1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /* CPU virtualization extensions handling
3  *
4  * This should carry the code for handling CPU virtualization extensions
5  * that needs to live in the kernel core.
6  *
7  * Author: Eduardo Habkost <ehabkost@redhat.com>
8  *
9  * Copyright (C) 2008, Red Hat Inc.
10  *
11  * Contains code from KVM, Copyright (C) 2006 Qumranet, Inc.
12  */
13 #ifndef _ASM_X86_VIRTEX_H
14 #define _ASM_X86_VIRTEX_H
15 
16 #include <asm/processor.h>
17 
18 #include <asm/vmx.h>
19 #include <asm/svm.h>
20 #include <asm/tlbflush.h>
21 
22 /*
23  * VMX functions:
24  */
25 
cpu_has_vmx(void)26 static inline int cpu_has_vmx(void)
27 {
28 	unsigned long ecx = cpuid_ecx(1);
29 	return test_bit(5, &ecx); /* CPUID.1:ECX.VMX[bit 5] -> VT */
30 }
31 
32 
33 /** Disable VMX on the current CPU
34  *
35  * vmxoff causes a undefined-opcode exception if vmxon was not run
36  * on the CPU previously. Only call this function if you know VMX
37  * is enabled.
38  */
cpu_vmxoff(void)39 static inline void cpu_vmxoff(void)
40 {
41 	asm volatile ("vmxoff");
42 	cr4_clear_bits(X86_CR4_VMXE);
43 }
44 
cpu_vmx_enabled(void)45 static inline int cpu_vmx_enabled(void)
46 {
47 	return __read_cr4() & X86_CR4_VMXE;
48 }
49 
50 /** Disable VMX if it is enabled on the current CPU
51  *
52  * You shouldn't call this if cpu_has_vmx() returns 0.
53  */
__cpu_emergency_vmxoff(void)54 static inline void __cpu_emergency_vmxoff(void)
55 {
56 	if (cpu_vmx_enabled())
57 		cpu_vmxoff();
58 }
59 
60 /** Disable VMX if it is supported and enabled on the current CPU
61  */
cpu_emergency_vmxoff(void)62 static inline void cpu_emergency_vmxoff(void)
63 {
64 	if (cpu_has_vmx())
65 		__cpu_emergency_vmxoff();
66 }
67 
68 
69 
70 
71 /*
72  * SVM functions:
73  */
74 
75 /** Check if the CPU has SVM support
76  *
77  * You can use the 'msg' arg to get a message describing the problem,
78  * if the function returns zero. Simply pass NULL if you are not interested
79  * on the messages; gcc should take care of not generating code for
80  * the messages on this case.
81  */
cpu_has_svm(const char ** msg)82 static inline int cpu_has_svm(const char **msg)
83 {
84 	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
85 	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON) {
86 		if (msg)
87 			*msg = "not amd or hygon";
88 		return 0;
89 	}
90 
91 	if (boot_cpu_data.extended_cpuid_level < SVM_CPUID_FUNC) {
92 		if (msg)
93 			*msg = "can't execute cpuid_8000000a";
94 		return 0;
95 	}
96 
97 	if (!boot_cpu_has(X86_FEATURE_SVM)) {
98 		if (msg)
99 			*msg = "svm not available";
100 		return 0;
101 	}
102 	return 1;
103 }
104 
105 
106 /** Disable SVM on the current CPU
107  *
108  * You should call this only if cpu_has_svm() returned true.
109  */
cpu_svm_disable(void)110 static inline void cpu_svm_disable(void)
111 {
112 	uint64_t efer;
113 
114 	wrmsrl(MSR_VM_HSAVE_PA, 0);
115 	rdmsrl(MSR_EFER, efer);
116 	wrmsrl(MSR_EFER, efer & ~EFER_SVME);
117 }
118 
119 /** Makes sure SVM is disabled, if it is supported on the CPU
120  */
cpu_emergency_svm_disable(void)121 static inline void cpu_emergency_svm_disable(void)
122 {
123 	if (cpu_has_svm(NULL))
124 		cpu_svm_disable();
125 }
126 
127 #endif /* _ASM_X86_VIRTEX_H */
128