Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753704Ab0LUWid (ORCPT ); Tue, 21 Dec 2010 17:38:33 -0500 Received: from claw.goop.org ([74.207.240.146]:33657 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752862Ab0LUWic (ORCPT ); Tue, 21 Dec 2010 17:38:32 -0500 Message-ID: <4D112C66.9040600@goop.org> Date: Tue, 21 Dec 2010 14:38:30 -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 08/10] xen/mmu: Bugfix. Fill the top entry page with appropriate middle layer pointers. References: <1292967460-15709-1-git-send-email-konrad.wilk@oracle.com> <1292967460-15709-9-git-send-email-konrad.wilk@oracle.com> In-Reply-To: <1292967460-15709-9-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: 1540 Lines: 38 On 12/21/2010 01:37 PM, Konrad Rzeszutek Wilk wrote: > If we swapped over from using an p2m_mid_identical to p2m_mid_missing > (earlier call to set_phys_to_machine) and then started going through the > PFNs in descending order to program a new MFN (balloon worker), we would > end up in this code path. At that point we would set up new page filled with > pointers to p2m_identity instead of p2m_missing. This had the disastrous > effect that get_phys_to_machine on that PFN would return an 1-1 mapping > instead of INVALID_P2M_ENTRY resulting in hitting a BUG check in balloon driver. > Are you going to fold this into the appropriate patch later? > Signed-off-by: Konrad Rzeszutek Wilk > --- > arch/x86/xen/mmu.c | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c > index 92f4fec..a917439 100644 > --- a/arch/x86/xen/mmu.c > +++ b/arch/x86/xen/mmu.c > @@ -480,7 +480,10 @@ static bool alloc_p2m(unsigned long pfn) > if (!mid) > return false; > > - p2m_mid_init(mid, p2m_identity); > + if (mid == p2m_mid_identity) > + p2m_mid_init(mid, p2m_identity); > + else > + p2m_mid_init(mid, p2m_missing); > > if (cmpxchg(top_p, mid_orig, mid) != mid_orig) > free_p2m_page(mid); -- 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/