4) Disable PTI support on 2-level paging by making it dependent
	   on CONFIG_X86_PAE. This is, imho, the least ugly option
	   because the machines that do not support PAE are most likely
	   too old to be affected my Meltdown anyway. We might also
	   consider switching i386_defconfig to PAE?

Any other thoughts?

The machines where I have PAE off are the ones that have less memory. 
PAE is off just for performance reasons, not lack of PAE. PAE should be 
present on all of my affected machines anyway and current distributions 
seem to mostly assume 686 and PAE anyway for 32-bit systems.

-- 
Meelis Roos (mroos@ut.ee)      http://www.cs.ut.ee/~mroos/