net: ethtool: only allow set_rxnfc with rss + ring_cookie if driver opts in

Ethtool ntuple filters with FLOW_RSS were originally defined as adding
 the base queue ID (ring_cookie) to the value from the indirection table,
 so that the same table could distribute over more than one set of queues
 when used by different filters.
However, some drivers / hardware ignore the ring_cookie, and simply use
 the indirection table entries as queue IDs directly.  Thus, for drivers
 which have not opted in by setting ethtool_ops.cap_rss_rxnfc_adds to
 declare that they support the original (addition) semantics, reject in
 ethtool_set_rxnfc any filter which combines FLOW_RSS and a nonzero ring.
(For a ring_cookie of zero, both behaviours are equivalent.)
Set the cap bit in sfc, as it is known to support this feature.

Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Reviewed-by: Martin Habets <habetsm.xilinx@gmail.com>
Link: https://patch.msgid.link/cc3da0844083b0e301a33092a6299e4042b65221.1731499022.git.ecree.xilinx@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/sfc/ef100_ethtool.c b/drivers/net/ethernet/sfc/ef100_ethtool.c
index 5c2551369812cb84720e777477d2774f8068e81c..6c3b74000d3b6a77422f61e8b06a53f8f52cae1a 100644 (file)
--- a/drivers/net/ethernet/sfc/ef100_ethtool.c
+++ b/drivers/net/ethernet/sfc/ef100_ethtool.c
@@ -59,6 +59,7 @@ const struct ethtool_ops ef100_ethtool_ops = {
        .get_rxfh_indir_size    = efx_ethtool_get_rxfh_indir_size,
        .get_rxfh_key_size      = efx_ethtool_get_rxfh_key_size,
        .rxfh_per_ctx_key       = true,
+       .cap_rss_rxnfc_adds     = true,
        .rxfh_priv_size         = sizeof(struct efx_rss_context_priv),
        .get_rxfh               = efx_ethtool_get_rxfh,
        .set_rxfh               = efx_ethtool_set_rxfh,

diff --git a/drivers/net/ethernet/sfc/ethtool.c b/drivers/net/ethernet/sfc/ethtool.c
index bb1930818beba44a9c20db73cb689810076df79a..83d715544f7fb238c573687f9af235fe3a311f5e 100644 (file)
--- a/drivers/net/ethernet/sfc/ethtool.c
+++ b/drivers/net/ethernet/sfc/ethtool.c
@@ -263,6 +263,7 @@ const struct ethtool_ops efx_ethtool_ops = {
        .get_rxfh_indir_size    = efx_ethtool_get_rxfh_indir_size,
        .get_rxfh_key_size      = efx_ethtool_get_rxfh_key_size,
        .rxfh_per_ctx_key       = true,
+       .cap_rss_rxnfc_adds     = true,
        .rxfh_priv_size         = sizeof(struct efx_rss_context_priv),
        .get_rxfh               = efx_ethtool_get_rxfh,
        .set_rxfh               = efx_ethtool_set_rxfh,

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 1199e308c8ddb056d9d1348d1dbebcbb22086ac7..299280c94d070ef3cb6446ec0a1e871911c5a2e2 100644 (file)
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -734,6 +734,9 @@ struct kernel_ethtool_ts_info {
  * @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.
+ * @cap_rss_rxnfc_adds: device supports nonzero ring_cookie in filters with
+ *     %FLOW_RSS flag; the queue ID from the filter is added to the value from
+ *     the indirection table to determine the delivery queue.
  * @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.
@@ -956,6 +959,7 @@ struct ethtool_ops {
        u32     cap_rss_ctx_supported:1;
        u32     cap_rss_sym_xor_supported:1;
        u32     rxfh_per_ctx_key:1;
+       u32     cap_rss_rxnfc_adds:1;
        u32     rxfh_indir_space;
        u16     rxfh_key_space;
        u16     rxfh_priv_size;

diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 7da94e26ced643ac10ca34b4f7f5d132d4074339..d86399bcf223ad9c8f1794a587927811d92175fe 100644 (file)
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -992,6 +992,11 @@ static noinline_for_stack int ethtool_set_rxnfc(struct net_device *dev,
        if (rc)
                return rc;
 
+       /* Nonzero ring with RSS only makes sense if NIC adds them together */
+       if (info.flow_type & FLOW_RSS && !ops->cap_rss_rxnfc_adds &&
+           ethtool_get_flow_spec_ring(info.fs.ring_cookie))
+               return -EINVAL;
+
        if (ops->get_rxfh) {
                struct ethtool_rxfh_param rxfh = {};