[Qemu-devel] [RFC] virtio-fc: draft idea of virtual fibre channel HBA

[Lin Ma]

Hi all,
 
We know that libvirt can create fibre channels vHBA on host
based on npiv, and present the LUNs to guest.
 
I'd like to implement a virtual fibre channel HBA for qemu,
I havn't investigate it deeply yet. The idea presents a fc
vHBA in guest, interact with remote fc switch through npiv,
The LUNs will be recognized inside guest. I sent this email
here to see if you are in agreement with this approach and
hope to get some ideas/suggestions.
 
The frontend is based on virtio, say virtio-fc-pci; the backend
is based on npiv of physical fc hba on host.
The implementation of this virtual fc hba doesn't support Fc-al,
only supports Fabric. It wrappers scsi data info fc frames, then
forwards them to backend, sounds like scsi over fc.
(maybe I can re-use some of virtio-scsi code/idea to deal with scsi data)
 
The minimum invocation may look like:
qemu-system-x86_64 \
...... \
-object fibrechannel-backend,id=fcdev0,host=0000:81:00.0 \
-device 
virtio-fc-pci,id=vfc0,fc_backend=fcdev0,wwpn=1000000000000001,wwnn=1100000000000001
 \
......
 
BTW, I have no idea how to make migration works:
How to deal with the BDF during migration?
How to deal with the Fabric ID during migration?
 
It's a draft idea, There are lots of related code I need to
investigate, Currently this is all thoughts I have.
 
Hello Paolo and Stefan, You are the authors of virtio-scsi,
and had some in-depth discuss about virtio-scsi in 2011
with Hannes, May I have your ideas/thoughts?
 
Thanks,
Lin