From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH 08/10] xen/mmu: Bugfix. Fill the top entry page with appropriate middle layer pointers. Date: Wed, 22 Dec 2010 10:11:16 -0500 Message-ID: <20101222151115.GI1760@dumpdata.com> References: <1292967460-15709-1-git-send-email-konrad.wilk@oracle.com> <1292967460-15709-9-git-send-email-konrad.wilk@oracle.com> <4D112C66.9040600@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <4D112C66.9040600@goop.org> Sender: linux-kernel-owner@vger.kernel.org To: Jeremy Fitzhardinge Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, Jan Beulich , xen-devel@lists.xensource.com, Konrad Rzeszutek Wilk List-Id: xen-devel@lists.xenproject.org On Tue, Dec 21, 2010 at 02:38:30PM -0800, Jeremy Fitzhardinge wrote: > 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? Yes. Rolled it in xen/mmu: Add the notion of identity (1-1) mapping.