From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: KVM is type 1 hypervisor, but... Date: Mon, 29 May 2017 01:13:23 -0700 Message-ID: <20170529081323.GB25630@infradead.org> References: <20170528115100.GA25269@infradead.org> <48902d71-d540-4cd6-b76b-196febf40db6@email.android.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org To: sylvain@chicoree.fr Return-path: Received: from bombadil.infradead.org ([65.50.211.133]:34462 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750947AbdE2INY (ORCPT ); Mon, 29 May 2017 04:13:24 -0400 Content-Disposition: inline In-Reply-To: <48902d71-d540-4cd6-b76b-196febf40db6@email.android.com> Sender: kvm-owner@vger.kernel.org List-ID: I never understood why people cared about it too much, the terms come from a academic paper in the 70s and we're even fully correct back then, and have gotten less an less useful. To make some sense of them it might be better to understand them in terms of use cases rather than implementation, e.g. in terms of KVM someone running a VM or two in addition to a normal desktop Linux (e.g. a kernel developer testing things, or a Windows VM for a certain application) fits into the type 2 model, while a server whos primary purpose is to host VMs it type 1. But with todays cloud or hyperconverged architectures a single host system very often runs VM and actualy workloads (e.g. storage backends or databases) as well. So in my eyes it's a very theoretical concept that doesn't have any practical relevance.