Re: [libvirt] RFC exposing SRIOV PF<->VF relationships

[Dave Allan <dallan redhat com>]

Daniel P. Berrange wrote:
> On Mon, Nov 16, 2009 at 04:14:34PM -0500, Dave Allan wrote:
> > It would be helpful to have an API that exposes the relationship between 
> > SR IOV physical functions (PFs) and virtual functions (VFs).  I'm 
> > thinking of implementing three new API calls and adding a small amount 
> > of additional information in the node device pci device capability, as 
> > in the attached patch.  Let me know what you think.
>
> Do we really need extra APis for this, vs exposing it in the XML ?
>
> I'd think we either use the existing parent/child relationship. ie
> munge a VF's parent link to point to the PF device, or we could just
> add a new element giving the device name of the physical function.

My first thought was also to use the parent/child relationship, but I 
talked to Chris Wright about it and the PF/VF relationship is in 
addition to, rather than a replacement of, the parent/child device 
relationship.  In other words, the parent of both a PF and VF is the PCI 
device, so we do need to add new elements for physical and virtual 
functions.  I'll dispense with the API and simply add to the XML.

Dave