Received: by 2002:ac0:da4c:0:0:0:0:0 with SMTP id a12csp1972727imi; Sun, 24 Jul 2022 02:57:12 -0700 (PDT) X-Google-Smtp-Source: AGRyM1t9ZS6T6txwKlX0EQbpRSuPkRzERFJ7qgLYzpRKCjJgMGHeFOJkzdi47hfr8SqnCNxq+4bc X-Received: by 2002:a63:f91b:0:b0:40d:d291:1555 with SMTP id h27-20020a63f91b000000b0040dd2911555mr6823009pgi.399.1658656632573; Sun, 24 Jul 2022 02:57:12 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1658656632; cv=none; d=google.com; s=arc-20160816; b=FfkQK4nzF3sFIPLkTcH/O6wXKiAbEK/JTjFBFSXudW1Smg7EkBvPhx0aH/aYLxE6ON yUN9bn/y/Z0KLtL7/e196xnw1jZxKv12zYtP67vu6D6kT/k4zbvQwc8+Zz+ZCg0IFjj6 l52r+ECAuaBvTANFhVhlym7kt8kqK7iM/UuvzDwjfmlGpb8tWewIk1G7m3GPWopEicv3 qzC6MubaBN85NphjQ+QuOhr2M5dvXSM55pMSyGWrNz1kpM4okPUrDAmW6vYTcE4BpMlH f3vl7iVw+cZADOJhBKaR7/dRTe+3pNpNRvLYkLLkdYIPSKQ2iuofiUsrGUpsJ0yODarZ ThXw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:user-agent:references:message-id :in-reply-to:subject:cc:to:from:date; bh=XIVxF9adOnRglAg/uAd7fvuP7AicdZdcS/G/7dP4PFM=; b=vmlyMP7+fwEqqKQPWgsE++a2b3pdFkjD70A3nfaTWKNXik+VDfRsYnYpe5VC4N+8/f WeZEsxBmb5lxuk9jtTQesIDixEV8aLhwOpJbcMGtXEWrwiRal71mIkITAz7UAG3bFvmS 0hcB3ri/c+604D0Ijc75g1lLgxzoqn5xHnepAHRWwxc+38vvL2x8ZaHBzacKvDg9Dw7V LkZ6L5Z+/lXIAmlff/X/Q+B5jySo05iefUyf2qaIXW/Ar66Nac150+ARrMtK344F3OVS B8atwq3Y05vmeXSZDQMn0XVpkoUXOEFJ1s9gl9Cd1AzqcsUIUl0A6zR3eOSKdhFBGZRA VnjA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id t2-20020a170902e84200b0016c4f0fc8dfsi13651488plg.598.2022.07.24.02.56.32; Sun, 24 Jul 2022 02:57:12 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229912AbiGXJZK (ORCPT + 99 others); Sun, 24 Jul 2022 05:25:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229450AbiGXJZJ (ORCPT ); Sun, 24 Jul 2022 05:25:09 -0400 Received: from a3.inai.de (a3.inai.de [IPv6:2a01:4f8:10b:45d8::f5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 798EF27D for ; Sun, 24 Jul 2022 02:25:06 -0700 (PDT) Received: by a3.inai.de (Postfix, from userid 25121) id 92C2D5878347E; Sun, 24 Jul 2022 11:25:04 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by a3.inai.de (Postfix) with ESMTP id 904B760D9DC8C; Sun, 24 Jul 2022 11:25:04 +0200 (CEST) Date: Sun, 24 Jul 2022 11:25:04 +0200 (CEST) From: Jan Engelhardt To: Adam Borowski cc: Greg Kroah-Hartman , Naresh Kamboju , open list , X86 ML , lkft-triage@lists.linaro.org, Borislav Petkov , Pawan Gupta , Peter Zijlstra , Josh Poimboeuf Subject: Re: RETBleed: WARNING: Spectre v2 mitigation leaves CPU vulnerable to RETBleed attacks, data leaks possible! In-Reply-To: Message-ID: <3139s0q2-2o3s-4334-o670-n3p223o34ps9@vanv.qr> References: User-Agent: Alpine 2.25 (LSU 592 2021-09-18) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 2022-07-23 23:50, Adam Borowski wrote: >> > We are booting the i386 kernel on an x86 machine. > >[..] And for quite some tasks, halved word >size (thus ~2/3 memory usage) can overcome register starvation and win >benchmarks. So how many benchmarks does a 32-bit userspace with a 32-bit kernel win over 32-bit userspace with a 64-bit kernel?