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 D99D61A02F6 for ; Tue, 2 Dec 2014 15:27:52 +1100 (AEDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 80A57140174 for ; Tue, 2 Dec 2014 15:27:51 +1100 (AEDT) Date: Mon, 1 Dec 2014 20:26:26 -0800 From: Greg KH To: Nathan Fontenot Subject: Re: Right location in sysfs for dlpar file Message-ID: <20141202042626.GC9271@kroah.com> References: <1417057941.5089.81.camel@kernel.crashing.org> <547C8C0F.5070701@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <547C8C0F.5070701@linux.vnet.ibm.com> Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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? Anyway, let's see the patches before I guess anything else, that will determine how things work out best. thanks, greg k-h