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Re: Interrupts in OoO

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scott@slp53.sl.home (Scott Lurndal) posted:

> MitchAlsup <user5857@newsgrouper.org.invalid> writes:
-----------------------------
> >> In my terminology I have Exceptions, Interrupts, and Errors.
> >> I take all the well defined stuff and put it in the Exception and
> >> Interrupt buckets, and take all the weird stuff and call it Errors.
> >
> >To a very large extent I agree with you. The things you call errors
> >I call Checks. Checks are never supposed to happen {{like late store
> >data ECC fails}}.
> 
> If it is "never supposed to happen", why bother to check at all...

Guest OS can run as if uncorrectable ECC can never happen. So, to
Guest OS it is never supposed to happen, and Guest OS is not setup
to deal with the problem if it does.

HyperVisor cannot run banking applications with UC ECC, whereas some
real-time control might be able to; so you punt it all the way up the
privilege ladder.
 
> For RAS reasons, if nothing else, one must assume that anything
> may happen.

But, still, Guest OS should not be burdened with those checks.
> 
> > 
>  <snip>
> 
> >> Errors are model and error specific, may be synchronous or asynchronous,
> >> may be precise (Faults or Traps) or imprecise (Aborts).
> >> Errors may or may not be deferred (maskable).
> >
> >It is at this point I generally point out that Checks {errors} deliver
> >control to the highest privilege level {HyperVisor} not the next higher
> >privilege level {Guest OS when in User}.
> 
> It's better if that is programmable, i.e. the highest privilege level
> (even higher than the hypervisor - i.e. the EL3 in ARM64, or SMM for
> intel/amd (or perhaps a BMC)).  The higher privilege levels can delegate
> the asynchronous "check" exception handling to a lower level, if necessary.

Or abort the lower level that suffered the check, possibly restarting it
from the last checkpoint with new/diffent memory.
 

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Re: Interrupts in OoO (was: Microarchitectural support for counting) quadibloc@invalid.com (John Savard) - 2026-10-23 23:57 +0000
  Re: Interrupts in OoO Robert Finch <robfi680@gmail.com> - 2026-10-23 21:12 -0400
  Re: Interrupts in OoO (was: Microarchitectural support for counting) MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-24 19:20 +0000
    Re: Interrupts in OoO (was: Microarchitectural support for counting) scott@slp53.sl.home (Scott Lurndal) - 2026-10-25 15:53 +0000
      Re: Interrupts in OoO EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-26 11:06 -0400
        Re: Interrupts in OoO Robert Finch <robfi680@gmail.com> - 2026-10-26 13:17 -0400
          Re: Interrupts in OoO EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-26 17:03 -0400
            Re: Interrupts in OoO "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-26 14:14 -0700
              Re: Interrupts in OoO EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-28 14:39 -0400
                Re: Interrupts in OoO "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-28 15:10 -0700
                Re: Interrupts in OoO EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-29 14:50 -0400
            Re: Interrupts in OoO MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-27 16:48 +0000
        Re: Interrupts in OoO MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-27 16:35 +0000
          Re: Interrupts in OoO scott@slp53.sl.home (Scott Lurndal) - 2026-10-27 18:33 +0000
            Re: Interrupts in OoO MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-27 21:07 +0000
              Re: Interrupts in OoO scott@slp53.sl.home (Scott Lurndal) - 2026-10-27 21:17 +0000
                Re: Interrupts in OoO MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-28 15:35 +0000
                Re: Interrupts in OoO George Neuner <gneuner2@comcast.net> - 2026-10-28 14:34 -0400
                Re: Interrupts in OoO scott@slp53.sl.home (Scott Lurndal) - 2026-10-28 20:16 +0000
                Re: Interrupts in OoO MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-29 02:17 +0000
                Re: Interrupts in OoO "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-28 21:21 -0700
                Re: Interrupts in OoO George Neuner <gneuner2@comcast.net> - 2026-10-29 21:49 -0400
              Re: Interrupts in OoO EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-28 14:57 -0400
                Re: Interrupts in OoO MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-29 02:27 +0000
          Re: Interrupts in OoO EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-28 14:19 -0400
            Re: Interrupts in OoO MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-28 19:02 +0000
  Re: Interrupts in OoO (was: Microarchitectural support for counting) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-26 17:45 +0000
    Re: Interrupts in OoO (was: Microarchitectural support for counting) MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-27 16:39 +0000

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