There is no need to worry about local APIC.
There is need to worry about I/O APIC, because I/O APIC
is replacing good old 8259. According to Nehemiah datasheet VIA is
using 3-wire bus to connect local APIC to I/O APIC.

"[...] When IA32_APIC_BASE[11] is set to 0, processor APICs based on the 3-wire APIC
 bus cannot be generally re-enabled until a system hardware reset. The 3-wire bus
 looses track of arbitration that would be necessary for complete re-enabling. Certain
 (local) APIC functionality can be enabled. [...]"

So we must set disable bit for each interrupt in I/O APIC registers.
Same situation as for PIC - we must poke registers direcly.
How to do this? I don't know. So at the moment it is better to fail.
Signed-off-by: Rafa³ Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>