Hi Alex, Cornelia, > -----Original Message----- > From: kvm-owner@xxxxxxxxxxxxxxx <kvm-owner@xxxxxxxxxxxxxxx> On Behalf > Of Parav Pandit > Sent: Tuesday, August 27, 2019 2:11 AM > To: alex.williamson@xxxxxxxxxx; Jiri Pirko <jiri@xxxxxxxxxxxx>; > kwankhede@xxxxxxxxxx; cohuck@xxxxxxxxxx; davem@xxxxxxxxxxxxx > Cc: kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > netdev@xxxxxxxxxxxxxxx; Parav Pandit <parav@xxxxxxxxxxxx> > Subject: [PATCH 0/4] Introduce variable length mdev alias > > To have consistent naming for the netdevice of a mdev and to have consistent > naming of the devlink port [1] of a mdev, which is formed using > phys_port_name of the devlink port, current UUID is not usable because UUID > is too long. > > UUID in string format is 36-characters long and in binary 128-bit. > Both formats are not able to fit within 15 characters limit of netdev name. > > It is desired to have mdev device naming consistent using UUID. > So that widely used user space framework such as ovs [2] can make use of > mdev representor in similar way as PCIe SR-IOV VF and PF representors. > > Hence, > (a) mdev alias is created which is derived using sha1 from the mdev name. > (b) Vendor driver describes how long an alias should be for the child mdev > created for a given parent. > (c) Mdev aliases are unique at system level. > (d) alias is created optionally whenever parent requested. > This ensures that non networking mdev parents can function without alias > creation overhead. > > This design is discussed at [3]. > > An example systemd/udev extension will have, > > 1. netdev name created using mdev alias available in sysfs. > > mdev UUID=83b8f4f2-509f-382f-3c1e-e6bfe0fa1001 > mdev 12 character alias=cd5b146a80a5 > > netdev name of this mdev = enmcd5b146a80a5 Here en = Ethernet link m = > mediated device > > 2. devlink port phys_port_name created using mdev alias. > devlink phys_port_name=pcd5b146a80a5 > > This patchset enables mdev core to maintain unique alias for a mdev. > > Patch-1 Introduces mdev alias using sha1. > Patch-2 Ensures that mdev alias is unique in a system. > Patch-3 Exposes mdev alias in a sysfs hirerchy. > Patch-4 Extends mtty driver to optionally provide alias generation. > This also enables to test UUID based sha1 collision and trigger error handling > for duplicate sha1 results. > > In future when networking driver wants to use mdev alias, mdev_alias() API will > be added to derive devlink port name. > Now that majority of above patches looks in shape and I addressed all comments, In next v1 post, I was considering to include mdev_alias() and have example use in mtty driver. This way, subsequent series of mlx5_core who intents to use mdev_alias() API makes it easy to review and merge through Dave M, netdev tree. Is that ok with you?
