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 #include <asm/system.h>
20
21 #include <asm/vmx.h>
22 #include <asm/svm.h>
23
24 /*
25 * VMX functions:
26 */
27
28 static 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 */
41 static inline void cpu_vmxoff(void)
42 {
43 asm volatile (ASM_VMX_VMXOFF : : : "cc");
44 write_cr4(read_cr4() & ~X86_CR4_VMXE);
45 }
46
47 static 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 */
56 static 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 */
64 static 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 */
84 static inline int cpu_has_svm(const char **msg)
85 {
86 uint32_t eax, ebx, ecx, edx;
87
88 if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
89 if (msg)
90 *msg = "not amd";
91 return 0;
92 }
93
94 cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
95 if (eax < SVM_CPUID_FUNC) {
96 if (msg)
97 *msg = "can't execute cpuid_8000000a";
98 return 0;
99 }
100
101 cpuid(0x80000001, &eax, &ebx, &ecx, &edx);
102 if (!(ecx & (1 << SVM_CPUID_FEATURE_SHIFT))) {
103 if (msg)
104 *msg = "svm not available";
105 return 0;
106 }
107 return 1;
108 }
109
110
111 /** Disable SVM on the current CPU
112 *
113 * You should call this only if cpu_has_svm() returned true.
114 */
115 static inline void cpu_svm_disable(void)
116 {
117 uint64_t efer;
118
119 wrmsrl(MSR_VM_HSAVE_PA, 0);
120 rdmsrl(MSR_EFER, efer);
121 wrmsrl(MSR_EFER, efer & ~EFER_SVME);
122 }
123
124 /** Makes sure SVM is disabled, if it is supported on the CPU
125 */
126 static inline void cpu_emergency_svm_disable(void)
127 {
128 if (cpu_has_svm(NULL))
129 cpu_svm_disable();
130 }
131
132 #endif /* _ASM_X86_VIRTEX_H */
133
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