Inception: A simple XOR can cause a Microarchitectural Stack Overflow

Re:Inception: A simple XOR can cause a Microarchitectural St... by pdw on Wednesday August 09, 2023 @02:35AM (#37059377)

Or the mistake is that we're running different trust domains on the same CPU core.

All the various mitigations have already been very costly (something like a performance loss of 10% on current-gen CPUs?). Getting rid of speculative execution entirely would cost far, far more.

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Re:Inception: A simple XOR can cause a Microarchitectural St... by bpye on Wednesday August 09, 2023 @02:40AM (#37059406)

There is state shared between cores too though, at the very least L3, probably IOMMUs, etc. I wouldn’t be entirely surprised if there are issues we haven’t found that exist there.

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Re:Inception: A simple XOR can cause a Microarchitectural St... by Dylan16807 on Wednesday August 09, 2023 @03:27AM (#37059637)

But the further out you push the shared state, the less it hurts to disable speculation that affects the shared state.

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Re:Inception: A simple XOR can cause a Microarchitectural St... by cryptonector on Wednesday August 09, 2023 @01:35PM (#37066050)

> Or the mistake is that we're running different trust domains on the same CPU core.

It's very hard to not make that mistake. Think of all the websites running in your browser on your laptop. Isolating all those trust domains is going to be quite costly.

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