Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756809Ab1EPVyn (ORCPT ); Mon, 16 May 2011 17:54:43 -0400 Received: from mga02.intel.com ([134.134.136.20]:43979 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756422Ab1EPVym (ORCPT ); Mon, 16 May 2011 17:54:42 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.65,221,1304319600"; d="scan'208";a="643473787" Message-ID: <4DD19D1F.3070506@linux.intel.com> Date: Mon, 16 May 2011 14:54:39 -0700 From: "H. Peter Anvin" Organization: Intel Open Source Technology Center User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc14 Thunderbird/3.1.10 MIME-Version: 1.0 To: Konrad Rzeszutek Wilk CC: Stefano Stabellini , "yinghai@kernel.org" , "jeremy@goop.org" , "hpa@zytor.com" , Ian Campbell , "linux-kernel@vger.kernel.org" , "xen-devel@lists.xensource.com" Subject: Re: Xen MMU's requirement to pin pages RO and initial_memory_mapping. References: <20110513153010.GB16519@dumpdata.com> <20110516154132.GA12486@dumpdata.com> In-Reply-To: <20110516154132.GA12486@dumpdata.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1114 Lines: 30 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? -hpa -- 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/