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SubjectRe: [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation
On Fri, Jan 26, 2018 at 07:11:47PM +0000, Hansen, Dave wrote:
> The need for RSB stuffing in all the various scenarios and what the heck it actually mitigates is freakishly complicated. I've tried to write it all down in one place:

Thank you for sharing that.

One question on the third from the top (' RSB Stuff (16) After

It says that :"Return from interrupt path (more than 16 deep) can empty

Just to clarify - you mean all the returns ('ret') that are happening after
we call do_IRQ and the stack unwinds - but before we do an 'iret' correct?

I am 99% sure that is what you mean, but just confirming as one could read
this as: 'Need to do RSB after an iret' (say you are in the kernel
and then get an interrupt and iret back to kernel).

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