Messages in this thread | | | Subject | Re: Improve retpoline for Skylake | From | David Woodhouse <> | Date | Mon, 15 Jan 2018 19:07:52 +0100 |
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On Mon, 2018-01-15 at 10:06 -0800, Andy Lutomirski wrote: > > > Refill or not, you are aware that a correctly timed SMI in a leaf > > function will cause the next ret to speculate into userspace, because > > there is guaranteed peturbance in the RSB? (On the expectation that the > > SMM handler isn't entirely devoid of function calls). > > Couldn't firmware fill the RSB with a some known safe address, maybe > even 0, and then immediately do RSM?
Why don't we just unconditionally declare that *all* firmware that uses SMI for anything at all is broken?
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