On 05/07/2012 05:30 PM, Anthony Liguori wrote: > On 05/06/2012 09:39 AM, Avi Kivity wrote: >> On 05/06/2012 05:35 PM, Anthony Liguori wrote: >>> On 05/06/2012 08:11 AM, Avi Kivity wrote: >>> libvirt is essentially the BMC for a virtual guest. I would suggest >>> looking at implementing an IPMI interface to libvirt and exposing it >>> to the guest through a USB RNDIS device. >>> >> >> That's the first option. One unanswered question is what to do when the >> guest is down? Someone should listen for IPMI events, but we can't make >> it libvirt unconditionally, since many instances of libvirt are active >> at any one time. >> >> Note the IPMI external interface needs to be migrated, like any other. > > For all intents and purposes, the BMC/RSA is a separate physical > machine. That's true for any other card on a machine. > If you really wanted to model it, you would launch two instances of > QEMU. The BMC instance would have a virtual NIC and would share a USB > bus with the slave QEMU instance (probably via USBoIP). The USB bus > is how the BMC exposes IPMI to the guest (via a USB rndis adapter), > remote media, etc. I believe some BMC's also expose IPMI over i2c but > that's pretty low bandwidth. That is one way to do it. Figure out the interactions between two different parts in a machine, define an interface for them to communicate, and split them into two processes. We don't usually do that; I believe your motivation is that the two have different power domains (but then so do NICs with wake-on-LAN support). > At any rate, you would have some sort of virtual hardware device that > essentially spoke QMP to the slave instance. You could just do > virtio-serial and call it a day actually. Sorry I lost you. Which is the master and which is the slave? > It really boils down to what you are trying to do. If you want to > just get some piece of software working that expects to do IPMI, the > easiest thing to do is run IPMI in the host and use a USB rndis > interface to interact with it. That would be most strange. A remote client connecting to the IPMI interface would control the power level of the host, not the guest. > I don't think there's a tremendous amount of value in QEMU making > itself look like an IBM IMM or whatever HP/Dell's equivalent is. As I > said, these stacks are hugely complicated and there are better ways of > doing out of band management (like talk to libvirt directly). I have to agree here. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
