Steven Royer <seroyer@xxxxxxxxxxxxxxxxxx> 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 <seroyer@xxxxxxxxxx> >>> >> >>> >>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. -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
