Perhaps the most valuable result here is how hard it is to get this anywhere near right. CPU vendors MUST acknowledge and fix Spectre v1.https://twitter.com/chandlerc1024/status/977139103849316353 …
I think even the first is potentially dangerous. If a reg contains a (non-ptr) value that's private and you trick branch prediction to branch to somewhere it's used as an index or ptr, part of its value potentially leaks.
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Possibly, but Spectre variant 1 uses a data dependent load to leak data i.e. two loads, the second load with a stride to cause a particular cache eviction. Still curious what the performance hit would be to disallow all speculative loads.
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My claim (no data but strong intuition) is that the hit would be minimal on most loads people care about, where most loads (pardon the pun) are either already in l1 (no penalty) or at least in l2/l3 (minimal stall compared to going to dram).
End of conversation
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