[Lguest] [PATCH RFC/RFB] x86_64, i386: interrupt dispatch changes

[H. Peter Anvin]

Ingo Molnar wrote:
> * Ingo Molnar <mingo at elte.hu> wrote:
> 
>> And as hpa's comments point it out, compressing the rather stupid 
>> irq stubs might be a third option that looks promising as well.
> 
> ... and we should try and see how far we can compress those stubs, 
> before we do any segment register based tricks.
> 

Using the techniques previously mentioned, for 224 vectors:

1792 bytes ( 8 bytes/stub) - trivial.
1568 bytes ( 7 bytes/stub) - same without alignment.
 952 bytes (~4 bytes/stub) - extra jump needed.

For comparison, the IDT itself is 2048 bytes on x86-32 and 4096 bytes on
x86-64.

	-hpa