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=-6.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,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 8494EC433DF for ; Wed, 29 Jul 2020 09:09:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5EA74206D4 for ; Wed, 29 Jul 2020 09:09:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="pmZEnPWo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728068AbgG2JJi (ORCPT ); Wed, 29 Jul 2020 05:09:38 -0400 Received: from smtp-fw-2101.amazon.com ([72.21.196.25]:48659 "EHLO smtp-fw-2101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726299AbgG2JJh (ORCPT ); Wed, 29 Jul 2020 05:09:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1596013777; x=1627549777; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=SciFhlKfOyQgoHR3W2u7HoyEVe3pSryfx/QBiBfKds8=; b=pmZEnPWomMJY0KtcEhkzCIU6S1wsBHtwU2FcLwE5RL/dyAmflqLrGZpj buZtwtLWD+uDJLdYDd1ac6JtjEiCJk0Eck+6RQ88IkdtdHoAO0lENHIRP XADF7GesljeYckuvCb62xv+3jD8zNjj3nSTjYS8w81txPOi6IWjs+EKAc M=; IronPort-SDR: iGhMXsEFZ7rmehllBU/6DXbQhQ9ceJjM/OTGQL0+l9iOw433CMybv2oqS2CGcWtQPX5PXSPwfO aV5zYwDbdVxA== X-IronPort-AV: E=Sophos;i="5.75,409,1589241600"; d="scan'208";a="44709903" Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-1d-37fd6b3d.us-east-1.amazon.com) ([10.43.8.2]) by smtp-border-fw-out-2101.iad2.amazon.com with ESMTP; 29 Jul 2020 09:09:35 +0000 Received: from EX13MTAUWC001.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan3.iad.amazon.com [10.40.159.166]) by email-inbound-relay-1d-37fd6b3d.us-east-1.amazon.com (Postfix) with ESMTPS id 4DA8628392C; Wed, 29 Jul 2020 09:09:31 +0000 (UTC) Received: from EX13D20UWC002.ant.amazon.com (10.43.162.163) by EX13MTAUWC001.ant.amazon.com (10.43.162.135) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 29 Jul 2020 09:09:31 +0000 Received: from 38f9d3867b82.ant.amazon.com (10.43.162.109) by EX13D20UWC002.ant.amazon.com (10.43.162.163) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 29 Jul 2020 09:09:28 +0000 Subject: Re: [PATCH] KVM: x86: Deflect unknown MSR accesses to user space To: Vitaly Kuznetsov , Jim Mattson CC: Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Wanpeng Li , Joerg Roedel , kvm list , , LKML , Aaron Lewis References: <20200728004446.932-1-graf@amazon.com> <87d04gm4ws.fsf@vitty.brq.redhat.com> <87y2n2log7.fsf@vitty.brq.redhat.com> From: Alexander Graf Message-ID: <173948e8-4c7a-6dc4-de17-99151bc56d91@amazon.com> Date: Wed, 29 Jul 2020 11:09:26 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <87y2n2log7.fsf@vitty.brq.redhat.com> Content-Language: en-US X-Originating-IP: [10.43.162.109] X-ClientProxiedBy: EX13D03UWC003.ant.amazon.com (10.43.162.79) To EX13D20UWC002.ant.amazon.com (10.43.162.163) Content-Type: text/plain; charset="windows-1252"; format="flowed" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29.07.20 10:23, Vitaly Kuznetsov wrote: > = > = > = > Jim Mattson writes: > = >> On Tue, Jul 28, 2020 at 5:41 AM Alexander Graf wrote: >>> > = > ... > = >>> While it does feel a bit overengineered, it would solve the problem that >>> we're turning in-KVM handled MSRs into an ABI. >> >> It seems unlikely that userspace is going to know what to do with a >> large number of MSRs. I suspect that a small enumerated list will >> suffice. > = > The list can also be 'wildcarded', i.e. > { > u32 index; > u32 mask; > ... > } > = > to make it really short. I like the idea of wildcards, but I can't quite wrap my head around how = we would implement ignore_msrs in user space with them? Alex Amazon Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B Sitz: Berlin Ust-ID: DE 289 237 879