Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756267Ab3GaNSJ (ORCPT ); Wed, 31 Jul 2013 09:18:09 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:36759 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751310Ab3GaNSH (ORCPT ); Wed, 31 Jul 2013 09:18:07 -0400 Date: Wed, 31 Jul 2013 09:17:57 -0400 From: Konrad Rzeszutek Wilk To: "H. Peter Anvin" Cc: Mike Rapoport , Rusty Russell , Ramkumar Ramachandra , LKML Subject: Re: [QUERY] lguest64 Message-ID: <20130731131757.GB22124@phenom.dumpdata.com> References: <51E97779.3020103@zytor.com> <87zjte9iah.fsf@rustcorp.com.au> <51F9005F.30501@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51F9005F.30501@zytor.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2024 Lines: 47 On Wed, Jul 31, 2013 at 05:17:35AM -0700, H. Peter Anvin wrote: > On 07/31/2013 02:39 AM, Mike Rapoport wrote: > > > > The use case I had in mind is to use lguest as a nested hypervisor in > > public clouds. As of today, major public clouds do not support nested > > virtualization and it's not clear at all if they will expose this > > ability in their deployments. Addition of 64-bit support for lguest > > won't require changes to pvops and, as far as I can tell, won't change > > the number of pvops users... > > > > "We can add a pvops user and that won't change the number of pvops > users" What?! > > >> Yes, the subset of x86-64 machines for which there isn't hardware > >> virtualization support is pretty uninteresting. > > > > There are plenty virtual machines in EC2, Rackspace, HP and other > > clouds that do not have hardware virtualization. I believe that > > running a hypervisor on them may be pretty interesting. > > The big problem with pvops is that they are a permanent tax on future > development -- a classic case of "the hooks problem." As such it is > important that there be a real, significant, use case with enough users > to make the pain worthwhile. With Xen looking at sunsetting PV support > with a long horizon, it might currently be possible to remove pvops some PV MMU parts specifically. > time in the early 2020s or so timeframe. Introducing and promoting a > new user now would definitely make that impossible. > > So it matters that the use case be real. > > -hpa > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/