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#include "x86.h"
23
24static u64 *find_mtrr(struct kvm_vcpu *vcpu, unsigned int msr)
25{
26 int index;
27
28 switch (msr) {
29 case MTRRphysBase_MSR(0) ... MTRRphysMask_MSR(KVM_NR_VAR_MTRR - 1):
30 index = msr - MTRRphysBase_MSR(0);
31 return &vcpu->arch.mtrr_state.var[index];
32 case MSR_MTRRfix64K_00000:
33 return &vcpu->arch.mtrr_state.fixed_64k;
34 case MSR_MTRRfix16K_80000:
35 case MSR_MTRRfix16K_A0000:
36 index = msr - MSR_MTRRfix16K_80000;
37 return &vcpu->arch.mtrr_state.fixed_16k[index];
38 case MSR_MTRRfix4K_C0000:
39 case MSR_MTRRfix4K_C8000:
40 case MSR_MTRRfix4K_D0000:
41 case MSR_MTRRfix4K_D8000:
42 case MSR_MTRRfix4K_E0000:
43 case MSR_MTRRfix4K_E8000:
44 case MSR_MTRRfix4K_F0000:
45 case MSR_MTRRfix4K_F8000:
46 index = msr - MSR_MTRRfix4K_C0000;
47 return &vcpu->arch.mtrr_state.fixed_4k[index];
48 case MSR_MTRRdefType:
49 return &vcpu->arch.mtrr_state.deftype;
50 default:
51 break;
52 }
53 return NULL;
54}
55
56static bool valid_mtrr_type(unsigned t)
57{
58 return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */
59}
60
61static bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data)
62{
63 int i;
64 u64 mask;
65
66 if (msr == MSR_MTRRdefType) {
67 if (data & ~0xcff)
68 return false;
69 return valid_mtrr_type(t: data & 0xff);
70 } else if (msr >= MSR_MTRRfix64K_00000 && msr <= MSR_MTRRfix4K_F8000) {
71 for (i = 0; i < 8 ; i++)
72 if (!valid_mtrr_type(t: (data >> (i * 8)) & 0xff))
73 return false;
74 return true;
75 }
76
77 /* variable MTRRs */
78 if (WARN_ON_ONCE(!(msr >= MTRRphysBase_MSR(0) &&
79 msr <= MTRRphysMask_MSR(KVM_NR_VAR_MTRR - 1))))
80 return false;
81
82 mask = kvm_vcpu_reserved_gpa_bits_raw(vcpu);
83 if ((msr & 1) == 0) {
84 /* MTRR base */
85 if (!valid_mtrr_type(t: data & 0xff))
86 return false;
87 mask |= 0xf00;
88 } else {
89 /* MTRR mask */
90 mask |= 0x7ff;
91 }
92
93 return (data & mask) == 0;
94}
95
96int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
97{
98 u64 *mtrr;
99
100 mtrr = find_mtrr(vcpu, msr);
101 if (!mtrr)
102 return 1;
103
104 if (!kvm_mtrr_valid(vcpu, msr, data))
105 return 1;
106
107 *mtrr = data;
108 return 0;
109}
110
111int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
112{
113 u64 *mtrr;
114
115 /* MSR_MTRRcap is a readonly MSR. */
116 if (msr == MSR_MTRRcap) {
117 /*
118 * SMRR = 0
119 * WC = 1
120 * FIX = 1
121 * VCNT = KVM_NR_VAR_MTRR
122 */
123 *pdata = 0x500 | KVM_NR_VAR_MTRR;
124 return 0;
125 }
126
127 mtrr = find_mtrr(vcpu, msr);
128 if (!mtrr)
129 return 1;
130
131 *pdata = *mtrr;
132 return 0;
133}
134

source code of linux/arch/x86/kvm/mtrr.c