From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A3BDB2264B1 for ; Fri, 27 Jun 2025 07:56:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751011013; cv=none; b=X9mlaS/skRW/wS6NYPZ+ruG9ydtyT+BwYzqQQc41eh9PEDGi+zaMwUxC0M5yMVTFJh8uikruvtKCk5HjQBJv4sodZE0BdoMtPIljLaGkrmXuqa026PpgB60WSvb8uhRCE1+XoaPcB8vsyX0HFLEpjDZyO4a9Ji5YGJ8AP5Nsvg4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751011013; c=relaxed/simple; bh=o+9R9X4qf1r8j39EZ1mR4c7s9H6+hwicix9ShM9qj5A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WMQHeboPHbhe0dd1i5b3nLQ7yaUgEUSRCZIyJA/RO8fpWzrToi949mx0W8Ey2mLljY3goFQPOvtYIz+G5BrYSK+G/VE6tGqo+7dxo9gP7QlexRRBSc1PriXxY94dsptbKCzYqiu+UnUZuOni3l/w5KL24/Qx78RdGEZTzWtTEuA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=uu7DPQRY; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="uu7DPQRY" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=cZ8KqJeTVmJcdtGEw5MJHSl2d+0iZtEQ4xk1+lQ2oHM=; b=uu7DPQRYdfBrecw83ZfbccZtH+ l+npjLCojr/cEvSUFn/3zBRzl1SGprqt5T7eQwkP69Hpp29Vg9IOn1h1g4hEKk1BbCKcs9D3lbVGo 6Ys/UmdkLoZao0t0p49bJEuI25JSL2ICzL2kWs96huhCYFPTArHCuwHL48CxG3tNwXCwLPNBbCZZh U+0NGC1A8qwvHsPkMJ2gw3Wdt1q/hV7AK5DQM7g1GNy6xQ19yyOX/V0ubnGsDPRXNp0u9EevumFs1 J99YuQWW6g0NjQ3EzzjnIRrT59G4O70/QIzhtuFUUxHC5LMuhrQZBZPEkXwIRWcDRuQ8cFz/+v/at Dnbmqnug==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1uV3wy-0000000DYJu-2mB0; Fri, 27 Jun 2025 07:56:44 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 4095E300222; Fri, 27 Jun 2025 09:56:43 +0200 (CEST) Date: Fri, 27 Jun 2025 09:56:43 +0200 From: Peter Zijlstra To: Nikolay Borisov Cc: David Kaplan , Thomas Gleixner , Borislav Petkov , Josh Poimboeuf , Pawan Gupta , Ingo Molnar , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] x86/bugs: Remove 'force' options for retbleed/ITS Message-ID: <20250627075643.GO1613200@noisy.programming.kicks-ass.net> References: <20250626142703.716997-1-david.kaplan@amd.com> <20250626144047.GN1613200@noisy.programming.kicks-ass.net> <295f94d4-f5e2-4849-ab62-9fdc75722e20@suse.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <295f94d4-f5e2-4849-ab62-9fdc75722e20@suse.com> 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 :/