++)
71 if (!valid_mtrr_type((data >> (i * 8)) & 0xff))
72 return false;
73 return true;
74 }
75
76 /* variable MTRRs */
77 if (WARN_ON_ONCE(!(msr >= MTRRphysBase_MSR(0) &&
78 msr <= MTRRphysMask_MSR(KVM_NR_VAR_MTRR - 1))))
79 return false;
80
81 mask = kvm_vcpu_reserved_gpa_bits_raw(vcpu);
82 if ((msr & 1) == 0) {
83 /* MTRR base */
84 if (!valid_mtrr_type(data & 0xff))
85 return false;
86 mask |= 0xf00;
87 } else {
88 /* MTRR mask */
89 mask |= 0x7ff;
90 }
91
92 return (data & mask) == 0;
93 }
94
95 int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
96 {
97 u64 *mtrr;
98
99 mtrr = find_mtrr(vcpu, msr);
100 if (!mtrr)
101 return 1;
102
103 if (!kvm_mtrr_valid(vcpu, msr, data))
104 return 1;
105
106 *mtrr = data;
107 return 0;
108 }
109
110 int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
111 {
112 u64 *mtrr;
113
114 /* MSR_MTRRcap is a readonly MSR. */
115 if (msr == MSR_MTRRcap) {
116 /*
117 * SMRR = 0
118 * WC = 1
119 * FIX = 1
120 * VCNT = KVM_NR_VAR_MTRR
121 */
122 *pdata = 0x500 | KVM_NR_VAR_MTRR;
123 return 0;
124 }
125
126 mtrr = find_mtrr(vcpu, msr);
127 if (!mtrr)
128 return 1;
129
130 *pdata = *mtrr;
131 return 0;
132 }
133
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.