From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f177.google.com ([209.85.220.177]:32827 "EHLO mail-qk0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751344AbeDEKPF (ORCPT ); Thu, 5 Apr 2018 06:15:05 -0400 Received: by mail-qk0-f177.google.com with SMTP id d206so25703200qkb.0 for ; Thu, 05 Apr 2018 03:15:05 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20180404142702.GA20460@kroah.com> <20180404144644.GA22656@kroah.com> <20180404154201.GA31981@kroah.com> <9cd0be43-6380-f5a0-0427-7f75fca966a9@suse.com> <20180405063314.GC5431@kroah.com> <20180405071448.GA9183@kroah.com> From: George Dunlap Date: Thu, 5 Apr 2018 11:15:04 +0100 Message-ID: Subject: Re: [Xen-devel] Patches for stable To: Juergen Gross Cc: Greg KH , xen-devel , Boris Ostrovsky , stable Content-Type: text/plain; charset="UTF-8" Sender: stable-owner@vger.kernel.org List-ID: On Thu, Apr 5, 2018 at 11:06 AM, George Dunlap wrote: > The fact is, that as it stands, a user could have a perfectly working > system with Xen 4.10 and a load of PVH guests running stock Linux > 4.15, and then upgrade to Xen 4.11 and have all those guests break for > no apparent reason. That's a pretty obnoxious thing to do, > particularly as we made such a fanfare about Xen 4.10 finally having > PVH support, and encouraging everyone to go and use it. How are all > of those users going to feel about Xen? I mean, imagine a cloud provider that's managed to get a bunch of *customers* using PVH, because it's more secure than either PV or HVM (fewer hypercalls and no device emulation). Then she upgrades to Xen 4.11, and suddenly all the guests break on reboot! Worse yet, the only way to fix it is to have the customers either boot into classic PV mode or HVM mode in order to actually get an updated kernel! That's a real jerk move to pull on the early adopters who are so critical for widespread adoption and feedback. -George