[libvirt] PF interface brought down if guest using a VF in hostdev mode under 802.1Qbh

Hi, In 802.1Qbh case where exists a SR-IOV capable network device, if any of the virtual functions of this device is used in hostdev mode for the guest, port-profile disassociate will also cause physical function interface to go down. This appears to be a bug, but wanted to find if this was done intentionally for some reasons. To be more specific, if a network device supports SRIOV and its VF is being used in pci passthrough mode, when the guest is shutdown or destroyed following happens - qemuProcessStop \_ qemuDomainReAttachHostdevDevices(hostdevs) \_ qemuDomainHostdevNetConfigRestore(hostdev) \_ virNetDevPortProfileDisassociate(linkdev) \_ virNetDevSetOnline(linkdev, false) In above, qemuDomainHostdevNetConfigRestore() finds out the PF for provided hostdev (which is VF) and passes it to virNetDevPortProfileDisassociate() as linkdev. Later, linkdev gets passed to virNetDevSetOnline() where the interface is brought down by clearing IFF_UP flag. However, in macvtap emulation mode, virNetDevMacVLanDeleteWithVPortProfile() passes VF as linkdev (and -1 as vf) to virNetDevPortProfileDisassociate(), hence, not affecting PF at all. Bringing down a PF, when only VF is being brought down is not expected behavior (unless, I'm missing something here). A way to get around it would be to check if there exists vf (>=0) in virNetDevPortProfileDisassociate(), and if so, it should only pass the interface name of this VF rather than PF itself to virNetDevSetOnline(). If it sounds reasonable, I'll send out a fix. Thanks, Nishank