From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guillaume Thouvenin Subject: VMX disabled by Feature Control MSR Date: Wed, 14 Jun 2006 13:45:49 +0200 Message-ID: <20060614134549.2b6e965d@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.comxen-devel@lists.xensource.com Cc: LAURENT VIVIER , JEAN-PIERRE DION List-Id: xen-devel@lists.xenproject.org Hello, I already posted a message about this problem on this mailing list but I went more deeply in the analysis of the problem and I'd like to have your opinion. The problem is: I have a processor (pentium D) that supports the VT technology but when I boot Xen I have the following message: (XEN) VMX disabled by Feature Control MSR. Here is how I understand that. Xen is using the CPUID instruction to identify the processor functionality. This is done in arch/x86/hvm/vmx/vmx.c:start_vmx(). As VMXON is controlled by the IA32_FEATURE_CONTROL we must test the lock bit (bit0) and the bit2. I found in the intel documentation that if the bit2 is clear, VMXON causes a general-protection exeption. In our case, we stop the start_vmx() function and display the message VMX disabled by feature control MSR. Thus my question is: What to do to set the bit 2 of the IA32_FEATURE_CONTROL to 1? Is it only possible by using the option in the BIOS menu (and it's not present in mine) or is it possible to set it to 1 before switching in protected mode when Xen is booting. For exemple somwhere in arch/x86/boot/x86_64.S? Thanks for your help, Guillaume