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1/* CPU virtualization extensions handling
2 *
3 * This should carry the code for handling CPU virtualization extensions
4 * that needs to live in the kernel core.
5 *
6 * Author: Eduardo Habkost <ehabkost@redhat.com>
7 *
8 * Copyright (C) 2008, Red Hat Inc.
9 *
10 * Contains code from KVM, Copyright (C) 2006 Qumranet, Inc.
11 *
12 * This work is licensed under the terms of the GNU GPL, version 2. See
13 * the COPYING file in the top-level directory.
14 */
15#ifndef _ASM_X86_VIRTEX_H
16#define _ASM_X86_VIRTEX_H
17
18#include <asm/processor.h>
19
20#include <asm/vmx.h>
21#include <asm/svm.h>
22
23/*
24 * VMX functions:
25 */
26
27static inline int cpu_has_vmx(void)
28{
29 unsigned long ecx = cpuid_ecx(1);
30 return test_bit(5, &ecx); /* CPUID.1:ECX.VMX[bit 5] -> VT */
31}
32
33
34/** Disable VMX on the current CPU
35 *
36 * vmxoff causes a undefined-opcode exception if vmxon was not run
37 * on the CPU previously. Only call this function if you know VMX
38 * is enabled.
39 */
40static inline void cpu_vmxoff(void)
41{
42 asm volatile (ASM_VMX_VMXOFF : : : "cc");
43 write_cr4(read_cr4() & ~X86_CR4_VMXE);
44}
45
46static inline int cpu_vmx_enabled(void)
47{
48 return read_cr4() & X86_CR4_VMXE;
49}
50
51/** Disable VMX if it is enabled on the current CPU
52 *
53 * You shouldn't call this if cpu_has_vmx() returns 0.
54 */
55static inline void __cpu_emergency_vmxoff(void)
56{
57 if (cpu_vmx_enabled())
58 cpu_vmxoff();
59}
60
61/** Disable VMX if it is supported and enabled on the current CPU
62 */
63static inline void cpu_emergency_vmxoff(void)
64{
65 if (cpu_has_vmx())
66 __cpu_emergency_vmxoff();
67}
68
69
70
71
72/*
73 * SVM functions:
74 */
75
76/** Check if the CPU has SVM support
77 *
78 * You can use the 'msg' arg to get a message describing the problem,
79 * if the function returns zero. Simply pass NULL if you are not interested
80 * on the messages; gcc should take care of not generating code for
81 * the messages on this case.
82 */
83static inline int cpu_has_svm(const char **msg)
84{
85 uint32_t eax, ebx, ecx, edx;
86
87 if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
88 if (msg)
89 *msg = "not amd";
90 return 0;
91 }
92
93 cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
94 if (eax < SVM_CPUID_FUNC) {
95 if (msg)
96 *msg = "can't execute cpuid_8000000a";
97 return 0;
98 }
99
100 cpuid(0x80000001, &eax, &ebx, &ecx, &edx);
101 if (!(ecx & (1 << SVM_CPUID_FEATURE_SHIFT))) {
102 if (msg)
103 *msg = "svm not available";
104 return 0;
105 }
106 return 1;
107}
108
109
110/** Disable SVM on the current CPU
111 *
112 * You should call this only if cpu_has_svm() returned true.
113 */
114static inline void cpu_svm_disable(void)
115{
116 uint64_t efer;
117
118 wrmsrl(MSR_VM_HSAVE_PA, 0);
119 rdmsrl(MSR_EFER, efer);
120 wrmsrl(MSR_EFER, efer & ~EFER_SVME);
121}
122
123/** Makes sure SVM is disabled, if it is supported on the CPU
124 */
125static inline void cpu_emergency_svm_disable(void)
126{
127 if (cpu_has_svm(NULL))
128 cpu_svm_disable();
129}
130
131#endif /* _ASM_X86_VIRTEX_H */