> From: Zhu, Lingshan <lingshan.zhu@xxxxxxxxx> > Sent: Tuesday, July 12, 2022 11:03 PM > > > On 7/13/2022 12:48 AM, Parav Pandit wrote: > >> From: Zhu, Lingshan <lingshan.zhu@xxxxxxxxx> > >> Sent: Sunday, July 10, 2022 10:30 PM > >>> Showing max_vq_pairs of 1 even when _MQ is not negotiated, > >>> incorrectly > >> says that max_vq_pairs is exposed to the guest, but it is not offered. > >>> So, please fix the iproute2 to not print max_vq_pairs when it is not > >> returned by the kernel. > >> iproute2 can report whether there is MQ feature in the device / > >> driver feature bits. > >> I think iproute2 only queries the number of max queues here. > >> > >> max_vq_pairs shows how many queue pairs there, this attribute's > >> existence does not depend on MQ, if no MQ, there are still one queue > >> pair, so just show one. > > This netlink attribute's existence is depending on the _MQ feature bit > existence. > why? If no MQ, then no queues? > > We can break that and report the value, but if we break that there are > many other config space bits who doesn’t have good default like > max_vq_pairs. > max_vq_paris may not have a default value, but we know if there is no MQ, > a virtio-net still have one queue pair to be functional. > > There is ambiguity for user space what to do with it and so in the kernel > space.. > > Instead of dealing with them differently in kernel, at present we attach > each netlink attribute to a respective feature bit wherever applicable. > > And code in kernel and user space is uniform to handle them. > I get your point, but you see, by "max_vq_pairs", the user space tool is > asking how many queue pairs there, it is not asking whether the device have > MQ. > Even no _MQ, we still need to tell the users that there are one queue pair, or > it is not a functional virtio-net, we should detect this error earlier in the > device initialization. It is not an error. :) When the user space which invokes netlink commands, detects that _MQ is not supported, hence it takes max_queue_pair = 1 by itself. > > I think it is still uniform, it there is _MQ, we return cfg.max_queue_pair, if no > _MQ, return 1, still by netlink. Better to do that in user space because we cannot do same for other config fields. > > Thanks _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
