From: Anthony Liguori <anthony@codemonkey.ws>
Subject: Re: Adding an IPMI BMC device to KVM
Date: Sun, 06 May 2012 09:35:10 -0500
Message-ID: <4FA68C1E.3070503@codemonkey.ws>
References: <4FA429BA.3040006@acm.org> <4FA6788A.8080500@redhat.com>
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Cc: qemu-devel <qemu-devel@nongnu.org>, Corey Minyard <tcminyard@gmail.com>,
	minyard@acm.org, kvm@vger.kernel.org
To: Avi Kivity <avi@redhat.com>
In-Reply-To: <4FA6788A.8080500@redhat.com>
Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org
Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org

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

>