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Bae" , Dave Hansen , "Maciej W. 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Bae wrote: > I think the first two points have played in this thread already. There > seems to be some caution, specifically around the authentication-failure > as per spec. What does an authentication failure mean in this context? Does that mean unauthenticated microcode components somehow got loaded? or that Someone attempted to load bogus microcode which was rejected by the processor? If it was rejected, then there is no need to panic, right? Just warning about the attempt should be enough. > > In summary, I think options are: > > 1. Panic on any partial update is the most conservative and secure > option, but it may unnecessarily disrupt systems and users My understanding of a panic is the OS saying "something catastrophic has happened and I don't know how to make forward progress". So, it's better to crash at this point than spew out incoherent information. > 2. Warn admins that the system has entered a taint state, assuming the > processor handles truly unrecoverable cases itself. If the processor chooses not to terminate itself after a partial update maybe the kernel shouldn't either and give the admin the opportunity to reconcile at their convenience. I think a strong warning makes the most sense here. In addition to a taint, should there also be a WARN()? That gives any paranoid admin the option to automatically convert WARN => PANIC via panic_on_warn. They can set panic_on_warn at runtime just before the microcode update and then clear it once the update is done. There seems to be a kernel command line option called panic_on_taint which can be configured to panic only for TAINT_CPU_OUT_OF_SPEC. But that may not be very useful because there isn't any runtime sysctl option.