From: Michael S. Tsirkin <mst@redhat.com>
Sent: Tuesday, August 9, 2022 3:36 PM

quoted

quoted

After applying this commit, when MQ = 0, iproute2 output:
$vdpa dev config show vdpa0
vdpa0: mac 00:e8:ca:11:be:05 link up link_announce false
max_vq_pairs 1 mtu 1500

No. We do not want to diverge returning values of config space for fields

which are not present as discussed in previous versions.

quoted

Please drop this patch.
Nack on this patch.

Wrt this patch as far as I'm concerned you guys are bikeshedding.

Parav generally don't send nacks please they are not helpful.

Ok. I explained the technical reasoning that we don't diverge in fields. All are linked to the respective feature bits uniformly.
This I explained repeatedly in almost v1 to v3.
And reporting 1 is mis-leading, because it says _MQ is not negotiated, how come this device tells its config space has max_qp = 1.

But if you want to proceed to diverge kernel on feature bits go ahead. It requires inspection feature but feature.
I just don't see how this can be well maintained.

Commit log doesn't even describe the weird use case that says "as user space, I do not want to read device feature bits and just want to read config space to decide...".
Odd..