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

[Jeremy Fitzhardinge]

Ingo Molnar wrote:
> ( another advantage is that the 6 bytes GDT descriptor is more 
>   compressed and hence uses up less L1/L2 cache footprint than the 
>   larger (~7 byte) trampolines we have at the moment. )
>   

Also its D cache rather than I cache, which is generally more 
plentiful.  However, I think the cost of GDT cache misses on exception 
latency is something that we've largely overlooked, and this will make 
it a bigger factor (vs cache misses on the actual exception handler code 
itself, which should be reduced).

    J