Date:   Mon, 13 Aug 2018 11:43:37 -0700
From:   Shannon Nelson <shannon.nelson@...cle.com>
To:     intel-wired-lan@...ts.osuosl.org, jeffrey.t.kirsher@...el.com
Cc:     steffen.klassert@...unet.com, netdev@...r.kernel.org
Subject: [PATCH next-queue 0/8] ixgbe/ixgbevf: IPsec offload support for VFs

This set of patches implements IPsec hardware offload for VF devices in
Intel's 10Gbe x540 family of Ethernet devices.

The IPsec HW offload feature has been in the x540/Niantic family of
network devices since their release in 2009, but there was no Linux
kernel support for the offload until 2017.  After the XFRM code added
support for the offload last year, the hw offload was added to the ixgbe
PF driver.

Since the related x540 VF device uses same setup as the PF for implementing
the offload, adding the feature to the ixgbevf seemed like a good idea.
In this case, the PF owns the device registers, so the VF simply packages
up the request information into a VF<->PF message and the PF does the
device configuration.  The resulting IPsec throughput is roughly equivalent
to what we see in the PF - nearly line-rate, with the expected drop in CPU
cycles burned.  (I'm not great at performance statistics, I'll let better
folks do the actual measurements as they pertain to their own usage)

To make use of the capability, first two things are needed: the PF must
be told to enable the offload for VFs (it is off by default) and the VF
must be trusted.  A new ethtool priv-flag for ixgbe is added to control
VF offload support.  For example:

	ethtool --set-priv-flags eth0 vf-ipsec on
	ip link set eth0 vf 1 trust on

Once those are set up and the VF device is UP, the user can add SAs the
same as for PFs, whether the VF is in the host or has been assigned to
a VM.

Note that the x540 chip supports a total of 1024 Rx plus 1024 Tx Security
Associations (SAs), shared among the PF and VFs that might request them.
It is entirely possible for a single VF to soak up all the offload
capability, which would likely annoy some people.  It seems rather
arbitrary to try to set a limit for how many a VF could be allowed,
but this is mitigated somewhat by the need for "trust" and "vf-ipsec"
to be enabled.  I suppose we could come up with a way to make a limit
configurable, but there is no existing method for adding that kind
configuration so I'll leave that to a future discussion.

Currently this doesn't support Tx offload as the hardware encryption
engine doesn't seem to engage on the Tx packets.  This may be a lingering
driver bug, more investigation is needed.  Until then, requests for a Tx
offload are failed and the userland requester will need to add Tx SAs
without the offload attribute.

Given that we don't have Tx offload support, the benefit here is less
than it could be, but is definitely still noticeable.  For example, with
informal iperf testing over a 10Gbps link, with full offload in a PF on
one side and a VF in a VM on the other side on a CPU with AES instructions:

    Reference:
	No IPsec:                         9.4 Gbps
	IPsec offload btwn two PFs:       9.2 Gbps
    VF as the iperf receiver:
	IPsec offload on PF, none on VF:  6.8 Gbps
	IPsec offload on PF and VF:       9.2 Gbps   << biggest benefit
    VF as the iperf sender:
	IPsec offload on PF, none on VF:  4.8 Gbps
	IPsec offload on PF and VF:       4.8 Gbps

The iperf traffic is primarily uni-directional, and we can see the most
benefit when VF is the iperf server and is receiving the test traffic.
Watching output from sar also shows a nice decrease in CPU utilization.


Shannon Nelson (8):
  ixgbe: reload ipsec ip table after sa tables
  ixgbe: prep ipsec constants for later use
  ixgbe: add VF ipsec management
  ixgbe: add VF IPsec offload enable flag
  ixgbe: add VF IPsec offload request message handling
  ixgbevf: add defines for IPsec offload request
  ixgbevf: add VF ipsec offload code
  ixgbevf: enable VF ipsec offload operations

 drivers/net/ethernet/intel/ixgbe/ixgbe.h          |  20 +-
 drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c  |   9 +
 drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.c    | 275 ++++++++-
 drivers/net/ethernet/intel/ixgbe/ixgbe_ipsec.h    |  13 +
 drivers/net/ethernet/intel/ixgbe/ixgbe_mbx.h      |   5 +
 drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c    |  17 +-
 drivers/net/ethernet/intel/ixgbevf/Makefile       |   1 +
 drivers/net/ethernet/intel/ixgbevf/defines.h      |  10 +-
 drivers/net/ethernet/intel/ixgbevf/ethtool.c      |   2 +
 drivers/net/ethernet/intel/ixgbevf/ipsec.c        | 673 ++++++++++++++++++++++
 drivers/net/ethernet/intel/ixgbevf/ipsec.h        |  66 +++
 drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      |  33 ++
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |  74 ++-
 drivers/net/ethernet/intel/ixgbevf/mbx.h          |   5 +
 drivers/net/ethernet/intel/ixgbevf/vf.c           |   4 +
 15 files changed, 1163 insertions(+), 44 deletions(-)
 create mode 100644 drivers/net/ethernet/intel/ixgbevf/ipsec.c
 create mode 100644 drivers/net/ethernet/intel/ixgbevf/ipsec.h

-- 
2.7.4

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