[ndctl PATCH v3 6/6] cxl: add command set-partition-info

[alison.schofield@intel.com]

From: Alison Schofield <alison.schofield@intel.com>

Users may want to change the partition layout of a memory
device using the CXL command line tool. Add a new CXL command,
'cxl set-partition-info', that operates on a CXL memdev, or a
set of memdevs, and allows the user to change the partition
layout of the device(s).

Synopsis:
Usage: cxl set-partition-info <mem0> [<mem1>..<memN>] [<options>]

	-v, --verbose		turn on debug
	-s, --volatile_size <n>
				next volatile partition size in bytes

The included MAN page explains how to find the partitioning
capabilities and restrictions of a CXL memory device.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
 Documentation/cxl/cxl-set-partition-info.txt |  53 ++++++++++
 Documentation/cxl/meson.build                |   1 +
 cxl/builtin.h                                |   1 +
 cxl/cxl.c                                    |   1 +
 cxl/memdev.c                                 | 101 +++++++++++++++++++
 5 files changed, 157 insertions(+)
 create mode 100644 Documentation/cxl/cxl-set-partition-info.txt

diff --git a/Documentation/cxl/cxl-set-partition-info.txt b/Documentation/cxl/cxl-set-partition-info.txt
new file mode 100644
index 0000000..d99a1b9
--- /dev/null
+++ b/Documentation/cxl/cxl-set-partition-info.txt
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0
+
+cxl-set-partition-info(1)
+=========================
+
+NAME
+----
+cxl-set-partition-info - set the partitioning between volatile and persistent capacity on a CXL memdev
+
+SYNOPSIS
+--------
+[verse]
+'cxl set-partition-info <mem> [ [<mem1>..<memN>] [<options>]'
+
+DESCRIPTION
+-----------
+Partition the device into volatile and persistent capacity. The change
+in partitioning will become the “next” configuration, to become active
+on the next device reset.
+
+Use "cxl list -m <memdev> -I" to examine the partitioning capabilities
+of a device. A partition_alignment_bytes value of zero means there are
+no partitionable bytes available and therefore the partitions cannot be
+changed.
+
+Using this command to change the size of the persistent capacity shall
+result in the loss of data stored.
+
+OPTIONS
+-------
+<memory device(s)>::
+include::memdev-option.txt[]
+
+-s::
+--size=::
+        Size in bytes of the volatile partition requested.
+
+        Size must align to the devices partition_alignment_bytes.
+        Use 'cxl list -m <memdev> -I' to find partition_alignment_bytes.
+
+        Size must be less than or equal to the device's partitionable bytes.
+        Calculate partitionable bytes by subracting the volatile_only_bytes,
+        and the persistent_only_bytes, from the total_bytes.
+        Use 'cxl list -m <memdev> -I' to find the above mentioned_byte values.
+
+-v::
+        Turn on verbose debug messages in the library (if libcxl was built with
+        logging and debug enabled).
+
+SEE ALSO
+--------
+linkcxl:cxl-list[1],
+CXL-2.0 8.2.9.5.2
diff --git a/Documentation/cxl/meson.build b/Documentation/cxl/meson.build
index 64ce13f..0108eea 100644
--- a/Documentation/cxl/meson.build
+++ b/Documentation/cxl/meson.build
@@ -28,6 +28,7 @@ cxl_manpages = [
   'cxl-read-labels.txt',
   'cxl-write-labels.txt',
   'cxl-zero-labels.txt',
+  'cxl-set-partition-info.txt',
 ]
 
 foreach man : cxl_manpages
diff --git a/cxl/builtin.h b/cxl/builtin.h
index 78eca6e..7f11f28 100644
--- a/cxl/builtin.h
+++ b/cxl/builtin.h
@@ -10,4 +10,5 @@ int cmd_read_labels(int argc, const char **argv, struct cxl_ctx *ctx);
 int cmd_zero_labels(int argc, const char **argv, struct cxl_ctx *ctx);
 int cmd_init_labels(int argc, const char **argv, struct cxl_ctx *ctx);
 int cmd_check_labels(int argc, const char **argv, struct cxl_ctx *ctx);
+int cmd_set_partition_info(int argc, const char **argv, struct cxl_ctx *ctx);
 #endif /* _CXL_BUILTIN_H_ */
diff --git a/cxl/cxl.c b/cxl/cxl.c
index 4b1661d..3153cf0 100644
--- a/cxl/cxl.c
+++ b/cxl/cxl.c
@@ -64,6 +64,7 @@ static struct cmd_struct commands[] = {
 	{ "zero-labels", .c_fn = cmd_zero_labels },
 	{ "read-labels", .c_fn = cmd_read_labels },
 	{ "write-labels", .c_fn = cmd_write_labels },
+	{ "set-partition-info", .c_fn = cmd_set_partition_info },
 };
 
 int main(int argc, const char **argv)
diff --git a/cxl/memdev.c b/cxl/memdev.c
index d063d51..e1348c8 100644
--- a/cxl/memdev.c
+++ b/cxl/memdev.c
@@ -6,6 +6,7 @@
 #include <unistd.h>
 #include <limits.h>
 #include <util/log.h>
+#include <util/size.h>
 #include <cxl/libcxl.h>
 #include <util/parse-options.h>
 #include <ccan/minmax/minmax.h>
@@ -24,6 +25,7 @@ static struct parameters {
 	unsigned len;
 	unsigned offset;
 	bool verbose;
+	const char *volatile_size;
 } param;
 
 #define fail(fmt, ...) \
@@ -48,6 +50,10 @@ OPT_UINTEGER('s', "size", &param.len, "number of label bytes to operate"), \
 OPT_UINTEGER('O', "offset", &param.offset, \
 	"offset into the label area to start operation")
 
+#define SET_PARTITION_OPTIONS() \
+OPT_STRING('s', "volatile_size",  &param.volatile_size, "volatile-size", \
+	"next volatile partition size in bytes")
+
 static const struct option read_options[] = {
 	BASE_OPTIONS(),
 	LABEL_OPTIONS(),
@@ -68,6 +74,12 @@ static const struct option zero_options[] = {
 	OPT_END(),
 };
 
+static const struct option set_partition_options[] = {
+	BASE_OPTIONS(),
+	SET_PARTITION_OPTIONS(),
+	OPT_END(),
+};
+
 static int action_zero(struct cxl_memdev *memdev, struct action_context *actx)
 {
 	size_t size;
@@ -175,6 +187,80 @@ out:
 	return rc;
 }
 
+static int validate_partition(struct cxl_memdev *memdev,
+		unsigned long long volatile_request)
+{
+	unsigned long long total_cap, volatile_only, persistent_only;
+	unsigned long long partitionable_bytes, partition_align_bytes;
+	const char *devname = cxl_memdev_get_devname(memdev);
+	struct cxl_cmd *cmd;
+	int rc;
+
+	cmd = cxl_cmd_new_identify(memdev);
+	if (!cmd)
+		return -ENXIO;
+	rc = cxl_cmd_submit(cmd);
+	if (rc < 0)
+		goto err;
+	rc = cxl_cmd_get_mbox_status(cmd);
+	if (rc != 0)
+		goto err;
+
+	partition_align_bytes = cxl_cmd_identify_get_partition_align(cmd);
+	if (partition_align_bytes == 0) {
+		fprintf(stderr, "%s: no partitionable capacity\n", devname);
+		rc = -EINVAL;
+		goto err;
+	}
+
+	total_cap = cxl_cmd_identify_get_total_bytes(cmd);
+	volatile_only = cxl_cmd_identify_get_volatile_only_bytes(cmd);
+	persistent_only = cxl_cmd_identify_get_persistent_only_bytes(cmd);
+
+	partitionable_bytes = total_cap - volatile_only - persistent_only;
+
+	if (volatile_request > partitionable_bytes) {
+		fprintf(stderr, "%s: volatile size %lld exceeds partitionable capacity %lld\n",
+			devname, volatile_request, partitionable_bytes);
+		rc = -EINVAL;
+		goto err;
+	}
+	if (!IS_ALIGNED(volatile_request, partition_align_bytes)) {
+		fprintf(stderr, "%s: volatile size %lld is not partition aligned %lld\n",
+			devname, volatile_request, partition_align_bytes);
+		rc = -EINVAL;
+	}
+err:
+	cxl_cmd_unref(cmd);
+	return rc;
+}
+
+static int action_set_partition(struct cxl_memdev *memdev,
+		struct action_context *actx)
+{
+	const char *devname = cxl_memdev_get_devname(memdev);
+	unsigned long long volatile_request;
+	int rc;
+
+	volatile_request = parse_size64(param.volatile_size);
+	if (volatile_request == ULLONG_MAX) {
+		fprintf(stderr, "%s: failed to parse volatile size '%s'\n",
+			devname, param.volatile_size);
+		return -EINVAL;
+	}
+
+	rc = validate_partition(memdev, volatile_request);
+	if (rc)
+		return rc;
+
+	rc = cxl_memdev_set_partition_info(memdev, volatile_request,
+			!cxl_cmd_partition_info_flag_immediate());
+	if (rc)
+		fprintf(stderr, "%s error: %s\n", devname, strerror(-rc));
+
+	return rc;
+}
+
 static int memdev_action(int argc, const char **argv, struct cxl_ctx *ctx,
 		int (*action)(struct cxl_memdev *memdev, struct action_context *actx),
 		const struct option *options, const char *usage)
@@ -235,6 +321,11 @@ static int memdev_action(int argc, const char **argv, struct cxl_ctx *ctx,
 		}
 	}
 
+	if (action == action_set_partition && !param.volatile_size) {
+		usage_with_options(u, options);
+		return -EINVAL;
+	}
+
 	if (param.verbose)
 		cxl_set_log_priority(ctx, LOG_DEBUG);
 
@@ -323,3 +414,13 @@ int cmd_zero_labels(int argc, const char **argv, struct cxl_ctx *ctx)
 			count > 1 ? "s" : "");
 	return count >= 0 ? 0 : EXIT_FAILURE;
 }
+
+int cmd_set_partition_info(int argc, const char **argv, struct cxl_ctx *ctx)
+{
+	int count = memdev_action(argc, argv, ctx, action_set_partition,
+			set_partition_options,
+			"cxl set-partition-info <mem0> [<mem1>..<memN>] [<options>]");
+	fprintf(stderr, "set_partition %d mem%s\n", count >= 0 ? count : 0,
+			count > 1 ? "s" : "");
+	return count >= 0 ? 0 : EXIT_FAILURE;
+}
-- 
2.31.1