From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: Ring privilege of host linux kernel Date: Fri, 8 Mar 2013 13:42:41 +0200 Message-ID: <20130308114241.GG24444@redhat.com> References: <51396172.70905@mymail.vcu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org To: "lim4@mymail.vcu.edu" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:26544 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752522Ab3CHLmn (ORCPT ); Fri, 8 Mar 2013 06:42:43 -0500 Content-Disposition: inline In-Reply-To: <51396172.70905@mymail.vcu.edu> Sender: kvm-owner@vger.kernel.org List-ID: 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.