From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-ea0-f182.google.com ([209.85.215.182]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WLS6X-0005IE-PL for kexec@lists.infradead.org; Thu, 06 Mar 2014 06:48:30 +0000 Received: by mail-ea0-f182.google.com with SMTP id b10so1494721eae.27 for ; Wed, 05 Mar 2014 22:48:01 -0800 (PST) Date: Thu, 6 Mar 2014 08:47:56 +0200 From: Muli Ben-Yehuda Subject: Re: How could we get rid of saved_max_pfn for calgary iommu? Message-ID: <20140306064756.GB16859@needle.mulix.org> References: <20140219061824.GA29703@dhcp-17-89.nay.redhat.com> <20140305053617.GE26240@dhcp-17-89.nay.redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20140305053617.GE26240@dhcp-17-89.nay.redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: WANG Chao Cc: discuss@x86-64.org, x86@kernel.org, Baoquan He , "Jon D. Mason" , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, "H. Peter Anvin" , Thomas Gleixner , Yinghai Lu , Vivek Goyal 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 :-) Cheers, Muli _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec