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From: Ben Widawsky <ben.widawsky@intel.com>
To: linux-cxl@vger.kernel.org
Cc: Ben Widawsky <ben.widawsky@intel.com>,
	linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-nvdimm@lists.01.org, linux-pci@vger.kernel.org,
	Bjorn Helgaas <helgaas@kernel.org>,
	Chris Browy <cbrowy@avery-design.com>,
	Christoph Hellwig <hch@infradead.org>,
	David Hildenbrand <david@redhat.com>,
	David Rientjes <rientjes@google.com>,
	Jon Masters <jcm@jonmasters.org>,
	Jonathan Cameron <Jonathan.Cameron@Huawei.com>,
	Rafael Wysocki <rafael.j.wysocki@intel.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	"John Groves (jgroves)" <jgroves@micron.com>,
	"Kelley, Sean V" <sean.v.kelley@intel.com>
Subject: [RFC PATCH v5 9/9] cxl/mem: Add payload dumping for debug
Date: Tue, 16 Feb 2021 20:09:58 -0800	[thread overview]
Message-ID: <20210217040958.1354670-10-ben.widawsky@intel.com> (raw)
In-Reply-To: <20210217040958.1354670-1-ben.widawsky@intel.com>

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
series.

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

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.
+
+config CXL_MEM_INSECURE_DEBUG
+	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.
 endif
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) ||
+	    IS_ENABLED(CONFIG_CXL_MEM_INSECURE_DEBUG)) {
+		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;
-- 
2.30.1
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      parent reply	other threads:[~2021-02-17  4:10 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-17  4:09 [PATCH v5 0/9] CXL 2.0 Support Ben Widawsky
2021-02-17  4:09 ` [PATCH v5 1/9] cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints Ben Widawsky
2021-02-20  0:54   ` Konrad Rzeszutek Wilk
2021-02-17  4:09 ` [PATCH v5 2/9] cxl/mem: Find device capabilities Ben Widawsky
2021-02-17 12:22   ` Jonathan Cameron
2021-02-17  4:09 ` [PATCH v5 3/9] cxl/mem: Register CXL memX devices Ben Widawsky
2021-02-17  4:09 ` [PATCH v5 4/9] cxl/mem: Add basic IOCTL interface Ben Widawsky
2021-02-17 14:16   ` Jonathan Cameron
2021-02-20  1:22   ` Konrad Rzeszutek Wilk
2021-02-20 16:33     ` Ben Widawsky
2021-02-20 17:48       ` Dan Williams
2021-02-17  4:09 ` [PATCH v5 5/9] cxl/mem: Add a "RAW" send command Ben Widawsky
2021-02-20  1:03   ` Konrad Rzeszutek Wilk
2021-02-17  4:09 ` [PATCH v5 6/9] cxl/mem: Enable commands via CEL Ben Widawsky
2021-02-20  1:11   ` Konrad Rzeszutek Wilk
2021-02-17  4:09 ` [PATCH v5 7/9] cxl/mem: Add set of informational commands Ben Widawsky
2021-02-20  1:12   ` Konrad Rzeszutek Wilk
2021-02-17  4:09 ` [PATCH v5 8/9] MAINTAINERS: Add maintainers of the CXL driver Ben Widawsky
2021-02-17  4:09 ` Ben Widawsky [this message]

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