Merge branch 'ethtool-rss-driver-tweaks'

Jakub Kicinski says:

====================
ethtool: rss: driver tweaks and netlink context dumps

This series is a semi-related collection of RSS patches.
Main point is supporting dumping RSS contexts via ethtool netlink.
At present additional RSS contexts can be queried one by one, and
assuming user know the right IDs. This series uses the XArray
added by Ed to provide netlink dump support for ETHTOOL_GET_RSS.

Patch 1 is a trivial selftest debug patch.
Patch 2 coverts mvpp2 for no real reason other than that I had
	a grand plan of converting all drivers at some stage.
Patch 3 removes a now moot check from mlx5 so that all tests
	can pass.
Patch 4 and 5 make a bit used for context support optional,
	for easier grepping of drivers which need converting
	if nothing else.
Patch 6 OTOH adds a new cap bit; some devices don't support
	using a different key per context and currently act
	in surprising ways.
Patch 7 and 8 update the RSS netlink code to use XArray.
Patch 9 and 10 add support for dumping contexts.
Patch 11 and 12 are small adjustments to spec and a new test.

I'm getting distracted with other work, so probably won't have
the time soon to complete next steps, but things which are missing
are (and some of these may be bad ideas):

 - better discovery

   Some sort of API to tell the user who many contexts the device
   can create. Upper bound, devices often share contexts between
   ports etc. so it's hard to tell exactly and upfront number of
   contexts for a netdev. But order of magnitude (4 vs 10s) may
   be enough for container management system to know whether to bother.

 - create/modify/delete via netlink

   The only question here is how to handle all the tricky IOCTL
   legacy. "No change" maps trivially to attribute not present.
   "reset" (indir_size = 0) probably needs to be a new NLA_FLAG?

 - better table size handling

   The current API assumes the LUT has fixed size, which isn't
   true for modern devices. We should have better APIs for the
   drivers to resize the tables, and in user facing API -
   the ability to specify pattern and min size rather than
   exact table expected (sort of like ethtool CLI already does).

 - recounted / socket-bound contexts

   Support for contexts which get "cleaned up" when their parent
   netlink socket gets closed. The major catch is that ntuple
   filters (which we don't currently track) depend on the context,
   so we need auto-removal for both.

v5:
 - fix build
v4: https://lore.kernel.org/20240809031827.2373341-1-kuba@kernel.org
 - adjust to the meaning of max context from net
v3: https://lore.kernel.org/20240806193317.1491822-1-kuba@kernel.org
 - quite a few code comments and commit message changes
 - mvpp2: fix interpretation of max_context_id (I'll take care of
   the net -> net-next merge as needed)
 - filter by ifindex in the selftest
v2: https://lore.kernel.org/20240803042624.970352-1-kuba@kernel.org
 - fix bugs and build in mvpp2
v1: https://lore.kernel.org/20240802001801.565176-1-kuba@kernel.org
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 1 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 989c94eddb2b..12f6dc567598 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -727,9 +727,13 @@ struct kernel_ethtool_ts_info {
  * @cap_link_lanes_supported: indicates if the driver supports lanes
  *	parameter.
  * @cap_rss_ctx_supported: indicates if the driver supports RSS
- *	contexts.
+ *	contexts via legacy API, drivers implementing @create_rxfh_context
+ *	do not have to set this bit.
  * @cap_rss_sym_xor_supported: indicates if the driver supports symmetric-xor
  *	RSS.
+ * @rxfh_per_ctx_key: device supports setting different RSS key for each
+ *	additional context. Netlink API should report hfunc, key, and input_xfrm
+ *	for every context, not just context 0.
  * @rxfh_indir_space: max size of RSS indirection tables, if indirection table
  *	size as returned by @get_rxfh_indir_size may change during lifetime
  *	of the device. Leave as 0 if the table size is constant.
@@ -951,6 +955,7 @@ struct ethtool_ops {
 	u32     cap_link_lanes_supported:1;
 	u32     cap_rss_ctx_supported:1;
 	u32	cap_rss_sym_xor_supported:1;
+	u32	rxfh_per_ctx_key:1;
 	u32	rxfh_indir_space;
 	u16	rxfh_key_space;
 	u16	rxfh_priv_size;