arch/x86/include/asm/virtext.h

   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
  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  */
  39 static inline void cpu_vmxoff(void)
  40 {
  41         asm volatile ("vmxoff");
  42         cr4_clear_bits(X86_CR4_VMXE);
  43 }
  44
  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  */
  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  */
  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  */
  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  */
 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  */
 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 */