Re: [net-next PATCH 01/11] octeontx2-af: Simplify context writing and reading to hardware

[Simon Horman <horms@kernel.org>]

+ Kees, linux-hardening

On Sun, Jul 13, 2025 at 09:00:59PM +0530, Subbaraya Sundeep wrote:
> Simplify NIX context reading and writing by using hardware
> maximum context size instead of using individual sizes of
> each context type.
> 
> Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
> ---
>  .../ethernet/marvell/octeontx2/af/rvu_nix.c   | 46 ++++++++++---------
>  1 file changed, 24 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
> index bdf4d852c15d..48d44911b663 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
> @@ -17,6 +17,8 @@
>  #include "lmac_common.h"
>  #include "rvu_npc_hash.h"
>  
> +#define NIX_MAX_CTX_SIZE	128
> +
>  static void nix_free_tx_vtag_entries(struct rvu *rvu, u16 pcifunc);
>  static int rvu_nix_get_bpid(struct rvu *rvu, struct nix_bp_cfg_req *req,
>  			    int type, int chan_id);
> @@ -1149,36 +1151,36 @@ static int rvu_nix_blk_aq_enq_inst(struct rvu *rvu, struct nix_hw *nix_hw,
>  	case NIX_AQ_INSTOP_WRITE:
>  		if (req->ctype == NIX_AQ_CTYPE_RQ)
>  			memcpy(mask, &req->rq_mask,
> -			       sizeof(struct nix_rq_ctx_s));
> +			       NIX_MAX_CTX_SIZE);
>  		else if (req->ctype == NIX_AQ_CTYPE_SQ)
>  			memcpy(mask, &req->sq_mask,
> -			       sizeof(struct nix_sq_ctx_s));
> +			       NIX_MAX_CTX_SIZE);
>  		else if (req->ctype == NIX_AQ_CTYPE_CQ)
>  			memcpy(mask, &req->cq_mask,
> -			       sizeof(struct nix_cq_ctx_s));
> +			       NIX_MAX_CTX_SIZE);
>  		else if (req->ctype == NIX_AQ_CTYPE_RSS)
>  			memcpy(mask, &req->rss_mask,
> -			       sizeof(struct nix_rsse_s));
> +			       NIX_MAX_CTX_SIZE);
>  		else if (req->ctype == NIX_AQ_CTYPE_MCE)
>  			memcpy(mask, &req->mce_mask,
> -			       sizeof(struct nix_rx_mce_s));
> +			       NIX_MAX_CTX_SIZE);
>  		else if (req->ctype == NIX_AQ_CTYPE_BANDPROF)
>  			memcpy(mask, &req->prof_mask,
> -			       sizeof(struct nix_bandprof_s));
> +			       NIX_MAX_CTX_SIZE);
>  		fallthrough;

Hi Subbaraya,

Unfortunately this patch adds string fortification warnings
because, e.g. the size of req->rss_mask is less than 128 bytes.

GCC 15.1.0 flags this as follows:

  In function 'fortify_memcpy_chk',
      inlined from 'rvu_nix_blk_aq_enq_inst' at drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c:1159:4:
  ./include/linux/fortify-string.h:580:4: warning: call to '__read_overflow2_field' declared with attribute warning: detected read beyond size of field (2nd parameter); maybe use struct_group()?
      __read_overflow2_field(q_size_field, size);
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

There may there is nicer way to do this. And it's entirely possible I've
muddled up the combination of structures and unions here. But I wonder if
an approach like this can reach your goals wile keeping the string
fortification checker happy.

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/mbox.h b/drivers/net/ethernet/marvell/octeontx2/af/mbox.h
index 0bc0dc79868b..0aa1e823cbd3 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/mbox.h
+++ b/drivers/net/ethernet/marvell/octeontx2/af/mbox.h
@@ -985,14 +985,17 @@ struct nix_aq_enq_req {
 		struct nix_rx_mce_s mce;
 		struct nix_bandprof_s prof;
 	};
-	union {
-		struct nix_rq_ctx_s rq_mask;
-		struct nix_sq_ctx_s sq_mask;
-		struct nix_cq_ctx_s cq_mask;
-		struct nix_rsse_s   rss_mask;
-		struct nix_rx_mce_s mce_mask;
-		struct nix_bandprof_s prof_mask;
-	};
+	struct_group(
+		mask,
+		union {
+			struct nix_rq_ctx_s rq_mask;
+			struct nix_sq_ctx_s sq_mask;
+			struct nix_cq_ctx_s cq_mask;
+			struct nix_rsse_s   rss_mask;
+			struct nix_rx_mce_s mce_mask;
+			struct nix_bandprof_s prof_mask;
+		};
+	);
 };
 
 struct nix_aq_enq_rsp {
diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
index bdf4d852c15d..4089933d5a0b 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
@@ -1147,24 +1147,7 @@ static int rvu_nix_blk_aq_enq_inst(struct rvu *rvu, struct nix_hw *nix_hw,
 
 	switch (req->op) {
 	case NIX_AQ_INSTOP_WRITE:
-		if (req->ctype == NIX_AQ_CTYPE_RQ)
-			memcpy(mask, &req->rq_mask,
-			       sizeof(struct nix_rq_ctx_s));
-		else if (req->ctype == NIX_AQ_CTYPE_SQ)
-			memcpy(mask, &req->sq_mask,
-			       sizeof(struct nix_sq_ctx_s));
-		else if (req->ctype == NIX_AQ_CTYPE_CQ)
-			memcpy(mask, &req->cq_mask,
-			       sizeof(struct nix_cq_ctx_s));
-		else if (req->ctype == NIX_AQ_CTYPE_RSS)
-			memcpy(mask, &req->rss_mask,
-			       sizeof(struct nix_rsse_s));
-		else if (req->ctype == NIX_AQ_CTYPE_MCE)
-			memcpy(mask, &req->mce_mask,
-			       sizeof(struct nix_rx_mce_s));
-		else if (req->ctype == NIX_AQ_CTYPE_BANDPROF)
-			memcpy(mask, &req->prof_mask,
-			       sizeof(struct nix_bandprof_s));
+		memcpy(mask, &req->mask, sizeof(req->mask));
 		fallthrough;
 	case NIX_AQ_INSTOP_INIT:
 		if (req->ctype == NIX_AQ_CTYPE_RQ)

...

-- 
pw-bot: changes-requested