From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758782AbYFPWCp (ORCPT ); Mon, 16 Jun 2008 18:02:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756136AbYFPWCg (ORCPT ); Mon, 16 Jun 2008 18:02:36 -0400 Received: from gw.goop.org ([64.81.55.164]:38904 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756125AbYFPWCf (ORCPT ); Mon, 16 Jun 2008 18:02:35 -0400 Message-ID: <4856E2D1.6000307@goop.org> Date: Mon, 16 Jun 2008 15:01:53 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: the arch/x86 maintainers CC: Linux Kernel Mailing List , Stable Kernel Subject: [PATCH 1/2] xen: mask unwanted pte bits in __supported_pte_mask X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Rather than ad-hoc masking unwanted bits when constructing a pte, just prevent them from ever being set by removing them from __supported_pte_mask. [ Stable: this isn't a bugfix in itself, but it's a pre-requiste for "xen: don't drop NX bit" ] Signed-off-by: Jeremy Fitzhardinge Cc: Stable Kernel --- arch/x86/xen/enlighten.c | 5 +++++ arch/x86/xen/mmu.c | 4 +--- 2 files changed, 6 insertions(+), 3 deletions(-) =================================================================== --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1294,6 +1294,11 @@ if (xen_feature(XENFEAT_supervisor_mode_kernel)) pv_info.kernel_rpl = 0; + /* Prevent unwanted bits from being set in PTEs. */ + __supported_pte_mask &= ~_PAGE_GLOBAL; + if (!is_initial_xendomain()) + __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD); + /* set the limit of our address space */ xen_reserve_top(); =================================================================== --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -375,10 +375,8 @@ pte_t xen_make_pte(pteval_t pte) { - if (pte & _PAGE_PRESENT) { + if (pte & _PAGE_PRESENT) pte = phys_to_machine(XPADDR(pte)).maddr; - pte &= ~(_PAGE_PCD | _PAGE_PWT); - } return (pte_t){ .pte = pte }; }