From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755777AbYISRqw (ORCPT ); Fri, 19 Sep 2008 13:46:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755307AbYISRqm (ORCPT ); Fri, 19 Sep 2008 13:46:42 -0400 Received: from gate.crashing.org ([63.228.1.57]:41281 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755258AbYISRql (ORCPT ); Fri, 19 Sep 2008 13:46:41 -0400 Subject: Re: Populating multiple ptes at fault time From: Benjamin Herrenschmidt Reply-To: benh@kernel.crashing.org To: Avi Kivity Cc: Jeremy Fitzhardinge , Nick Piggin , Hugh Dickens , Linux Memory Management List , Linux Kernel Mailing List , Avi Kivity , Andrew Morton , Rik van Riel In-Reply-To: <48D17E75.80807@redhat.com> References: <48D142B2.3040607@goop.org> <48D17E75.80807@redhat.com> Content-Type: text/plain Date: Fri, 19 Sep 2008 10:45:03 -0700 Message-Id: <1221846303.8077.27.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2008-09-17 at 15:02 -0700, Avi Kivity wrote: > Jeremy Fitzhardinge wrote: > > Minor faults are easier; if the page already exists in memory, we should > > just create mappings to it. If neighbouring pages are also already > > present, then we can can cheaply create mappings for them too. > > > > > > One problem is the accessed bit. If it's unset, the shadow code cannot > make the pte present (since it has to trap in order to set the accessed > bit); if it's set, we're lying to the vm. > > This doesn't affect Xen, only kvm. Other archs too. On powerpc, !accessed -> not hashed (or not in the TLB for SW loaded TLB platforms). Ben.