From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A14F6C001DB for ; Mon, 14 Aug 2023 15:46:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229924AbjHNPqL convert rfc822-to-8bit (ORCPT ); Mon, 14 Aug 2023 11:46:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47314 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229744AbjHNPpi (ORCPT ); Mon, 14 Aug 2023 11:45:38 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.85.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B41EF10E4 for ; Mon, 14 Aug 2023 08:45:37 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-264-4VDMbRvdM6CccUdMezF-iA-1; Mon, 14 Aug 2023 16:45:35 +0100 X-MC-Unique: 4VDMbRvdM6CccUdMezF-iA-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Mon, 14 Aug 2023 16:45:22 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Mon, 14 Aug 2023 16:45:22 +0100 From: David Laight To: 'Peter Zijlstra' , Borislav Petkov CC: Josh Poimboeuf , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "David.Kaplan@amd.com" , "Andrew.Cooper3@citrix.com" , "gregkh@linuxfoundation.org" Subject: RE: [RFC][PATCH 06/17] x86/cpu: Add SRSO untrain to retbleed= Thread-Topic: [RFC][PATCH 06/17] x86/cpu: Add SRSO untrain to retbleed= Thread-Index: AQHZzRDK8HwTTXk3aUC67vPYTNvPsK/p8R2g Date: Mon, 14 Aug 2023 15:45:22 +0000 Message-ID: References: <20230809071218.000335006@infradead.org> <20230809072200.850338672@infradead.org> <20230810154404.GOZNUFxHxLIMth6j9s@fat_crate.local> <20230810161003.i65d37ozlt3d5xse@treble> <20230811102748.GEZNYNJEeDxTqcOLvj@fat_crate.local> <20230812113256.GC749618@hirez.programming.kicks-ass.net> In-Reply-To: <20230812113256.GC749618@hirez.programming.kicks-ass.net> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra > Sent: 12 August 2023 12:33 > > On Fri, Aug 11, 2023 at 12:27:48PM +0200, Borislav Petkov wrote: > > On Thu, Aug 10, 2023 at 12:10:03PM -0400, Josh Poimboeuf wrote: > > > I tend to agree that SRSO is a new issue and should have its own sysfs > > > and cmdline options (though a separate CONFIG option is overkill IMO). > > > > Yeah, there's a patch floating around adding a config option for every > > mitigation. Apparently people want to build-time disable them all. > > So I really hate that .Kconfig explosion, that's the very last thing we > need :-( More random options that can cause build time trouble. > > I might see value in one knob that kills all speculation nonsense at > build time, but not one per mitigation, that's maddness. Or a very limited number of options for things that are pretty separate. Maybe the call/indirect jump are separate enough from the return ones? An one big KNOB to disable them all (DEPEND_ON !NO_MIGIGATIONS ?). David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)