AMD chips suffer from Spectre too (which is the hard to fix issue). They didn't really take any fewer "shortcuts" than Intel. And they weren't "shortcuts".
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Speculative execution is not really a "shortcut". Intel did make one shortcut but that resulted in Meltdown, which is easy to fix (conceptually anyway - I'm sure it was a lot of work!)
Any idea why I've been downvoted so much for saying something that surely everyone here remembers (wasn't that long ago) and is easily verified on Wikipedia:
https://en.m.wikipedia.org/wiki/Spectre_(security_vulnerabil...
> As of 2018, almost every computer system is affected by Spectre, including desktops, laptops, and mobile devices. Specifically, Spectre has been shown to work on Intel, AMD, ARM-based, and IBM processors.
The context of the discussion was cpuguy83's suggestion that compared to AMD, Intel has been "suffering from shortcuts leading to Spectre/Meltdown and the performance regressions due to patching those".
cpuguy83's comment was very concise, so let me elaborate that the distinction between Spectre and Meltdown is essential here. Both are security flaws in CPUs that were published at the same time. Spectre is an industry-wide problem that also hit AMD, but "Meltdown" is the result of an Intel-specific implementation choice that I think one might fairly describe as a "shortcut". (Even IshKebab later agrees: https://news.ycombinator.com/item?id=21342048) Meltdown was also more immediately dangerous, and the software workarounds that were necessary to mitigate it in existing CPUs cost a lot of performance.
Given this context, I'll quote the relevant item from cpuguy83 again and then IshKebab's reply:
> cpuguy83: Intel [... has been ...] suffering from shortcuts leading to Spectre/Meltdown and the performance regressions due to patching those.
> IshKebab: AMD chips suffer from Spectre too (which is the hard to fix issue). They didn't really take any fewer "shortcuts" than Intel. And they weren't "shortcuts".
Note how IshKebab carefully ignores the Meltdown part of cpuguy83's comment to be able to claim that Intel hasn't been doing any worse than AMD, and that there were no shortcuts. For Spectre in the stricter sense, that's technically true. It's not true in the context of the entire Spectre/Meltdown event, which was cpuguy83's argument.
Meltdown arguably does fit your description, but AFAIK the cost of checking permissions in the right place is almost zero, so it’s arguably better described as “we never realized it would be dangerous to not check permissions here” than “we skipped the check for performance’s sake”. (AMD processors were not vulnerable to Meltdown.)
Spectre, on the other hand, is sort of an inherent flaw of speculative execution (not related to permissions checks). Speculative execution itself is definitely a shortcut, but it’s a shortcut that’s crucial to the performance of all modern high-performance processors, with the result that nobody really knows how to deal with Spectre. Intel was apparently hit harder than AMD by side channel mitigations collectively, apparently because Intel was doing more aggressive speculation – but those mitigations are only partial. Both vendors’ processors are still vulnerable to Spectre attacks even with mitigations applied [1], and that will remain the case even on future processors, for the foreseeable future.
AMD essentially got lucky on this one - their neural-network based branch predictor is difficult for an attacker to train to follow specific code paths, which is a necessary component of Meltdown/Spectre style attacks. Pretty much every other processor that does speculation is affected.
The potential for cache timing to serve as a side-channel leak was not widely appreciated in the industry, although it was theoretically described as far back as the early 90s.
Yes, the response is technically correct. But...