Ideas on dealing with mttcg_enabled/use_icount globals

[Anton Johansson]

Hi Phil,

I've been staring myself blind trying to deal with
qemu_tcg_mttcg_enabled()/icount_enabled() and I'm wondering if you have
an ideas.

I'm leaning towards moving these globals to some TCG accelerator
specific state (TCGState?) that's initialized once we know how many/what
cpus are in the system. The problem is then making sure all uses have 
access to this state.

For qemu_tcg_mttcg_enabled() there is one trickier use in
tcg_region_init(). We probably need to delay the initialization of the
tcg region until we know the cpus in the system, this is getting close 
to the configuration/initialization order issues we've discussed 
previously so I'm not sure how easy this would be.

As for icount_enabled(), I'm not entirely sure yet, its uses are a lot 
more scattered throughout the codebase and I'm still going through them.

Cheers,
-- 
Anton Johansson
rev.ng Labs Srl.