[eigenform]

fwiw "knee-jerk reaction to Apple MIE" is not exactly the right characterization of this. MPX existed and faded away, and it's not very surprising that x86-world would wait for someone else to try shipping hardware support for memory safety features before trying again.

[OneDeuxTriSeiGo]

I wouldn't say that's fair. MPX failed because it was a very problematic solution to this problem.

MPX had a large (greater than 15-20%) overhead and was brittle. It didn't play well with other x86 instructions and the developer experience was extremely poor (common C and C++ design patterns would cause memory faults with MPX).

Apple MIE (which is essentially ARM MTE v2) and MTE on the other hand have near invisible levels of overhead (~5-10%) with the ability to alternate between synchronous and asynchronous tracing of faults where the latter has a much lower overhead than the former (allowing you to check in production for very little overhead and get better debugging in test). They also work essentially seamlessly with the rest of the ARM ecosystem and it takes very little to integrate the functionality into any language ecosystem or toolchain.

If MPX was comparable with MTE, it certainly would have gotten the adoption that MTE is getting but the "tech" just wasn't there to justify it's use.

[eigenform]

I'm not arguing MPX was a good solution, just that it's silly to assume folks designing x86 machines have been totally ignoring developments in that space for the past ten years.

[OneDeuxTriSeiGo]

fair.