- Add interrupt shielding (direct hardware interrupts away from the
specified CPUs). Not documented just yet but will be soon.
- Redo /dev/cpu time_t compat so no kernel changes are needed.
x86:
- Make intr_establish, intr_disestablish safe to use when !cold.
- Distribute hardware interrupts among the CPUs, instead of directing
everything to the boot CPU.
- Add MD code for interrupt sheilding. This works in most cases but there is
a bug where delivery is not accepted by an LAPIC after redistribution. It
also needs re-balancing to make things fair after interrupts are turned
back on for a CPU.