Hi Simon,
Thanks for the review i fixed it in v4.
On 9/5/25 3:25 PM, Simon Horman wrote:
On Thu, Sep 04, 2025 at 12:43:05AM +0300, [email protected] wrote:
From: Mohammad Heib <[email protected]>
Currently the i40e driver enforces its own internally calculated per-VF MAC
filter limit, derived from the number of allocated VFs and available
hardware resources. This limit is not configurable by the administrator,
which makes it difficult to control how many MAC addresses each VF may
use.
This patch adds support for the new generic devlink runtime parameter
"max_mac_per_vf" which provides administrators with a way to cap the
number of MAC addresses a VF can use:
- When the parameter is set to 0 (default), the driver continues to use
its internally calculated limit.
- When set to a non-zero value, the driver applies this value as a strict
cap for VFs, overriding the internal calculation.
Important notes:
- The configured value is a theoretical maximum. Hardware limits may
still prevent additional MAC addresses from being added, even if the
parameter allows it.
- Since MAC filters are a shared hardware resource across all VFs,
setting a high value may cause resource contention and starve other
VFs.
- This change gives administrators predictable and flexible control over
VF resource allocation, while still respecting hardware limitations.
- Previous discussion about this change:
https://lore.kernel.org/netdev/[email protected]
https://lore.kernel.org/netdev/[email protected]
Signed-off-by: Mohammad Heib <[email protected]>
---
Documentation/networking/devlink/i40e.rst | 32 +++++++++++++
drivers/net/ethernet/intel/i40e/i40e.h | 4 ++
.../net/ethernet/intel/i40e/i40e_devlink.c | 48 ++++++++++++++++++-
.../ethernet/intel/i40e/i40e_virtchnl_pf.c | 31 ++++++++----
4 files changed, 105 insertions(+), 10 deletions(-)
diff --git a/Documentation/networking/devlink/i40e.rst
b/Documentation/networking/devlink/i40e.rst
index d3cb5bb5197e..524524fdd3de 100644
--- a/Documentation/networking/devlink/i40e.rst
+++ b/Documentation/networking/devlink/i40e.rst
@@ -7,6 +7,38 @@ i40e devlink support
This document describes the devlink features implemented by the ``i40e``
device driver.
+Parameters
+==========
+
+.. list-table:: Generic parameters implemented
+ :widths: 5 5 90
+
+ * - Name
+ - Mode
+ - Notes
+ * - ``max_mac_per_vf``
+ - runtime
+ - Controls the maximum number of MAC addresses a VF can use
+ on i40e devices.
+
+ By default (``0``), the driver enforces its internally calculated
per-VF
+ MAC filter limit, which is based on the number of allocated VFS.
+
+ If set to a non-zero value, this parameter acts as a strict cap:
+ the driver will use the user-provided value instead of its internal
+ calculation.
+
+ **Important notes:**
+ - MAC filters are a **shared hardware resource** across all VFs.
Sorry for not noticing this before sending my previous response.
make htmldocs is unhappy about the line above. Could you look into it?
.../i40e.rst:33: ERROR: Unexpected indentation. [docutils]
+ Setting a high value may cause other VFs to be starved of filters.
+
+ - This value is a **theoretical maximum**. The hardware may return
+ errors when its absolute limit is reached, regardless of the value
+ set here.
+
+ The default value is ``0`` (internal calculation is used).
+
+
...
