From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Will KVM support "Xen on KVM" type in nested virtualization ? Date: Sun, 12 Aug 2012 11:52:24 +0300 Message-ID: <50276EC8.4080105@redhat.com> References: <1B4B44D9196EFF41AE41FDA404FC0A1014015E@SHSMSX101.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "kvm@vger.kernel.org" , Marcelo Tosatti To: "Ren, Yongjie" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:19581 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750824Ab2HLIw3 (ORCPT ); Sun, 12 Aug 2012 04:52:29 -0400 In-Reply-To: <1B4B44D9196EFF41AE41FDA404FC0A1014015E@SHSMSX101.ccr.corp.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/11/2012 12:20 PM, Ren, Yongjie wrote: > Hi folks, > I did some basic testing on nested virtualization on Intel x86-64 platform. > Will KVM support Xen as L1 guest in nested virtualization ? > > When I tried "Xen on KVM" mode, I found VMX can't be initialized in L1 Xen hypervisor. > I tried both "-cpu host" and "-cpu qemu64,+vmx" parameters in qemu-kvm command line. > -------some log in 'xl dmesg' command line in L1 Xen --- > (XEN) VMX: CPU0 has insufficent CPU-Based Exec Control (b299868c but requires min 2299968c) > (XEN) VMX: CPU0 has insufficent VMExit Control (00000200 but requires min 00008200) > (XEN) VMX: failed to initialise. > ------more details in the attached "xl-dmesg-L1.log"---- > In Xen source code, I found the following related to the mentioned error. > "xen-unstable.hg/xen/include/asm-x86/hvm/vmx/vmcs.h" > #define CPU_BASED_RDTSC_EXITING 0x00001000 > #define VM_EXIT_ACK_INTR_ON_EXIT 0x00008000 > > Will KVM expose these two features in its vCPU ? Those are two bugs in kvm. The first is trivial to fix, the second is harder. I will take a look. -- error compiling committee.c: too many arguments to function