diff options
Diffstat (limited to 'arch/x86/include/asm/virtext.h')
| -rw-r--r-- | arch/x86/include/asm/virtext.h | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h index 0116b2ee9e64..62810550024d 100644 --- a/arch/x86/include/asm/virtext.h +++ b/arch/x86/include/asm/virtext.h @@ -89,12 +89,6 @@ static inline int cpu_has_svm(const char **msg) return 0; } - if (boot_cpu_data.extended_cpuid_level < SVM_CPUID_FUNC) { - if (msg) - *msg = "can't execute cpuid_8000000a"; - return 0; - } - if (!boot_cpu_has(X86_FEATURE_SVM)) { if (msg) *msg = "svm not available"; @@ -114,7 +108,21 @@ static inline void cpu_svm_disable(void) wrmsrl(MSR_VM_HSAVE_PA, 0); rdmsrl(MSR_EFER, efer); - wrmsrl(MSR_EFER, efer & ~EFER_SVME); + if (efer & EFER_SVME) { + /* + * Force GIF=1 prior to disabling SVM to ensure INIT and NMI + * aren't blocked, e.g. if a fatal error occurred between CLGI + * and STGI. Note, STGI may #UD if SVM is disabled from NMI + * context between reading EFER and executing STGI. In that + * case, GIF must already be set, otherwise the NMI would have + * been blocked, so just eat the fault. + */ + asm_volatile_goto("1: stgi\n\t" + _ASM_EXTABLE(1b, %l[fault]) + ::: "memory" : fault); +fault: + wrmsrl(MSR_EFER, efer & ~EFER_SVME); + } } /** Makes sure SVM is disabled, if it is supported on the CPU |