Re: [Qemu-devel] Adding an IPMI BMC device to KVM
On 05/18/2012 08:08 AM, Stefan Hajnoczi wrote: On Mon, May 7, 2012 at 3:30 PM, Anthony Liguori wrote: On 05/06/2012 09:39 AM, Avi Kivity wrote: On 05/06/2012 05:35 PM, Anthony Liguori wrote: So what's really the use case here? Would an IPMI -> libvirt bridge get you what you need? I really think that's the best path forward. Sorry for sending this twice. I thought my mailer was set to disable HTML. Many of our customer use the standard watchdog timer and power controls on IPMI. Basically, the watchdog timer needs to be able to power off, power cycle, reset, and send an NMI. The IPMI watchdog can be configured to do all those things. (The NMI is for a "pretimeout" that generally triggers a panic.) Power control is no big surprise. It's true that you have ACPI to do this, but that's not terribly useful on non-x86 (and non ia64, I suppose) systems. Do you want to expose host sensors - the challenge is that they don't reflect the hardware that the virtual machine sees? Or do you want to have synthetic sensors - which virtual sensors are useful to have? A few sensors, notably the watchdog timer sensor, are not synthetic. The others generally are. Sensors cover things beyond just power and temperature. Important other ones in IPMI deal with the presence of FRUs in the system, BIOS/OS state, and intrusion detection. Two main reasons for synthesized sensors exist. One, in a legacy situation, is to "fool" the management system into thinking everything is ok, since it is expecting to see these sensors with specific values. You could even possibly reflect the state of real sensors, mapping them somehow, if you wanted. The other reason is for testing. It's pretty hard to induce some of these sensors to go out of range in a real system. So without simulation, you need a hack-ed up management controller in a real system to truly test your software. Is the IPMI watchdog useful, QEMU already supports the i6300esb PCI watchdog (see qemu -watchdog option documentation)? That's only useful if you can simulate an i6300esb. Probably not possible on non-x86. Plus legacy systems may be expecting the capabilities of the IPMI watchdog. Some use cases that illustrate how the guest is going to use IPMI would be interesting and could help guide the discussion. You are probably right. I've mentioned a couple above. One other possible one, that someone else mentioned, is the ability to control a VM using standard tools like ipmitool or OpenIPMI over network interfaces. People may already have management systems that are designed around IPMI, and it would make a move to virtual machines easier. This was the request mentioned that was in the Redhat database. Such a capability would require re-thinking things a bit. You have two basic options that I see. Either have the "management controller" run outside qemu and define a simple interface to it, or modify qemu to be able to run the management controller internally. My preference in to run it outside qemu, for the following reasons: * It decouples things that are IPMI internals from having to go through getting into qemu repositories. * The management controller then becomes useful for a number of other purposes. I already have one mostly done that I use for testing. It could be used by other VMs. * A full management controller is a fairly big piece of software, especially if you include the network access. It probably doesn't belong in qemu. * No offense, I don't want to muck around inside qemu to accomplish this :). There are, of course, disadvantages. Some I can think of: * There can be confusion about which versions of two things work together. * Overall, it is more complex to get working. * There are possible security implications. So I guess those are points we can talk about... -corey -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
On Mon, May 7, 2012 at 3:30 PM, Anthony Liguori wrote: > On 05/06/2012 09:39 AM, Avi Kivity wrote: >> >> On 05/06/2012 05:35 PM, Anthony Liguori wrote: > So what's really the use case here? Would an IPMI -> libvirt bridge get you > what you need? I really think that's the best path forward. I'm still curious about this and didn't see it answered in the thread. You mentioned "watchdog timer, sensors and power control" but what exactly should they expose? Do you want to expose host sensors - the challenge is that they don't reflect the hardware that the virtual machine sees? Or do you want to have synthetic sensors - which virtual sensors are useful to have? Is the IPMI watchdog useful, QEMU already supports the i6300esb PCI watchdog (see qemu -watchdog option documentation)? Some use cases that illustrate how the guest is going to use IPMI would be interesting and could help guide the discussion. Stefan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
On 05/07/2012 01:07 PM, Corey Minyard wrote: I think we are getting a little out of hand here, and we are mixing up concepts :). There are lots of things IPMI *can* do (including serial access, VGA snooping, LAN access, etc.) but I don't see any value it that. The main thing here is to emulate the interface to the guest. OOB management is really more appropriately handled with libvirt. How the BMC integrates into the hardware varies a *lot* between systems, but it's really kind of irrelevant. (Well, almost irrelevant, BMCs can provide a direct I2C messaging capability, and that may matter.) A guest can have one (or more) of a number of interfaces (that are all fairly bad, unfortunately). The standard ones are called "KCS", "BT" and "SMIC" and they generally are directly on the ISA bus, but are in memory on non-x86 boxes (and on some x86 boxes) and sometimes on the PCI bus. Some systems also have interfaces over I2C, but that hasn't really caught on. Others have interfaces over serial ports, and that unfortunately has caught on in the ATCA world. And there are at least 3 different basic types of serial port interfaces with sub-variants :(. I'm not sure what the USB rndis device is, but I'll look at it. But there is no IPMI over USB. USB rndis == USB network adapater. It's just seen by the machine as IPMI over LAN. Regards, Anthony Liguori -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
On 05/07/2012 02:45 PM, Dave Allan wrote: FWIW, the idea of an IPMI interface to VMs was proposed for libvirt not too long ago. See: https://bugzilla.redhat.com/show_bug.cgi?id=815136 Well, it wouldn't be to hard to do. I already have working emulation code that does the IPMI LAN interface (including the IPMI 2.0 stuff for more reasonable security). I have a KCS interface and a minimal IPMI controller working in KVM, though I'm not quite sure the best final way to hook it in. Configuration is going to be the hardest part, but a minimal configuration for providing basic management would be easy. -corey Dave On Mon, May 07, 2012 at 01:07:45PM -0500, Corey Minyard wrote: I think we are getting a little out of hand here, and we are mixing up concepts :). There are lots of things IPMI *can* do (including serial access, VGA snooping, LAN access, etc.) but I don't see any value it that. The main thing here is to emulate the interface to the guest. OOB management is really more appropriately handled with libvirt. How the BMC integrates into the hardware varies a *lot* between systems, but it's really kind of irrelevant. (Well, almost irrelevant, BMCs can provide a direct I2C messaging capability, and that may matter.) A guest can have one (or more) of a number of interfaces (that are all fairly bad, unfortunately). The standard ones are called "KCS", "BT" and "SMIC" and they generally are directly on the ISA bus, but are in memory on non-x86 boxes (and on some x86 boxes) and sometimes on the PCI bus. Some systems also have interfaces over I2C, but that hasn't really caught on. Others have interfaces over serial ports, and that unfortunately has caught on in the ATCA world. And there are at least 3 different basic types of serial port interfaces with sub-variants :(. I'm not sure what the USB rndis device is, but I'll look at it. But there is no IPMI over USB. The big things a guest can do are sensor management, watchdog timer, reset, and power control. In complicated IPMI-based systems like ATCA, a guest may want to send messages through its local IPMI controller to other guest's IPMI controllers or to a central BMC that runs an entire chassis of systems. So that may need to be supported, depending on what people want to do and how hard they want to work on it. My proposal is to start small, with just a local interface, watchdog timer, sensors and power control. But have an architecture that would allow external LAN access, tying BMCs in different qemu instances together, perhaps serial over IPMI, and other things of that nature. -corey On 05/07/2012 10:21 AM, Anthony Liguori wrote: On 05/07/2012 10:11 AM, Avi Kivity wrote: On 05/07/2012 05:55 PM, Anthony Liguori wrote: For all intents and purposes, the BMC/RSA is a separate physical machine. That's true for any other card on a machine. It has a separate power source for all intents and purposes. If you think of it in QOM terms, what connects the nodes together ultimately is the "Vcc" pin that travels across all devices. The RTC is a little special because it has a battery backed CMOS/clock but it's also handled specially. And we fail to emulate it correctly as well, wrt. alarms. The BMC does not share Vcc. It's no different than a separate physical box. It just shares a couple buses. It controls the main power place, reset line, can read VGA and emulate keyboard, seems pretty well integrated. Emulating the keyboard is done through USB. How the VGA thing works is very vendor dependent. The VGA snooping can happen as part of the display path (essentially connected via a VGA cable) or it can be a side-band using a special graphics adapter. I think QEMU VNC emulation is a pretty good analogy actually. 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). The power still comes from the PCI bus. Maybe. But it's on when the rest of the machine is off. So Vcc is not shared. That's all plumbed through the PCI bus FWIW. Think of something like a blade center. Each individual blade does not have it's own BMC. There's a single common BMC that provides an IPMI interface for all blades. Yet each blade still sees an IPMI interface via a USB rndis device. You can rip out the memory, PCI devices, etc. from a box while the Power is in and the BMC will be unaffected. 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? The BMC is the master, system being controlled is the slave. Ah okay. It also has to read the VGA output (say via vnc) and supply keyboard inp
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
FWIW, the idea of an IPMI interface to VMs was proposed for libvirt not too long ago. See: https://bugzilla.redhat.com/show_bug.cgi?id=815136 Dave On Mon, May 07, 2012 at 01:07:45PM -0500, Corey Minyard wrote: > I think we are getting a little out of hand here, and we are mixing > up concepts :). > > There are lots of things IPMI *can* do (including serial access, VGA > snooping, LAN access, etc.) but I don't see any value it that. The > main thing here is to emulate the interface to the guest. OOB > management is really more appropriately handled with libvirt. How > the BMC integrates into the hardware varies a *lot* between systems, > but it's really kind of irrelevant. (Well, almost irrelevant, BMCs > can provide a direct I2C messaging capability, and that may matter.) > > A guest can have one (or more) of a number of interfaces (that are > all fairly bad, unfortunately). The standard ones are called "KCS", > "BT" and "SMIC" and they generally are directly on the ISA bus, but > are in memory on non-x86 boxes (and on some x86 boxes) and sometimes > on the PCI bus. Some systems also have interfaces over I2C, but > that hasn't really caught on. Others have interfaces over serial > ports, and that unfortunately has caught on in the ATCA world. And > there are at least 3 different basic types of serial port interfaces > with sub-variants :(. I'm not sure what the USB rndis device is, > but I'll look at it. But there is no IPMI over USB. > > The big things a guest can do are sensor management, watchdog timer, > reset, and power control. In complicated IPMI-based systems like > ATCA, a guest may want to send messages through its local IPMI > controller to other guest's IPMI controllers or to a central BMC > that runs an entire chassis of systems. So that may need to be > supported, depending on what people want to do and how hard they > want to work on it. > > My proposal is to start small, with just a local interface, watchdog > timer, sensors and power control. But have an architecture that > would allow external LAN access, tying BMCs in different qemu > instances together, perhaps serial over IPMI, and other things of > that nature. > > -corey > > > On 05/07/2012 10:21 AM, Anthony Liguori wrote: > >On 05/07/2012 10:11 AM, Avi Kivity wrote: > >>On 05/07/2012 05:55 PM, Anthony Liguori wrote: > >For all intents and purposes, the BMC/RSA is a separate physical > >machine. > > That's true for any other card on a machine. > >>> > >>> > >>>It has a separate power source for all intents and purposes. If you > >>>think of it in QOM terms, what connects the nodes together ultimately > >>>is the "Vcc" pin that travels across all devices. The RTC is a little > >>>special because it has a battery backed CMOS/clock but it's also > >>>handled specially. > >> > >>And we fail to emulate it correctly as well, wrt. alarms. > >> > >>> > >>>The BMC does not share Vcc. It's no different than a separate > >>>physical box. It just shares a couple buses. > >> > >>It controls the main power place, reset line, can read VGA and emulate > >>keyboard, seems pretty well integrated. > > > >Emulating the keyboard is done through USB. How the VGA thing > >works is very vendor dependent. The VGA snooping can happen as > >part of the display path (essentially connected via a VGA cable) > >or it can be a side-band using a special graphics adapter. I > >think QEMU VNC emulation is a pretty good analogy actually. > > > >> > 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). > >>> > >>>The power still comes from the PCI bus. > >> > >>Maybe. But it's on when the rest of the machine is off. So Vcc is not > >>shared. > > > >That's all plumbed through the PCI bus FWIW. > > > >> > >>> > >>>Think of something like a blade center. Each individual blade does > >>>not have it's own BMC. There's a single common BMC that provides an > >>>IPMI interface for all blades. Yet each blade still sees an IPMI > >>>interface via a USB rndis device. > >>> > >>>You can rip out the memory, PCI devices, etc. from a box while the > >>>Power is in and the BMC will be unaffected. > >>> > > >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? > >>> > >>>The BMC is the master, system being controlled is the slave. > >> > >>Ah okay. It also has to read the VGA output (say via vnc) and supply > >>keyboard input (via sendkey). > > > >Right, QMP + VNC is a pretty accurate analogy. > > > >It really boils down
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
I think we are getting a little out of hand here, and we are mixing up concepts :). There are lots of things IPMI *can* do (including serial access, VGA snooping, LAN access, etc.) but I don't see any value it that. The main thing here is to emulate the interface to the guest. OOB management is really more appropriately handled with libvirt. How the BMC integrates into the hardware varies a *lot* between systems, but it's really kind of irrelevant. (Well, almost irrelevant, BMCs can provide a direct I2C messaging capability, and that may matter.) A guest can have one (or more) of a number of interfaces (that are all fairly bad, unfortunately). The standard ones are called "KCS", "BT" and "SMIC" and they generally are directly on the ISA bus, but are in memory on non-x86 boxes (and on some x86 boxes) and sometimes on the PCI bus. Some systems also have interfaces over I2C, but that hasn't really caught on. Others have interfaces over serial ports, and that unfortunately has caught on in the ATCA world. And there are at least 3 different basic types of serial port interfaces with sub-variants :(. I'm not sure what the USB rndis device is, but I'll look at it. But there is no IPMI over USB. The big things a guest can do are sensor management, watchdog timer, reset, and power control. In complicated IPMI-based systems like ATCA, a guest may want to send messages through its local IPMI controller to other guest's IPMI controllers or to a central BMC that runs an entire chassis of systems. So that may need to be supported, depending on what people want to do and how hard they want to work on it. My proposal is to start small, with just a local interface, watchdog timer, sensors and power control. But have an architecture that would allow external LAN access, tying BMCs in different qemu instances together, perhaps serial over IPMI, and other things of that nature. -corey On 05/07/2012 10:21 AM, Anthony Liguori wrote: On 05/07/2012 10:11 AM, Avi Kivity wrote: On 05/07/2012 05:55 PM, Anthony Liguori wrote: For all intents and purposes, the BMC/RSA is a separate physical machine. That's true for any other card on a machine. It has a separate power source for all intents and purposes. If you think of it in QOM terms, what connects the nodes together ultimately is the "Vcc" pin that travels across all devices. The RTC is a little special because it has a battery backed CMOS/clock but it's also handled specially. And we fail to emulate it correctly as well, wrt. alarms. The BMC does not share Vcc. It's no different than a separate physical box. It just shares a couple buses. It controls the main power place, reset line, can read VGA and emulate keyboard, seems pretty well integrated. Emulating the keyboard is done through USB. How the VGA thing works is very vendor dependent. The VGA snooping can happen as part of the display path (essentially connected via a VGA cable) or it can be a side-band using a special graphics adapter. I think QEMU VNC emulation is a pretty good analogy actually. 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). The power still comes from the PCI bus. Maybe. But it's on when the rest of the machine is off. So Vcc is not shared. That's all plumbed through the PCI bus FWIW. Think of something like a blade center. Each individual blade does not have it's own BMC. There's a single common BMC that provides an IPMI interface for all blades. Yet each blade still sees an IPMI interface via a USB rndis device. You can rip out the memory, PCI devices, etc. from a box while the Power is in and the BMC will be unaffected. 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? The BMC is the master, system being controlled is the slave. Ah okay. It also has to read the VGA output (say via vnc) and supply keyboard input (via sendkey). Right, QMP + VNC is a pretty accurate analogy. 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. IPMI with a custom backend is what I mean. That's what I mean by an IPMI -> libvirt bridge. You could build a libvirt client that exposes an IPMI interface and when you issue IPMI commands, it translate
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
On 05/07/2012 10:11 AM, Avi Kivity wrote: On 05/07/2012 05:55 PM, Anthony Liguori wrote: For all intents and purposes, the BMC/RSA is a separate physical machine. That's true for any other card on a machine. It has a separate power source for all intents and purposes. If you think of it in QOM terms, what connects the nodes together ultimately is the "Vcc" pin that travels across all devices. The RTC is a little special because it has a battery backed CMOS/clock but it's also handled specially. And we fail to emulate it correctly as well, wrt. alarms. The BMC does not share Vcc. It's no different than a separate physical box. It just shares a couple buses. It controls the main power place, reset line, can read VGA and emulate keyboard, seems pretty well integrated. Emulating the keyboard is done through USB. How the VGA thing works is very vendor dependent. The VGA snooping can happen as part of the display path (essentially connected via a VGA cable) or it can be a side-band using a special graphics adapter. I think QEMU VNC emulation is a pretty good analogy actually. 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). The power still comes from the PCI bus. Maybe. But it's on when the rest of the machine is off. So Vcc is not shared. That's all plumbed through the PCI bus FWIW. Think of something like a blade center. Each individual blade does not have it's own BMC. There's a single common BMC that provides an IPMI interface for all blades. Yet each blade still sees an IPMI interface via a USB rndis device. You can rip out the memory, PCI devices, etc. from a box while the Power is in and the BMC will be unaffected. 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? The BMC is the master, system being controlled is the slave. Ah okay. It also has to read the VGA output (say via vnc) and supply keyboard input (via sendkey). Right, QMP + VNC is a pretty accurate analogy. 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. IPMI with a custom backend is what I mean. That's what I mean by an IPMI -> libvirt bridge. You could build a libvirt client that exposes an IPMI interface and when you issue IPMI commands, it translate it to libvirt operations. This can run as a normal process on the host and then network it to the guest via an emulated USB rndis device. Existing software on the guest shouldn't be able to tell the difference as long as it doesn't try to use I2C to talk to the BMC. I still like the single process solution, it is more in line with the rest of qemu and handles live migration better. Two QEMU processes could be migrated in unison if you really wanted to support that... With qemu-system-mips/sh4 you could probably even run the real BMC software stack if you were so inclined :-) But even better would be not to do this at all, and satisfy the remote management requirements using the existing tools. Right. Regards, Anthony Liguori -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
On 05/07/2012 05:55 PM, Anthony Liguori wrote: >>> For all intents and purposes, the BMC/RSA is a separate physical >>> machine. >> >> That's true for any other card on a machine. > > > It has a separate power source for all intents and purposes. If you > think of it in QOM terms, what connects the nodes together ultimately > is the "Vcc" pin that travels across all devices. The RTC is a little > special because it has a battery backed CMOS/clock but it's also > handled specially. And we fail to emulate it correctly as well, wrt. alarms. > > The BMC does not share Vcc. It's no different than a separate > physical box. It just shares a couple buses. It controls the main power place, reset line, can read VGA and emulate keyboard, seems pretty well integrated. >> 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). > > The power still comes from the PCI bus. Maybe. But it's on when the rest of the machine is off. So Vcc is not shared. > > Think of something like a blade center. Each individual blade does > not have it's own BMC. There's a single common BMC that provides an > IPMI interface for all blades. Yet each blade still sees an IPMI > interface via a USB rndis device. > > You can rip out the memory, PCI devices, etc. from a box while the > Power is in and the BMC will be unaffected. > >> >>> 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? > > The BMC is the master, system being controlled is the slave. Ah okay. It also has to read the VGA output (say via vnc) and supply keyboard input (via sendkey). >>> 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. > > IPMI with a custom backend is what I mean. That's what I mean by an > IPMI -> libvirt bridge. You could build a libvirt client that exposes > an IPMI interface and when you issue IPMI commands, it translate it to > libvirt operations. > > This can run as a normal process on the host and then network it to > the guest via an emulated USB rndis device. Existing software on the > guest shouldn't be able to tell the difference as long as it doesn't > try to use I2C to talk to the BMC. I still like the single process solution, it is more in line with the rest of qemu and handles live migration better. But even better would be not to do this at all, and satisfy the remote management requirements using the existing tools. -- 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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
On 05/07/2012 09:44 AM, Avi Kivity wrote: 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. It has a separate power source for all intents and purposes. If you think of it in QOM terms, what connects the nodes together ultimately is the "Vcc" pin that travels across all devices. The RTC is a little special because it has a battery backed CMOS/clock but it's also handled specially. The BMC does not share Vcc. It's no different than a separate physical box. It just shares a couple buses. 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). The power still comes from the PCI bus. Think of something like a blade center. Each individual blade does not have it's own BMC. There's a single common BMC that provides an IPMI interface for all blades. Yet each blade still sees an IPMI interface via a USB rndis device. You can rip out the memory, PCI devices, etc. from a box while the Power is in and the BMC will be unaffected. 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? The BMC is the master, system being controlled 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. IPMI with a custom backend is what I mean. That's what I mean by an IPMI -> libvirt bridge. You could build a libvirt client that exposes an IPMI interface and when you issue IPMI commands, it translate it to libvirt operations. This can run as a normal process on the host and then network it to the guest via an emulated USB rndis device. Existing software on the guest shouldn't be able to tell the difference as long as it doesn't try to use I2C to talk to the BMC. 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. Regards, Anthony Liguori -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
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. 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. 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. 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. 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). So what's really the use case here? Would an IPMI -> libvirt bridge get you what you need? I really think that's the best path forward. Regards, Anthony Liguori -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
On 05/06/2012 05:35 PM, Anthony Liguori wrote: > On 05/06/2012 08:11 AM, Avi Kivity wrote: >> (copied qemu-devel) >> >> On 05/04/2012 10:10 PM, Corey Minyard wrote: >>> >>> Either way, is this interesting for including into KVM? >> >> Not kvm, but certainly it would make a good addition to qemu, which kvm >> then uses. >> >>> Does anyone have any >>> opinions on the possible ways to implement this? >> >> My preference would be the second alternative. The issue you raise is a >> good one. There are two ways we can approach it: >> >> - have the management system intercept IPMI requests, start up a qemu >> instance (if it's down), and let it handle the event. >> - change the whole system to keep a running qemu even when the guest is >> down. This is a much larger change; it involves reducing the memory >> footprint to almost nothing when the guest is down (deallocating memory >> and threads) so it doesn't impact guest density, but it allows for other >> minor features such as wake-on-LAN and RTC alarm wakeups. > > 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. -- 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 majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [Qemu-devel] Adding an IPMI BMC device to KVM
On 05/06/2012 08:11 AM, Avi Kivity wrote: (copied qemu-devel) On 05/04/2012 10:10 PM, Corey Minyard wrote: Either way, is this interesting for including into KVM? Not kvm, but certainly it would make a good addition to qemu, which kvm then uses. Does anyone have any opinions on the possible ways to implement this? My preference would be the second alternative. The issue you raise is a good one. There are two ways we can approach it: - have the management system intercept IPMI requests, start up a qemu instance (if it's down), and let it handle the event. - change the whole system to keep a running qemu even when the guest is down. This is a much larger change; it involves reducing the memory footprint to almost nothing when the guest is down (deallocating memory and threads) so it doesn't impact guest density, but it allows for other minor features such as wake-on-LAN and RTC alarm wakeups. 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. Regards, Anthony Liguori -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
