[PATCH v2] net/bnxt: fix aliasing in firmware command writes

[Alexander Goodkind]

Use memcpy to copy each firmware command word into a local uint32_t
before writing it to the card. Replace the uint32_t pointer reads in
bnxt_hwrm_send_message() with byte access.

Fixes: 1cd45aeb3270 ("net/bnxt: support Stratus VF device")
Cc: stable at dpdk.org

Signed-off-by: Alexander Goodkind <alex at goodkind.io>
---

v2: The previous patch got corrupted during email delivery.

VPP could not initialize the interfaces on my PowerEdge XR11 with a
Broadcom BCM57504 card, using SR-IOV virtual functions inside an Ubuntu
LXC container on Proxmox. The debugger showed an empty command header
immediately before the driver wrote it to the card.

The original pointer reads violate GCC's strict-aliasing rule [1].
The patched driver initialized the interfaces and transferred packets
with DPDK 26.03.0 and VPP 26.06-release. Separate build and software
tests passed against the current Broadcom source.

[1] https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html

 .mailmap                     |  1 +
 drivers/net/bnxt/bnxt_hwrm.c | 11 +++++++----
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/.mailmap b/.mailmap
index 5d1df79860..3143e642b5 100644
--- a/.mailmap
+++ b/.mailmap
@@ -65,6 +65,7 @@ Alex Zelezniak <alexz at att.com>
 Alexander Bechikov <asb.tyum at gmail.com>
 Alexander Belyakov <abelyako at gmail.com>
 Alexander Chernavin <achernavin at netgate.com>
+Alexander Goodkind <alex at goodkind.io>
 Alexander Guy <alexander at andern.org>
 Alexander Kozyrev <akozyrev at nvidia.com> <akozyrev at mellanox.com>
 Alexander Matushevsky <matua at amazon.com>
diff --git a/drivers/net/bnxt/bnxt_hwrm.c b/drivers/net/bnxt/bnxt_hwrm.c
index ab1521953a..573a33b2de 100644
--- a/drivers/net/bnxt/bnxt_hwrm.c
+++ b/drivers/net/bnxt/bnxt_hwrm.c
@@ -483,7 +483,7 @@ static int bnxt_hwrm_send_message(struct bnxt *bp, void *msg,
 	unsigned int i;
 	struct input *req = msg;
 	struct output *resp = bp->hwrm_cmd_resp_addr;
-	uint32_t *data = msg;
+	const uint8_t *data = msg;
 	uint8_t *bar;
 	uint8_t *valid;
 	uint16_t max_req_len = bp->max_req_len;
@@ -526,7 +526,7 @@ static int bnxt_hwrm_send_message(struct bnxt *bp, void *msg,
 		short_input.req_addr =
 			rte_cpu_to_le_64(bp->hwrm_short_cmd_req_dma_addr);
 
-		data = (uint32_t *)&short_input;
+		data = (const uint8_t *)&short_input;
 		msg_len = sizeof(short_input);
 
 		max_req_len = BNXT_HWRM_SHORT_REQ_LEN;
@@ -534,9 +534,12 @@ static int bnxt_hwrm_send_message(struct bnxt *bp, void *msg,
 
 	/* Write request msg to hwrm channel */
 	for (i = 0; i < msg_len; i += 4) {
+		uint32_t request_word;
+
 		bar = (uint8_t *)bp->bar0 + bar_offset + i;
-		rte_write32(*data, bar);
-		data++;
+		memcpy(&request_word, data, sizeof(request_word));
+		rte_write32(request_word, bar);
+		data += sizeof(request_word);
 	}
 
 	/* Zero the rest of the request space */

base-commit: af80aca47b05d46f4a5e1951de3ce8372bd726b6
-- 
2.54.0 (Apple Git-157)