From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Nadav Har'El" Subject: Re: drop -enable-nesting Date: Mon, 30 May 2011 18:16:23 +0300 Message-ID: <20110530151623.GA3630@fermat.math.technion.ac.il> References: <4DDAD5CF.5050805@redhat.com> <4DE0B4B1.1000407@web.de> <20110530081847.GC27062@amd.com> <4DE3A3EC.80201@siemens.com> <20110530143846.GA2957@fermat.math.technion.ac.il> <4DE3B1E2.7020006@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Roedel, Joerg" , john cooper , "qemu-devel@nongnu.org" , Anthony Liguori , kvm To: Jan Kiszka Return-path: Received: from mailgw12.technion.ac.il ([132.68.225.12]:4811 "EHLO mailgw12.technion.ac.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755385Ab1E3PQZ (ORCPT ); Mon, 30 May 2011 11:16:25 -0400 Content-Disposition: inline In-Reply-To: <4DE3B1E2.7020006@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, May 30, 2011, Jan Kiszka wrote about "Re: drop -enable-nesting": > > "-enable-nesting" could remain as a synonym for enabling either VMX or SVM > > in the guest, depending on what was available in the host (because KVM now > > supports both nested SVM and nested VMX, but not SVM-on-VMX or vice versa). > > Why? Once nesting is stable (I think SVM already is), there is no reason > for an explicit enable. And you can always mask it out via -cpu. As far as I understand (and this was previously discussed on the QEMU mailing list), the default emulated CPU does not include the "vmx" capability, and you need to enable it with something like "-cpu qemu64,+vmx" (or "-cpu host"). I am not sure if it does enable the "svm" capability. If it does, it isn't useful when KVM is enabled and the underlying host has VMX, not SVM. Nadav. -- Nadav Har'El | Monday, May 30 2011, 27 Iyyar 5771 nyh@math.technion.ac.il |----------------------------------------- Phone +972-523-790466, ICQ 13349191 |Why do we drive on a parkway and park on http://nadav.harel.org.il |a driveway?