Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758873AbXKTB2w (ORCPT ); Mon, 19 Nov 2007 20:28:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757036AbXKTBO6 (ORCPT ); Mon, 19 Nov 2007 20:14:58 -0500 Received: from gw.goop.org ([64.81.55.164]:33632 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757009AbXKTBO5 (ORCPT ); Mon, 19 Nov 2007 20:14:57 -0500 Message-ID: <474234E7.4070505@goop.org> Date: Mon, 19 Nov 2007 17:14:15 -0800 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Takashi Iwai CC: Zachary Amsden , Christoph Hellwig , Tobias Powalowski , linux-kernel@vger.kernel.org, Ingo Molnar , Thomas Gleixner Subject: Re: [PATCH] x86/paravirt: revert exports to restore old behaviour References: <200711131139.42791.t.powa@gmx.de> <473A073C.2020201@goop.org> <20071113222212.GA1322@infradead.org> <1195001464.6352.109.camel@bodhitayantram.eng.vmware.com> In-Reply-To: X-Enigmail-Version: 0.95.5 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2043 Lines: 56 Takashi Iwai wrote: > I took at this problem (as I have an nvidia card on one of my > workstations), and found out that the following suffer from > EXPORT_SYMBOL_GPL changes: > Which kernel version are you using? This is different in .24-rc compared to .23. > * local_disable_irq(), local_irq_save*(), etc. > These should be OK either way. pv_irq_ops is not _GPL. > * MSR-related macros like rdmsr(), wrmsr(), read_cr0(), etc. > wbinvd(), too. > These could reasonably use the the native_* versions anyway, since the driver won't be being used in an environment where these won't work. Perhaps they should be split out separate from the gdt/ldt operations, which they should have no business touching. > * pmd_val(), pgd_val(), etc are all involved with pv_mm_ops. > pmd_large() and pmd_bad() is also indirectly involved. > __flush_tlb() and friends suffer, too. > Yeah, I guess they can be expected to play with pagetables. > The easiest workaround I found was to undefine CONFIG_PARAVIRT before > inclusion of linux kernel headers, but it is really ugly and hacky. > Yeah. It will explode if you are running in a virtual environment which still gives the virtual machine graphics hardware access. > Redefinig with raw_*() and native_*() is another way, but it takes > much more work than defining these primitive functions in assembly. > > So, in short, with EXPORT_SYMBOL_GPL change, it's pretty hard to write > a non-GPL driver in a same manner... > Yeah. I think removing the difference between PARAVIRT and non-PARAVIRT is enough to justify the exports. If we want to make the policy decision that modules can't use pagetable or msr operations at all, then that's a separate decision which can be applied uniformly to PARAVIRT and non-PARAVIRT. J - 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/