The bug prevents MWAIT from waking up after a write to the monitored cache line. KVM might emulate a CPU model that shouldn't have the bug, so the guest would not employ a workaround and possibly miss wakeups. Better to avoid the situation. Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx> --- arch/x86/kvm/x86.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index 3ed7dd8737ab..63d5fb65ea30 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -231,6 +231,9 @@ static inline bool kvm_mwait_in_guest(void) return false; } + if (boot_cpu_has_bug(X86_BUG_MONITOR)) + return false; + /* * Intel CPUs without CPUID5_ECX_INTERRUPT_BREAK are problematic as * they would allow guest to stop the CPU completely by disabling -- 2.12.2
