From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [patch 06/26] Xen-paravirt_ops: paravirt_ops: allocate a fixmap slot Date: Tue, 27 Feb 2007 11:11:43 +0100 Message-ID: <20070227101143.GC10827@elte.hu> References: <20070227081337.434798469@goop.org> <20070227081631.122933982@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20070227081631.122933982@goop.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jeremy Fitzhardinge Cc: Zachary Amsden , xen-devel@lists.xensource.com, virtualization@lists.osdl.org, Rusty Russell , linux-kernel@vger.kernel.org, Chris Wright , Andi Kleen , Andrew Morton List-Id: virtualization@lists.linuxfoundation.org * Jeremy Fitzhardinge wrote: > Allocate a fixmap slot for use by a paravirt_ops implementation. Xen > uses this to map the hypervisor's shared info page, which doesn't have > a pseudo-physical page number, and therefore can't be mapped > ordinarily. why not vmalloc it on the guest side? fixmaps are bad for this purpose for a general paravirt implementation, it limits the size of the shared info page, etc. Ingo From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932891AbXB0KS5 (ORCPT ); Tue, 27 Feb 2007 05:18:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932936AbXB0KS5 (ORCPT ); Tue, 27 Feb 2007 05:18:57 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:40242 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932891AbXB0KS4 (ORCPT ); Tue, 27 Feb 2007 05:18:56 -0500 Date: Tue, 27 Feb 2007 11:11:43 +0100 From: Ingo Molnar To: Jeremy Fitzhardinge Cc: Andi Kleen , Andrew Morton , linux-kernel@vger.kernel.org, virtualization@lists.osdl.org, xen-devel@lists.xensource.com, Chris Wright , Zachary Amsden , Rusty Russell Subject: Re: [patch 06/26] Xen-paravirt_ops: paravirt_ops: allocate a fixmap slot Message-ID: <20070227101143.GC10827@elte.hu> References: <20070227081337.434798469@goop.org> <20070227081631.122933982@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070227081631.122933982@goop.org> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: 1.0 X-ELTE-SpamLevel: s X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=1.0 required=5.9 tests=BAYES_50 autolearn=no SpamAssassin version=3.1.7 1.0 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.4067] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Jeremy Fitzhardinge wrote: > Allocate a fixmap slot for use by a paravirt_ops implementation. Xen > uses this to map the hypervisor's shared info page, which doesn't have > a pseudo-physical page number, and therefore can't be mapped > ordinarily. why not vmalloc it on the guest side? fixmaps are bad for this purpose for a general paravirt implementation, it limits the size of the shared info page, etc. Ingo