[libvirt] RFC: managing "pci passthrough" usage of sriov VFs via a new network forward type

[Laine Stump]

On 08/24/2011 05:48 AM, Daniel P. Berrange wrote:
> Having transient <hostdev>s does not really work nicely, because we want
> all PCI devices in the guest to be persistently in the XML, so we can
> ensure the guest PCI address does not get changed each time the guest
> is run.


Ah, well that clinches it - definitely an absolute requirement :-(




>   It also doesn't really solve the problem of finding all attached
> host devices for a guest, since you still have to look at two different
> places when the guest is shutoff. IMHO the<hostdev>  needs to be persistent


Yep, you've convinced me (at least that the guest-side PCI info needs to 
be persistent, and the proper place for that is in a <hostdev>). I'm 
still not comfortable with having all that other extra info in the 
<hostdev> though. Let me take a few days to think about it and maybe 
come up with a logical method of having the hostdev reference back to 
the higher level info rather than containing it directly. If I can't 
think of something that doesn't look like a kludge, then we'll just have 
to do it by including mac address, port profile, etc as subelements of 
<hostdev>.