diff mbox series

[RFC,v5,9/9] cxl/mem: Add payload dumping for debug

Message ID 20210217040958.1354670-10-ben.widawsky@intel.com
State New
Headers show
Series CXL 2.0 Support | expand

Commit Message

Ben Widawsky Feb. 17, 2021, 4:09 a.m. UTC
It's often useful in debug scenarios to see what the hardware has dumped
out. As it stands today, any device error will result in the payload not
being copied out, so there is no way to triage commands which weren't
expected to fail (and sometimes the payload may have that information).

The functionality is protected by normal kernel security mechanisms as
well as a CONFIG option in the CXL driver.

This was extracted from the original version of the CXL enabling patch

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
 drivers/cxl/Kconfig | 13 +++++++++++++
 drivers/cxl/mem.c   |  8 ++++++++
 2 files changed, 21 insertions(+)
diff mbox series


diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index 97dc4d751651..3eec9276e586 100644
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -50,4 +50,17 @@  config CXL_MEM_RAW_COMMANDS
 	  potential impact to memory currently in use by the kernel.
 	  If developing CXL hardware or the driver say Y, otherwise say N.
+	bool "CXL.mem debugging"
+	depends on CXL_MEM
+	help
+	  Enable debug of all CXL command payloads.
+	  Some CXL devices and controllers support encryption and other
+	  security features. The payloads for the commands that enable
+	  those features may contain sensitive clear-text security
+	  material. Disable debug of those command payloads by default.
+	  If you are a kernel developer actively working on CXL
+	  security enabling say Y, otherwise say N.
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 6d7d3870b5da..d63c8eaf23c7 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -346,6 +346,14 @@  static int __cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm,
 	/* #5 */
 	rc = cxl_mem_wait_for_doorbell(cxlm);
+	if (!cxl_is_security_command(mbox_cmd->opcode) ||
+		print_hex_dump_debug("Payload ", DUMP_PREFIX_OFFSET, 16, 1,
+				     mbox_cmd->payload_in, mbox_cmd->size_in,
+				     true);
+	}
 	if (rc == -ETIMEDOUT) {
 		cxl_mem_mbox_timeout(cxlm, mbox_cmd);
 		return rc;