From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Deegan Subject: Re: [PATCH RFC v13 03/20] Introduce pv guest type and has_hvm_container macros Date: Thu, 26 Sep 2013 12:53:59 +0100 Message-ID: <20130926115359.GC54428@ocelot.phlegethon.org> References: <1379955000-11050-1-git-send-email-george.dunlap@eu.citrix.com> <1379955000-11050-4-git-send-email-george.dunlap@eu.citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1379955000-11050-4-git-send-email-george.dunlap@eu.citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: George Dunlap Cc: Keir Fraser , Jan Beulich , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org Hi, At 17:49 +0100 on 23 Sep (1379958583), George Dunlap wrote: > The goal of this patch is to classify conditionals more clearly, as to > whether they relate to pv guests, hvm-only guests, or guests with an > "hvm container" (which will eventually include PVH). - speculative wombling begins - Reading this for the (apparently) 13th time, it strikes me that this distinction feels wrong, like entities are being multiplied beyond necessity. A PVH guest is basically a HVM guest that starts with paging enabled and uses event channel instead of virtual APIC. I'm not sure this needs any special treatment from Xen. We can supply a PVH guest with an APIC and if it never uses it, fine. And we can supply all HVM guests with any extra hypercalls that PVH needs (for vcpu bringup &c). Things like not having a qemu process to serve ioreqs can be arranged by the toolstack. This is from a position of ignorance, of course, and I'm happy to be corrected by the people who've actually been hacking on the code. - normal wombling resumes - Tim.