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 5CA3EC001B0 for ; Thu, 10 Aug 2023 16:10:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236533AbjHJQKo (ORCPT ); Thu, 10 Aug 2023 12:10:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236481AbjHJQK0 (ORCPT ); Thu, 10 Aug 2023 12:10:26 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E22F30DA for ; Thu, 10 Aug 2023 09:10:09 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A13C56629E for ; Thu, 10 Aug 2023 16:10:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16FBAC433C9; Thu, 10 Aug 2023 16:10:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1691683808; bh=NzYbY6fgKqePhu5kbnmOHqphDUf1P3cZSTDiD6+oCWU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CrnN1X9SckoYQXfAWns1HxdtwNDdymCiYqpoxmKbzGa2sAxxTzjDyJIsjVMOd2hi8 qJ9n266NSjQBNARr4Sj0DQoRFWwdWP+dbKJjjInNGN6J4sXk5ylXwWtMzZAZf3E6ua m841ZeUjHZ2lPxPzIx/EmrZJhnBgrbfpgr4gD9KS3xut0L5NGnqmgfQql0Z99XnPmF xm50O91hOQWkjjRDl/GNZ4p0sWnhcDlWid8LV+Db8Uv16w9xn5CFQdvac2ksfqs9qo FzLGG+CBsARBN3YDK9140SmuvbCpDvh8FiAb4Lg7KK247Kjhqf8AZBtH1WQHMamgXt 38jr6K8xD+/fg== Date: Thu, 10 Aug 2023 12:10:03 -0400 From: Josh Poimboeuf To: Borislav Petkov Cc: Peter Zijlstra , 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: <20230810161003.i65d37ozlt3d5xse@treble> References: <20230809071218.000335006@infradead.org> <20230809072200.850338672@infradead.org> <20230810154404.GOZNUFxHxLIMth6j9s@fat_crate.local> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230810154404.GOZNUFxHxLIMth6j9s@fat_crate.local> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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). -- Josh