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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 732F4C32751 for ; Wed, 31 Jul 2019 19:22:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5851E208E4 for ; Wed, 31 Jul 2019 19:22:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730863AbfGaTWY (ORCPT ); Wed, 31 Jul 2019 15:22:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46204 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730413AbfGaTWX (ORCPT ); Wed, 31 Jul 2019 15:22:23 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7D0917FDFB; Wed, 31 Jul 2019 19:22:23 +0000 (UTC) Received: from linux-ws.nc.xsintricity.com (ovpn-112-50.rdu2.redhat.com [10.10.112.50]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E459010016EA; Wed, 31 Jul 2019 19:22:21 +0000 (UTC) Message-ID: <96896eaeaac7cefed65098da268f92e96db69591.camel@redhat.com> Subject: Re: [PATCH V2] IB/core: Add mitigation for Spectre V1 From: Doug Ledford To: "Gustavo A. R. Silva" , "Luck, Tony" , Ira Weiny Cc: Jason Gunthorpe , Leon Romanovsky , Parav Pandit , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 31 Jul 2019 15:22:19 -0400 In-Reply-To: References: <20190730202407.31046-1-tony.luck@intel.com> <95f5cf70-1a1d-f48c-efac-f389360f585e@embeddedor.com> <20190731042801.GA2179@iweiny-DESK2.sc.intel.com> <20190731043957.GA1600@agluck-desk2.amr.corp.intel.com> <09a994054e43c8bd6ee49b7d1087c9c4e793058f.camel@redhat.com> <1fc90610-7189-c99b-2af1-ae516faa20b4@embeddedor.com> Organization: Red Hat, Inc. Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-Wv/u9qT9ydWeDsWxVynx" User-Agent: Evolution 3.32.4 (3.32.4-1.fc30) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 31 Jul 2019 19:22:23 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-Wv/u9qT9ydWeDsWxVynx Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2019-07-31 at 14:52 -0400, Doug Ledford wrote: > On Wed, 2019-07-31 at 12:52 -0500, Gustavo A. R. Silva wrote: > > This is insufficient. The speculation windows are large: > >=20 > > "Speculative execution on modern CPUs can run several > > hundred instructions ahead." [1] > >=20 > > [1] https://spectreattack.com/spectre.pdf >=20 > Thanks, I'll take a look at that. That issue aside, returning without > wasting time on two mutexes is still better IMO, so I like my patch > more > than the proposed one. Tony, would you like to resubmit? >=20 Never mind, I took your V2 and fixed it up like I wanted. Patch applied, thanks. --=20 Doug Ledford GPG KeyID: B826A3330E572FDD Fingerprint =3D AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD --=-Wv/u9qT9ydWeDsWxVynx Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEErmsb2hIrI7QmWxJ0uCajMw5XL90FAl1B6msACgkQuCajMw5X L920EQ//ZnYSHmoGTzfKPPATbtwiddtsOQRjlO2abLNYDTXpOCjGHf0FZBmvoWgt jiRcT2P/pPCoHhijeJdpRJwazHTc6NXrtI7lz2kCjP3aZh17Fb5uWB6tupwokFrR 8ODtSzJ3emIn6bxiJy+Ej8RKUpAbqaIuytCN5EAsToqJoi1vxz5/I8HeLquMDf0a RtKujhNtiGgGgqHiT6QfsREGiTF0KnCJUvJzpyqgbaHqI7HfFRrXda65pR/GKvWu Oc45GQCACy9g8AorLaclu7WxxMMAkRwWY5oRHE6TyXhDdCu+551rzQMmYBZUPrZI N1ybzIM+GXJigzEKrnQeMunxCe1NfWoTV9fUbRHk0ItDw+5QwRGOFPFC3bzPAxsw BARfqsWhlUkD1paEaskXZLQP72bxGjnuXaCZbqcYoCquvN2yRpM2+C4mL8uZF1/X tOcQL1GUS/H4i2+w1mNjoBV4g7ft0Rm7zmWzCuV4+y2lYbMIMaH/xY1wCf56cHsI PZ10Nkb+KiXbivDvzbGqmJNyotxZh7JZw1ZfoOGgU6YQABY2vsMEiU/q5IOjM3Rt 5zo+9VpR9FQhmF2zAZ89trqFOR4xltv+b3iTKgvMl6gQEcrdcpOGaJvgSmiSzg8v lzqJhIELmSF+ZlBobJejKZMDCUa29ZXGq0LSZneFII0HgVY6cUM= =biB6 -----END PGP SIGNATURE----- --=-Wv/u9qT9ydWeDsWxVynx--