From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752651AbVHHBQG (ORCPT ); Sun, 7 Aug 2005 21:16:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753189AbVHHBQG (ORCPT ); Sun, 7 Aug 2005 21:16:06 -0400 Received: from mailout1.vmware.com ([65.113.40.130]:59917 "EHLO mailout1.vmware.com") by vger.kernel.org with ESMTP id S1752651AbVHHBQG (ORCPT ); Sun, 7 Aug 2005 21:16:06 -0400 Message-ID: <42F6B254.2090404@vmware.com> Date: Sun, 07 Aug 2005 18:16:04 -0700 From: Zachary Amsden User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040803 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Chris Wright Cc: Andrew Morton , "Martin J. Bligh" , linux-kernel@vger.kernel.org, Pratap Subrahmanyam , virtualization@lists.osdl.org Subject: Re: [PATCH] abstract out bits of ldt.c References: <372830000.1123456808@[10.10.2.4]> <20050807234411.GE7991@shell0.pdx.osdl.net> <374910000.1123459025@[10.10.2.4]> <20050807174129.20c7202f.akpm@osdl.org> <20050808004645.GT7762@shell0.pdx.osdl.net> <42F6AF8E.60107@vmware.com> <20050808010828.GU7762@shell0.pdx.osdl.net> In-Reply-To: <20050808010828.GU7762@shell0.pdx.osdl.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 08 Aug 2005 01:16:03.0375 (UTC) FILETIME=[BE9583F0:01C59BB6] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Chris Wright wrote: >* Zachary Amsden (zach@vmware.com) wrote: > > >>Does Xen assume page aligned descriptor tables? I assume from this >> >> > >Yes. > > > >>patch and snippets I have gathered from others, that is a yes, and other >>things here imply that DT pages are not shadowed. If so, Xen itself >>must have live segments in the GDT pages, so how do you allocate space >>for the per-CPU GDT pages on SMP? >> >> > >early during boot. > > Doesn't that require 16 pages per CPU? That seems excessive to impose on a native build. Perhaps we could get away with 1 page per CPU for the GDT on native boots and bump that up to 16 if compiling for a virtualized sub-architecture - i.e. move GDT to a page aligned struct for native (doesn't cost too much), and give it MACH_GDT_PAGES of space which is defined by the sub-architecture. Let's take this thread over to virtualization@lists.osdl.org as well. Zach