[PATCH 1/2] RDMA/efa: Check stored completion CTX command ID with received one

[Yonatan Nachum <ynachum@amazon.com>]

In admin command completion, we receive a CQE with the command ID which
is constructed from context index and entropy bits from the admin queue
producer counter. To try to detect memory corruptions in the received
CQE, validate the full command ID of the fetched context with the CQE
command ID. If there is a mismatch, complete the CQE with error.
Also use LSBs of the admin queue producer counter to better detect
entropy mismatch between smaller number of commands.

Reviewed-by: Daniel Kranzdorf <dkkranzd@amazon.com>
Reviewed-by: Michael Margolin <mrgolin@amazon.com>
Signed-off-by: Yonatan Nachum <ynachum@amazon.com>
---
 drivers/infiniband/hw/efa/efa_com.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/efa/efa_com.c b/drivers/infiniband/hw/efa/efa_com.c
index 0e979ca10d24..b31478f3a121 100644
--- a/drivers/infiniband/hw/efa/efa_com.c
+++ b/drivers/infiniband/hw/efa/efa_com.c
@@ -3,6 +3,8 @@
  * Copyright 2018-2025 Amazon.com, Inc. or its affiliates. All rights reserved.
  */
 
+#include <linux/log2.h>
+
 #include "efa_com.h"
 #include "efa_regs_defs.h"
 
@@ -317,7 +319,7 @@ static struct efa_comp_ctx *__efa_com_submit_admin_cmd(struct efa_com_admin_queu
 
 	/* cmd_id LSBs are the ctx_id and MSBs are entropy bits from pc */
 	cmd_id = ctx_id & queue_size_mask;
-	cmd_id |= aq->sq.pc & ~queue_size_mask;
+	cmd_id |= aq->sq.pc << ilog2(aq->depth);
 	cmd_id &= EFA_ADMIN_AQ_COMMON_DESC_COMMAND_ID_MASK;
 
 	cmd->aq_common_descriptor.command_id = cmd_id;
@@ -418,7 +420,7 @@ static int efa_com_handle_single_admin_completion(struct efa_com_admin_queue *aq
 			 EFA_ADMIN_ACQ_COMMON_DESC_COMMAND_ID);
 
 	comp_ctx = efa_com_get_comp_ctx(aq, cmd_id, false);
-	if (comp_ctx->status != EFA_CMD_SUBMITTED) {
+	if (comp_ctx->status != EFA_CMD_SUBMITTED || comp_ctx->cmd_id != cmd_id) {
 		ibdev_err(aq->efa_dev,
 			  "Received completion with unexpected command id[%d], sq producer: %d, sq consumer: %d, cq consumer: %d\n",
 			  cmd_id, aq->sq.pc, aq->sq.cc, aq->cq.cc);
-- 
2.47.3