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. > > > > 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? -- MST _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
