Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752745Ab0LVIx5 (ORCPT ); Wed, 22 Dec 2010 03:53:57 -0500 Received: from smtp.citrix.com ([66.165.176.89]:62248 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751868Ab0LVIx4 (ORCPT ); Wed, 22 Dec 2010 03:53:56 -0500 X-IronPort-AV: E=Sophos;i="4.60,212,1291611600"; d="scan'208";a="11652601" Subject: Re: [Xen-devel] [PATCH 03/10] xen/mmu: Add the notion of IDENTITY_P2M_ENTRY. From: Ian Campbell To: Konrad Rzeszutek Wilk CC: "linux-kernel@vger.kernel.org" , "jeremy@goop.org" , "hpa@zytor.com" , Konrad Rzeszutek Wilk , "xen-devel@lists.xensource.com" , Jan Beulich In-Reply-To: <1292967460-15709-4-git-send-email-konrad.wilk@oracle.com> References: <1292967460-15709-1-git-send-email-konrad.wilk@oracle.com> <1292967460-15709-4-git-send-email-konrad.wilk@oracle.com> Content-Type: text/plain; charset="ISO-8859-1" Organization: Citrix Systems, Inc. Date: Wed, 22 Dec 2010 08:44:19 +0000 Message-ID: <1293007459.3998.33.camel@localhost.localdomain> MIME-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 980 Lines: 25 On Tue, 2010-12-21 at 21:37 +0000, Konrad Rzeszutek Wilk wrote: > P.S. > We cannot set the IDENTITY_P2M_ENTRY in the P2M tree. This is b/c > the toolstack considers that invalid and would abort during > migration of the PV guest. What do we do instead, just write the actual identity MFN value? Does using 1UL<<30 (or 1UL<<62 on 64 bit, note that Jeremy recently fixed FOREIGN_FRAME_BIT too) as IDENTITY_P2M_ENTRY keep the toolstack happy while still allowing us to distinguish from identity from happens-to-be-the-same as necessary? To some extent 1-1 I/O regions could be considered foreign mappings (of "memory" owned by DOMIO) so perhaps it's possible that setting the FOREIGN_FRAME_BIT is both sufficient and correct? Ian. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/