Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965105AbVKHM5F (ORCPT ); Tue, 8 Nov 2005 07:57:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965115AbVKHM5B (ORCPT ); Tue, 8 Nov 2005 07:57:01 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:9652 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S965105AbVKHM5A (ORCPT ); Tue, 8 Nov 2005 07:57:00 -0500 Date: Tue, 8 Nov 2005 13:57:09 +0100 From: Ingo Molnar To: Zachary Amsden Cc: Andrew Morton , Chris Wright , Linus Torvalds , Linux Kernel Mailing List , Virtualization Mailing List , "H. Peter Anvin" , Zwane Mwaikambo , Martin Bligh , Pratap Subrahmanyam , Christopher Li , "Eric W. Biederman" Subject: Re: [PATCH 4/21] i386 Broken bios common Message-ID: <20051108125709.GA4218@elte.hu> References: <200511080422.jA84MQxK009859@zach-dev.vmware.com> <20051108071935.GB28201@elte.hu> <43709E86.8010203@vmware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43709E86.8010203@vmware.com> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: 0.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.0 required=5.9 tests=AWL autolearn=disabled SpamAssassin version=3.0.4 0.0 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1102 Lines: 26 * Zachary Amsden wrote: > >>- gdt[0x40 / 8] = bad_bios_desc; > >>+ gdt[0x40 / 8] = gdt[GDT_ENTRY_BAD_BIOS_CACHE]; > > > >i like the cleanup, but wouldnt it be simpler to dedicate GDT entry #8 > >to the 0x40 descriptor, and hence be compatible with such broken BIOSes > >by default? Right now entry #8 is taken up by TLS segment #2, but we > >could change GDT_ENTRY_TLS_MIN from 6 to 9 and push the TLS segments to > >entries 9,10,11. [ Could there be any buggy SMM code that relies on > >having something at 0x40? ] > > I worry that there could be buggy userspace code that relies on having > selector 0x40 - notably Wine. So although I would like to make 0x40 > the default, can't be guaranteed. why use up a GDT entry then for GDT_ENTRY_BAD_BIOS_CACHE? Just put it into a global variable, into the readmostly section. Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/