Compared to the x86 patches, these are still in the review stage, aiming to upstream for 4.16.
I guess they'll find their way into Android trees before then.
What of Apple’s An-series processors (Fusion, Bionic,...) in it’s iPhone and iPad ranges? Those are customised ARM_64 devices so presumably they’re vulnerable to attack just as any other implementation, and will require an iOS patch to fix. If this patch has the performance impact being bandied about for the x86 patch we’re going to be looking at a more sluggish mobile experience (especially when switching apps or doing I/O intensive work) and heightened battery drain (because that wasn’t enough of a problem already).