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From:   "Luck, Tony" <tony.luck@intel.com>
To:     Greg KH <gregkh@linuxfoundation.org>
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Subject: RE: [RFC 00/10] Introduce In Field Scan driver
Thread-Topic: [RFC 00/10] Introduce In Field Scan driver
Thread-Index: AQHYLaZcmKq0UuRYGU6xp1k7P7vRw6yre5AAgAABJQCAFBlxgIABAjIAgAAEKTA=
Date:   Tue, 15 Mar 2022 14:59:03 +0000
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>> This seems a novel use of uevent ... is it OK, or is is abuse?
>
> Don't create "novel" uses of uevents.  They are there to express a
> change in state of a device so that userspace can then go and do
> something with that information.  If that pattern fits here, wonderful.

Maybe Dan will chime in here to better explain his idea. I think for
the case where the core test fails, there is a good match with uevent.
The device (one CPU core) has changed state from "working" to
"untrustworthy". Userspace can do things like: take the logical CPUs
on that core offline, initiate a service call, or in a VMM cluster environm=
ent
migrate work to a different node.

> I doubt you can report "test results" via a uevent in a way that the
> current uevent states and messages would properly convey, but hey, maybe
> I'm wrong.

But here things get a bit sketchy. Reporting "pass", or "didn't complete th=
e test"
isn't a state change.  But it seems like a poor interface if there is no fe=
edback
that the test was run. Using different methods to report pass/fail/incomple=
te
also seems user hostile.

> good luck!
Thanks ... we may need it :-)

-Tony