On Sun, Mar 29, 2015 at 4:51 PM, Or Gerlitz <[email protected]> wrote:
> Under the existing implementation for virtual GIDs, if the SM is not
> reachable or incurs a delayed response, or if the VF is probed into a
> VM before their GUID is registered with the SM, there exists a window
> in time in which the VF sees an incorrect GID, i.e., not the GID that
> was intended by the admin. This results in exposing a temporal identity
> to the VF.

Hi Roland, so your for-next branch is again way behind, still on 3.19
and while 4.0 is soon @ rc6, we couldn't even rebase this series on
it. It's really hard where your tree is really active once every nine
weeks or so, e.g only few days before/after rc1's. I'm not sure what
you expect us to do, kernel development simply needs not be like this.

April 3rd-12th is holiday here, and we would like to really really
know early this week what you intend to pull for 4.1 out of the
pending things in linux-rdma.

Or.


> Moreover, a subsequent change in the alias GID causes a spec-incompliant
> change to the VF identity. Some guest operating systems, such as Windows,
> cannot tolerate such changes.
>
> This series solves above problem by exposing the admin desired value instead
> of the value that was approved by the SM. As long as the SM doesn't approve
> the GID, the VF would see its link as down.
>
> In addition, we request GIDs from the SM on demand, i.e., when a VF actually
> needs them, and release them when the GIDs are no longer in use. In cloud
> environments, this is useful for GID migrations, in which a GID is assigned to
> a VF on the destination HCA, while the VF on the source HCA is shut down (but
> the GID was not administratively released).
>
> For reasons of compatibility, an explicit admin request to set/change a GUID
> entry is done immediately, regardless of whether the VF is active or not. This
> allows administrators to change the GUID without the need to unbind/bind the 
> VF.
>
> In addition, the existing implementation doesn't support a persistency
> mechanism to retry a GUID request when the SM has rejected it for any reason.
> The PF driver shall keep trying to acquire the specified GUID indefinitely by
> utilizing an exponential back off scheme, this should be managed per GUID and
> be aligned with other incoming admin requests.
>
> This ability needed especially for the on-demand GUID feature. In this case, 
> we
> must manage the GUID's status per entry and handle cases that some entries are
> temporarily rejected.
>
> The first patch adds the persistency support and is pre-requisites for the
> series.  Further patches make the change to use the admin VF behavior as
> described above.
>
> Finally, the default mode is changed to be HOST assigned instead of SM
> assigned. This is the expected operational mode, because it doesn't depend on
> SM availability as described above.
>
> Yishai and Or.
>
> Yishai Hadas (9):
>   IB/mlx4: Alias GUID adding persistency support
>   net/mlx4_core: Manage alias GUID per VF
>   net/mlx4_core: Set initial admin GUIDs for VFs
>   IB/mlx4: Manage admin alias GUID upon admin request
>   IB/mlx4: Change init flow to request alias GUIDs for active VFs
>   IB/mlx4: Request alias GUID on demand
>   net/mlx4_core: Raise slave shutdown event upon FLR
>   net/mlx4_core: Return the admin alias GUID upon host view request
>   IB/mlx4: Change alias guids default to be host assigned
>
>  drivers/infiniband/hw/mlx4/alias_GUID.c   |  468 
> +++++++++++++++++++++--------
>  drivers/infiniband/hw/mlx4/main.c         |   26 ++-
>  drivers/infiniband/hw/mlx4/mlx4_ib.h      |   14 +-
>  drivers/infiniband/hw/mlx4/sysfs.c        |   44 +--
>  drivers/net/ethernet/mellanox/mlx4/cmd.c  |   42 ++-
>  drivers/net/ethernet/mellanox/mlx4/eq.c   |    2 +
>  drivers/net/ethernet/mellanox/mlx4/main.c |   39 +++
>  drivers/net/ethernet/mellanox/mlx4/mlx4.h |    1 +
>  include/linux/mlx4/device.h               |    4 +
>  9 files changed, 459 insertions(+), 181 deletions(-)
>
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