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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADF22C04FDF for ; Mon, 14 Aug 2023 12:38:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229959AbjHNMhh (ORCPT ); Mon, 14 Aug 2023 08:37:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57632 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230063AbjHNMhW (ORCPT ); Mon, 14 Aug 2023 08:37:22 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D203E4A for ; Mon, 14 Aug 2023 05:37:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=VmbUR9tUP0TcTP+lPR92EBnfGUDP6/2qUwJVhdNUHNs=; b=rHFIPdQCNKT6dKcmT7hnfDKxtb sPjTomS5yXHNPdbBfSsv5p8eanIcFFMpdZq7KX3YDJ59RXoZnrzTIGxaMA9ANElpW8vXRKMlIVoAa XbOhpWp3ahvz2WGghZT8eOGC9Q+8Jj/rmIddaEoVUAa9ZlU+mmDKWxqCJ/VEc3VB9X6FxdoxVUrqF ELBfU9SvyTd5PxUEyJfLDlIFys74+ljtqn/vSPAe6iZPSMMBkoQjr6iFyBZbK1F1656opUQ+YQqBa uo9QnijZnqZsDjDKt3a2FDlh6448YhQiXYhToSI8in7gOdWOVL2tNDbGKLRMB9stgVdCYuZZTzChu 2Ep/8muA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qVWor-00Aac3-2R; Mon, 14 Aug 2023 12:37:14 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 6946F300137; Mon, 14 Aug 2023 14:37:13 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 51F0420C1700F; Mon, 14 Aug 2023 14:37:13 +0200 (CEST) Date: Mon, 14 Aug 2023 14:37:13 +0200 From: Peter Zijlstra To: Mikhail Gavrilov Cc: Borislav Petkov , Linux List Kernel Mailing , x86@kernel.org Subject: Re: [regression/bisected] Add IBPB decreases performance in two times Message-ID: <20230814123713.GI776869@hirez.programming.kicks-ass.net> References: <20230813082413.GAZNiTLaOxUNUHPvlf@fat_crate.local> <20230813093502.GBZNijxgueFxBTxWwG@fat_crate.local> <20230813111425.GEZNi7EXyHOLQTNzFg@fat_crate.local> <20230813141945.GFZNjmgZbHvMhLYtJl@fat_crate.local> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 14, 2023 at 03:30:51AM +0500, Mikhail Gavrilov wrote: > On Sun, Aug 13, 2023 at 7:19 PM Borislav Petkov wrote: > > Nah, most people search the net and usually find the documentation, as > > past experience shows. In this case, they will find: > > > > https://kernel.org/doc/html/latest/admin-guide/hw-vuln/srso.html > > > > It will be there next week but here's the source: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/admin-guide/hw-vuln/srso.rst > > > > -- > > Regards/Gruss, > > Boris. > > > > https://people.kernel.org/tglx/notes-about-netiquette > > I am figure out why I noticed lage impact of safe RET on my system. > safe-ret + KASAN = decrease performance for 50% in all scenarios > I use KASAN on a daily basis to catch bugs. > Is it possible for systems with KASAN to make a more optimal approach of SRSO? Why do you care about speculation things on a dev box?