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.
Reviewed-by: Alexander Graf <ag...@suse.de>
Signed-off-by: Radim Krčmář <rkrc...@redhat.com>
---
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 d0b95b7a90b4..81f5f50794f6 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -281,6 +281,9 @@ 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
--
2.14.2
