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 E4186C0015E for ; Sat, 12 Aug 2023 11:24:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232159AbjHLLYX (ORCPT ); Sat, 12 Aug 2023 07:24:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231307AbjHLLYV (ORCPT ); Sat, 12 Aug 2023 07:24:21 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01A2D110 for ; Sat, 12 Aug 2023 04:24:24 -0700 (PDT) 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=uRy5b2NDQ5YKh+tB78UZj7bxdV6CalOnVkbxdfzY2JU=; b=AiCIrL48rafub7NnMeQYmStmqP 7aZf4f3ww+/XVQX6zSmeA+ujCLf+RlMHkLwJcW+LqOOT05naYe5oTxl6V4zpTj0hRcHWnTXAgNheN ECyug4DUXb8pWV4cQ3WNKQFryBjLXuSKCXx5DM9cEOwOF/WEOiRrDGpZ7f883bCVWKEBnrJ4neINO dvDqHkCMWXRP5Sv7tdpYKHqkvdzAyB0c083j3gyfLsnz5TlEpQMR8pg6aIsEH0mlHqYPz/iwqvdrj tg/U7C+Homybpsj5Ou4hVnrBdf2gLNgbDmiYH4FZHdifDha8fDDFs0/fSNIQ07jOcYWBcTPQeoIgh HVxlv6UA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1qUmiz-0078qN-MU; Sat, 12 Aug 2023 11:24:05 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D4BA730057E; Sat, 12 Aug 2023 13:24:04 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id B791820410DA2; Sat, 12 Aug 2023 13:24:04 +0200 (CEST) Date: Sat, 12 Aug 2023 13:24:04 +0200 From: Peter Zijlstra To: Josh Poimboeuf Cc: Borislav Petkov , 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= Message-ID: <20230812112404.GB749618@hirez.programming.kicks-ass.net> References: <20230809071218.000335006@infradead.org> <20230809072200.850338672@infradead.org> <20230810154404.GOZNUFxHxLIMth6j9s@fat_crate.local> <20230810161003.i65d37ozlt3d5xse@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230810161003.i65d37ozlt3d5xse@treble> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 10, 2023 at 12:10:03PM -0400, Josh Poimboeuf wrote: > On Thu, Aug 10, 2023 at 05:44:04PM +0200, Borislav Petkov wrote: > > On Wed, Aug 09, 2023 at 09:12:24AM +0200, Peter Zijlstra wrote: > > > Since it is now readily apparent that the two SRSO > > > untrain_ret+return_thunk variants are exactly the same mechanism as > > > the existing (retbleed) zen untrain_ret+return_thunk, add them to the > > > existing retbleed options. > > > > Except that Zen3/4 are not affected by retbleed, according to my current > > state of information. > > > > I don't like this lumping together of the issues even if their > > mitigations are more or less similar. > > 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). > > The mitigations are unfortunately intertwined, but we've been in that > situation several times before (e.g., spectre_v2 + intel retbleed). That very experience wants me to avoid doing it again :-/ But you all really want to keep the parameter, can we at least rename it something you can remember how to type, like 'srso=' instead of this horrific 'spec_rstack_overflow=' thing?