Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756090Ab1EQRuA (ORCPT ); Tue, 17 May 2011 13:50:00 -0400 Received: from smtp.ctxuk.citrix.com ([62.200.22.115]:41321 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755912Ab1EQRt7 (ORCPT ); Tue, 17 May 2011 13:49:59 -0400 X-IronPort-AV: E=Sophos;i="4.65,226,1304294400"; d="scan'208";a="5807648" Date: Tue, 17 May 2011 18:51:58 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball-desktop To: "H. Peter Anvin" CC: Konrad Rzeszutek Wilk , Stefano Stabellini , "yinghai@kernel.org" , "jeremy@goop.org" , "hpa@zytor.com" , Ian Campbell , Keir Fraser , "linux-kernel@vger.kernel.org" , "xen-devel@lists.xensource.com" Subject: Re: Xen MMU's requirement to pin pages RO and initial_memory_mapping. In-Reply-To: <4DD19D1F.3070506@linux.intel.com> Message-ID: References: <20110513153010.GB16519@dumpdata.com> <20110516154132.GA12486@dumpdata.com> <4DD19D1F.3070506@linux.intel.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) 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 Content-Length: 1284 Lines: 32 CC'ing Keir in case he knows something I am missing. On Mon, 16 May 2011, H. Peter Anvin wrote: > On 05/16/2011 08:41 AM, Konrad Rzeszutek Wilk wrote: > >> They become pagetable pages when: > >> > >> - they are explicitly pinned by pin_pagetable_pfn > >> > >> - they are hooked into the current pagetable > > > > Ok, so could we use those two calls to trigger the pagetable walk > > and mark them RO as appropiate? Which call sites are those? The > > xen_set_pgd/xen_set_pud/xen_set_pmd ? Presumarily we don't have > > to do that for the PTE's that are already mapped (as > > xen_setup_kernel_pagetable, and xen_map_identity_early do this > > already). > > > >> Like you wrote, considering that the x86_64 version of > >> kernel_physical_mapping_init hooks the pagetable pages into the > >> currently used pagetable, it wouldn't be possible to mark the pagetable > >> pages RO after init_memory_mapping. > > > > Doesn't Xen have some kind of compatibility mode which could be used > during setup? Unfortunately not that I am aware. -- 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/