Fwd: VAX + Spectre

However, even speculative execution isn't enough to make Spectre possible or feasible. For example, the PowerPC G3 and 7400 CPUs speculatively execute, but because indirect branches can only be done on special-purpose registers and the G3 and 7400 halt speculative execution until the SPR is loaded with the destination address, this means they won't speculatively execute after any indirect branch in code and makes them resistant to the currently known variants of Spectre. Given how weird the VAX can be in some respects, I wouldn't be surprised if similar idiosyncratic behaviours exist that confound such attacks similarly. http://tenfourfox.blogspot.com/2018/01/actual-field-testing-of-spectre-on.h… -- ------------------------------------ personal: http://www.cameronkaiser.com/ -- Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com -- When you're in it up to your ears, keep your mouth shut. -------------------