diff --git a/sys/conf/files.x86 b/sys/conf/files.x86
--- a/sys/conf/files.x86
+++ b/sys/conf/files.x86
@@ -318,7 +318,7 @@
 x86/x86/mp_x86.c		optional	smp
 x86/x86/mp_watchdog.c		optional	mp_watchdog smp
 x86/x86/nexus.c			standard
-x86/x86/pvclock.c		standard
+x86/x86/pvclock.c		optional	xenhvm
 x86/x86/stack_machdep.c		optional	ddb | stack
 x86/x86/tsc.c			standard
 x86/x86/ucode.c			standard