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140 lines
3.0 KiB
140 lines
3.0 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* CPU virtualization extensions handling |
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* |
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* This should carry the code for handling CPU virtualization extensions |
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* that needs to live in the kernel core. |
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* |
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* Author: Eduardo Habkost <[email protected]> |
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* |
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* Copyright (C) 2008, Red Hat Inc. |
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* |
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* Contains code from KVM, Copyright (C) 2006 Qumranet, Inc. |
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*/ |
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#ifndef _ASM_X86_VIRTEX_H |
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#define _ASM_X86_VIRTEX_H |
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#include <asm/processor.h> |
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#include <asm/vmx.h> |
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#include <asm/svm.h> |
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#include <asm/tlbflush.h> |
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/* |
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* VMX functions: |
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*/ |
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static inline int cpu_has_vmx(void) |
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{ |
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unsigned long ecx = cpuid_ecx(1); |
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return test_bit(5, &ecx); /* CPUID.1:ECX.VMX[bit 5] -> VT */ |
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} |
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/** |
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* cpu_vmxoff() - Disable VMX on the current CPU |
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* |
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* Disable VMX and clear CR4.VMXE (even if VMXOFF faults) |
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* |
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* Note, VMXOFF causes a #UD if the CPU is !post-VMXON, but it's impossible to |
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* atomically track post-VMXON state, e.g. this may be called in NMI context. |
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* Eat all faults as all other faults on VMXOFF faults are mode related, i.e. |
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* faults are guaranteed to be due to the !post-VMXON check unless the CPU is |
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* magically in RM, VM86, compat mode, or at CPL>0. |
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*/ |
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static inline int cpu_vmxoff(void) |
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{ |
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asm_volatile_goto("1: vmxoff\n\t" |
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_ASM_EXTABLE(1b, %l[fault]) |
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::: "cc", "memory" : fault); |
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cr4_clear_bits(X86_CR4_VMXE); |
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return 0; |
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fault: |
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cr4_clear_bits(X86_CR4_VMXE); |
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return -EIO; |
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} |
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static inline int cpu_vmx_enabled(void) |
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{ |
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return __read_cr4() & X86_CR4_VMXE; |
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} |
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/** Disable VMX if it is enabled on the current CPU |
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* |
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* You shouldn't call this if cpu_has_vmx() returns 0. |
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*/ |
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static inline void __cpu_emergency_vmxoff(void) |
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{ |
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if (cpu_vmx_enabled()) |
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cpu_vmxoff(); |
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} |
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/** Disable VMX if it is supported and enabled on the current CPU |
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*/ |
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static inline void cpu_emergency_vmxoff(void) |
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{ |
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if (cpu_has_vmx()) |
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__cpu_emergency_vmxoff(); |
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} |
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/* |
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* SVM functions: |
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*/ |
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/** Check if the CPU has SVM support |
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* |
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* You can use the 'msg' arg to get a message describing the problem, |
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* if the function returns zero. Simply pass NULL if you are not interested |
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* on the messages; gcc should take care of not generating code for |
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* the messages on this case. |
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*/ |
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static inline int cpu_has_svm(const char **msg) |
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{ |
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if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD && |
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boot_cpu_data.x86_vendor != X86_VENDOR_HYGON) { |
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if (msg) |
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*msg = "not amd or hygon"; |
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return 0; |
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} |
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if (boot_cpu_data.extended_cpuid_level < SVM_CPUID_FUNC) { |
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if (msg) |
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*msg = "can't execute cpuid_8000000a"; |
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return 0; |
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} |
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if (!boot_cpu_has(X86_FEATURE_SVM)) { |
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if (msg) |
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*msg = "svm not available"; |
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return 0; |
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} |
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return 1; |
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} |
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/** Disable SVM on the current CPU |
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* |
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* You should call this only if cpu_has_svm() returned true. |
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*/ |
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static inline void cpu_svm_disable(void) |
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{ |
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uint64_t efer; |
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wrmsrl(MSR_VM_HSAVE_PA, 0); |
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rdmsrl(MSR_EFER, efer); |
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wrmsrl(MSR_EFER, efer & ~EFER_SVME); |
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} |
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/** Makes sure SVM is disabled, if it is supported on the CPU |
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*/ |
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static inline void cpu_emergency_svm_disable(void) |
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{ |
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if (cpu_has_svm(NULL)) |
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cpu_svm_disable(); |
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} |
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#endif /* _ASM_X86_VIRTEX_H */
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