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#include <asm/tlbflush.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	cr4_clear_bits(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 */

  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
 26static 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/**
 34 * cpu_vmxoff() - Disable VMX on the current CPU
 35 *
 36 * Disable VMX and clear CR4.VMXE (even if VMXOFF faults)
 37 *
 38 * Note, VMXOFF causes a #UD if the CPU is !post-VMXON, but it's impossible to
 39 * atomically track post-VMXON state, e.g. this may be called in NMI context.
 40 * Eat all faults as all other faults on VMXOFF faults are mode related, i.e.
 41 * faults are guaranteed to be due to the !post-VMXON check unless the CPU is
 42 * magically in RM, VM86, compat mode, or at CPL>0.
 43 */
 44static inline int cpu_vmxoff(void)
 45{
 46	asm_volatile_goto("1: vmxoff\n\t"
 47			  _ASM_EXTABLE(1b, %l[fault])
 48			  ::: "cc", "memory" : fault);
 49
 50	cr4_clear_bits(X86_CR4_VMXE);
 51	return 0;
 52
 53fault:
 54	cr4_clear_bits(X86_CR4_VMXE);
 55	return -EIO;
 56}
 57
 58static inline int cpu_vmx_enabled(void)
 59{
 60	return __read_cr4() & X86_CR4_VMXE;
 61}
 62
 63/** Disable VMX if it is enabled on the current CPU
 64 *
 65 * You shouldn't call this if cpu_has_vmx() returns 0.
 66 */
 67static inline void __cpu_emergency_vmxoff(void)
 68{
 69	if (cpu_vmx_enabled())
 70		cpu_vmxoff();
 71}
 72
 73/** Disable VMX if it is supported and enabled on the current CPU
 74 */
 75static inline void cpu_emergency_vmxoff(void)
 76{
 77	if (cpu_has_vmx())
 78		__cpu_emergency_vmxoff();
 79}
 80
 81
 82
 83
 84/*
 85 * SVM functions:
 86 */
 87
 88/** Check if the CPU has SVM support
 89 *
 90 * You can use the 'msg' arg to get a message describing the problem,
 91 * if the function returns zero. Simply pass NULL if you are not interested
 92 * on the messages; gcc should take care of not generating code for
 93 * the messages on this case.
 94 */
 95static inline int cpu_has_svm(const char **msg)
 96{
 97	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
 98	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON) {
 
 99		if (msg)
100			*msg = "not amd or hygon";
101		return 0;
102	}
103
104	if (boot_cpu_data.extended_cpuid_level < SVM_CPUID_FUNC) {
 
105		if (msg)
106			*msg = "can't execute cpuid_8000000a";
107		return 0;
108	}
109
110	if (!boot_cpu_has(X86_FEATURE_SVM)) {
 
111		if (msg)
112			*msg = "svm not available";
113		return 0;
114	}
115	return 1;
116}
117
118
119/** Disable SVM on the current CPU
120 *
121 * You should call this only if cpu_has_svm() returned true.
122 */
123static inline void cpu_svm_disable(void)
124{
125	uint64_t efer;
126
127	wrmsrl(MSR_VM_HSAVE_PA, 0);
128	rdmsrl(MSR_EFER, efer);
129	wrmsrl(MSR_EFER, efer & ~EFER_SVME);
130}
131
132/** Makes sure SVM is disabled, if it is supported on the CPU
133 */
134static inline void cpu_emergency_svm_disable(void)
135{
136	if (cpu_has_svm(NULL))
137		cpu_svm_disable();
138}
139
140#endif /* _ASM_X86_VIRTEX_H */