• Jack Morgenstein's avatar
    IB/mlx4: Use correct subnet-prefix in QP1 mads under SR-IOV · 6bec514a
    Jack Morgenstein authored
    commit 8ec07bf8 upstream.
    
    When sending QP1 MAD packets which use a GRH, the source GID
    (which consists of the 64-bit subnet prefix, and the 64 bit port GUID)
    must be included in the packet GRH.
    
    For SR-IOV, a GID cache is used, since the source GID needs to be the
    slave's source GID, and not the Hypervisor's GID. This cache also
    included a subnet_prefix. Unfortunately, the subnet_prefix field in
    the cache was never initialized (to the default subnet prefix 0xfe80::0).
    As a result, this field remained all zeroes.  Therefore, when SR-IOV
    was active, all QP1 packets which included a GRH had a source GID
    subnet prefix of all-zeroes.
    
    However, the subnet-prefix should initially be 0xfe80::0 (the default
    subnet prefix). In addition, if OpenSM modifies a port's subnet prefix,
    the new subnet prefix must be used in the GRH when sending QP1 packets.
    To fix this we now initialize the subnet prefix in the SR-IOV GID cache
    to the default subnet prefix. We update the cached value if/when OpenSM
    modifies the port's subnet prefix. We take this cached value when sending
    QP1 packets when SR-IOV is active.
    
    Note that the value is stored as an atomic64. This eliminates any need
    for locking when the subnet prefix is being updated.
    
    Note also that we depend on the FW generating the "port management change"
    event for tracking subnet-prefix changes performed by OpenSM. If running
    early FW (before 2.9.4630), subnet prefix changes will not be tracked (but
    the default subnet prefix still will be stored in the cache; therefore
    users who do not modify the subnet prefix will not have a problem).
    IF there is a need for such tracking also for early FW, we will add that
    capability in a subsequent patch.
    
    Fixes: 1ffeb2eb ("IB/mlx4: SR-IOV IB context objects and proxy/tunnel SQP support")
    Signed-off-by: default avatarJack Morgenstein <jackm@dev.mellanox.co.il>
    Signed-off-by: default avatarLeon Romanovsky <leon@kernel.org>
    Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    6bec514a
qp.c 95.2 KB