From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linutronix.de (193.142.43.55:993) by crypto-ml.lab.linutronix.de with IMAP4-SSL for ; 16 Oct 2019 05:05:42 -0000 Received: from mx2.suse.de ([195.135.220.15] helo=mx1.suse.de) by Galois.linutronix.de with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iKbVE-0005aM-T3 for speck@linutronix.de; Wed, 16 Oct 2019 07:05:41 +0200 Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 75FE3B289 for ; Wed, 16 Oct 2019 05:05:35 +0000 (UTC) Date: Wed, 16 Oct 2019 07:05:33 +0200 (CEST) From: Jiri Kosina Subject: [MODERATED] Re: [PATCH v5 08/11] TAAv5 8 In-Reply-To: Message-ID: References: <20191015103454.GW317@dhcp22.suse.cz> <20191015130627.7jkhqy2zrtm35ool@treble> <20191015152649.yim4krwuttrh6xgi@treble> <20191015200024.hxs4brxi7gbvmcdy@treble> <20191015205631.GF30412@guptapadev.amr> <20191015231252.kggxh6ffrciz2dfy@treble> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit To: speck@linutronix.de List-ID: On Wed, 16 Oct 2019, speck for Jiri Kosina wrote: > But then we're not defaulting to safe behavior, which is confusing too, > because we almost (SMT being the exception) always did in the past for all > the other previous issues. > > So I believe the above is the best compromise between having as few > regressions as possible, while still maintaining security (by default). > > I agree it's not nice, but nothing is, if you ask me. But again, given Pawan's (surprising to me, I'd still like to find this detail documented somewhere in Intel's materials) statement that there will never be a situation when some older CPU with MDS_NO will see ARCH_CAP_TSX_CTRL_MSR exposed by new ucode, I see this as much less pressing issue, and we could get away with tsx=off, as the number immediate regressions will be minimal. And there will be enough time to push the information (need for commandline option) to the TSX users for the future CPUs. Thanks, -- Jiri Kosina SUSE Labs