From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Tramnitz Subject: Re: pv_ops dom0 kernel and VT cpu extensions Date: Tue, 29 Dec 2009 10:53:38 +0100 Message-ID: References: <4B398B40.3040204@verizon.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4B398B40.3040204@verizon.net> 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.com List-Id: xen-devel@lists.xenproject.org Gerry Reno wrote: > I compiled a pv_ops dom0 kernel from Jeremy's latest git tree and > upgraded Xen to 3.4.1 following one of Boris' blog entries. From the > Xen perspective everything seems to work as expected. But, I want to be > able to run both Xen and KVM existing guests in a single cloud on a farm > of VT-enabled machines. So after booting into the new pv_ops dom0 > kernel as a test I tried starting one of my KVM guests. It ran > extremely slow so I knew immediately that it wasnt' using the VT > acceleration. I then looked at /proc/cpuinfo and saw that the VT cpu > flag (svm on this machine) was not there. The machine has a VT > processor and hardware virtualization is enabled in the BIOS and I > rebooted to check with a regular kernel and it of course the guest runs > with VT acceleration there. > My question is how can I get pv_ops dom0 kernel or Xen 3.4.1 to pass the > cpu VT flags through so that existing KVM guests will run with cpu VT > acceleration at full speed? > You need to start the pvops kernel on bare metal (without Xen) to make use of VT. dom0 is already a (privileged) guest (of Xen), so the hardware assisted virtualization interface is simply not accessible at this point anymore... Best regards, Christian