Received: by 2002:ad5:474a:0:0:0:0:0 with SMTP id i10csp2414282imu; Wed, 21 Nov 2018 11:14:39 -0800 (PST) X-Google-Smtp-Source: AJdET5flaxzCF5U/5F7ILimHngCwGxUa3LFgjfSjKOn4TXFUJ0VwhWFyQTEuT8CdjC6zmiUzzg1h X-Received: by 2002:a62:c42:: with SMTP id u63-v6mr8218220pfi.43.1542827678955; Wed, 21 Nov 2018 11:14:38 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1542827678; cv=none; d=google.com; s=arc-20160816; b=T23C2zmqOU29y2yfqxWylbCWAel3CG3YLdXn5gX43DwinZIDQ0GI5Tezz1DP0AE+DU +jZj13caYFb7cIdLSo0Xfeancfmmhn444oZySgi/nqBdhby5pUrM/MSdkSPxuSEALyz7 GGXo7hC79Fi6NTVqB2xqo5E+/VOuKfgvhmHxT/1QSFg4l95l8qjuomhAJQ4OgLBHL5lx s0zXS8ud4U8hdialhbN7/45x926GAbEpY+S6a3+HgzD6mF3Z3jJ81Qajul2EM7EnxU+6 xLQbho5bwTtsM1/wD+g3jE+SFK/WBnsn9urflgObzsL1Ucj2u/nxAyjMWeEBYfi0Vdk8 N/zw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:mime-version:user-agent:references :message-id:in-reply-to:subject:cc:to:from:date; bh=VelHHWzNErymvUnmf71ESKxaja0SepTZbjAgrg7lc4I=; b=R8yon5MrYMrzziMMD/1T7YKE+KBGJ+SGaVMygmyTRxaWUrBbN0hYlogtwCobAc9PqT ip2lZhLiF1gkZ5z9N2zHSFGoI4BNQCWqB8m6fuclR6t2HPHNFTPqRD4EFclvxbF0SYze IrheqgmZ3iGGVswxm67J5GlBZUUZy4J+dcBlqtls/H4ggpWRnNw6L6yRB8B3WeeVKSln qCVoL3U9fWu5DKV2xfjGmvpJ1lF2uKBKIufaFgnnbAUpDWM0SxsZrmGy/I/NVqxo+J3e lRr6Bttrv11odasF4A62IRGrlXcONkS0tnta5429ejyZI28MneH1+ELMs2GxxCOcqGdy oqcg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id b7si10436802plk.206.2018.11.21.11.14.24; Wed, 21 Nov 2018 11:14:38 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733101AbeKVE5A (ORCPT + 99 others); Wed, 21 Nov 2018 23:57:00 -0500 Received: from mx2.suse.de ([195.135.220.15]:55132 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729128AbeKVE5A (ORCPT ); Wed, 21 Nov 2018 23:57:00 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 4A76AB0AF; Wed, 21 Nov 2018 18:21:33 +0000 (UTC) Date: Wed, 21 Nov 2018 19:21:31 +0100 (CET) From: Jiri Kosina To: Tim Chen cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Thomas Gleixner , Peter Zijlstra , Josh Poimboeuf , Andrea Arcangeli , WoodhouseDavid , Andi Kleen , SchauflerCasey , Dave Stewart Subject: Re: [PATCH 4.19 041/361] x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation In-Reply-To: <41234d20-294f-d0f4-336c-64bf9fcb92a7@linux.intel.com> Message-ID: References: <20181111221619.915519183@linuxfoundation.org> <20181111221625.598298393@linuxfoundation.org> <20181121135611.GA26411@kroah.com> <41234d20-294f-d0f4-336c-64bf9fcb92a7@linux.intel.com> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 21 Nov 2018, Tim Chen wrote: > > Is it reverted in Linus's tree? If not, then anything that comes "later > > on" will not apply here, right? > > > > I see the thread asking about this, but I got really conflicting > > messages here, and now it's in all of the latest releases, and no > > testing seems to have uncovered issues. Is it just a "slow down" > > problem? > > Greg, > > It could be a big slow down in excess of 20% for some applications. > And cross sibling Spectre v2 attack is quite hard to pull off. > > So till we have the accompanying patchset that only apply STIBP on processes > that really need it instead of universally, it should be withheld from > stable. Agreed; it will be trivially reintroduced with the rest, once it's ready. It's being built on top of that patch. Thanks, -- Jiri Kosina SUSE Labs