arch/x86/include/asm/virtext.h

   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 */