From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751997Ab2G0KRq (ORCPT ); Fri, 27 Jul 2012 06:17:46 -0400 Received: from nat28.tlf.novell.com ([130.57.49.28]:44177 "EHLO nat28.tlf.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751363Ab2G0KRo convert rfc822-to-8bit (ORCPT ); Fri, 27 Jul 2012 06:17:44 -0400 Message-Id: <501286E50200007800090ECB@nat28.tlf.novell.com> X-Mailer: Novell GroupWise Internet Agent 12.0.0 Date: Fri, 27 Jul 2012 11:17:41 +0100 From: "Jan Beulich" To: "Ian Campbell" Cc: "Ian Jackson" , "xen-devel" , "Konrad Rzeszutek Wilk" , "linux-kernel@vger.kernel.org" Subject: Re: [Xen-devel] [RFC PATCH] Boot PV guests with more than 128GB (v1) for 3.7 References: <1343335652-5659-1-git-send-email-konrad.wilk@oracle.com> <501260980200007800090E08@nat28.tlf.novell.com> <1343383205.6812.137.camel@zakaz.uk.xensource.com> In-Reply-To: <1343383205.6812.137.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> On 27.07.12 at 12:00, Ian Campbell wrote: > On Fri, 2012-07-27 at 08:34 +0100, Jan Beulich wrote: >> >>> On 26.07.12 at 22:47, Konrad Rzeszutek Wilk wrote: >> > 2). Allocate a new array, copy the existing P2M into it, >> > revector the P2M tree to use that, and return the old >> > P2M to the memory allocate. This has the advantage that >> > it sets the stage for using XEN_ELF_NOTE_INIT_P2M >> > feature. That feature allows us to set the exact virtual >> > address space we want for the P2M - and allows us to >> > boot as initial domain on large machines. >> >> And I would hope that the tools would get updated to recognize >> this note too, so that huge DomU-s would become possible as >> well. > > Does this help us with >160GB 32 bit PV guests too? I'm guessing not > since the real limitation there is the relatively small amount of kernel > address space. Correct - 32-bit PV guests are limited anyway (and it's for a reason the Dom0 support in the hypervisor only deals with 64-bit ones). And honestly, considering the huge page information table such a memory amount would require, I doubt this big a PV guest would even boot (or if it does, be of any use). Jan