From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH 0/30] nVMX: Nested VMX, v9 Date: Mon, 23 May 2011 16:58:55 +0200 Message-ID: <20110523145855.GF23407@8bytes.org> References: <20110512163115.GA13138@fermat.math.technion.ac.il> <20110512165157.GC20193@redhat.com> <20110522193239.GA13130@fermat.math.technion.ac.il> <4DDA2E72.8070907@redhat.com> <20110523130226.GC23407@8bytes.org> <4DDA5C30.10107@redhat.com> <20110523134052.GD23407@8bytes.org> <4DDA66AF.7020505@redhat.com> <20110523142846.GE23407@8bytes.org> <4DDA706C.1000200@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Nadav Har'El , Gleb Natapov , kvm@vger.kernel.org, abelg@il.ibm.com To: Avi Kivity Return-path: Received: from 8bytes.org ([88.198.83.132]:58231 "EHLO 8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755333Ab1EWO64 (ORCPT ); Mon, 23 May 2011 10:58:56 -0400 Content-Disposition: inline In-Reply-To: <4DDA706C.1000200@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, May 23, 2011 at 05:34:20PM +0300, Avi Kivity wrote: > On 05/23/2011 05:28 PM, Joerg Roedel wrote: >> To user-space we can provide a VCPU_FREEZE/VCPU_UNFREEZE ioctl which >> does all the necessary things. > > Or we can automatically flush things on any exit to userspace. They > should be very rare in guest mode. This would make nesting mostly transparent to migration, so it sounds good in this regard. I do not completly agree that user-space exits in guest-mode are rare, this depends on the hypervisor in the L1. In Hyper-V for example the root-domain uses hardware virtualization too and has direct access to devices (at least to some degree). IOIO is not intercepted in the root-domain, for example. Not sure about the MMIO regions. Joerg