From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Nadav Har'El" Subject: Re: [PATCH 07/31] nVMX: Introduce vmcs02: VMCS used to run L2 Date: Fri, 20 May 2011 23:32:11 +0300 Message-ID: <20110520203211.GA5519@fermat.math.technion.ac.il> References: <1305575004-nyh@il.ibm.com> <201105161947.p4GJlUJb001735@rice.haifa.ibm.com> <625BA99ED14B2D499DC4E29D8138F1505C9BEEFE29@shsmsx502.ccr.corp.intel.com> <625BA99ED14B2D499DC4E29D8138F1505C9BEEFE8F@shsmsx502.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "kvm@vger.kernel.org" , "gleb@redhat.com" , "avi@redhat.com" To: "Tian, Kevin" Return-path: Received: from mailgw12.technion.ac.il ([132.68.225.12]:2818 "EHLO mailgw12.technion.ac.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750716Ab1ETUcR (ORCPT ); Fri, 20 May 2011 16:32:17 -0400 Content-Disposition: inline In-Reply-To: <625BA99ED14B2D499DC4E29D8138F1505C9BEEFE8F@shsmsx502.ccr.corp.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, May 20, 2011, Tian, Kevin wrote about "RE: [PATCH 07/31] nVMX: Introduce vmcs02: VMCS used to run L2": > btw, shouldn't you clear recycled VMCS and reset 'cpu' and 'launched' fields? Well, I believe the answer is "no": As far as I understood, a host is allowed to take a VMCS that has been used once to launch a certain guest, and then modify all the VMCS's fields to define a completely different guest, and then VMRESUME it, without doing the regular VMCLEAR/VMLAUNCH, even though it's "a different guest". Is there something wrong in my assumption? Does VMX keep anything constant between successive VMRESUMEs? > Have you tried SMP L2 guest? It "sort of" works, but it *does* appear to still have a bug which I didn't yet have the time to hunt... In one case, for example, an 8-vcpu L2 on an 8-vcpu L1 seemed to work well (e.g., doing parallel make) for about a minute, and then hung with some sort of page fault in the kernel. Nadav. -- Nadav Har'El | Friday, May 20 2011, 17 Iyyar 5771 nyh@math.technion.ac.il |----------------------------------------- Phone +972-523-790466, ICQ 13349191 |Anyone is entitled to their own opinions. http://nadav.harel.org.il |No one is entitled to their own facts.