From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andres Lagar-Cavilla Subject: Re: Question on save/restore mfn canonicalization Date: Fri, 28 Sep 2007 14:55:01 -0400 Message-ID: <46FD4E05.60600@cs.toronto.edu> References: <46FD2AF8.30107@cs.toronto.edu> <20070928175429.GE17700@totally.trollied.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20070928175429.GE17700@totally.trollied.org.uk> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: John Levon Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Well, when you're in school you don't have to care about breaking ABI's :) So, the answer is then "no particular reason"? Andres John Levon wrote: > On Fri, Sep 28, 2007 at 12:25:28PM -0400, Andres Lagar-Cavilla wrote: > > >> While exploring the paravirt save/restore code path, I noted a >> (seemingly) lack of consistency between where/who canonicalizes >> something and who un-canonicalizes. For example, the guest kernel >> canonicalizes the store and console mfn's in pre_suspend, but >> xc_domain_restore uncanonicalizes them before scheduling back the >> restored guest. >> The question is if there is a mandatory reason for this, or is just the >> way the code was written. Can I, e.g, fill the >> pfn_to_mfn_frame_list(_list) entries from "outside" and remove that code >> from post_suspend, or will something break? >> > > You'll break the ABI. I don't know of a reason why it's so inconsistent. > > regards > john >