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
  20 #include <asm/vmx.h>
  21 #include <asm/svm.h>
  22
  23 /*
  24  * VMX functions:
  25  */
  26
  27 static inline int cpu_has_vmx(void)
  28 {
  29         unsigned long ecx = cpuid_ecx(1);
  30         return test_bit(5, &ecx); /* CPUID.1:ECX.VMX[bit 5] -> VT */
  31 }
  32
  33
  34 /** Disable VMX on the current CPU
  35  *
  36  * vmxoff causes a undefined-opcode exception if vmxon was not run
  37  * on the CPU previously. Only call this function if you know VMX
  38  * is enabled.
  39  */
  40 static inline void cpu_vmxoff(void)
  41 {
  42         asm volatile (ASM_VMX_VMXOFF : : : "cc");
  43         write_cr4(read_cr4() & ~X86_CR4_VMXE);
  44 }
  45
  46 static inline int cpu_vmx_enabled(void)
  47 {
  48         return read_cr4() & X86_CR4_VMXE;
  49 }
  50
  51 /** Disable VMX if it is enabled on the current CPU
  52  *
  53  * You shouldn't call this if cpu_has_vmx() returns 0.
  54  */
  55 static inline void __cpu_emergency_vmxoff(void)
  56 {
  57         if (cpu_vmx_enabled())
  58                 cpu_vmxoff();
  59 }
  60
  61 /** Disable VMX if it is supported and enabled on the current CPU
  62  */
  63 static inline void cpu_emergency_vmxoff(void)
  64 {
  65         if (cpu_has_vmx())
  66                 __cpu_emergency_vmxoff();
  67 }
  68
  69
  70
  71
  72 /*
  73  * SVM functions:
  74  */
  75
  76 /** Check if the CPU has SVM support
  77  *
  78  * You can use the 'msg' arg to get a message describing the problem,
  79  * if the function returns zero. Simply pass NULL if you are not interested
  80  * on the messages; gcc should take care of not generating code for
  81  * the messages on this case.
  82  */
  83 static inline int cpu_has_svm(const char **msg)
  84 {
  85         uint32_t eax, ebx, ecx, edx;
  86
  87         if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
  88                 if (msg)
  89                         *msg = "not amd";
  90                 return 0;
  91         }
  92
  93         cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
  94         if (eax < SVM_CPUID_FUNC) {
  95                 if (msg)
  96                         *msg = "can't execute cpuid_8000000a";
  97                 return 0;
  98         }
  99
 100         cpuid(0x80000001, &eax, &ebx, &ecx, &edx);
 101         if (!(ecx & (1 << SVM_CPUID_FEATURE_SHIFT))) {
 102                 if (msg)
 103                         *msg = "svm not available";
 104                 return 0;
 105         }
 106         return 1;
 107 }
 108
 109
 110 /** Disable SVM on the current CPU
 111  *
 112  * You should call this only if cpu_has_svm() returned true.
 113  */
 114 static inline void cpu_svm_disable(void)
 115 {
 116         uint64_t efer;
 117
 118         wrmsrl(MSR_VM_HSAVE_PA, 0);
 119         rdmsrl(MSR_EFER, efer);
 120         wrmsrl(MSR_EFER, efer & ~EFER_SVME);
 121 }
 122
 123 /** Makes sure SVM is disabled, if it is supported on the CPU
 124  */
 125 static inline void cpu_emergency_svm_disable(void)
 126 {
 127         if (cpu_has_svm(NULL))
 128                 cpu_svm_disable();
 129 }
 130
 131 #endif /* _ASM_X86_VIRTEX_H */