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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 3B44CC3A5A1 for ; Wed, 28 Aug 2019 16:16:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0EB6D22DA7 for ; Wed, 28 Aug 2019 16:16:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="DESqQHh2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726829AbfH1QQ6 (ORCPT ); Wed, 28 Aug 2019 12:16:58 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:33684 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726395AbfH1QQ5 (ORCPT ); Wed, 28 Aug 2019 12:16:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=ICJAa08tadoxVPLwvjSEX3IwJxKlsW5cqkoOWAu/x8M=; b=DESqQHh2cNViea0m7r8+H3fu4 1dFucgAEMAvngpKuOByQxETWWcVYF63MS9s/79ByDMlJnv6qVLGka3yxIR5TK2iA2KU5rmNEouNTS 8NG7VowmDv2KNIew7s0qLUb9qUexQOyNvqDGS/eCN0echuCOdJRrn6xZCsZqW/jRAzw4oSJTmHbmh kr117gOELOdhx6Xo3ultpIVg5PbXH/2dYFYcUwdVWshiYLPYs+FLR93/QefbbERy+AcAP1Z0nyMqL p6rJekQVD/8egGLC9IiSLimuDDhsZq60Y64g0+47/xSF8wFIaBHaZcl6/n7GTzfTu0Qfut1ZPb1fC 1nb2DF8iA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1i30cm-0005WW-LX; Wed, 28 Aug 2019 16:16:44 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id EA2C1307594; Wed, 28 Aug 2019 18:16:07 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id E174C20230B32; Wed, 28 Aug 2019 18:16:41 +0200 (CEST) Date: Wed, 28 Aug 2019 18:16:41 +0200 From: Peter Zijlstra To: Tim Chen Cc: Matthew Garrett , Vineeth Remanan Pillai , Nishanth Aravamudan , Julien Desfossez , mingo@kernel.org, tglx@linutronix.de, pjt@google.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, subhra.mazumdar@oracle.com, fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com, Phil Auld , Aaron Lu , Aubrey Li , Valentin Schneider , Mel Gorman , Pawan Gupta , Paolo Bonzini Subject: Re: [RFC PATCH v3 00/16] Core scheduling v3 Message-ID: <20190828161641.GJ2369@hirez.programming.kicks-ass.net> References: <20190827211417.snpwgnhsu5t6u52y@srcf.ucam.org> <20190827215035.GH2332@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 28, 2019 at 08:59:21AM -0700, Tim Chen wrote: > On 8/27/19 2:50 PM, Peter Zijlstra wrote: > > On Tue, Aug 27, 2019 at 10:14:17PM +0100, Matthew Garrett wrote: > >> Apple have provided a sysctl that allows applications to indicate that > >> specific threads should make use of core isolation while allowing > >> the rest of the system to make use of SMT, and browsers (Safari, Firefox > >> and Chrome, at least) are now making use of this. Trying to do something > >> similar using cgroups seems a bit awkward. Would something like this be > >> reasonable? > > > > Sure; like I wrote earlier; I only did the cgroup thing because I was > > lazy and it was the easiest interface to hack on in a hurry. > > > > The rest of the ABI nonsense can 'trivially' be done later; if when we > > decide to actually do this. > > > > And given MDS, I'm still not entirely convinced it all makes sense. If > > it were just L1TF, then yes, but now... > > > > For MDS, core-scheduler does prevent thread to thread > attack between user space threads running on sibling CPU threads. > Yes, it doesn't prevent the user to kernel attack from sibling > which will require additional mitigation measure. However, it does > block a major attack vector for MDS if HT is enabled. I'm not sure what your argument is; the dike has two holes; you plug one, you still drown.