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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 55894C2D0EA for ; Wed, 8 Apr 2020 08:38:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1C88B20747 for ; Wed, 8 Apr 2020 08:38:19 +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="Ly7jlU8l" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727356AbgDHIiS (ORCPT ); Wed, 8 Apr 2020 04:38:18 -0400 Received: from merlin.infradead.org ([205.233.59.134]:39386 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725932AbgDHIiS (ORCPT ); Wed, 8 Apr 2020 04:38:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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; bh=ACkspuPIfoQ3/5/zaLoUtXyvTpTXAnBFfLWAYMZ/rzs=; b=Ly7jlU8l1rKqdWtymw+5P8Us5L zj0u5X2Sk/xu4B6bimPchBI9xQJzfL+rp6mT1HAivIcL6kb/bgwF+gaol4/0MhsD6bhwwXwZWfLv+ MHff0X6MDVM7nsWpSujSjZ0YqY+srJPWBn7DBlpedVY+yyliB4WS4aB2mQ/rLVDi9gEFHMqsy5qOq C6bbz6a4sAhvAf0sUsVb1iMXpOKlfF65TVnLZZ1t9uCGPSw8oB9E+1B2eszB7/esrz6PbeENtWt5H DNCQARtypj9TUiug8vb+FI6Jsv819f8UWAttNcyK12wTCIqR+mhK2fNt1MX57cn+BBcDAa4hcc0sP dLsIFGGA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jM6DO-00067X-DJ; Wed, 08 Apr 2020 08:37:42 +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 1586F3025C3; Wed, 8 Apr 2020 10:37:39 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id EEC9B2BA879E0; Wed, 8 Apr 2020 10:37:38 +0200 (CEST) Date: Wed, 8 Apr 2020 10:37:38 +0200 From: Peter Zijlstra To: Paolo Bonzini Cc: Andrew Cooper , Nadav Amit , Thomas Gleixner , LKML , hch@infradead.org, Sean Christopherson , mingo , bp , hpa@zytor.com, x86 , "Kenneth R. Crudup" , Jessica Yu , Rasmus Villemoes , Fenghua Yu , Xiaoyao Li , Thomas Hellstrom , Tony Luck , Steven Rostedt , Greg Kroah-Hartman , jannh@google.com, keescook@chromium.org, David.Laight@aculab.com, Doug Covelli , mhiramat@kernel.org Subject: Re: [PATCH 4/4] x86,module: Detect CRn and DRn manipulation Message-ID: <20200408083738.GO20713@hirez.programming.kicks-ass.net> References: <20200407110236.930134290@infradead.org> <20200407111007.429362016@infradead.org> <10ABBCEE-A74D-4100-99D9-05B4C1758FF6@gmail.com> <20200407193853.GP2452@worktop.programming.kicks-ass.net> <90B32DAE-0BB5-4455-8F73-C43037695E7C@gmail.com> <20200407205042.GT2452@worktop.programming.kicks-ass.net> <96C2F23A-D6F4-4A04-82B6-284788C5D2CC@gmail.com> <04f4fc03-95cd-df2e-e93d-e9c4fa221ae4@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 08, 2020 at 02:22:45AM +0200, Paolo Bonzini wrote: > On 08/04/20 01:15, Andrew Cooper wrote: > >> Anyhow, I do not think it is the only use-case which is not covered by your > >> patches (even considering CRs/DRs alone). For example, there is no kernel > >> function to turn on CR4.VMXE, which is required to run hypervisors on x86. > > How about taking this opportunity to see if there is a way to improve on > > the status quo for co-existing hypervisor modules? > > Almost serious question: why? I can understand VMware, but why can't at > least VirtualBox use KVM on Linux? I am not sure if they are still > running device emulation in ring zero, but if so do you really want to > do that these days? Having had the 'joy' of looking at the virtual-puke^Wbox code recently, nobody with half a hair of sense on their head will want to ever touch that thing again. It's a security nightmare, and that's the best part of it.