summaryrefslogtreecommitdiff
path: root/drivers/cxl/core/mbox.c
blob: 576796a5d9f34537422d0e81a9988489ee513ddd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2020 Intel Corporation. All rights reserved. */
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/security.h>
#include <linux/debugfs.h>
#include <linux/mutex.h>
#include <cxlmem.h>
#include <cxl.h>

#include "core.h"

static bool cxl_raw_allow_all;

/**
 * DOC: cxl mbox
 *
 * Core implementation of the CXL 2.0 Type-3 Memory Device Mailbox. The
 * implementation is used by the cxl_pci driver to initialize the device
 * and implement the cxl_mem.h IOCTL UAPI. It also implements the
 * backend of the cxl_pmem_ctl() transport for LIBNVDIMM.
 */

#define cxl_for_each_cmd(cmd)                                                  \
	for ((cmd) = &cxl_mem_commands[0];                                     \
	     ((cmd) - cxl_mem_commands) < ARRAY_SIZE(cxl_mem_commands); (cmd)++)

#define CXL_CMD(_id, sin, sout, _flags)                                        \
	[CXL_MEM_COMMAND_ID_##_id] = {                                         \
	.info =	{                                                              \
			.id = CXL_MEM_COMMAND_ID_##_id,                        \
			.size_in = sin,                                        \
			.size_out = sout,                                      \
		},                                                             \
	.opcode = CXL_MBOX_OP_##_id,                                           \
	.flags = _flags,                                                       \
	}

/*
 * This table defines the supported mailbox commands for the driver. This table
 * is made up of a UAPI structure. Non-negative values as parameters in the
 * table will be validated against the user's input. For example, if size_in is
 * 0, and the user passed in 1, it is an error.
 */
static struct cxl_mem_command cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
	CXL_CMD(IDENTIFY, 0, 0x43, CXL_CMD_FLAG_FORCE_ENABLE),
#ifdef CONFIG_CXL_MEM_RAW_COMMANDS
	CXL_CMD(RAW, ~0, ~0, 0),
#endif
	CXL_CMD(GET_SUPPORTED_LOGS, 0, ~0, CXL_CMD_FLAG_FORCE_ENABLE),
	CXL_CMD(GET_FW_INFO, 0, 0x50, 0),
	CXL_CMD(GET_PARTITION_INFO, 0, 0x20, 0),
	CXL_CMD(GET_LSA, 0x8, ~0, 0),
	CXL_CMD(GET_HEALTH_INFO, 0, 0x12, 0),
	CXL_CMD(GET_LOG, 0x18, ~0, CXL_CMD_FLAG_FORCE_ENABLE),
	CXL_CMD(SET_PARTITION_INFO, 0x0a, 0, 0),
	CXL_CMD(SET_LSA, ~0, 0, 0),
	CXL_CMD(GET_ALERT_CONFIG, 0, 0x10, 0),
	CXL_CMD(SET_ALERT_CONFIG, 0xc, 0, 0),
	CXL_CMD(GET_SHUTDOWN_STATE, 0, 0x1, 0),
	CXL_CMD(SET_SHUTDOWN_STATE, 0x1, 0, 0),
	CXL_CMD(GET_POISON, 0x10, ~0, 0),
	CXL_CMD(INJECT_POISON, 0x8, 0, 0),
	CXL_CMD(CLEAR_POISON, 0x48, 0, 0),
	CXL_CMD(GET_SCAN_MEDIA_CAPS, 0x10, 0x4, 0),
	CXL_CMD(SCAN_MEDIA, 0x11, 0, 0),
	CXL_CMD(GET_SCAN_MEDIA, 0, ~0, 0),
};

/*
 * Commands that RAW doesn't permit. The rationale for each:
 *
 * CXL_MBOX_OP_ACTIVATE_FW: Firmware activation requires adjustment /
 * coordination of transaction timeout values at the root bridge level.
 *
 * CXL_MBOX_OP_SET_PARTITION_INFO: The device memory map may change live
 * and needs to be coordinated with HDM updates.
 *
 * CXL_MBOX_OP_SET_LSA: The label storage area may be cached by the
 * driver and any writes from userspace invalidates those contents.
 *
 * CXL_MBOX_OP_SET_SHUTDOWN_STATE: Set shutdown state assumes no writes
 * to the device after it is marked clean, userspace can not make that
 * assertion.
 *
 * CXL_MBOX_OP_[GET_]SCAN_MEDIA: The kernel provides a native error list that
 * is kept up to date with patrol notifications and error management.
 */
static u16 cxl_disabled_raw_commands[] = {
	CXL_MBOX_OP_ACTIVATE_FW,
	CXL_MBOX_OP_SET_PARTITION_INFO,
	CXL_MBOX_OP_SET_LSA,
	CXL_MBOX_OP_SET_SHUTDOWN_STATE,
	CXL_MBOX_OP_SCAN_MEDIA,
	CXL_MBOX_OP_GET_SCAN_MEDIA,
};

/*
 * Command sets that RAW doesn't permit. All opcodes in this set are
 * disabled because they pass plain text security payloads over the
 * user/kernel boundary. This functionality is intended to be wrapped
 * behind the keys ABI which allows for encrypted payloads in the UAPI
 */
static u8 security_command_sets[] = {
	0x44, /* Sanitize */
	0x45, /* Persistent Memory Data-at-rest Security */
	0x46, /* Security Passthrough */
};

static bool cxl_is_security_command(u16 opcode)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(security_command_sets); i++)
		if (security_command_sets[i] == (opcode >> 8))
			return true;
	return false;
}

static struct cxl_mem_command *cxl_mem_find_command(u16 opcode)
{
	struct cxl_mem_command *c;

	cxl_for_each_cmd(c)
		if (c->opcode == opcode)
			return c;

	return NULL;
}

/**
 * cxl_mem_mbox_send_cmd() - Send a mailbox command to a memory device.
 * @cxlm: The CXL memory device to communicate with.
 * @opcode: Opcode for the mailbox command.
 * @in: The input payload for the mailbox command.
 * @in_size: The length of the input payload
 * @out: Caller allocated buffer for the output.
 * @out_size: Expected size of output.
 *
 * Context: Any context. Will acquire and release mbox_mutex.
 * Return:
 *  * %>=0	- Number of bytes returned in @out.
 *  * %-E2BIG	- Payload is too large for hardware.
 *  * %-EBUSY	- Couldn't acquire exclusive mailbox access.
 *  * %-EFAULT	- Hardware error occurred.
 *  * %-ENXIO	- Command completed, but device reported an error.
 *  * %-EIO	- Unexpected output size.
 *
 * Mailbox commands may execute successfully yet the device itself reported an
 * error. While this distinction can be useful for commands from userspace, the
 * kernel will only be able to use results when both are successful.
 *
 * See __cxl_mem_mbox_send_cmd()
 */
int cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm, u16 opcode, void *in,
			  size_t in_size, void *out, size_t out_size)
{
	const struct cxl_mem_command *cmd = cxl_mem_find_command(opcode);
	struct cxl_mbox_cmd mbox_cmd = {
		.opcode = opcode,
		.payload_in = in,
		.size_in = in_size,
		.size_out = out_size,
		.payload_out = out,
	};
	int rc;

	if (out_size > cxlm->payload_size)
		return -E2BIG;

	rc = cxlm->mbox_send(cxlm, &mbox_cmd);
	if (rc)
		return rc;

	/* TODO: Map return code to proper kernel style errno */
	if (mbox_cmd.return_code != CXL_MBOX_SUCCESS)
		return -ENXIO;

	/*
	 * Variable sized commands can't be validated and so it's up to the
	 * caller to do that if they wish.
	 */
	if (cmd->info.size_out >= 0 && mbox_cmd.size_out != out_size)
		return -EIO;

	return 0;
}
EXPORT_SYMBOL_GPL(cxl_mem_mbox_send_cmd);

static bool cxl_mem_raw_command_allowed(u16 opcode)
{
	int i;

	if (!IS_ENABLED(CONFIG_CXL_MEM_RAW_COMMANDS))
		return false;

	if (security_locked_down(LOCKDOWN_PCI_ACCESS))
		return false;

	if (cxl_raw_allow_all)
		return true;

	if (cxl_is_security_command(opcode))
		return false;

	for (i = 0; i < ARRAY_SIZE(cxl_disabled_raw_commands); i++)
		if (cxl_disabled_raw_commands[i] == opcode)
			return false;

	return true;
}

/**
 * cxl_validate_cmd_from_user() - Check fields for CXL_MEM_SEND_COMMAND.
 * @cxlm: &struct cxl_mem device whose mailbox will be used.
 * @send_cmd: &struct cxl_send_command copied in from userspace.
 * @out_cmd: Sanitized and populated &struct cxl_mem_command.
 *
 * Return:
 *  * %0	- @out_cmd is ready to send.
 *  * %-ENOTTY	- Invalid command specified.
 *  * %-EINVAL	- Reserved fields or invalid values were used.
 *  * %-ENOMEM	- Input or output buffer wasn't sized properly.
 *  * %-EPERM	- Attempted to use a protected command.
 *  * %-EBUSY	- Kernel has claimed exclusive access to this opcode
 *
 * The result of this command is a fully validated command in @out_cmd that is
 * safe to send to the hardware.
 *
 * See handle_mailbox_cmd_from_user()
 */
static int cxl_validate_cmd_from_user(struct cxl_mem *cxlm,
				      const struct cxl_send_command *send_cmd,
				      struct cxl_mem_command *out_cmd)
{
	const struct cxl_command_info *info;
	struct cxl_mem_command *c;

	if (send_cmd->id == 0 || send_cmd->id >= CXL_MEM_COMMAND_ID_MAX)
		return -ENOTTY;

	/*
	 * The user can never specify an input payload larger than what hardware
	 * supports, but output can be arbitrarily large (simply write out as
	 * much data as the hardware provides).
	 */
	if (send_cmd->in.size > cxlm->payload_size)
		return -EINVAL;

	/*
	 * Checks are bypassed for raw commands but a WARN/taint will occur
	 * later in the callchain
	 */
	if (send_cmd->id == CXL_MEM_COMMAND_ID_RAW) {
		const struct cxl_mem_command temp = {
			.info = {
				.id = CXL_MEM_COMMAND_ID_RAW,
				.flags = 0,
				.size_in = send_cmd->in.size,
				.size_out = send_cmd->out.size,
			},
			.opcode = send_cmd->raw.opcode
		};

		if (send_cmd->raw.rsvd)
			return -EINVAL;

		/*
		 * Unlike supported commands, the output size of RAW commands
		 * gets passed along without further checking, so it must be
		 * validated here.
		 */
		if (send_cmd->out.size > cxlm->payload_size)
			return -EINVAL;

		if (!cxl_mem_raw_command_allowed(send_cmd->raw.opcode))
			return -EPERM;

		memcpy(out_cmd, &temp, sizeof(temp));

		return 0;
	}

	if (send_cmd->flags & ~CXL_MEM_COMMAND_FLAG_MASK)
		return -EINVAL;

	if (send_cmd->rsvd)
		return -EINVAL;

	if (send_cmd->in.rsvd || send_cmd->out.rsvd)
		return -EINVAL;

	/* Convert user's command into the internal representation */
	c = &cxl_mem_commands[send_cmd->id];
	info = &c->info;

	/* Check that the command is enabled for hardware */
	if (!test_bit(info->id, cxlm->enabled_cmds))
		return -ENOTTY;

	/* Check that the command is not claimed for exclusive kernel use */
	if (test_bit(info->id, cxlm->exclusive_cmds))
		return -EBUSY;

	/* Check the input buffer is the expected size */
	if (info->size_in >= 0 && info->size_in != send_cmd->in.size)
		return -ENOMEM;

	/* Check the output buffer is at least large enough */
	if (info->size_out >= 0 && send_cmd->out.size < info->size_out)
		return -ENOMEM;

	memcpy(out_cmd, c, sizeof(*c));
	out_cmd->info.size_in = send_cmd->in.size;
	/*
	 * XXX: out_cmd->info.size_out will be controlled by the driver, and the
	 * specified number of bytes @send_cmd->out.size will be copied back out
	 * to userspace.
	 */

	return 0;
}

int cxl_query_cmd(struct cxl_memdev *cxlmd,
		  struct cxl_mem_query_commands __user *q)
{
	struct device *dev = &cxlmd->dev;
	struct cxl_mem_command *cmd;
	u32 n_commands;
	int j = 0;

	dev_dbg(dev, "Query IOCTL\n");

	if (get_user(n_commands, &q->n_commands))
		return -EFAULT;

	/* returns the total number if 0 elements are requested. */
	if (n_commands == 0)
		return put_user(ARRAY_SIZE(cxl_mem_commands), &q->n_commands);

	/*
	 * otherwise, return max(n_commands, total commands) cxl_command_info
	 * structures.
	 */
	cxl_for_each_cmd(cmd) {
		const struct cxl_command_info *info = &cmd->info;

		if (copy_to_user(&q->commands[j++], info, sizeof(*info)))
			return -EFAULT;

		if (j == n_commands)
			break;
	}

	return 0;
}

/**
 * handle_mailbox_cmd_from_user() - Dispatch a mailbox command for userspace.
 * @cxlm: The CXL memory device to communicate with.
 * @cmd: The validated command.
 * @in_payload: Pointer to userspace's input payload.
 * @out_payload: Pointer to userspace's output payload.
 * @size_out: (Input) Max payload size to copy out.
 *            (Output) Payload size hardware generated.
 * @retval: Hardware generated return code from the operation.
 *
 * Return:
 *  * %0	- Mailbox transaction succeeded. This implies the mailbox
 *		  protocol completed successfully not that the operation itself
 *		  was successful.
 *  * %-ENOMEM  - Couldn't allocate a bounce buffer.
 *  * %-EFAULT	- Something happened with copy_to/from_user.
 *  * %-EINTR	- Mailbox acquisition interrupted.
 *  * %-EXXX	- Transaction level failures.
 *
 * Creates the appropriate mailbox command and dispatches it on behalf of a
 * userspace request. The input and output payloads are copied between
 * userspace.
 *
 * See cxl_send_cmd().
 */
static int handle_mailbox_cmd_from_user(struct cxl_mem *cxlm,
					const struct cxl_mem_command *cmd,
					u64 in_payload, u64 out_payload,
					s32 *size_out, u32 *retval)
{
	struct device *dev = cxlm->dev;
	struct cxl_mbox_cmd mbox_cmd = {
		.opcode = cmd->opcode,
		.size_in = cmd->info.size_in,
		.size_out = cmd->info.size_out,
	};
	int rc;

	if (cmd->info.size_out) {
		mbox_cmd.payload_out = kvzalloc(cmd->info.size_out, GFP_KERNEL);
		if (!mbox_cmd.payload_out)
			return -ENOMEM;
	}

	if (cmd->info.size_in) {
		mbox_cmd.payload_in = vmemdup_user(u64_to_user_ptr(in_payload),
						   cmd->info.size_in);
		if (IS_ERR(mbox_cmd.payload_in)) {
			kvfree(mbox_cmd.payload_out);
			return PTR_ERR(mbox_cmd.payload_in);
		}
	}

	dev_dbg(dev,
		"Submitting %s command for user\n"
		"\topcode: %x\n"
		"\tsize: %ub\n",
		cxl_command_names[cmd->info.id].name, mbox_cmd.opcode,
		cmd->info.size_in);

	dev_WARN_ONCE(dev, cmd->info.id == CXL_MEM_COMMAND_ID_RAW,
		      "raw command path used\n");

	rc = cxlm->mbox_send(cxlm, &mbox_cmd);
	if (rc)
		goto out;

	/*
	 * @size_out contains the max size that's allowed to be written back out
	 * to userspace. While the payload may have written more output than
	 * this it will have to be ignored.
	 */
	if (mbox_cmd.size_out) {
		dev_WARN_ONCE(dev, mbox_cmd.size_out > *size_out,
			      "Invalid return size\n");
		if (copy_to_user(u64_to_user_ptr(out_payload),
				 mbox_cmd.payload_out, mbox_cmd.size_out)) {
			rc = -EFAULT;
			goto out;
		}
	}

	*size_out = mbox_cmd.size_out;
	*retval = mbox_cmd.return_code;

out:
	kvfree(mbox_cmd.payload_in);
	kvfree(mbox_cmd.payload_out);
	return rc;
}

int cxl_send_cmd(struct cxl_memdev *cxlmd, struct cxl_send_command __user *s)
{
	struct cxl_mem *cxlm = cxlmd->cxlm;
	struct device *dev = &cxlmd->dev;
	struct cxl_send_command send;
	struct cxl_mem_command c;
	int rc;

	dev_dbg(dev, "Send IOCTL\n");

	if (copy_from_user(&send, s, sizeof(send)))
		return -EFAULT;

	rc = cxl_validate_cmd_from_user(cxlmd->cxlm, &send, &c);
	if (rc)
		return rc;

	/* Prepare to handle a full payload for variable sized output */
	if (c.info.size_out < 0)
		c.info.size_out = cxlm->payload_size;

	rc = handle_mailbox_cmd_from_user(cxlm, &c, send.in.payload,
					  send.out.payload, &send.out.size,
					  &send.retval);
	if (rc)
		return rc;

	if (copy_to_user(s, &send, sizeof(send)))
		return -EFAULT;

	return 0;
}

static int cxl_xfer_log(struct cxl_mem *cxlm, uuid_t *uuid, u32 size, u8 *out)
{
	u32 remaining = size;
	u32 offset = 0;

	while (remaining) {
		u32 xfer_size = min_t(u32, remaining, cxlm->payload_size);
		struct cxl_mbox_get_log log = {
			.uuid = *uuid,
			.offset = cpu_to_le32(offset),
			.length = cpu_to_le32(xfer_size)
		};
		int rc;

		rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_GET_LOG, &log,
					   sizeof(log), out, xfer_size);
		if (rc < 0)
			return rc;

		out += xfer_size;
		remaining -= xfer_size;
		offset += xfer_size;
	}

	return 0;
}

/**
 * cxl_walk_cel() - Walk through the Command Effects Log.
 * @cxlm: Device.
 * @size: Length of the Command Effects Log.
 * @cel: CEL
 *
 * Iterate over each entry in the CEL and determine if the driver supports the
 * command. If so, the command is enabled for the device and can be used later.
 */
static void cxl_walk_cel(struct cxl_mem *cxlm, size_t size, u8 *cel)
{
	struct cxl_cel_entry *cel_entry;
	const int cel_entries = size / sizeof(*cel_entry);
	int i;

	cel_entry = (struct cxl_cel_entry *) cel;

	for (i = 0; i < cel_entries; i++) {
		u16 opcode = le16_to_cpu(cel_entry[i].opcode);
		struct cxl_mem_command *cmd = cxl_mem_find_command(opcode);

		if (!cmd) {
			dev_dbg(cxlm->dev,
				"Opcode 0x%04x unsupported by driver", opcode);
			continue;
		}

		set_bit(cmd->info.id, cxlm->enabled_cmds);
	}
}

static struct cxl_mbox_get_supported_logs *cxl_get_gsl(struct cxl_mem *cxlm)
{
	struct cxl_mbox_get_supported_logs *ret;
	int rc;

	ret = kvmalloc(cxlm->payload_size, GFP_KERNEL);
	if (!ret)
		return ERR_PTR(-ENOMEM);

	rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_GET_SUPPORTED_LOGS, NULL,
				   0, ret, cxlm->payload_size);
	if (rc < 0) {
		kvfree(ret);
		return ERR_PTR(rc);
	}

	return ret;
}

enum {
	CEL_UUID,
	VENDOR_DEBUG_UUID,
};

/* See CXL 2.0 Table 170. Get Log Input Payload */
static const uuid_t log_uuid[] = {
	[CEL_UUID] = DEFINE_CXL_CEL_UUID,
	[VENDOR_DEBUG_UUID] = DEFINE_CXL_VENDOR_DEBUG_UUID,
};

/**
 * cxl_mem_enumerate_cmds() - Enumerate commands for a device.
 * @cxlm: The device.
 *
 * Returns 0 if enumerate completed successfully.
 *
 * CXL devices have optional support for certain commands. This function will
 * determine the set of supported commands for the hardware and update the
 * enabled_cmds bitmap in the @cxlm.
 */
int cxl_mem_enumerate_cmds(struct cxl_mem *cxlm)
{
	struct cxl_mbox_get_supported_logs *gsl;
	struct device *dev = cxlm->dev;
	struct cxl_mem_command *cmd;
	int i, rc;

	gsl = cxl_get_gsl(cxlm);
	if (IS_ERR(gsl))
		return PTR_ERR(gsl);

	rc = -ENOENT;
	for (i = 0; i < le16_to_cpu(gsl->entries); i++) {
		u32 size = le32_to_cpu(gsl->entry[i].size);
		uuid_t uuid = gsl->entry[i].uuid;
		u8 *log;

		dev_dbg(dev, "Found LOG type %pU of size %d", &uuid, size);

		if (!uuid_equal(&uuid, &log_uuid[CEL_UUID]))
			continue;

		log = kvmalloc(size, GFP_KERNEL);
		if (!log) {
			rc = -ENOMEM;
			goto out;
		}

		rc = cxl_xfer_log(cxlm, &uuid, size, log);
		if (rc) {
			kvfree(log);
			goto out;
		}

		cxl_walk_cel(cxlm, size, log);
		kvfree(log);

		/* In case CEL was bogus, enable some default commands. */
		cxl_for_each_cmd(cmd)
			if (cmd->flags & CXL_CMD_FLAG_FORCE_ENABLE)
				set_bit(cmd->info.id, cxlm->enabled_cmds);

		/* Found the required CEL */
		rc = 0;
	}

out:
	kvfree(gsl);
	return rc;
}
EXPORT_SYMBOL_GPL(cxl_mem_enumerate_cmds);

/**
 * cxl_mem_get_partition_info - Get partition info
 * @cxlm: cxl_mem instance to update partition info
 *
 * Retrieve the current partition info for the device specified.  The active
 * values are the current capacity in bytes.  If not 0, the 'next' values are
 * the pending values, in bytes, which take affect on next cold reset.
 *
 * Return: 0 if no error: or the result of the mailbox command.
 *
 * See CXL @8.2.9.5.2.1 Get Partition Info
 */
static int cxl_mem_get_partition_info(struct cxl_mem *cxlm)
{
	struct cxl_mbox_get_partition_info {
		__le64 active_volatile_cap;
		__le64 active_persistent_cap;
		__le64 next_volatile_cap;
		__le64 next_persistent_cap;
	} __packed pi;
	int rc;

	rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_GET_PARTITION_INFO,
				   NULL, 0, &pi, sizeof(pi));

	if (rc)
		return rc;

	cxlm->active_volatile_bytes =
		le64_to_cpu(pi.active_volatile_cap) * CXL_CAPACITY_MULTIPLIER;
	cxlm->active_persistent_bytes =
		le64_to_cpu(pi.active_persistent_cap) * CXL_CAPACITY_MULTIPLIER;
	cxlm->next_volatile_bytes =
		le64_to_cpu(pi.next_volatile_cap) * CXL_CAPACITY_MULTIPLIER;
	cxlm->next_persistent_bytes =
		le64_to_cpu(pi.next_volatile_cap) * CXL_CAPACITY_MULTIPLIER;

	return 0;
}

/**
 * cxl_mem_identify() - Send the IDENTIFY command to the device.
 * @cxlm: The device to identify.
 *
 * Return: 0 if identify was executed successfully.
 *
 * This will dispatch the identify command to the device and on success populate
 * structures to be exported to sysfs.
 */
int cxl_mem_identify(struct cxl_mem *cxlm)
{
	/* See CXL 2.0 Table 175 Identify Memory Device Output Payload */
	struct cxl_mbox_identify id;
	int rc;

	rc = cxl_mem_mbox_send_cmd(cxlm, CXL_MBOX_OP_IDENTIFY, NULL, 0, &id,
				   sizeof(id));
	if (rc < 0)
		return rc;

	cxlm->total_bytes =
		le64_to_cpu(id.total_capacity) * CXL_CAPACITY_MULTIPLIER;
	cxlm->volatile_only_bytes =
		le64_to_cpu(id.volatile_capacity) * CXL_CAPACITY_MULTIPLIER;
	cxlm->persistent_only_bytes =
		le64_to_cpu(id.persistent_capacity) * CXL_CAPACITY_MULTIPLIER;
	cxlm->partition_align_bytes =
		le64_to_cpu(id.partition_align) * CXL_CAPACITY_MULTIPLIER;

	dev_dbg(cxlm->dev,
		"Identify Memory Device\n"
		"     total_bytes = %#llx\n"
		"     volatile_only_bytes = %#llx\n"
		"     persistent_only_bytes = %#llx\n"
		"     partition_align_bytes = %#llx\n",
		cxlm->total_bytes, cxlm->volatile_only_bytes,
		cxlm->persistent_only_bytes, cxlm->partition_align_bytes);

	cxlm->lsa_size = le32_to_cpu(id.lsa_size);
	memcpy(cxlm->firmware_version, id.fw_revision, sizeof(id.fw_revision));

	return 0;
}
EXPORT_SYMBOL_GPL(cxl_mem_identify);

int cxl_mem_create_range_info(struct cxl_mem *cxlm)
{
	int rc;

	if (cxlm->partition_align_bytes == 0) {
		cxlm->ram_range.start = 0;
		cxlm->ram_range.end = cxlm->volatile_only_bytes - 1;
		cxlm->pmem_range.start = cxlm->volatile_only_bytes;
		cxlm->pmem_range.end = cxlm->volatile_only_bytes +
				       cxlm->persistent_only_bytes - 1;
		return 0;
	}

	rc = cxl_mem_get_partition_info(cxlm);
	if (rc) {
		dev_err(cxlm->dev, "Failed to query partition information\n");
		return rc;
	}

	dev_dbg(cxlm->dev,
		"Get Partition Info\n"
		"     active_volatile_bytes = %#llx\n"
		"     active_persistent_bytes = %#llx\n"
		"     next_volatile_bytes = %#llx\n"
		"     next_persistent_bytes = %#llx\n",
		cxlm->active_volatile_bytes, cxlm->active_persistent_bytes,
		cxlm->next_volatile_bytes, cxlm->next_persistent_bytes);

	cxlm->ram_range.start = 0;
	cxlm->ram_range.end = cxlm->active_volatile_bytes - 1;

	cxlm->pmem_range.start = cxlm->active_volatile_bytes;
	cxlm->pmem_range.end =
		cxlm->active_volatile_bytes + cxlm->active_persistent_bytes - 1;

	return 0;
}
EXPORT_SYMBOL_GPL(cxl_mem_create_range_info);

struct cxl_mem *cxl_mem_create(struct device *dev)
{
	struct cxl_mem *cxlm;

	cxlm = devm_kzalloc(dev, sizeof(*cxlm), GFP_KERNEL);
	if (!cxlm) {
		dev_err(dev, "No memory available\n");
		return ERR_PTR(-ENOMEM);
	}

	mutex_init(&cxlm->mbox_mutex);
	cxlm->dev = dev;

	return cxlm;
}
EXPORT_SYMBOL_GPL(cxl_mem_create);

static struct dentry *cxl_debugfs;

void __init cxl_mbox_init(void)
{
	struct dentry *mbox_debugfs;

	cxl_debugfs = debugfs_create_dir("cxl", NULL);
	mbox_debugfs = debugfs_create_dir("mbox", cxl_debugfs);
	debugfs_create_bool("raw_allow_all", 0600, mbox_debugfs,
			    &cxl_raw_allow_all);
}

void cxl_mbox_exit(void)
{
	debugfs_remove_recursive(cxl_debugfs);
}