On July 5, 2022 3:00:04 PM PDT, Borislav Petkov <bp@xxxxxxxxx> wrote: >On Tue, Jul 05, 2022 at 02:50:34PM -0700, H. Peter Anvin wrote: >> It's just math. The only variable is your confidence level, i.e. at >> what level do you decide that the likelihood of pure chance is way >> smaller than the likelihood of hardware failure. > >That might be but the likelyhood of certain BIOSes dropping the ball >after resume is 100%: > >7879fc4bdc75 ("x86/rdrand: Sanity-check RDRAND output") > What I'm wondering is if we shouldn't be simply instrument *every* invocation, and set the trust to zero if we ever trip it.