[libvirt] [PATCH REPOST v2 0/3] Add callback mech for qemu and nodedev

[Paolo Bonzini]

On 22/02/2017 11:05, Daniel P. Berrange wrote:
> I'd also suggest just assigning the whole vHBA

What do you mean by "assigning the whole vHBA"?  There is no concept of
a vHBA as e.g. a PCI virtual function.

> , but We can still make
> it possible for a mgmt app to dynamically add/remove LUNS from a vHBA.


> Our node device APIs can report events when devices appear/disappear
> so an app can create a vHBA and monitor for LUN changes & update the
> guest. That said I'm curious how you'd handle remove, because surely
> by the time you see a LUN disappear at vHBA, the guest is already
> broken as its got an orphaned device. This seems like another reason
> to just assign the vHBA itself to let the guest deal with LUN removal
> more directly.

This is the same on bare metal: the device is orphaned at the time you
unplug it.  If the guest is using it and doesn't have a fallback, bad
things happen.  If it is not using it, or if it's using multipath,
things ought to work just fine.

Paolo