Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753552Ab0LUW3e (ORCPT ); Tue, 21 Dec 2010 17:29:34 -0500 Received: from claw.goop.org ([74.207.240.146]:45466 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752391Ab0LUW3d (ORCPT ); Tue, 21 Dec 2010 17:29:33 -0500 Message-ID: <4D112A4B.5000503@goop.org> Date: Tue, 21 Dec 2010 14:29:31 -0800 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Lightning/1.0b3pre Thunderbird/3.1.7 MIME-Version: 1.0 To: Konrad Rzeszutek Wilk CC: linux-kernel@vger.kernel.org, hpa@zytor.com, Jan Beulich , xen-devel@lists.xensource.com, Konrad Rzeszutek Wilk Subject: Re: [PATCH 04/10] xen/mmu: For 1-1 mapping, automatically set _PAGE_IOMAP. References: <1292967460-15709-1-git-send-email-konrad.wilk@oracle.com> <1292967460-15709-5-git-send-email-konrad.wilk@oracle.com> In-Reply-To: <1292967460-15709-5-git-send-email-konrad.wilk@oracle.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1212 Lines: 34 On 12/21/2010 01:37 PM, Konrad Rzeszutek Wilk wrote: > This means that for PFNs (specifically: those in any E820 gaps > or non-RAM E820 regions) that have 1-1 mapping we set the > _PAGE_IOMAP flag. > > Later on we could remove the _PAGE_IOMAP code handling, but > for right now lets keep this in to not introduce any bisection > failures across this patchset. > > Signed-off-by: Konrad Rzeszutek Wilk > --- > arch/x86/xen/mmu.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c > index 4ba7e4e..bd02e7d 100644 > --- a/arch/x86/xen/mmu.c > +++ b/arch/x86/xen/mmu.c > @@ -832,6 +832,9 @@ static pteval_t pte_pfn_to_mfn(pteval_t val) > pteval_t flags = val & PTE_FLAGS_MASK; > unsigned long mfn = pfn_to_mfn(pfn); > > + if (mfn == pfn) > + flags |= _PAGE_IOMAP; Why? Does it really make sense to set _PAGE_IOMAP if they just happen to be the same value? J -- 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/