Messages in this thread | | | Date | Wed, 17 Aug 2022 14:10:51 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v3 3/5] x86/microcode: Avoid any chance of MCE's during microcode update |
| |
On Wed, Aug 17, 2022 at 11:57:37AM +0000, Ashok Raj wrote: > You have this reversed. if you get an MCE and MCIP=1 -> shutdown
Yeah yeah.
> When MCE's happen during the update they are always fatal errors.
How did you decide that?
Because all CPUs are executing the loop and thus no user process?
> What we do here by setting MCIP=1, we promote to a more severe shutdown.
It probably should say somewhere that a shutdown is possible. Because if the shutdown really happens, you get a black screen and no info as to why...
> Ideally I would rather let the fallout happen since its observable vs a > blind shutdown is what we are promoting to.
What fallout do you mean exactly?
> Shutdown, shutdown.. There is only 1 MCE no matter how many CPUs you have.
Because all CPUs are executing the loop? Or how do you decide this?
> Exception is the Local MCE which is recoverable, but only to user space. > > If you get an error in the atomic we are polling, its a fatal error since > SW can't recover and we shutdown.
Aha, I think you mean that: the MCE is fatal because if it happens on any CPU, it will be in kernel mode.
> Overthinking :-).. If there is concensus, if Boris feels comfortable > enough, i would drop this patch.
This is what we're doing right now - thinking about the consensus. And Boris will feel comfortable once we've arrived at a sensible decision.
:-)
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
| |