On Sat, Aug 14, 2021 at 03:03:52AM +0000, William Kucharski wrote: > I noticed that under certain circumstances, GID 0 for some interfaces is reported as all 0s, or empty. > > This seems to be correlated with code in drivers/infiniband/core/roce_gid_mgmt.c in the routine > ndev_event_link(), which does this: > > /* > * When a lower netdev is linked to its upper bonding > * netdev, delete lower slave netdev's default GIDs. > */ > cmds[0] = bonding_default_del_cmd; > cmds[0].ndev = event_ndev; > cmds[0].filter_ndev = changeupper_info->upper_dev; > > bonding_default_del_cmd will result in a call to del_default_gids(). > > However, given version 1.2.1 of the IB spec, looking at page 145, line 20: > > 4.1.1 GID USAGE AND PROPERTIES > > 1) Each endport shall be assigned at least one unicast GID. The first unicast GID assigned shall be > created using the manufacturer assigned EUI-64 identifier. This GID is referred to as GID index 0 > and is formed by techniques 3(a) or 3(b) described below. > > 2) The default GID prefix shall be (0xFE80::0). A packet using the default GID prefix and either a > manufacturer assigned or SM assigned EUI-64 must always be accepted by an endnode. A packet > containing a GRH with a destination GID with this prefix must never be forwarded by a router, > i.e. it is restricted to the local subnet. > > 3) A unicast GID shall be created using one or more of the following mechanisms: > > a) Concatenation of the default GID prefix with the manufacturer as > signed EUI-64 identifier associated with an endport. This GID is > referred to as the default GID. > > b) Concatenation of a subnet manager assigned 64-bit GID prefix and the > manufacturer assigned EUI-64 identifier associated with an endport. > > c) Assignment of a GID by the subnet manager. The subnet manager creates a > GID by concatenating the GID prefix (default or assigned) with a set of > locally assigned EUI-64 values (at GID index 1 or above). > > Each endport must be assigned at least one unicast GID using (a). Additional > GIDs may be assigned using (b) and/or (c). Note: A subnet 2 shall only have > one assigned GID prefix (non default) at any given time. > > make_default_gid()and add default_gids() seem to have that all taken care of. > > What concerns me is the code that removes GID index 0, as page 436, line 35, states: > > C10-2: For each GID Table, the first entry in the table shall contain the read-only invariant value of GID index 0. > > So is it actually OK to remove GID 0 when removing default GIDs via del_default_gids(), or should it be preserving GID index 0 at all times? > > This is because it appears a call to rdma_query_gid() (as in ib_find_gid()) will return -EINVAL for a table if GID 0 has been deleted. > > Am I misreading the spec, or is there a bug here? This language can not apply to rocev2 which does not have a default GID at all. Jason
