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

Dave Allan dallan at redhat.com
Tue Nov 17 19:27:02 UTC 2009

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.


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