Need MTTCG support for x86 guests

MTTCG support is notably absent for x86_64 guests.  The last Wiki update on MTTCG was back in 2015, and I am having some difficulty determining the current status of the underlying requirements to enable this feature on x86 hosts.

For instance, has support for strong-on-weak memory consistency been added into QEMU GIT at this point?

Thanks!