From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754655Ab2HTL7B (ORCPT ); Mon, 20 Aug 2012 07:59:01 -0400 Received: from smtp.ctxuk.citrix.com ([62.200.22.115]:8537 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754378Ab2HTL66 (ORCPT ); Mon, 20 Aug 2012 07:58:58 -0400 X-IronPort-AV: E=Sophos;i="4.77,796,1336348800"; d="scan'208";a="14083372" Date: Mon, 20 Aug 2012 12:58:37 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Ian Campbell CC: Stefano Stabellini , Konrad Rzeszutek Wilk , "xen-devel@lists.xensource.com" , "linux-kernel@vger.kernel.org" Subject: Re: [Xen-devel] [PATCH 06/11] xen/mmu: For 64-bit do not call xen_map_identity_early In-Reply-To: <1345463624.28762.67.camel@zakaz.uk.xensource.com> Message-ID: References: <1345133009-21941-1-git-send-email-konrad.wilk@oracle.com> <1345133009-21941-7-git-send-email-konrad.wilk@oracle.com> <20120817174549.GA14257@phenom.dumpdata.com> <1345463624.28762.67.camel@zakaz.uk.xensource.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 20 Aug 2012, Ian Campbell wrote: > On Mon, 2012-08-20 at 12:45 +0100, Stefano Stabellini wrote: > > On Fri, 17 Aug 2012, Konrad Rzeszutek Wilk wrote: > > > On Fri, Aug 17, 2012 at 06:41:23PM +0100, Stefano Stabellini wrote: > > > > On Thu, 16 Aug 2012, Konrad Rzeszutek Wilk wrote: > > > > > B/c we do not need it. During the startup the Xen provides > > > > > us with all the memory mapped that we need to function. > > > > > > > > Shouldn't we check to make sure that is actually true (I am thinking at > > > > nr_pt_frames)? > > > > > > I was looking at the source code (hypervisor) to figure it out and > > > that is certainly true. > > > > > > > > > > Or is it actually stated somewhere in the Xen headers? > > > > > > Couldn't find it, but after looking so long at the source code > > > I didn't even bother looking for it. > > > > > > Thought to be honest - I only looked at how the 64-bit pagetables > > > were set up, so I didn't dare to touch the 32-bit. Hence the #ifdef > > > > I think that we need to involve some Xen maintainers and get this > > written down somewhere in the public headers, otherwise we have no > > guarantees that it is going to stay as it is in the next Xen versions. > > > > Maybe we just need to add a couple of lines of comment to > > xen/include/public/xen.h. > > The start of day memory layout for PV guests is written down in the > comment just before struct start_info at > http://xenbits.xen.org/docs/unstable/hypercall/include,public,xen.h.html#Struct_start_info > > (I haven't read this thread to determine if what is documented matches > what you guys are talking about relying on) but it is not written down how much physical memory is going to be mapped in the bootstrap page tables.