xref: /dpdk/drivers/common/mlx5/mlx5_common.c (revision 85209924039c4b317ba50018befff1f5ea66ba73)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright 2019 Mellanox Technologies, Ltd
3  */
4 
5 #include <unistd.h>
6 #include <string.h>
7 #include <stdio.h>
8 
9 #include <rte_errno.h>
10 #include <rte_mempool.h>
11 #include <rte_class.h>
12 #include <rte_malloc.h>
13 
14 #include "mlx5_common.h"
15 #include "mlx5_common_os.h"
16 #include "mlx5_common_log.h"
17 #include "mlx5_common_defs.h"
18 #include "mlx5_common_private.h"
19 
20 uint8_t haswell_broadwell_cpu;
21 
22 /* In case this is an x86_64 intel processor to check if
23  * we should use relaxed ordering.
24  */
25 #ifdef RTE_ARCH_X86_64
26 /**
27  * This function returns processor identification and feature information
28  * into the registers.
29  *
30  * @param eax, ebx, ecx, edx
31  *		Pointers to the registers that will hold cpu information.
32  * @param level
33  *		The main category of information returned.
34  */
35 static inline void mlx5_cpu_id(unsigned int level,
36 				unsigned int *eax, unsigned int *ebx,
37 				unsigned int *ecx, unsigned int *edx)
38 {
39 	__asm__("cpuid\n\t"
40 		: "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx)
41 		: "0" (level));
42 }
43 #endif
44 
45 RTE_LOG_REGISTER_DEFAULT(mlx5_common_logtype, NOTICE)
46 
47 /* Head of list of drivers. */
48 static TAILQ_HEAD(mlx5_drivers, mlx5_class_driver) drivers_list =
49 				TAILQ_HEAD_INITIALIZER(drivers_list);
50 
51 /* Head of devices. */
52 static TAILQ_HEAD(mlx5_devices, mlx5_common_device) devices_list =
53 				TAILQ_HEAD_INITIALIZER(devices_list);
54 static pthread_mutex_t devices_list_lock;
55 
56 static const struct {
57 	const char *name;
58 	unsigned int drv_class;
59 } mlx5_classes[] = {
60 	{ .name = "vdpa", .drv_class = MLX5_CLASS_VDPA },
61 	{ .name = "eth", .drv_class = MLX5_CLASS_ETH },
62 	/* Keep class "net" for backward compatibility. */
63 	{ .name = "net", .drv_class = MLX5_CLASS_ETH },
64 	{ .name = "regex", .drv_class = MLX5_CLASS_REGEX },
65 	{ .name = "compress", .drv_class = MLX5_CLASS_COMPRESS },
66 	{ .name = "crypto", .drv_class = MLX5_CLASS_CRYPTO },
67 };
68 
69 static int
70 class_name_to_value(const char *class_name)
71 {
72 	unsigned int i;
73 
74 	for (i = 0; i < RTE_DIM(mlx5_classes); i++) {
75 		if (strcmp(class_name, mlx5_classes[i].name) == 0)
76 			return mlx5_classes[i].drv_class;
77 	}
78 	return -EINVAL;
79 }
80 
81 static struct mlx5_class_driver *
82 driver_get(uint32_t class)
83 {
84 	struct mlx5_class_driver *driver;
85 
86 	TAILQ_FOREACH(driver, &drivers_list, next) {
87 		if ((uint32_t)driver->drv_class == class)
88 			return driver;
89 	}
90 	return NULL;
91 }
92 
93 /**
94  * Verify and store value for devargs.
95  *
96  * @param[in] key
97  *   Key argument to verify.
98  * @param[in] val
99  *   Value associated with key.
100  * @param opaque
101  *   User data.
102  *
103  * @return
104  *   0 on success, a negative errno value otherwise and rte_errno is set.
105  */
106 static int
107 mlx5_common_args_check_handler(const char *key, const char *val, void *opaque)
108 {
109 	struct mlx5_common_dev_config *config = opaque;
110 	signed long tmp;
111 
112 	errno = 0;
113 	tmp = strtol(val, NULL, 0);
114 	if (errno) {
115 		rte_errno = errno;
116 		DRV_LOG(WARNING, "%s: \"%s\" is an invalid integer.", key, val);
117 		return -rte_errno;
118 	}
119 	if (strcmp(key, "tx_db_nc") == 0) {
120 		if (tmp != MLX5_TXDB_CACHED &&
121 		    tmp != MLX5_TXDB_NCACHED &&
122 		    tmp != MLX5_TXDB_HEURISTIC) {
123 			DRV_LOG(ERR, "Invalid Tx doorbell mapping parameter.");
124 			rte_errno = EINVAL;
125 			return -rte_errno;
126 		}
127 		config->dbnc = tmp;
128 	} else if (strcmp(key, "mr_ext_memseg_en") == 0) {
129 		config->mr_ext_memseg_en = !!tmp;
130 	} else if (strcmp(key, "mr_mempool_reg_en") == 0) {
131 		config->mr_mempool_reg_en = !!tmp;
132 	} else if (strcmp(key, "sys_mem_en") == 0) {
133 		config->sys_mem_en = !!tmp;
134 	}
135 	return 0;
136 }
137 
138 /**
139  * Parse common device parameters.
140  *
141  * @param devargs
142  *   Device arguments structure.
143  * @param config
144  *   Pointer to device configuration structure.
145  *
146  * @return
147  *   0 on success, a negative errno value otherwise and rte_errno is set.
148  */
149 static int
150 mlx5_common_config_get(struct rte_devargs *devargs,
151 		       struct mlx5_common_dev_config *config)
152 {
153 	struct rte_kvargs *kvlist;
154 	int ret = 0;
155 
156 	/* Set defaults. */
157 	config->mr_ext_memseg_en = 1;
158 	config->mr_mempool_reg_en = 1;
159 	config->sys_mem_en = 0;
160 	config->dbnc = MLX5_ARG_UNSET;
161 	if (devargs == NULL)
162 		return 0;
163 	kvlist = rte_kvargs_parse(devargs->args, NULL);
164 	if (kvlist == NULL) {
165 		rte_errno = EINVAL;
166 		return -rte_errno;
167 	}
168 	ret = rte_kvargs_process(kvlist, NULL, mlx5_common_args_check_handler,
169 				 config);
170 	if (ret)
171 		ret = -rte_errno;
172 	rte_kvargs_free(kvlist);
173 	DRV_LOG(DEBUG, "mr_ext_memseg_en is %u.", config->mr_ext_memseg_en);
174 	DRV_LOG(DEBUG, "mr_mempool_reg_en is %u.", config->mr_mempool_reg_en);
175 	DRV_LOG(DEBUG, "sys_mem_en is %u.", config->sys_mem_en);
176 	DRV_LOG(DEBUG, "Tx doorbell mapping parameter is %d.", config->dbnc);
177 	return ret;
178 }
179 
180 static int
181 devargs_class_handler(__rte_unused const char *key,
182 		      const char *class_names, void *opaque)
183 {
184 	int *ret = opaque;
185 	int class_val;
186 	char *scratch;
187 	char *found;
188 	char *refstr = NULL;
189 
190 	*ret = 0;
191 	scratch = strdup(class_names);
192 	if (scratch == NULL) {
193 		*ret = -ENOMEM;
194 		return *ret;
195 	}
196 	found = strtok_r(scratch, ":", &refstr);
197 	if (found == NULL)
198 		/* Empty string. */
199 		goto err;
200 	do {
201 		/* Extract each individual class name. Multiple
202 		 * classes can be supplied as class=net:regex:foo:bar.
203 		 */
204 		class_val = class_name_to_value(found);
205 		/* Check if its a valid class. */
206 		if (class_val < 0) {
207 			*ret = -EINVAL;
208 			goto err;
209 		}
210 		*ret |= class_val;
211 		found = strtok_r(NULL, ":", &refstr);
212 	} while (found != NULL);
213 err:
214 	free(scratch);
215 	if (*ret < 0)
216 		DRV_LOG(ERR, "Invalid mlx5 class options: %s.\n", class_names);
217 	return *ret;
218 }
219 
220 static int
221 parse_class_options(const struct rte_devargs *devargs)
222 {
223 	struct rte_kvargs *kvlist;
224 	int ret = 0;
225 
226 	if (devargs == NULL)
227 		return 0;
228 	if (devargs->cls != NULL && devargs->cls->name != NULL)
229 		/* Global syntax, only one class type. */
230 		return class_name_to_value(devargs->cls->name);
231 	/* Legacy devargs support multiple classes. */
232 	kvlist = rte_kvargs_parse(devargs->args, NULL);
233 	if (kvlist == NULL)
234 		return 0;
235 	rte_kvargs_process(kvlist, RTE_DEVARGS_KEY_CLASS,
236 			   devargs_class_handler, &ret);
237 	rte_kvargs_free(kvlist);
238 	return ret;
239 }
240 
241 static const unsigned int mlx5_class_invalid_combinations[] = {
242 	MLX5_CLASS_ETH | MLX5_CLASS_VDPA,
243 	/* New class combination should be added here. */
244 };
245 
246 static int
247 is_valid_class_combination(uint32_t user_classes)
248 {
249 	unsigned int i;
250 
251 	/* Verify if user specified unsupported combination. */
252 	for (i = 0; i < RTE_DIM(mlx5_class_invalid_combinations); i++) {
253 		if ((mlx5_class_invalid_combinations[i] & user_classes) ==
254 		    mlx5_class_invalid_combinations[i])
255 			return -EINVAL;
256 	}
257 	/* Not found any invalid class combination. */
258 	return 0;
259 }
260 
261 static bool
262 device_class_enabled(const struct mlx5_common_device *device, uint32_t class)
263 {
264 	return (device->classes_loaded & class) > 0;
265 }
266 
267 static bool
268 mlx5_bus_match(const struct mlx5_class_driver *drv,
269 	       const struct rte_device *dev)
270 {
271 	if (mlx5_dev_is_pci(dev))
272 		return mlx5_dev_pci_match(drv, dev);
273 	return true;
274 }
275 
276 static struct mlx5_common_device *
277 to_mlx5_device(const struct rte_device *rte_dev)
278 {
279 	struct mlx5_common_device *cdev;
280 
281 	TAILQ_FOREACH(cdev, &devices_list, next) {
282 		if (rte_dev == cdev->dev)
283 			return cdev;
284 	}
285 	return NULL;
286 }
287 
288 int
289 mlx5_dev_to_pci_str(const struct rte_device *dev, char *addr, size_t size)
290 {
291 	struct rte_pci_addr pci_addr = { 0 };
292 	int ret;
293 
294 	if (mlx5_dev_is_pci(dev)) {
295 		/* Input might be <BDF>, format PCI address to <DBDF>. */
296 		ret = rte_pci_addr_parse(dev->name, &pci_addr);
297 		if (ret != 0)
298 			return -ENODEV;
299 		rte_pci_device_name(&pci_addr, addr, size);
300 		return 0;
301 	}
302 #ifdef RTE_EXEC_ENV_LINUX
303 	return mlx5_auxiliary_get_pci_str(RTE_DEV_TO_AUXILIARY_CONST(dev),
304 			addr, size);
305 #else
306 	rte_errno = ENODEV;
307 	return -rte_errno;
308 #endif
309 }
310 
311 static void
312 mlx5_common_dev_release(struct mlx5_common_device *cdev)
313 {
314 	pthread_mutex_lock(&devices_list_lock);
315 	TAILQ_REMOVE(&devices_list, cdev, next);
316 	pthread_mutex_unlock(&devices_list_lock);
317 	rte_free(cdev);
318 }
319 
320 static struct mlx5_common_device *
321 mlx5_common_dev_create(struct rte_device *eal_dev)
322 {
323 	struct mlx5_common_device *cdev;
324 	int ret;
325 
326 	cdev = rte_zmalloc("mlx5_common_device", sizeof(*cdev), 0);
327 	if (!cdev) {
328 		DRV_LOG(ERR, "Device allocation failure.");
329 		rte_errno = ENOMEM;
330 		return NULL;
331 	}
332 	cdev->dev = eal_dev;
333 	if (rte_eal_process_type() != RTE_PROC_PRIMARY)
334 		goto exit;
335 	/* Parse device parameters. */
336 	ret = mlx5_common_config_get(eal_dev->devargs, &cdev->config);
337 	if (ret < 0) {
338 		DRV_LOG(ERR, "Failed to process device arguments: %s",
339 			strerror(rte_errno));
340 		rte_free(cdev);
341 		return NULL;
342 	}
343 	mlx5_malloc_mem_select(cdev->config.sys_mem_en);
344 exit:
345 	pthread_mutex_lock(&devices_list_lock);
346 	TAILQ_INSERT_HEAD(&devices_list, cdev, next);
347 	pthread_mutex_unlock(&devices_list_lock);
348 	return cdev;
349 }
350 
351 static int
352 drivers_remove(struct mlx5_common_device *cdev, uint32_t enabled_classes)
353 {
354 	struct mlx5_class_driver *driver;
355 	int local_ret = -ENODEV;
356 	unsigned int i = 0;
357 	int ret = 0;
358 
359 	enabled_classes &= cdev->classes_loaded;
360 	while (enabled_classes) {
361 		driver = driver_get(RTE_BIT64(i));
362 		if (driver != NULL) {
363 			local_ret = driver->remove(cdev);
364 			if (local_ret == 0)
365 				cdev->classes_loaded &= ~RTE_BIT64(i);
366 			else if (ret == 0)
367 				ret = local_ret;
368 		}
369 		enabled_classes &= ~RTE_BIT64(i);
370 		i++;
371 	}
372 	if (local_ret != 0 && ret == 0)
373 		ret = local_ret;
374 	return ret;
375 }
376 
377 static int
378 drivers_probe(struct mlx5_common_device *cdev, uint32_t user_classes)
379 {
380 	struct mlx5_class_driver *driver;
381 	uint32_t enabled_classes = 0;
382 	bool already_loaded;
383 	int ret;
384 
385 	TAILQ_FOREACH(driver, &drivers_list, next) {
386 		if ((driver->drv_class & user_classes) == 0)
387 			continue;
388 		if (!mlx5_bus_match(driver, cdev->dev))
389 			continue;
390 		already_loaded = cdev->classes_loaded & driver->drv_class;
391 		if (already_loaded && driver->probe_again == 0) {
392 			DRV_LOG(ERR, "Device %s is already probed",
393 				cdev->dev->name);
394 			ret = -EEXIST;
395 			goto probe_err;
396 		}
397 		ret = driver->probe(cdev);
398 		if (ret < 0) {
399 			DRV_LOG(ERR, "Failed to load driver %s",
400 				driver->name);
401 			goto probe_err;
402 		}
403 		enabled_classes |= driver->drv_class;
404 	}
405 	cdev->classes_loaded |= enabled_classes;
406 	return 0;
407 probe_err:
408 	/* Only unload drivers which are enabled which were enabled
409 	 * in this probe instance.
410 	 */
411 	drivers_remove(cdev, enabled_classes);
412 	return ret;
413 }
414 
415 int
416 mlx5_common_dev_probe(struct rte_device *eal_dev)
417 {
418 	struct mlx5_common_device *cdev;
419 	uint32_t classes = 0;
420 	bool new_device = false;
421 	int ret;
422 
423 	DRV_LOG(INFO, "probe device \"%s\".", eal_dev->name);
424 	ret = parse_class_options(eal_dev->devargs);
425 	if (ret < 0) {
426 		DRV_LOG(ERR, "Unsupported mlx5 class type: %s",
427 			eal_dev->devargs->args);
428 		return ret;
429 	}
430 	classes = ret;
431 	if (classes == 0)
432 		/* Default to net class. */
433 		classes = MLX5_CLASS_ETH;
434 	cdev = to_mlx5_device(eal_dev);
435 	if (!cdev) {
436 		cdev = mlx5_common_dev_create(eal_dev);
437 		if (!cdev)
438 			return -ENOMEM;
439 		new_device = true;
440 	}
441 	/*
442 	 * Validate combination here.
443 	 * For new device, the classes_loaded field is 0 and it check only
444 	 * the classes given as user device arguments.
445 	 */
446 	ret = is_valid_class_combination(classes | cdev->classes_loaded);
447 	if (ret != 0) {
448 		DRV_LOG(ERR, "Unsupported mlx5 classes combination.");
449 		goto class_err;
450 	}
451 	ret = drivers_probe(cdev, classes);
452 	if (ret)
453 		goto class_err;
454 	return 0;
455 class_err:
456 	if (new_device)
457 		mlx5_common_dev_release(cdev);
458 	return ret;
459 }
460 
461 int
462 mlx5_common_dev_remove(struct rte_device *eal_dev)
463 {
464 	struct mlx5_common_device *cdev;
465 	int ret;
466 
467 	cdev = to_mlx5_device(eal_dev);
468 	if (!cdev)
469 		return -ENODEV;
470 	/* Matching device found, cleanup and unload drivers. */
471 	ret = drivers_remove(cdev, cdev->classes_loaded);
472 	if (ret == 0)
473 		mlx5_common_dev_release(cdev);
474 	return ret;
475 }
476 
477 int
478 mlx5_common_dev_dma_map(struct rte_device *dev, void *addr, uint64_t iova,
479 			size_t len)
480 {
481 	struct mlx5_class_driver *driver = NULL;
482 	struct mlx5_class_driver *temp;
483 	struct mlx5_common_device *mdev;
484 	int ret = -EINVAL;
485 
486 	mdev = to_mlx5_device(dev);
487 	if (!mdev)
488 		return -ENODEV;
489 	TAILQ_FOREACH(driver, &drivers_list, next) {
490 		if (!device_class_enabled(mdev, driver->drv_class) ||
491 		    driver->dma_map == NULL)
492 			continue;
493 		ret = driver->dma_map(dev, addr, iova, len);
494 		if (ret)
495 			goto map_err;
496 	}
497 	return ret;
498 map_err:
499 	TAILQ_FOREACH(temp, &drivers_list, next) {
500 		if (temp == driver)
501 			break;
502 		if (device_class_enabled(mdev, temp->drv_class) &&
503 		    temp->dma_map && temp->dma_unmap)
504 			temp->dma_unmap(dev, addr, iova, len);
505 	}
506 	return ret;
507 }
508 
509 int
510 mlx5_common_dev_dma_unmap(struct rte_device *dev, void *addr, uint64_t iova,
511 			  size_t len)
512 {
513 	struct mlx5_class_driver *driver;
514 	struct mlx5_common_device *mdev;
515 	int local_ret = -EINVAL;
516 	int ret = 0;
517 
518 	mdev = to_mlx5_device(dev);
519 	if (!mdev)
520 		return -ENODEV;
521 	/* There is no unmap error recovery in current implementation. */
522 	TAILQ_FOREACH_REVERSE(driver, &drivers_list, mlx5_drivers, next) {
523 		if (!device_class_enabled(mdev, driver->drv_class) ||
524 		    driver->dma_unmap == NULL)
525 			continue;
526 		local_ret = driver->dma_unmap(dev, addr, iova, len);
527 		if (local_ret && (ret == 0))
528 			ret = local_ret;
529 	}
530 	if (local_ret)
531 		ret = local_ret;
532 	return ret;
533 }
534 
535 void
536 mlx5_class_driver_register(struct mlx5_class_driver *driver)
537 {
538 	mlx5_common_driver_on_register_pci(driver);
539 	TAILQ_INSERT_TAIL(&drivers_list, driver, next);
540 }
541 
542 static void mlx5_common_driver_init(void)
543 {
544 	mlx5_common_pci_init();
545 #ifdef RTE_EXEC_ENV_LINUX
546 	mlx5_common_auxiliary_init();
547 #endif
548 }
549 
550 static bool mlx5_common_initialized;
551 
552 /**
553  * One time innitialization routine for run-time dependency on glue library
554  * for multiple PMDs. Each mlx5 PMD that depends on mlx5_common module,
555  * must invoke in its constructor.
556  */
557 void
558 mlx5_common_init(void)
559 {
560 	if (mlx5_common_initialized)
561 		return;
562 
563 	pthread_mutex_init(&devices_list_lock, NULL);
564 	mlx5_glue_constructor();
565 	mlx5_common_driver_init();
566 	mlx5_common_initialized = true;
567 }
568 
569 /**
570  * This function is responsible of initializing the variable
571  *  haswell_broadwell_cpu by checking if the cpu is intel
572  *  and reading the data returned from mlx5_cpu_id().
573  *  since haswell and broadwell cpus don't have improved performance
574  *  when using relaxed ordering we want to check the cpu type before
575  *  before deciding whether to enable RO or not.
576  *  if the cpu is haswell or broadwell the variable will be set to 1
577  *  otherwise it will be 0.
578  */
579 RTE_INIT_PRIO(mlx5_is_haswell_broadwell_cpu, LOG)
580 {
581 #ifdef RTE_ARCH_X86_64
582 	unsigned int broadwell_models[4] = {0x3d, 0x47, 0x4F, 0x56};
583 	unsigned int haswell_models[4] = {0x3c, 0x3f, 0x45, 0x46};
584 	unsigned int i, model, family, brand_id, vendor;
585 	unsigned int signature_intel_ebx = 0x756e6547;
586 	unsigned int extended_model;
587 	unsigned int eax = 0;
588 	unsigned int ebx = 0;
589 	unsigned int ecx = 0;
590 	unsigned int edx = 0;
591 	int max_level;
592 
593 	mlx5_cpu_id(0, &eax, &ebx, &ecx, &edx);
594 	vendor = ebx;
595 	max_level = eax;
596 	if (max_level < 1) {
597 		haswell_broadwell_cpu = 0;
598 		return;
599 	}
600 	mlx5_cpu_id(1, &eax, &ebx, &ecx, &edx);
601 	model = (eax >> 4) & 0x0f;
602 	family = (eax >> 8) & 0x0f;
603 	brand_id = ebx & 0xff;
604 	extended_model = (eax >> 12) & 0xf0;
605 	/* Check if the processor is Haswell or Broadwell */
606 	if (vendor == signature_intel_ebx) {
607 		if (family == 0x06)
608 			model += extended_model;
609 		if (brand_id == 0 && family == 0x6) {
610 			for (i = 0; i < RTE_DIM(broadwell_models); i++)
611 				if (model == broadwell_models[i]) {
612 					haswell_broadwell_cpu = 1;
613 					return;
614 				}
615 			for (i = 0; i < RTE_DIM(haswell_models); i++)
616 				if (model == haswell_models[i]) {
617 					haswell_broadwell_cpu = 1;
618 					return;
619 				}
620 		}
621 	}
622 #endif
623 	haswell_broadwell_cpu = 0;
624 }
625 
626 /**
627  * Allocate the User Access Region with DevX on specified device.
628  *
629  * @param [in] ctx
630  *   Infiniband device context to perform allocation on.
631  * @param [in] mapping
632  *   MLX5DV_UAR_ALLOC_TYPE_BF - allocate as cached memory with write-combining
633  *				attributes (if supported by the host), the
634  *				writes to the UAR registers must be followed
635  *				by write memory barrier.
636  *   MLX5DV_UAR_ALLOC_TYPE_NC - allocate as non-cached nenory, all writes are
637  *				promoted to the registers immediately, no
638  *				memory barriers needed.
639  *   mapping < 0 - the first attempt is performed with MLX5DV_UAR_ALLOC_TYPE_BF,
640  *		   if this fails the next attempt with MLX5DV_UAR_ALLOC_TYPE_NC
641  *		   is performed. The drivers specifying negative values should
642  *		   always provide the write memory barrier operation after UAR
643  *		   register writings.
644  * If there is no definitions for the MLX5DV_UAR_ALLOC_TYPE_xx (older rdma
645  * library headers), the caller can specify 0.
646  *
647  * @return
648  *   UAR object pointer on success, NULL otherwise and rte_errno is set.
649  */
650 void *
651 mlx5_devx_alloc_uar(void *ctx, int mapping)
652 {
653 	void *uar;
654 	uint32_t retry, uar_mapping;
655 	void *base_addr;
656 
657 	for (retry = 0; retry < MLX5_ALLOC_UAR_RETRY; ++retry) {
658 #ifdef MLX5DV_UAR_ALLOC_TYPE_NC
659 		/* Control the mapping type according to the settings. */
660 		uar_mapping = (mapping < 0) ?
661 			      MLX5DV_UAR_ALLOC_TYPE_NC : mapping;
662 #else
663 		/*
664 		 * It seems we have no way to control the memory mapping type
665 		 * for the UAR, the default "Write-Combining" type is supposed.
666 		 */
667 		uar_mapping = 0;
668 		RTE_SET_USED(mapping);
669 #endif
670 		uar = mlx5_glue->devx_alloc_uar(ctx, uar_mapping);
671 #ifdef MLX5DV_UAR_ALLOC_TYPE_NC
672 		if (!uar &&
673 		    mapping < 0 &&
674 		    uar_mapping == MLX5DV_UAR_ALLOC_TYPE_BF) {
675 			/*
676 			 * In some environments like virtual machine the
677 			 * Write Combining mapped might be not supported and
678 			 * UAR allocation fails. We tried "Non-Cached" mapping
679 			 * for the case.
680 			 */
681 			DRV_LOG(WARNING, "Failed to allocate DevX UAR (BF)");
682 			uar_mapping = MLX5DV_UAR_ALLOC_TYPE_NC;
683 			uar = mlx5_glue->devx_alloc_uar(ctx, uar_mapping);
684 		} else if (!uar &&
685 			   mapping < 0 &&
686 			   uar_mapping == MLX5DV_UAR_ALLOC_TYPE_NC) {
687 			/*
688 			 * If Verbs/kernel does not support "Non-Cached"
689 			 * try the "Write-Combining".
690 			 */
691 			DRV_LOG(WARNING, "Failed to allocate DevX UAR (NC)");
692 			uar_mapping = MLX5DV_UAR_ALLOC_TYPE_BF;
693 			uar = mlx5_glue->devx_alloc_uar(ctx, uar_mapping);
694 		}
695 #endif
696 		if (!uar) {
697 			DRV_LOG(ERR, "Failed to allocate DevX UAR (BF/NC)");
698 			rte_errno = ENOMEM;
699 			goto exit;
700 		}
701 		base_addr = mlx5_os_get_devx_uar_base_addr(uar);
702 		if (base_addr)
703 			break;
704 		/*
705 		 * The UARs are allocated by rdma_core within the
706 		 * IB device context, on context closure all UARs
707 		 * will be freed, should be no memory/object leakage.
708 		 */
709 		DRV_LOG(WARNING, "Retrying to allocate DevX UAR");
710 		uar = NULL;
711 	}
712 	/* Check whether we finally succeeded with valid UAR allocation. */
713 	if (!uar) {
714 		DRV_LOG(ERR, "Failed to allocate DevX UAR (NULL base)");
715 		rte_errno = ENOMEM;
716 	}
717 	/*
718 	 * Return void * instead of struct mlx5dv_devx_uar *
719 	 * is for compatibility with older rdma-core library headers.
720 	 */
721 exit:
722 	return uar;
723 }
724 
725 RTE_PMD_EXPORT_NAME(mlx5_common_driver, __COUNTER__);
726