From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linutronix.de (146.0.238.70:993) by crypto-ml.lab.linutronix.de with IMAP4-SSL for ; 05 Mar 2019 14:57:56 -0000 Received: from mx1.redhat.com ([209.132.183.28]) by Galois.linutronix.de with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1h0rDW-0004Xn-MD for speck@linutronix.de; Mon, 04 Mar 2019 18:17:31 +0100 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 08FE630832DC for ; Mon, 4 Mar 2019 17:17:24 +0000 (UTC) Received: from treble (ovpn-122-204.rdu2.redhat.com [10.10.122.204]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AAE8B60261 for ; Mon, 4 Mar 2019 17:17:23 +0000 (UTC) Date: Mon, 4 Mar 2019 11:17:21 -0600 From: Josh Poimboeuf Subject: [MODERATED] Re: Encrypted Message Message-ID: <20190304171721.e6qyv722i32ilza4@treble> References: <20190304012138.gikabpafseh2swre@treble> <20190304012455.xi23xfddnexvdz2r@treble> <03c35306-dca6-9299-3db6-7396ba82674a@redhat.com> MIME-Version: 1.0 In-Reply-To: <03c35306-dca6-9299-3db6-7396ba82674a@redhat.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit To: speck@linutronix.de List-ID: On Sun, Mar 03, 2019 at 10:58:01PM -0500, speck for Jon Masters wrote: > On 3/3/19 8:24 PM, speck for Josh Poimboeuf wrote: > > > + if (sched_smt_active() && !boot_cpu_has(X86_BUG_MSBDS_ONLY)) > > + pr_warn_once(MDS_MSG_SMT); > > It's never fully safe to use SMT. I get that if we only had MSBDS then > it's unlikely we'll hit the e.g. power state change cases needed to > exploit it but I think it would be prudent to display something anyway? My understanding is that the idle state changes are mitigated elsewhere in the MDS patches, so it should be safe in theory. -- Josh