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 544CAC32771 for ; Tue, 28 Jan 2020 02:40:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 23E3C2467B for ; Tue, 28 Jan 2020 02:40:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726294AbgA1CkP (ORCPT ); Mon, 27 Jan 2020 21:40:15 -0500 Received: from mx2.suse.de ([195.135.220.15]:39004 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726080AbgA1CkP (ORCPT ); Mon, 27 Jan 2020 21:40:15 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 1A89DAE44; Tue, 28 Jan 2020 02:40:12 +0000 (UTC) Message-ID: <09b279683e1b5ba1759ac3e9f644d290564902d3.camel@suse.com> Subject: Re: [RFC PATCH v4 00/19] Core scheduling v4 From: Dario Faggioli To: Vineeth Remanan Pillai , Tim Chen Cc: Nishanth Aravamudan , Julien Desfossez , Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Paul Turner , Linus Torvalds , Linux List Kernel Mailing , =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , Kees Cook , Greg Kerr , Phil Auld , Aaron Lu , Aubrey Li , Valentin Schneider , Mel Gorman , Pawan Gupta , Paolo Bonzini Date: Tue, 28 Jan 2020 03:40:09 +0100 In-Reply-To: References: <5e3cea14-28d1-bf1e-cabe-fb5b48fdeadc@linux.intel.com> <3c3c56c1-b8dc-652c-535e-74f6dcf45560@linux.intel.com> Organization: SUSE Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-0QOLAV3RIX/hw2NT7iyf" User-Agent: Evolution 3.34.3 MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-0QOLAV3RIX/hw2NT7iyf Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2020-01-14 at 10:40 -0500, Vineeth Remanan Pillai wrote: > On Mon, Jan 13, 2020 at 8:12 PM Tim Chen >=20 > > As a side effect of the fix, each core can now operate in core- > > scheduling > > mode or non core-scheduling mode, depending on how many online SMT > > threads it has. > >=20 > > Vineet, are you guys planning to refresh v4 and update it to > > v5? Aubrey posted > > a port to the latest kernel earlier. > >=20 > We are investigating a performance issue > with > high overcommit io intensive workload and also we are trying to see > if > we can add synchronization during VMEXITs so that a guest vm cannot > run > run alongside with host kernel.=20 > So, about this VMEXIT sync thing. I do agree that we should at least try and do it (and assess performance). I was wondering, however, what we think about core-scheduling + address space isolation (or whatever it is/will be called). More specifically, whether such a solution wouldn't be considered an equally safe setup (at least for the virt use-cases, of course). Basically, core-scheduling would prevent VM-to-VM attacks while ASI would mitigate VM-to-hypervisor attacks. Of course, such a solution would need to be fully implemented and evaluated too... I just wanted to toss it around, mostly to know what you think about it and whether or not it is already on your radar. Thanks and Regards --=20 Dario Faggioli, Ph.D http://about.me/dario.faggioli Virtualization Software Engineer SUSE Labs, SUSE https://www.suse.com/ ------------------------------------------------------------------- <> (Raistlin Majere) --=-0QOLAV3RIX/hw2NT7iyf Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEES5ssOj3Vhr0WPnOLFkJ4iaW4c+4FAl4vnwoACgkQFkJ4iaW4 c+5h/A//UHsF2sGkTJI/L4vFvNv5Hy4kB6RugQqLpfePV5pELOgB65JHwdeuafHM re5e/wkFSvLWTokxZZrGvQAoBmN4BrlsMgc5qMrH5zMxpAaKjq75ZbAPc45IdKXs gIUQMUKQvCKPEEDi5r2oPKvqTdUBoo7MOE3apcqf8KUYKQJLSqINAAPblW1WWP3W Cj5pnlEf0X1JsM0U+NTKw11zKyDPY0TdkF4d/CK9W5J7BpnMuBYg5zsPzuBFbE/N xhjYjeLIXqdxWfdqquE5QYqvuKh2eHWM8Kd82ki4azOZCMIimTB3sQ1VrQ2ezUOh HiLYzj5JoW+PiXfSEvUKuTxIt+PniY8o4B4G2Oeu0D884huT9vZGz3Nx8i4A1njY 98bQBJpk5qJ08rq/m89gjVqXgcKBDuD0JI1UZUGO9fszChA2txxzFqkzMysd87tQ tOnOcGlIvZuB8XuJ21wzmwKmpNfqW0DnytooxVcr3qf+KKymYTrMtyBmycOOKSfh 1DDW4JkShbJZJseB7gr5lg9k4D/LQw+Iz2Bq0iV4WlcmK7rW28VVnQ0GNEmIoSt1 xeCQV2b85VAQAQYrFBiFQJsEsz6VYnhJoyOrHUX6rFC8StwI1qgj+Ldqr7SBVWKB sZOMEv+Igdn2eGdxU1U5VGCuWMfooi3LyG58brF1lHC4bUgCBgY= =xIKT -----END PGP SIGNATURE----- --=-0QOLAV3RIX/hw2NT7iyf--