From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id A11321A006D for ; Thu, 4 Dec 2014 14:06:43 +1100 (AEDT) Received: from e35.co.us.ibm.com (e35.co.us.ibm.com [32.97.110.153]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id E6AE31400D2 for ; Thu, 4 Dec 2014 14:06:42 +1100 (AEDT) Received: from /spool/local by e35.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 3 Dec 2014 20:06:41 -0700 Received: from b03cxnp07029.gho.boulder.ibm.com (b03cxnp07029.gho.boulder.ibm.com [9.17.130.16]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 3B2671FF0041 for ; Wed, 3 Dec 2014 19:55:22 -0700 (MST) Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id sB436bUD49807592 for ; Wed, 3 Dec 2014 20:06:37 -0700 Received: from d03av02.boulder.ibm.com (localhost [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id sB436atd002794 for ; Wed, 3 Dec 2014 20:06:37 -0700 Message-ID: <547FCFBB.8000408@linux.vnet.ibm.com> Date: Wed, 03 Dec 2014 21:06:35 -0600 From: Nathan Fontenot MIME-Version: 1.0 To: Michael Ellerman Subject: Re: Right location in sysfs for dlpar file References: <1417057941.5089.81.camel@kernel.crashing.org> <547C8C0F.5070701@linux.vnet.ibm.com> <1417496963.31336.6.camel@concordia> In-Reply-To: <1417496963.31336.6.camel@concordia> Content-Type: text/plain; charset=utf-8 Cc: linuxppc-dev@ozlabs.org, Greg KH List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 12/01/2014 11:09 PM, Michael Ellerman wrote: > On Mon, 2014-12-01 at 09:41 -0600, Nathan Fontenot wrote: >> On 11/26/2014 09:12 PM, Benjamin Herrenschmidt wrote: >>> Hi Greg, >>> >>> So Nathan is working on a patch series to cleanup and improve our >>> "DLPAR" infrastructure which is basically our hotplug mechanism when >>> running under the PowerVM (aka pHyp) and KVM hypervisors. >> >> The cleanup to the dlpar infrastructure will move the entire operation >> of hotplugging a device to the kernel instead of doing it partially in >> userspace and partially in the kernel as is currently done. >> > ... >> >> For PowerVM systems we need this sysfs file to deliver what is >> essentially a binary blob (specifically a rtas error log) to the >> kernel. > > Those two statements don't really agree with each other. ie. "move the entire > operation .. to the kernel", but then we need a sysfs file so userspace can > deliver us a blob? > > I think what you mean is that all the actual logic will move into the kernel, > and the only thing userspace will do (on PowerVM) is write the blog to kick off > the process. > > On PowerKVM the entire process will be handled in the kernel (after some > additional patches to hook up the rtas event to the hotplug). > This is correct. I should have explained it better. > > As ugly as it is, we already have /proc/rtas, which includes a bunch of files, > including error_log, which is where you can *read* the RTAS error logs from. > I have no problem making this a writeable file. I think keeping all of the rtas error log communication between the kernel userspace in one place would be a good idea. > So maybe we just extend that, either a new file, or just by making error_log > writable? > > It'd be nice to drop all that rtas gunk and move to something cleaner in /sys, > but I don't think we can realistically do that any time soon anyway? > Perhaps doing this at a later time would be worthwhile. -Nathan