From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754790Ab2AYPsR (ORCPT ); Wed, 25 Jan 2012 10:48:17 -0500 Received: from smtp.ctxuk.citrix.com ([62.200.22.115]:55776 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753727Ab2AYPsQ (ORCPT ); Wed, 25 Jan 2012 10:48:16 -0500 X-IronPort-AV: E=Sophos;i="4.71,568,1320624000"; d="scan'208";a="10285648" Subject: RE: [Xen-devel] Regressions in v3.3-rc1 introduced by "xen/granttable: Grant tables V2 implementation" From: Ian Campbell To: Paul Durrant CC: Konrad Rzeszutek Wilk , "annie.li@oracle.com" , "xen-devel@lists.xensource.com" , "linux-kernel@vger.kernel.org" Date: Wed, 25 Jan 2012 15:47:42 +0000 In-Reply-To: <291EDFCB1E9E224A99088639C4762022C80E2F0F20@LONPMAILBOX01.citrite.net> References: <20120125044949.GB29759@phenom.dumpdata.com> <20120125051253.GA15501@phenom.dumpdata.com> <1327485333.24561.232.camel@zakaz.uk.xensource.com> <291EDFCB1E9E224A99088639C4762022C80E2F0F20@LONPMAILBOX01.citrite.net> Organization: Citrix Systems, Inc. Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.0.3- Content-Transfer-Encoding: 7bit Message-ID: <1327506463.24561.335.camel@zakaz.uk.xensource.com> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2012-01-25 at 15:16 +0000, Paul Durrant wrote: > > -----Original Message----- > > > > On HVM for gnttab_shared we make an add_to_physmap call with > > XENMAPSPACE_grant_table (in gnttab_map). I don't see any support call to > > do something similar for the status array though and I don't see a > > XENMAPSPACE_* specifically for that case either in the hypervisor either. > > > > There is no map-space for the status pages. To map them you use the > standard map space but OR a bit (top bit IIRC) into in the idx. It's a > bit icky, but that's how it is. I can't see that happening anywhere in the current Linux tree, there's only one call to XENMAPSPACE_grant_table and it doesn't set the top bit, so presumably this is at least part of the problem. I hope that "top bit" is consistent for 32 and 64 bit domains.... Ian.