i40e: add ability to reset VF for Tx and Rx MDD events

Implement "mdd-auto-reset-vf" priv-flag to handle Tx and Rx MDD events for VFs.
This flag is also used in other network adapters like ICE.

Usage:
- "on"  - The problematic VF will be automatically reset
	  if a malformed descriptor is detected.
- "off" - The problematic VF will be disabled.

In cases where a VF sends malformed packets classified as malicious, it can
cause the Tx queue to freeze, rendering it unusable for several minutes. When
an MDD event occurs, this new implementation allows for a graceful VF reset to
quickly restore operational state.

Currently, VF queues are disabled if an MDD event occurs. This patch adds the
ability to reset the VF if a Tx or Rx MDD event occurs. It also includes MDD
event logging throttling to avoid dmesg pollution and unifies the format of
Tx and Rx MDD messages.

Note: Standard message rate limiting functions like dev_info_ratelimited()
do not meet our requirements. Custom rate limiting is implemented,
please see the code for details.

Co-developed-by: Jan Sokolowski <jan.sokolowski@intel.com>
Signed-off-by: Jan Sokolowski <jan.sokolowski@intel.com>
Co-developed-by: Padraig J Connolly <padraig.j.connolly@intel.com>
Signed-off-by: Padraig J Connolly <padraig.j.connolly@intel.com>
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Reviewed-by: Michal Schmidt <mschmidt@redhat.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Link: https://patch.msgid.link/20250106221929.956999-13-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/Documentation/networking/device_drivers/ethernet/intel/i40e.rst b/Documentation/networking/device_drivers/ethernet/intel/i40e.rst
index 4fbaa1a2d674..53d9d5829d69 100644
--- a/Documentation/networking/device_drivers/ethernet/intel/i40e.rst
+++ b/Documentation/networking/device_drivers/ethernet/intel/i40e.rst
@@ -299,6 +299,18 @@ Use ethtool to view and set link-down-on-close, as follows::
   ethtool --show-priv-flags ethX
   ethtool --set-priv-flags ethX link-down-on-close [on|off]
 
+Setting the mdd-auto-reset-vf Private Flag
+------------------------------------------
+
+When the mdd-auto-reset-vf private flag is set to "on", the problematic VF will
+be automatically reset if a malformed descriptor is detected. If the flag is
+set to "off", the problematic VF will be disabled.
+
+Use ethtool to view and set mdd-auto-reset-vf, as follows::
+
+  ethtool --show-priv-flags ethX
+  ethtool --set-priv-flags ethX mdd-auto-reset-vf [on|off]
+
 Viewing Link Messages
 ---------------------
 Link messages will not be displayed to the console if the distribution is