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Linux kernel mirror (for testing)
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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#include <asm/tlbflush.h>
23
24/*
25 * VMX functions:
26 */
27
28static inline int cpu_has_vmx(void)
29{
30 unsigned long ecx = cpuid_ecx(1);
31 return test_bit(5, &ecx); /* CPUID.1:ECX.VMX[bit 5] -> VT */
32}
33
34
35/** Disable VMX on the current CPU
36 *
37 * vmxoff causes a undefined-opcode exception if vmxon was not run
38 * on the CPU previously. Only call this function if you know VMX
39 * is enabled.
40 */
41static inline void cpu_vmxoff(void)
42{
43 asm volatile (ASM_VMX_VMXOFF : : : "cc");
44 cr4_clear_bits(X86_CR4_VMXE);
45}
46
47static inline int cpu_vmx_enabled(void)
48{
49 return __read_cr4() & X86_CR4_VMXE;
50}
51
52/** Disable VMX if it is enabled on the current CPU
53 *
54 * You shouldn't call this if cpu_has_vmx() returns 0.
55 */
56static inline void __cpu_emergency_vmxoff(void)
57{
58 if (cpu_vmx_enabled())
59 cpu_vmxoff();
60}
61
62/** Disable VMX if it is supported and enabled on the current CPU
63 */
64static inline void cpu_emergency_vmxoff(void)
65{
66 if (cpu_has_vmx())
67 __cpu_emergency_vmxoff();
68}
69
70
71
72
73/*
74 * SVM functions:
75 */
76
77/** Check if the CPU has SVM support
78 *
79 * You can use the 'msg' arg to get a message describing the problem,
80 * if the function returns zero. Simply pass NULL if you are not interested
81 * on the messages; gcc should take care of not generating code for
82 * the messages on this case.
83 */
84static inline int cpu_has_svm(const char **msg)
85{
86 if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
87 if (msg)
88 *msg = "not amd";
89 return 0;
90 }
91
92 if (boot_cpu_data.extended_cpuid_level < SVM_CPUID_FUNC) {
93 if (msg)
94 *msg = "can't execute cpuid_8000000a";
95 return 0;
96 }
97
98 if (!boot_cpu_has(X86_FEATURE_SVM)) {
99 if (msg)
100 *msg = "svm not available";
101 return 0;
102 }
103 return 1;
104}
105
106
107/** Disable SVM on the current CPU
108 *
109 * You should call this only if cpu_has_svm() returned true.
110 */
111static inline void cpu_svm_disable(void)
112{
113 uint64_t efer;
114
115 wrmsrl(MSR_VM_HSAVE_PA, 0);
116 rdmsrl(MSR_EFER, efer);
117 wrmsrl(MSR_EFER, efer & ~EFER_SVME);
118}
119
120/** Makes sure SVM is disabled, if it is supported on the CPU
121 */
122static inline void cpu_emergency_svm_disable(void)
123{
124 if (cpu_has_svm(NULL))
125 cpu_svm_disable();
126}
127
128#endif /* _ASM_X86_VIRTEX_H */