From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: Vanilla Linux and has_foreign_mapping Date: Tue, 29 Apr 2008 10:32:22 -0700 Message-ID: <48175BA6.1090700@goop.org> References: <48112345.5000503@goop.org> <481210C0.6070109@cmu.edu> <48122153.1070007@goop.org> <48122378.2090802@cmu.edu> <48125C42.6030709@goop.org> <7EA259C2-60B9-46FF-AF13-BD52C2E071A2@cmu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <7EA259C2-60B9-46FF-AF13-BD52C2E071A2@cmu.edu> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Michael Abd-El-Malek Cc: Mark McLoughlin , xen-devel , Andrea Arcangeli , Eduardo Habkost , Keir Fraser , Christoph Lameter List-Id: xen-devel@lists.xenproject.org Michael Abd-El-Malek wrote: > Some drivers may need to do additional tasks besides just clearing the > PTE. For example, when unzapping my kernel PTE, I need to restore > the physical mapping of the page. (On the initial set_pte (which I've > overridden), I removed the physical backing of the page.) > > If we really want to avoid a zap_pte hook, I suppose we can add flags > to the page/PTE that indicate things like "this page needs to have its > physical backing restored". Is that something that needs to happen synchronously with the unmap, or could the driver do it in its vma callback? What do you mean by remove/restoring the physical backing? Do any of the in-tree drivers do this? In the PAE case, which I think we can regard as usual these days, we have 64-bits to store per-mapping info, so stashing a callback or callback index seems pretty straightforward if we need full generality. J