From mboxrd@z Thu Jan 1 00:00:00 1970 From: "lim4@mymail.vcu.edu" Subject: Ring privilege of host linux kernel Date: Thu, 07 Mar 2013 22:56:34 -0500 Message-ID: <51396172.70905@mymail.vcu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from mail-qa0-f52.google.com ([209.85.216.52]:45529 "EHLO mail-qa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756126Ab3CHD4j (ORCPT ); Thu, 7 Mar 2013 22:56:39 -0500 Received: by mail-qa0-f52.google.com with SMTP id bs12so763377qab.4 for ; Thu, 07 Mar 2013 19:56:38 -0800 (PST) Sender: kvm-owner@vger.kernel.org List-ID: 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? Maybe my thoughts about KVM privilege ring is not correct. :-) Please give me some comments and I will really appreciate for your help. Thank you, Best Regards, Min Li