bnxt_en: Check TQM rings for maximum supported value.

TQM rings are hardware resources that require host context memory
managed by the driver.  The driver supports up to 9 TQM rings and
the number of rings to use is requested by firmware during run-time.
Cap this number to the maximum supported to prevent accessing beyond
the array.  Future firmware may request more than 9 TQM rings.  Define
macros to remove the magic number 9 from the C code.

Fixes: ac3158cb ("bnxt_en: Allocate TQM ring context memory according to fw specification.")
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Reviewed-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -6790,8 +6790,10 @@ static int bnxt_hwrm_func_backing_store_qcaps(struct bnxt *bp)
 		ctx->tqm_fp_rings_count = resp->tqm_fp_rings_count;
 		if (!ctx->tqm_fp_rings_count)
 			ctx->tqm_fp_rings_count = bp->max_q;
+		else if (ctx->tqm_fp_rings_count > BNXT_MAX_TQM_FP_RINGS)
+			ctx->tqm_fp_rings_count = BNXT_MAX_TQM_FP_RINGS;
 
-		tqm_rings = ctx->tqm_fp_rings_count + 1;
+		tqm_rings = ctx->tqm_fp_rings_count + BNXT_MAX_TQM_SP_RINGS;
 		ctx_pg = kcalloc(tqm_rings, sizeof(*ctx_pg), GFP_KERNEL);
 		if (!ctx_pg) {
 			kfree(ctx);
@@ -6925,7 +6927,8 @@ static int bnxt_hwrm_func_backing_store_cfg(struct bnxt *bp, u32 enables)
 	     pg_attr = &req.tqm_sp_pg_size_tqm_sp_lvl,
 	     pg_dir = &req.tqm_sp_page_dir,
 	     ena = FUNC_BACKING_STORE_CFG_REQ_ENABLES_TQM_SP;
-	     i < 9; i++, num_entries++, pg_attr++, pg_dir++, ena <<= 1) {
+	     i < BNXT_MAX_TQM_RINGS;
+	     i++, num_entries++, pg_attr++, pg_dir++, ena <<= 1) {
 		if (!(enables & ena))
 			continue;
 

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -1436,6 +1436,11 @@ struct bnxt_ctx_pg_info {
 	struct bnxt_ctx_pg_info **ctx_pg_tbl;
 };
 
+#define BNXT_MAX_TQM_SP_RINGS		1
+#define BNXT_MAX_TQM_FP_RINGS		8
+#define BNXT_MAX_TQM_RINGS		\
+	(BNXT_MAX_TQM_SP_RINGS + BNXT_MAX_TQM_FP_RINGS)
+
 struct bnxt_ctx_mem_info {
 	u32	qp_max_entries;
 	u16	qp_min_qp1_entries;
@@ -1474,7 +1479,7 @@ struct bnxt_ctx_mem_info {
 	struct bnxt_ctx_pg_info stat_mem;
 	struct bnxt_ctx_pg_info mrav_mem;
 	struct bnxt_ctx_pg_info tim_mem;
-	struct bnxt_ctx_pg_info *tqm_mem[9];
+	struct bnxt_ctx_pg_info *tqm_mem[BNXT_MAX_TQM_RINGS];
 };
 
 struct bnxt_fw_health {