Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933612AbdGKTNn (ORCPT ); Tue, 11 Jul 2017 15:13:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48910 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932483AbdGKTNm (ORCPT ); Tue, 11 Jul 2017 15:13:42 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com F3FC2C04B31C Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=rkrcmar@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com F3FC2C04B31C Date: Tue, 11 Jul 2017 21:13:34 +0200 From: Radim =?utf-8?B?S3LEjW3DocWZ?= To: Bandan Das Cc: Jim Mattson , David Hildenbrand , kvm list , Paolo Bonzini , LKML Subject: Re: [PATCH v4 3/3] KVM: nVMX: Emulate EPTP switching for the L1 hypervisor Message-ID: <20170711191334.GB3442@potion> References: <20170710204936.4001-1-bsd@redhat.com> <20170710204936.4001-4-bsd@redhat.com> <2d50ebc4-9328-ce08-b55b-6a331ee13cc3@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Tue, 11 Jul 2017 19:13:42 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 814 Lines: 20 2017-07-11 14:35-0400, Bandan Das: > Jim Mattson writes: > ... > >>> I can find the definition for an vmexit in case of index >= > >>> VMFUNC_EPTP_ENTRIES, but not for !vmcs12->eptp_list_address in the SDM. > >>> > >>> Can you give me a hint? > >> > >> I don't think there is. Since, we are basically emulating eptp switching > >> for L2, this is a good check to have. > > > > There is nothing wrong with a hypervisor using physical page 0 for > > whatever purpose it likes, including an EPTP list. > > Right, but of all the things, a l1 hypervisor wanting page 0 for a eptp list > address most likely means it forgot to initialize it. Whatever damage it does will > still end up with vmfunc vmexit anyway. Most likely, but not certainly. I also don't see a to diverge from the spec here.