Re: [PATCH v4 -ndctl] cxl/memdev: Introduce sanitize-memdev functionality

[Alison Schofield <alison.schofield@intel.com>]

On Tue, Mar 18, 2025 at 04:45:43PM -0700, Davidlohr Bueso wrote:
> Add a new cxl_memdev_sanitize() to libcxl to support triggering memory
> device sanitation, in either Sanitize and/or Secure Erase, per the
> CXL 3.0 spec.
> 
> This is analogous to 'ndctl sanitize-dimm'.
> 
> Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>

Hi David,

Is there anyone you can ping directly to review this one?

It's been lingering a bit and I'd want to see a review by someone other
than me before merging.

--Alison



> ---
> changes from v3: added missing cxl-sanitize-memdev.txt to the patch
> 
>  Documentation/cxl/cxl-sanitize-memdev.txt | 52 +++++++++++++++++++++++
>  Documentation/cxl/cxl-wait-sanitize.txt   |  1 +
>  Documentation/cxl/meson.build             |  1 +
>  cxl/builtin.h                             |  1 +
>  cxl/cxl.c                                 |  1 +
>  cxl/lib/libcxl.c                          | 15 +++++++
>  cxl/lib/libcxl.sym                        |  1 +
>  cxl/libcxl.h                              |  1 +
>  cxl/memdev.c                              | 38 +++++++++++++++++
>  test/cxl-sanitize.sh                      |  4 +-
>  10 files changed, 113 insertions(+), 2 deletions(-)
>  create mode 100644 Documentation/cxl/cxl-sanitize-memdev.txt
> 
> diff --git a/Documentation/cxl/cxl-sanitize-memdev.txt b/Documentation/cxl/cxl-sanitize-memdev.txt
> new file mode 100644
> index 000000000000..7a7c9a79b19f
> --- /dev/null
> +++ b/Documentation/cxl/cxl-sanitize-memdev.txt
> @@ -0,0 +1,52 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +cxl-sanitize-memdev(1)
> +======================
> +
> +NAME
> +----
> +cxl-sanitize-memdev - Perform a cryptographic destruction or sanitization
> +of the contents of the given memdev(s).
> +
> +SYNOPSIS
> +--------
> +[verse]
> +'cxl sanitize-memdev <mem0> [<mem1>..<memN>] [<options>]'
> +
> +DESCRIPTION
> +-----------
> +The 'sanitize-memdev' command performs two different methods of sanitization,
> +per the CXL 3.0+ specification. The default is 'sanitize', but additionally,
> +a 'secure-erase' option is available. It is required that the memdev be
> +disabled before sanitizing, such that the device cannot be actively decoding
> +any HPA ranges at the time.
> +
> +A device Sanitize is meant to securely re-purpose or decommission it. This
> +is done by ensuring that all user data and meta data, whether it resides
> +in persistent capacity, volatile capacity, or the label storage area,
> +is made permanently unavailable by whatever means is appropriate for
> +the media type. This sanitization request is merely submitted to the
> +kernel, and the completion is asynchronous. Depending on the medium and
> +capacity, sanitize may take tens of minutes to many hours. Subsequently,
> +'cxl wait-sanitize’ can be used to wait for the memdevs that are under
> +the sanitization.
> +
> +OPTIONS
> +-------
> +
> +include::bus-option.txt[]
> +
> +-e::
> +--secure-erase::
> +	Erase user data by changing the media encryption keys for all user
> +	data areas of the device.
> +
> +include::verbose-option.txt[]
> +
> +include::../copyright.txt[]
> +
> +SEE ALSO
> +--------
> +linkcxl:cxl-wait-sanitize[1],
> +linkcxl:cxl-disable-memdev[1],
> +linkcxl:cxl-list[1],
> diff --git a/Documentation/cxl/cxl-wait-sanitize.txt b/Documentation/cxl/cxl-wait-sanitize.txt
> index e8f2044e4882..9391c66eec52 100644
> --- a/Documentation/cxl/cxl-wait-sanitize.txt
> +++ b/Documentation/cxl/cxl-wait-sanitize.txt
> @@ -42,3 +42,4 @@ include::../copyright.txt[]
>  SEE ALSO
>  --------
>  linkcxl:cxl-list[1],
> +linkcxl:cxl-sanitize-memdev[1],
> diff --git a/Documentation/cxl/meson.build b/Documentation/cxl/meson.build
> index 8085c1c2c87e..99e6ee782a1c 100644
> --- a/Documentation/cxl/meson.build
> +++ b/Documentation/cxl/meson.build
> @@ -49,6 +49,7 @@ cxl_manpages = [
>    'cxl-monitor.txt',
>    'cxl-update-firmware.txt',
>    'cxl-set-alert-config.txt',
> +  'cxl-sanitize-memdev.txt',
>    'cxl-wait-sanitize.txt',
>  ]
>  
> diff --git a/cxl/builtin.h b/cxl/builtin.h
> index c483f301e5e0..29c8ad2a0ad9 100644
> --- a/cxl/builtin.h
> +++ b/cxl/builtin.h
> @@ -16,6 +16,7 @@ int cmd_reserve_dpa(int argc, const char **argv, struct cxl_ctx *ctx);
>  int cmd_free_dpa(int argc, const char **argv, struct cxl_ctx *ctx);
>  int cmd_update_fw(int argc, const char **argv, struct cxl_ctx *ctx);
>  int cmd_set_alert_config(int argc, const char **argv, struct cxl_ctx *ctx);
> +int cmd_sanitize_memdev(int argc, const char **argv, struct cxl_ctx *ctx);
>  int cmd_wait_sanitize(int argc, const char **argv, struct cxl_ctx *ctx);
>  int cmd_disable_port(int argc, const char **argv, struct cxl_ctx *ctx);
>  int cmd_enable_port(int argc, const char **argv, struct cxl_ctx *ctx);
> diff --git a/cxl/cxl.c b/cxl/cxl.c
> index 16436671dc53..9c9f217c5a93 100644
> --- a/cxl/cxl.c
> +++ b/cxl/cxl.c
> @@ -80,6 +80,7 @@ static struct cmd_struct commands[] = {
>  	{ "disable-region", .c_fn = cmd_disable_region },
>  	{ "destroy-region", .c_fn = cmd_destroy_region },
>  	{ "monitor", .c_fn = cmd_monitor },
> +	{ "sanitize-memdev", .c_fn = cmd_sanitize_memdev },
>  };
>  
>  int main(int argc, const char **argv)
> diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c
> index 63aa4ef3acdc..d9dd37519aa4 100644
> --- a/cxl/lib/libcxl.c
> +++ b/cxl/lib/libcxl.c
> @@ -1414,6 +1414,21 @@ CXL_EXPORT int cxl_memdev_get_id(struct cxl_memdev *memdev)
>  	return memdev->id;
>  }
>  
> +CXL_EXPORT int cxl_memdev_sanitize(struct cxl_memdev *memdev, char *op)
> +{
> +	struct cxl_ctx *ctx = cxl_memdev_get_ctx(memdev);
> +	char *path = memdev->dev_buf;
> +	int len = memdev->buf_len;
> +
> +	if (snprintf(path, len,
> +		     "%s/security/%s", memdev->dev_path, op) >= len) {
> +		err(ctx, "%s: buffer too small!\n",
> +		    cxl_memdev_get_devname(memdev));
> +		return -ERANGE;
> +	}
> +	return sysfs_write_attr(ctx, path, "1\n");
> +}
> +
>  CXL_EXPORT int cxl_memdev_wait_sanitize(struct cxl_memdev *memdev,
>  					int timeout_ms)
>  {
> diff --git a/cxl/lib/libcxl.sym b/cxl/lib/libcxl.sym
> index 0c155a40ad47..bff45d47c29b 100644
> --- a/cxl/lib/libcxl.sym
> +++ b/cxl/lib/libcxl.sym
> @@ -287,4 +287,5 @@ LIBECXL_8 {
>  global:
>  	cxl_memdev_trigger_poison_list;
>  	cxl_region_trigger_poison_list;
> +	cxl_memdev_sanitize;
>  } LIBCXL_7;
> diff --git a/cxl/libcxl.h b/cxl/libcxl.h
> index 0a5fd0e13cc2..e10ea741bf6d 100644
> --- a/cxl/libcxl.h
> +++ b/cxl/libcxl.h
> @@ -79,6 +79,7 @@ bool cxl_memdev_fw_update_in_progress(struct cxl_memdev *memdev);
>  size_t cxl_memdev_fw_update_get_remaining(struct cxl_memdev *memdev);
>  int cxl_memdev_update_fw(struct cxl_memdev *memdev, const char *fw_path);
>  int cxl_memdev_cancel_fw_update(struct cxl_memdev *memdev);
> +int cxl_memdev_sanitize(struct cxl_memdev *memdev, char *op);
>  int cxl_memdev_wait_sanitize(struct cxl_memdev *memdev, int timeout_ms);
>  
>  /* ABI spelling mistakes are forever */
> diff --git a/cxl/memdev.c b/cxl/memdev.c
> index 6e44d1578d03..4a2daab2bbe5 100644
> --- a/cxl/memdev.c
> +++ b/cxl/memdev.c
> @@ -35,6 +35,8 @@ static struct parameters {
>  	bool align;
>  	bool cancel;
>  	bool wait;
> +	bool sanitize;
> +	bool secure_erase;
>  	const char *type;
>  	const char *size;
>  	const char *decoder_filter;
> @@ -160,6 +162,10 @@ OPT_STRING('\0', "pmem-err-alert",                                            \
>  	   &param.corrected_pmem_err_alert, "'on' or 'off'",                  \
>  	   "enable or disable corrected pmem error warning alert")
>  
> +#define SANITIZE_OPTIONS()			      \
> +OPT_BOOLEAN('e', "secure-erase", &param.secure_erase, \
> +	    "Secure Erase a memdev")
> +
>  #define WAIT_SANITIZE_OPTIONS()                \
>  OPT_INTEGER('t', "timeout", &param.timeout,    \
>  	    "time in milliseconds to wait for overwrite completion (default: infinite)")
> @@ -226,6 +232,12 @@ static const struct option set_alert_options[] = {
>  	OPT_END(),
>  };
>  
> +static const struct option sanitize_options[] = {
> +	BASE_OPTIONS(),
> +	SANITIZE_OPTIONS(),
> +	OPT_END(),
> +};
> +
>  static const struct option wait_sanitize_options[] = {
>  	BASE_OPTIONS(),
>  	WAIT_SANITIZE_OPTIONS(),
> @@ -772,6 +784,19 @@ out_err:
>  	return rc;
>  }
>  
> +static int action_sanitize_memdev(struct cxl_memdev *memdev,
> +				  struct action_context *actx)
> +{
> +	int rc;
> +
> +	if (param.secure_erase)
> +		rc = cxl_memdev_sanitize(memdev, "erase");
> +        else
> +		rc = cxl_memdev_sanitize(memdev, "sanitize");
> +
> +	return rc;
> +}
> +
>  static int action_wait_sanitize(struct cxl_memdev *memdev,
>  				struct action_context *actx)
>  {
> @@ -1228,6 +1253,19 @@ int cmd_set_alert_config(int argc, const char **argv, struct cxl_ctx *ctx)
>  	return count >= 0 ? 0 : EXIT_FAILURE;
>  }
>  
> +int cmd_sanitize_memdev(int argc, const char **argv, struct cxl_ctx *ctx)
> +{
> +	int count = memdev_action(
> +		argc, argv, ctx, action_sanitize_memdev, sanitize_options,
> +		"cxl sanitize-memdev <mem0> [<mem1>..<memn>] [<options>]");
> +
> +	log_info(&ml, "sanitize %s on %d mem device%s\n",
> +		 count >= 0 ? "completed/started" : "failed",
> +		 count >= 0 ? count : 0,  count > 1 ? "s" : "");
> +
> +	return count >= 0 ? 0 : EXIT_FAILURE;
> +}
> +
>  int cmd_wait_sanitize(int argc, const char **argv, struct cxl_ctx *ctx)
>  {
>  	int count = memdev_action(
> diff --git a/test/cxl-sanitize.sh b/test/cxl-sanitize.sh
> index 9c161014ccb7..8c5027ab9f48 100644
> --- a/test/cxl-sanitize.sh
> +++ b/test/cxl-sanitize.sh
> @@ -45,7 +45,7 @@ count=${#active_mem[@]}
>  set_timeout ${active_mem[0]} 2000
>  
>  # sanitize with an active memdev should fail
> -echo 1 > /sys/bus/cxl/devices/${active_mem[0]}/security/sanitize && err $LINENO
> +"$CXL" sanitize-memdev ${active_mem[0]} && err $LINENO
>  
>  # find an inactive mem
>  inactive=""
> @@ -67,7 +67,7 @@ done
>  # secounds
>  set_timeout $inactive 3000
>  start=$SECONDS
> -echo 1 > /sys/bus/cxl/devices/${inactive}/security/sanitize &
> +"$CXL" sanitize-memdev $inactive || err $LINENO
>  "$CXL" wait-sanitize $inactive || err $LINENO
>  ((SECONDS > start + 2)) || err $LINENO
>  
> -- 
> 2.39.5
>