From mboxrd@z Thu Jan 1 00:00:00 1970 From: Min Li Subject: Re: Ring privilege of host linux kernel Date: Fri, 08 Mar 2013 09:27:04 -0500 Message-ID: <5139F538.1040504@vcu.edu> References: <51396172.70905@mymail.vcu.edu> <20130308114241.GG24444@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "lim4@mymail.vcu.edu" , kvm@vger.kernel.org, lim4@vcu.edu To: Gleb Natapov Return-path: Received: from mail-qe0-f42.google.com ([209.85.128.42]:49424 "EHLO mail-qe0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932413Ab3CHO1L (ORCPT ); Fri, 8 Mar 2013 09:27:11 -0500 Received: by mail-qe0-f42.google.com with SMTP id f6so1006825qej.15 for ; Fri, 08 Mar 2013 06:27:10 -0800 (PST) In-Reply-To: <20130308114241.GG24444@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 03/08/2013 06:42 AM, Gleb Natapov wrote: > On Thu, Mar 07, 2013 at 10:56:34PM -0500, lim4@mymail.vcu.edu wrote: >> As we have known, in KVM full virtualization, guest VM is running in >> non-root mode and KVM is running in root mode. While, in non-root >> mode, guest kernel is running in Ring 0 and Apps are running in Ring >> 3. However, what about the ring privilege for host linux? >> >> In my knowledge, host linux is not controlled by VMX instructions >> and VMCS/VMCB. therefore, host linux should be running in root mode. >> Before we install KVM, host linux just run in Ring 0 (at that time, >> there is no root mode or non-root mode because VMX is not active). >> Hence, after we install KVM module, host linux kernel should be >> still in Ring 0 of root mode and Apps in host should run in Ring 3 >> of root mode. Is KVM running in higher privileged mode like Ring -1 >> of root mode or also running in Ring 0 of root mode? >> > KVM and the Linux kernel are running in Ring 0 in root mode. > > -- > Gleb. Hi, Gleb Really appreciate for your answer because this question has confused me for several days. Best, Min