linux-kernel - Re: [RFC PATCH] x86/bugs: Remove 'force' options for retbleed/ITS

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Message-ID: <20250627075643.GO1613200@noisy.programming.kicks-ass.net>
Date: Fri, 27 Jun 2025 09:56:43 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Nikolay Borisov <nik.borisov@...e.com>
Cc: David Kaplan <david.kaplan@....com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Borislav Petkov <bp@...en8.de>,
	Josh Poimboeuf <jpoimboe@...nel.org>,
	Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
	Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH] x86/bugs: Remove 'force' options for retbleed/ITS

On Thu, Jun 26, 2025 at 06:13:05PM +0300, Nikolay Borisov wrote:

> > Testing; I use these things for testing. Makes I don't have to run on
> > affected hardware, I can just force the feature on and inspect the code
> > and ensures it runs.
> > 
> > If you use force, you get to keep all pieces -- no warranties.
> 
> I concur, however using force won't always guarantee that the code runs
> though, 

Which is why you should run gdb on /proc/kcore to check what you ended
up with :-)

> because there can be other condition that must/must not be met i.e
> trying to run ITS on AMD hw (yeah, yeah I know :) ) also required commenting
> out some checks in patch_retpoline.

Ah, I might not have hit that, due to not actually having any AMD
machines for testing :/