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 ; 21 Feb 2019 09:33:17 -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 1gwkjD-0005cp-Ch for speck@linutronix.de; Thu, 21 Feb 2019 10:33:16 +0100 Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id B63A6AE30 for ; Thu, 21 Feb 2019 09:33:09 +0000 (UTC) Date: Thu, 21 Feb 2019 10:33:00 +0100 From: Borislav Petkov Subject: [MODERATED] Re: Re: [patch V2 03/10] MDS basics+ 3 Message-ID: <20190221093300.GA13125@zn.tnic> References: <20190220150753.665964899@linutronix.de> <20190220151400.217101404@linutronix.de> <1edb2eec-d17f-eefd-4c96-3c5c3eb69d09@citrix.com> MIME-Version: 1.0 In-Reply-To: <1edb2eec-d17f-eefd-4c96-3c5c3eb69d09@citrix.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable To: speck@linutronix.de List-ID: On Thu, Feb 21, 2019 at 02:12:19AM +0000, speck for Andrew Cooper wrote: > For least latency (allegedly to avoid a static prediction stall in > microcode), it should be a writeable data segment which is hot in the > cache, and being adjacent to __KERNEL_CS is a pretty good bet. That should be in a comment somewhere. > I don't understand why everyone is so concerned about VERW modifying > ZF.=C2=A0 Its not as if this fact is relevant anywhere that the mitigation = is > liable to be used. Err, so that gcc can know that it is clobbered? What do you mean here? --=20 Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imend=C3=B6rffer, Jane Smithard, Graham Norton, HR= B 21284 (AG N=C3=BCrnberg) --=20