LXR linux/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
  28static 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 */
  41static inline void cpu_vmxoff(void)
  42{
  43        asm volatile (ASM_VMX_VMXOFF : : : "cc");
  44        write_cr4(read_cr4() & ~X86_CR4_VMXE);
  45}
  46
  47static 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 */
  56static 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 */
  64static 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 */
  84static 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 */
 115static 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 */
 126static 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