Re: [PATCH v4 00/13] "Task_isolation" mode

Peter Zijlstra
2020-07-23T14:26:38Z

On Thu, Jul 23, 2020 at 03:17:04PM +0200, Thomas Gleixner wrote:

> 2) Instruction synchronization
>
> Trying to do instruction synchronization delayed is a clear recipe
> for hard to diagnose failures. Just because it blew not up in your
> face does not make it correct in any way. It's broken by design and
> violates _all_ rules of safe instruction patching and introduces a
> complete trainwreck in x86 NMI processing.
>
> If you really think that this is correct, then please have at least
> the courtesy to come up with a detailed and precise argumentation
> why this is a valid approach.
>
> While writing that up you surely will find out why it is not.

So delaying the sync_core() IPIs for kernel text patching _might_ be
possible, but it very much wants to be a separate patchset and not
something hidden inside a 'gem' like this.