From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Wolf Subject: Re: Re: [PATCH] qemu-xen: Fix PV segfault Date: Thu, 03 Jul 2008 13:05:06 +0200 Message-ID: <486CB262.8070208@suse.de> References: <4863E1F6.60909@suse.de> <18538.27111.959001.890654@mariner.uk.xensource.com> <486B3428.5000006@suse.de> <486B3E88.1020904@redhat.com> <20080702141917.GD23929@totally.trollied.org.uk> <486C876E.8040504@redhat.com> <486C8AF1.6080804@suse.de> <486CB023.3080605@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <486CB023.3080605@redhat.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Gerd Hoffmann Cc: xen-devel@lists.xensource.com, Ian Jackson , John Levon List-Id: xen-devel@lists.xenproject.org Gerd Hoffmann schrieb: > Kevin Wolf wrote: >> Actually, I think Xen PV is a different architecture, not just a >> different PC machine. > > That isn't visible to qemu though as cpu virtualization is handled by > the xen hypervisor. > >> So to be consistent with qemu it would be a >> separate binary like qemu-system-xenpv. > > I wouldn't do it that way for the reason outlined above, but it is an > option, yes. It's not only the CPU virtualization I'm talking about. PV machines also have "hardware" devices completely different from PCs. Just look at pc_init1(), that's all stuff PV machines won't need. Concerning the CPU, I think of it as an architecture which is only usable through an accelerator. Certainly it would be possible to do a normal qemu emulation for this architecture, it just wouldn't make too much sense. >> HVM on the other hand would be more of an accelerator for the existing >> x86 system emulation, just like kqemu or KVM. > > Yep, sort of. And some plumbing for xenbus for guests with pv-on-hvm > drivers installed. > > Glauber Costa is working on a nice abstraction layer for qemu > accelerators btw. Intention is to get kvm upstream merged. It should > also make it easier to get xen hvm support merged upstream. Yes, I'm aware of his patches. That's actually why I used the term "accelerator". Kevin