> From: Zhu, Lingshan <lingshan.zhu@xxxxxxxxx> > Sent: Friday, July 8, 2022 2:16 AM > > On 7/2/2022 6:02 AM, Parav Pandit wrote: > > > >> From: Zhu Lingshan <lingshan.zhu@xxxxxxxxx> > >> Sent: Friday, July 1, 2022 9:28 AM > >> > >> This commit adds a new vDPA netlink attribution > >> VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES. Userspace can query > features > >> of vDPA devices through this new attr. > >> > >> Fixes: a64917bc2e9b vdpa: (Provide interface to read driver feature) > > Missing the "" in the line. > will fix > > I reviewed the patches again. > > > > However, this is not the fix. > > A fix cannot add a new UAPI. > I think we have discussed this, on why we can not re-name the existing > wrong named attr, and why we can not re-use the attr. > So are you suggesting remove this fixes tag? > And why a fix can not add a new uAPI? Because a new attribute cannot fix any existing attribute. What is done in the patch is show current attributes of the vdpa device (which sometimes contains a different value than the mgmt. device). So it is a new functionality that cannot have fixes tag. > > > > Code is already considering negotiated driver features to return the device > config space. > > Hence it is fine. > No, the spec says: > The device MUST allow reading of any device-specific configuration field > before FEATURES_OK is set by the driver. > > > > This patch intents to provide device features to user space. > > First what vdpa device are capable of, are already returned by features > attribute on the management device. > > This is done in commit [1]. > we have discussed this in another thread, vDPA device feature bits can be > different from the management device feature bits. > > Yes. > > The only reason to have it is, when one management device indicates that > feature is supported, but device may end up not supporting this feature if > such feature is shared with other devices on same physical device. > > For example all VFs may not be symmetric after large number of them are > in use. In such case features bit of management device can differ (more > features) than the vdpa device of this VF. > > Hence, showing on the device is useful. > > > > As mentioned before in V2, commit [1] has wrongly named the attribute to > VDPA_ATTR_DEV_SUPPORTED_FEATURES. > > It should have been, > VDPA_ATTR_DEV_MGMTDEV_SUPPORTED_FEATURES. > > Because it is in UAPI, and since we don't want to break compilation of > > iproute2, It cannot be renamed anymore. > Yes, rename it will break current uAPI, so I can not rename it. > > I know, which is why this patch needs to do following listed changes described in previous email. > > Given that, we do not want to start trend of naming device attributes with > additional _VDPA_ to it as done in this patch. > > Error in commit [1] was exception. > > > > Hence, please reuse VDPA_ATTR_DEV_SUPPORTED_FEATURES to return > for device features too. > > > > Secondly, you need output example for showing device features in the > commit log. > > > > 3rd, please drop the fixes tag as new capability is not a fix. > > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
