quoted

 struct smp_ops_t smp_85xx_ops =3D {
 	.kick_cpu =3D smp_85xx_kick_cpu,
-#ifdef CONFIG_KEXEC
+#ifdef CONFIG_HOTPLUG_CPU
+	.cpu_disable	=3D generic_cpu_disable,
+	.cpu_die	=3D generic_cpu_die,
+#endif
 	.give_timebase	=3D smp_generic_give_timebase,
 	.take_timebase	=3D smp_generic_take_timebase,
-#endif
 };

=20
We need to stop using smp_generic_give/take_timebase, not expand its use.
This stuff breaks under hypervisors where timebase can't be written.  It
wasn't too bad before since we generally didn't enable CONFIG_KEXEC, but
we're more likely to want CONFIG_HOTPLUG_CPU.

I understand that the guest OS shouldn't change the real timebase.  But no =
matter what timebase syncing method we are using, the timebase need to be c=
hanged anyway for certain features.  I think the better way should be trapp=
ing timebase modification in the hypervisor.

=20
Do the timebase sync the way U-Boot does -- if you find the appropriate
guts node in the device tree.

That involves stopping timebase for a short time on all cores including the=
 cores that are still online.  Won't this be a potential issue?

- Leo=20