Re: [PATCHv4 3/5] KVM: emulator: move some address manipulation function out of emulator code.

[Avi Kivity <avi@redhat.com>]

On 07/19/2012 01:49 PM, Gleb Natapov wrote:
>> All those exports suggest it's better to move the fast path into the
>> emulator. 
> 
> We've already being through that. Putting the code into emulator gives
> us nothing unless it also works on emulator context and working on
> partially initialized emulator context is first dangerous and second
> slower.

We can make it work on an x86_pio_ctxt.  What it gives us is common
code. (x86_emulate_ctxt can include a x86_pio_ctxt when it does pio).

> 
>>  Suppose we change register access to use callbacks instead of
>> bulk load/save, could we reuse the exising code?
>> 
> I do not see that problem. This helper function do basic arithmetics
> on three values. The value itself will be fetched on demand by the emulator.

I meant to reduce the emulator initialization cost, so it isn't slow.

btw, I'm guessing that the main speedup comes not from avoiding the
decode, but by doing page-at-a-time instead of word-at-a-time.

-- 
error compiling committee.c: too many arguments to function