> From: Michael S. Tsirkin <mst@xxxxxxxxxx> > Sent: Tuesday, July 26, 2022 3:49 PM > > On Tue, Jul 26, 2022 at 03:54:06PM +0000, Parav Pandit wrote: > > > > > From: Michael S. Tsirkin <mst@xxxxxxxxxx> > > > Sent: Wednesday, July 13, 2022 1:27 AM > > > > > > On Fri, Jul 01, 2022 at 10:07:59PM +0000, Parav Pandit wrote: > > > > > > > > > > > > > From: Zhu Lingshan <lingshan.zhu@xxxxxxxxx> > > > > > Sent: Friday, July 1, 2022 9:28 AM If VIRTIO_NET_F_MQ == 0, the > > > > > virtio device should have one queue pair, so when userspace > > > > > querying queue pair numbers, it should return mq=1 than zero. > > > > > > > > > > Function vdpa_dev_net_config_fill() fills the attributions of > > > > > the vDPA devices, so that it should call > > > > > vdpa_dev_net_mq_config_fill() so the parameter in > > > > > vdpa_dev_net_mq_config_fill() should be feature_device than > > > > > feature_driver for the vDPA devices themselves > > > > > > > > > > Before this change, 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 0 mtu 1500 > > > > > > > > > The fix belongs to user space. > > > > When a feature bit _MQ is not negotiated, vdpa kernel space will > > > > not add > > > attribute VDPA_ATTR_DEV_NET_CFG_MAX_VQP. > > > > When such attribute is not returned by kernel, max_vq_pairs should > > > > not be > > > shown by the iproute2. > > > > > > > > We have many config space fields that depend on the feature bits > > > > and > > > some of them do not have any defaults. > > > > To keep consistency of existence of config space fields among all, > > > > we don't > > > want to show default like below. > > > > > > > > Please fix the iproute2 to not print max_vq_pairs when it is not > > > > returned by > > > the kernel. > > > > > > Parav I read the discussion and don't get your argument. From > > > driver's POV _MQ with 1 VQ pair and !_MQ are exactly functionally > equivalent. > > But we are talking from user POV here. > > From spec POV there's just driver and device, user would be part of driver here. User space application still need to inspect the _MQ bit to > > > > > > > It's true that iproute probably needs to be fixed too, to handle old kernels. > > > But iproute is not the only userspace, why not make it's life easier > > > by fixing the kernel? > > Because it cannot be fixed for other config space fields which are control by > feature bits those do not have any defaults. > > So better to treat all in same way from user POV. > > Consistency is good for sure. What are these other fields though? > Can you give examples so I understand please? speed only exists if VIRTIO_NET_F_SPEED_DUPLEX. rss_max_key_size exists only if VIRTIO_NET_F_RSS exists. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
