From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Lqiyz-0003ds-El for qemu-devel@nongnu.org; Mon, 06 Apr 2009 03:11:01 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1Lqiyu-0003dG-AO for qemu-devel@nongnu.org; Mon, 06 Apr 2009 03:11:00 -0400 Received: from [199.232.76.173] (port=40217 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Lqiyu-0003dD-5v for qemu-devel@nongnu.org; Mon, 06 Apr 2009 03:10:56 -0400 Received: from mx20.gnu.org ([199.232.41.8]:59820) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1Lqiyt-0001sH-PL for qemu-devel@nongnu.org; Mon, 06 Apr 2009 03:10:55 -0400 Received: from mx2.redhat.com ([66.187.237.31]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1Lqiyt-0005Vo-6Z for qemu-devel@nongnu.org; Mon, 06 Apr 2009 03:10:55 -0400 Message-ID: <49D9AAFA.606@redhat.com> Date: Mon, 06 Apr 2009 09:10:50 +0200 From: Gerd Hoffmann MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH 00/10] xen: pv domain support. References: <1238621982-18333-1-git-send-email-kraxel@redhat.com> <1238706878.5426.1.camel@Quad> <49D6708D.4000601@redhat.com> <88ADCEFD-E057-4264-8447-9E53A661B35D@suse.de> <49D87044.3030406@redhat.com> <803692EA-B562-4D41-A809-7EF552180B8F@suse.de> In-Reply-To: <803692EA-B562-4D41-A809-7EF552180B8F@suse.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: qemu-devel , xen-devel@lists.xensource.com, Avi Kivity , Laurent Vivier Alexander Graf wrote: > 1) Migration path. If you could already use KVM on a Xen host, you could > have Xen PV guests and KVM guests in parallel, easing migration to KVM > for customers. I still plan to make xenner handle that use case. You can also run xen inside kvm via nested svm. > 2) Alternative to HVM. That's how this came up from Gerd's mail. We do > have KVM support in upstream qemu, but we don't have Xen HVM support. > That way you could use the same binary for all your needs. Admittedly, > it might make more sense to just implement HVM support :-). HVM is more difficuilt. Xen considers the tools <-> hypervisor interface private, i.e. it is a moving target. For PV this isn't a big issue as there is little reason to actually change something. HVM usually has quite a few changes from release to release though, due to emulation changes/improvements and other reasons. cheers, Gerd