kvm,lapic: Justify use of swait_active()

A comment might serve future readers.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index aaf10b6f5380d6d41531b25365b433eac9d42c48..69c5612be786fbc7909b6f81a8d0a29f2cd324a6 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1324,6 +1324,10 @@ static void apic_timer_expired(struct kvm_lapic *apic)
        atomic_inc(&apic->lapic_timer.pending);
        kvm_set_pending_timer(vcpu);
 
+       /*
+        * For x86, the atomic_inc() is serialized, thus
+        * using swait_active() is safe.
+        */
        if (swait_active(q))
                swake_up(q);