From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) (using TLSv1.2 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id E2EED1A044F for ; Thu, 18 Feb 2016 16:30:30 +1100 (AEDT) Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 17 Feb 2016 22:30:28 -0700 Received: from b03cxnp07029.gho.boulder.ibm.com (b03cxnp07029.gho.boulder.ibm.com [9.17.130.16]) by d03dlp03.boulder.ibm.com (Postfix) with ESMTP id D15AE19D8041 for ; Wed, 17 Feb 2016 22:18:22 -0700 (MST) Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u1I5UPC612255332 for ; Wed, 17 Feb 2016 22:30:25 -0700 Received: from d03av01.boulder.ibm.com (localhost [127.0.0.1]) by d03av01.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u1I5UORi002335 for ; Wed, 17 Feb 2016 22:30:24 -0700 From: Stewart Smith To: Steven Royer , Greg Kroah-Hartman Cc: Arnd Bergmann , linux-doc@vger.kernel.org, Jonathan Corbet , linux-kernel@vger.kernel.org, Steven Royer , Paul Mackerras , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] add POWER Virtual Management Channel driver In-Reply-To: <0523320d3efd5c9dcac10a85aecd1fe1@imap.linux.ibm.com> References: <1455655393-3137-1-git-send-email-seroyer@linux.vnet.ibm.com> <20160216221822.GA32255@kroah.com> <20160217223141.GA16341@kroah.com> <0523320d3efd5c9dcac10a85aecd1fe1@imap.linux.ibm.com> Date: Thu, 18 Feb 2016 16:30:12 +1100 Message-ID: <87fuwqio0r.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Steven Royer writes: > On 2016-02-17 16:31, Greg Kroah-Hartman wrote: >> On Wed, Feb 17, 2016 at 03:18:26PM -0600, Steven Royer wrote: >>> On 2016-02-16 16:18, Greg Kroah-Hartman wrote: >>> >On Tue, Feb 16, 2016 at 02:43:13PM -0600, Steven Royer wrote: >>> >>From: Steven Royer >>> >> >>> >>The ibmvmc driver is a device driver for the POWER Virtual Management >>> >>Channel virtual adapter on the PowerVM platform. It is used to >>> >>communicate with the hypervisor for virtualization management. It >>> >>provides both request/response and asynchronous message support through >>> >>the /dev/ibmvmc node. >>> > >>> >What is the protocol for that device node? >>> The protocol is not currently published. I am pushing on getting it >>> published, but that process will take time. If you have a PowerVM >>> system >>> with NovaLink, it would not be hard to reverse engineer it... If you >>> don't >>> have a PowerVM system, then this driver isn't interesting anyway... Stephen - if you need some help pushing for it to be published, let me know, there's a few internal things I could help push. >> You can't just expect us to review this code without at least having a >> clue as to how it is supposed to work? > There are two layers to the protocol. The first layer is the only layer > that the driver actually cares about. The second layer is just a > payload that is between the application and the hypervisor and can > change independently from the kernel/driver (this is what is transported > over the /dev/ibmvmc node). The first layer technically is published in > the PAPR (appendix G), but it is not trivial for most people to access https://members.openpowerfoundation.org/document/dl/469 is LoPAPR which has been published through OpenPower Foundation and anyone can access, although Appendix G there is on EEH. Although VMC (Virtual Management Channel) is mentioned in that document the details aren't there... so it's possible that this is only in some other PAPR version :/ and... looking in internal places, it is. *sigh* With my OpenPower Foundation hat on, I'll say that it's a work-in-progress getting all this documentation in order. The questions of if it's a sensible hypervisor to partition interface and if it's a sensible userspace API are open for debate :) Would we implement this way of communicating between a KVM guest and the host linux system? If not, then it's probably not a generally good idea. That being said, it seems to be what already exists in PowerVM -- Stewart Smith OPAL Architect, IBM.