From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751141AbaCFGvh (ORCPT ); Thu, 6 Mar 2014 01:51:37 -0500 Received: from terminus.zytor.com ([198.137.202.10]:42012 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750810AbaCFGvg (ORCPT ); Thu, 6 Mar 2014 01:51:36 -0500 Message-ID: <53181AC1.2020807@zytor.com> Date: Wed, 05 Mar 2014 22:50:41 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Muli Ben-Yehuda , WANG Chao CC: "Jon D. Mason" , Thomas Gleixner , Vivek Goyal , Yinghai Lu , Baoquan He , kexec@lists.infradead.org, discuss@x86-64.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: How could we get rid of saved_max_pfn for calgary iommu? References: <20140219061824.GA29703@dhcp-17-89.nay.redhat.com> <20140305053617.GE26240@dhcp-17-89.nay.redhat.com> <20140306064756.GB16859@needle.mulix.org> In-Reply-To: <20140306064756.GB16859@needle.mulix.org> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/05/2014 10:47 PM, Muli Ben-Yehuda wrote: > On Wed, Mar 05, 2014 at 01:36:17PM +0800, WANG Chao wrote: > >> Hi, Muli >> >> saved_max_pfn is becoming a setback for kexec-tools. Ideally calgary >> could get rid of saved_max_pfn at all. But If this can't work, how >> about exporting a calgary tce table size to user space, so that >> kexec-tools can simply pass calgary=xxx cmdline to 2nd kernel. > > As Jon noted, this code is used to so that the TCE table remains > consistent between the original and the kexec'd kernel. I see two > options: either we hard code the TCE table size to the max so that > this bit of code becomes redundant, or we explicitly pass the original > table size (or the original max_pfn) to the kexec'd kernel. The first > option is more appealing, because I don't think anyone is actually > using the TCE table size -- we mostly added it for debugging the IOMMU > TCE code at the time -- but since I don't have a Calgary machine > anymore, I don't have any way to test it. The second option is uglier > but would be fully backward-compatible and less likely to break > things. Given that very few people are likely running the latest > upstream kernel on Calgary/CalIOC2 machines, I'm inclined towards the > first option. > >> BTW MAINTAINERS file still uses your old email, please update >> accordingly. > > I think you are the first person to actually look up the Calgary > maintainers in the last few years :-) > OK, second question... is it time to axe Calgary? -hpa