From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id F076D1A006D for ; Thu, 4 Dec 2014 14:07:34 +1100 (AEDT) Received: from e34.co.us.ibm.com (e34.co.us.ibm.com [32.97.110.152]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 47DC31400A0 for ; Thu, 4 Dec 2014 14:07:34 +1100 (AEDT) Received: from /spool/local by e34.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 3 Dec 2014 20:07:32 -0700 Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by d03dlp03.boulder.ibm.com (Postfix) with ESMTP id 102FA19D803F for ; Wed, 3 Dec 2014 19:56:09 -0700 (MST) Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id sB437SrP35782854 for ; Wed, 3 Dec 2014 20:07:28 -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 sB437S9l007020 for ; Wed, 3 Dec 2014 20:07:28 -0700 Message-ID: <547FCFEF.8090001@linux.vnet.ibm.com> Date: Wed, 03 Dec 2014 21:07:27 -0600 From: Nathan Fontenot MIME-Version: 1.0 To: Greg KH Subject: Re: Right location in sysfs for dlpar file References: <1417057941.5089.81.camel@kernel.crashing.org> <547C8C0F.5070701@linux.vnet.ibm.com> <20141202042626.GC9271@kroah.com> In-Reply-To: <20141202042626.GC9271@kroah.com> Content-Type: text/plain; charset=windows-1252 Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 12/01/2014 10:26 PM, Greg KH wrote: > On Mon, Dec 01, 2014 at 09:41:03AM -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. >> >>> >>> I'll let Nathan give you a bit more details/background and answer >>> subsequent question you might have as this is really his area of >>> expertise. >>> >>> To cut a long story short, we need a sysfs file that allows our >>> userspace tools to notify the kernel of hotplug events coming from >>> the management console (which talks to userspace daemons using a >>> proprietary protocol) to "initiate" the hotplug operations, which in >>> turn get dispatched internally in the kernel to the right subsystem >>> (memory, cpu, pci, ...) based on the resource type. >>> >>> On IRC, Greg suggested /sys/firmware and /sys/hypervisor which both >>> look like a reasonable option to me, probably better than dlpar... >> >> For PowerVM systems we need this sysfs file to deliver what is >> essentially a binary blob (specifically a rtas error log) to the >> kernel. The current patch set is creating /sys/kernel/dlpar. As Ben >> mentioned we would like your input on what would be the proper place >> to create this file. > > And what is the kernel supposed to do with such a binary blob? Parse > it? Or pass it to something else? The kernel will parse it and perform the requested hotplug operation. > > Anyway, let's see the patches before I guess anything else, that will > determine how things work out best. I'll cc you on the next version of the patch set. -Nathan