From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Deegan Subject: Re: [PATCH 00/11] Alternate p2m: support multiple copies of host p2m Date: Sat, 17 Jan 2015 10:31:47 +0100 Message-ID: <20150117093147.GA35432@deinos.phlegethon.org> References: <1420838801-11704-1-git-send-email-edmund.h.white@intel.com> <20150115161519.GA57240@deinos.phlegethon.org> <54B805B0.8090604@intel.com> <20150116183306.GJ48064@deinos.phlegethon.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20150116183306.GJ48064@deinos.phlegethon.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ed White Cc: ian.jackson@eu.citrix.com, keir@xen.org, ian.campbell@citrix.com, jbeulich@suse.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org Hi, At 19:33 +0100 on 16 Jan (1421433186), Tim Deegan wrote: > > > - Feature compatibilty/completeness. You pointed out yourself that > > > it doesn't work with nested HVM or migration. I think I'd have to > > > add mem_event/access/paging and PCI passthrough to the list of > > > features that ought to still work. I'm resigned to the idea that > > > many new features don't work with shadow pagetables. :) > > > > > > > The intention is that mem_event/access should still work. I haven't > > specifically looked at paging, but I don't see any fundamental reason > > why it shouldn't. PCI passthrough I suspect won't. Does nested HVM > > work with migration? Is it simply not acceptable to submit a feature > > as experimental, with known compatibility issues? I had assumed that > > it was, based on the nested HVM status as documented in the release > > notes. > > Potentially, yes, if we have reasonable confidence that you (or > someone else) will work towards fixing those things. If you can't > make promises yourself, perhaps you can talk to someone who can. It occurs to me that I should make the distinction between migration and passthrough, which are first-class features, and the others, which are 'preview'. So migration and passthrough are hard requirements, and the others should have a bit more room for negotiation. Our process around all this is far from clear, which I can see must be frustrating to work with. I wonder whether we can make some clearer guidelines. Tim.