xref: /dpdk/drivers/bus/pci/pci_common.c (revision daa02b5cddbb8e11b31d41e2bf7bb1ae64dcae2f)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2014 Intel Corporation.
3  * Copyright 2013-2014 6WIND S.A.
4  */
5 
6 #include <string.h>
7 #include <inttypes.h>
8 #include <stdint.h>
9 #include <stdbool.h>
10 #include <stdlib.h>
11 #include <stdio.h>
12 #include <sys/queue.h>
13 #include <rte_errno.h>
14 #include <rte_interrupts.h>
15 #include <rte_log.h>
16 #include <rte_bus.h>
17 #include <rte_pci.h>
18 #include <rte_bus_pci.h>
19 #include <rte_lcore.h>
20 #include <rte_per_lcore.h>
21 #include <rte_memory.h>
22 #include <rte_eal.h>
23 #include <rte_eal_paging.h>
24 #include <rte_string_fns.h>
25 #include <rte_common.h>
26 #include <rte_devargs.h>
27 #include <rte_vfio.h>
28 
29 #include "private.h"
30 
31 
32 #define SYSFS_PCI_DEVICES "/sys/bus/pci/devices"
33 
34 const char *rte_pci_get_sysfs_path(void)
35 {
36 	const char *path = NULL;
37 
38 #ifdef RTE_EXEC_ENV_LINUX
39 	path = getenv("SYSFS_PCI_DEVICES");
40 	if (path == NULL)
41 		return SYSFS_PCI_DEVICES;
42 #endif
43 
44 	return path;
45 }
46 
47 static struct rte_devargs *
48 pci_devargs_lookup(const struct rte_pci_addr *pci_addr)
49 {
50 	struct rte_devargs *devargs;
51 	struct rte_pci_addr addr;
52 
53 	RTE_EAL_DEVARGS_FOREACH("pci", devargs) {
54 		devargs->bus->parse(devargs->name, &addr);
55 		if (!rte_pci_addr_cmp(pci_addr, &addr))
56 			return devargs;
57 	}
58 	return NULL;
59 }
60 
61 void
62 pci_name_set(struct rte_pci_device *dev)
63 {
64 	struct rte_devargs *devargs;
65 
66 	/* Each device has its internal, canonical name set. */
67 	rte_pci_device_name(&dev->addr,
68 			dev->name, sizeof(dev->name));
69 	devargs = pci_devargs_lookup(&dev->addr);
70 	dev->device.devargs = devargs;
71 
72 	/* When using a blocklist, only blocked devices will have
73 	 * an rte_devargs. Allowed devices won't have one.
74 	 */
75 	if (devargs != NULL)
76 		/* If an rte_devargs exists, the generic rte_device uses the
77 		 * given name as its name.
78 		 */
79 		dev->device.name = dev->device.devargs->name;
80 	else
81 		/* Otherwise, it uses the internal, canonical form. */
82 		dev->device.name = dev->name;
83 }
84 
85 /* map a particular resource from a file */
86 void *
87 pci_map_resource(void *requested_addr, int fd, off_t offset, size_t size,
88 		 int additional_flags)
89 {
90 	void *mapaddr;
91 
92 	/* Map the PCI memory resource of device */
93 	mapaddr = rte_mem_map(requested_addr, size,
94 		RTE_PROT_READ | RTE_PROT_WRITE,
95 		RTE_MAP_SHARED | additional_flags, fd, offset);
96 	if (mapaddr == NULL) {
97 		RTE_LOG(ERR, EAL,
98 			"%s(): cannot map resource(%d, %p, 0x%zx, 0x%llx): %s (%p)\n",
99 			__func__, fd, requested_addr, size,
100 			(unsigned long long)offset,
101 			rte_strerror(rte_errno), mapaddr);
102 	} else
103 		RTE_LOG(DEBUG, EAL, "  PCI memory mapped at %p\n", mapaddr);
104 
105 	return mapaddr;
106 }
107 
108 /* unmap a particular resource */
109 void
110 pci_unmap_resource(void *requested_addr, size_t size)
111 {
112 	if (requested_addr == NULL)
113 		return;
114 
115 	/* Unmap the PCI memory resource of device */
116 	if (rte_mem_unmap(requested_addr, size)) {
117 		RTE_LOG(ERR, EAL, "%s(): cannot mem unmap(%p, %#zx): %s\n",
118 			__func__, requested_addr, size,
119 			rte_strerror(rte_errno));
120 	} else
121 		RTE_LOG(DEBUG, EAL, "  PCI memory unmapped at %p\n",
122 				requested_addr);
123 }
124 /*
125  * Match the PCI Driver and Device using the ID Table
126  */
127 int
128 rte_pci_match(const struct rte_pci_driver *pci_drv,
129 	      const struct rte_pci_device *pci_dev)
130 {
131 	const struct rte_pci_id *id_table;
132 
133 	for (id_table = pci_drv->id_table; id_table->vendor_id != 0;
134 	     id_table++) {
135 		/* check if device's identifiers match the driver's ones */
136 		if (id_table->vendor_id != pci_dev->id.vendor_id &&
137 				id_table->vendor_id != RTE_PCI_ANY_ID)
138 			continue;
139 		if (id_table->device_id != pci_dev->id.device_id &&
140 				id_table->device_id != RTE_PCI_ANY_ID)
141 			continue;
142 		if (id_table->subsystem_vendor_id !=
143 		    pci_dev->id.subsystem_vendor_id &&
144 		    id_table->subsystem_vendor_id != RTE_PCI_ANY_ID)
145 			continue;
146 		if (id_table->subsystem_device_id !=
147 		    pci_dev->id.subsystem_device_id &&
148 		    id_table->subsystem_device_id != RTE_PCI_ANY_ID)
149 			continue;
150 		if (id_table->class_id != pci_dev->id.class_id &&
151 				id_table->class_id != RTE_CLASS_ANY_ID)
152 			continue;
153 
154 		return 1;
155 	}
156 
157 	return 0;
158 }
159 
160 /*
161  * If vendor/device ID match, call the probe() function of the
162  * driver.
163  */
164 static int
165 rte_pci_probe_one_driver(struct rte_pci_driver *dr,
166 			 struct rte_pci_device *dev)
167 {
168 	int ret;
169 	bool already_probed;
170 	struct rte_pci_addr *loc;
171 
172 	if ((dr == NULL) || (dev == NULL))
173 		return -EINVAL;
174 
175 	loc = &dev->addr;
176 
177 	/* The device is not blocked; Check if driver supports it */
178 	if (!rte_pci_match(dr, dev))
179 		/* Match of device and driver failed */
180 		return 1;
181 
182 	RTE_LOG(DEBUG, EAL, "PCI device "PCI_PRI_FMT" on NUMA socket %i\n",
183 			loc->domain, loc->bus, loc->devid, loc->function,
184 			dev->device.numa_node);
185 
186 	/* no initialization when marked as blocked, return without error */
187 	if (dev->device.devargs != NULL &&
188 		dev->device.devargs->policy == RTE_DEV_BLOCKED) {
189 		RTE_LOG(INFO, EAL, "  Device is blocked, not initializing\n");
190 		return 1;
191 	}
192 
193 	if (dev->device.numa_node < 0) {
194 		if (rte_socket_count() > 1)
195 			RTE_LOG(INFO, EAL, "Device %s is not NUMA-aware, defaulting socket to 0\n",
196 					dev->name);
197 		dev->device.numa_node = 0;
198 	}
199 
200 	already_probed = rte_dev_is_probed(&dev->device);
201 	if (already_probed && !(dr->drv_flags & RTE_PCI_DRV_PROBE_AGAIN)) {
202 		RTE_LOG(DEBUG, EAL, "Device %s is already probed\n",
203 				dev->device.name);
204 		return -EEXIST;
205 	}
206 
207 	RTE_LOG(DEBUG, EAL, "  probe driver: %x:%x %s\n", dev->id.vendor_id,
208 		dev->id.device_id, dr->driver.name);
209 
210 	/*
211 	 * reference driver structure
212 	 * This needs to be before rte_pci_map_device(), as it enables to use
213 	 * driver flags for adjusting configuration.
214 	 */
215 	if (!already_probed) {
216 		enum rte_iova_mode dev_iova_mode;
217 		enum rte_iova_mode iova_mode;
218 
219 		dev_iova_mode = pci_device_iova_mode(dr, dev);
220 		iova_mode = rte_eal_iova_mode();
221 		if (dev_iova_mode != RTE_IOVA_DC &&
222 		    dev_iova_mode != iova_mode) {
223 			RTE_LOG(ERR, EAL, "  Expecting '%s' IOVA mode but current mode is '%s', not initializing\n",
224 				dev_iova_mode == RTE_IOVA_PA ? "PA" : "VA",
225 				iova_mode == RTE_IOVA_PA ? "PA" : "VA");
226 			return -EINVAL;
227 		}
228 
229 		dev->driver = dr;
230 	}
231 
232 	if (!already_probed && (dr->drv_flags & RTE_PCI_DRV_NEED_MAPPING)) {
233 		/* map resources for devices that use igb_uio */
234 		ret = rte_pci_map_device(dev);
235 		if (ret != 0) {
236 			dev->driver = NULL;
237 			return ret;
238 		}
239 	}
240 
241 	RTE_LOG(INFO, EAL, "Probe PCI driver: %s (%x:%x) device: "PCI_PRI_FMT" (socket %i)\n",
242 			dr->driver.name, dev->id.vendor_id, dev->id.device_id,
243 			loc->domain, loc->bus, loc->devid, loc->function,
244 			dev->device.numa_node);
245 	/* call the driver probe() function */
246 	ret = dr->probe(dr, dev);
247 	if (already_probed)
248 		return ret; /* no rollback if already succeeded earlier */
249 	if (ret) {
250 		dev->driver = NULL;
251 		if ((dr->drv_flags & RTE_PCI_DRV_NEED_MAPPING) &&
252 			/* Don't unmap if device is unsupported and
253 			 * driver needs mapped resources.
254 			 */
255 			!(ret > 0 &&
256 				(dr->drv_flags & RTE_PCI_DRV_KEEP_MAPPED_RES)))
257 			rte_pci_unmap_device(dev);
258 	} else {
259 		dev->device.driver = &dr->driver;
260 	}
261 
262 	return ret;
263 }
264 
265 /*
266  * If vendor/device ID match, call the remove() function of the
267  * driver.
268  */
269 static int
270 rte_pci_detach_dev(struct rte_pci_device *dev)
271 {
272 	struct rte_pci_addr *loc;
273 	struct rte_pci_driver *dr;
274 	int ret = 0;
275 
276 	if (dev == NULL)
277 		return -EINVAL;
278 
279 	dr = dev->driver;
280 	loc = &dev->addr;
281 
282 	RTE_LOG(DEBUG, EAL, "PCI device "PCI_PRI_FMT" on NUMA socket %i\n",
283 			loc->domain, loc->bus, loc->devid,
284 			loc->function, dev->device.numa_node);
285 
286 	RTE_LOG(DEBUG, EAL, "  remove driver: %x:%x %s\n", dev->id.vendor_id,
287 			dev->id.device_id, dr->driver.name);
288 
289 	if (dr->remove) {
290 		ret = dr->remove(dev);
291 		if (ret < 0)
292 			return ret;
293 	}
294 
295 	/* clear driver structure */
296 	dev->driver = NULL;
297 	dev->device.driver = NULL;
298 
299 	if (dr->drv_flags & RTE_PCI_DRV_NEED_MAPPING)
300 		/* unmap resources for devices that use igb_uio */
301 		rte_pci_unmap_device(dev);
302 
303 	return 0;
304 }
305 
306 /*
307  * If vendor/device ID match, call the probe() function of all
308  * registered driver for the given device. Return < 0 if initialization
309  * failed, return 1 if no driver is found for this device.
310  */
311 static int
312 pci_probe_all_drivers(struct rte_pci_device *dev)
313 {
314 	struct rte_pci_driver *dr = NULL;
315 	int rc = 0;
316 
317 	if (dev == NULL)
318 		return -EINVAL;
319 
320 	FOREACH_DRIVER_ON_PCIBUS(dr) {
321 		rc = rte_pci_probe_one_driver(dr, dev);
322 		if (rc < 0)
323 			/* negative value is an error */
324 			return rc;
325 		if (rc > 0)
326 			/* positive value means driver doesn't support it */
327 			continue;
328 		return 0;
329 	}
330 	return 1;
331 }
332 
333 /*
334  * Scan the content of the PCI bus, and call the probe() function for
335  * all registered drivers that have a matching entry in its id_table
336  * for discovered devices.
337  */
338 static int
339 pci_probe(void)
340 {
341 	struct rte_pci_device *dev = NULL;
342 	size_t probed = 0, failed = 0;
343 	int ret = 0;
344 
345 	FOREACH_DEVICE_ON_PCIBUS(dev) {
346 		probed++;
347 
348 		ret = pci_probe_all_drivers(dev);
349 		if (ret < 0) {
350 			if (ret != -EEXIST) {
351 				RTE_LOG(ERR, EAL, "Requested device "
352 					PCI_PRI_FMT " cannot be used\n",
353 					dev->addr.domain, dev->addr.bus,
354 					dev->addr.devid, dev->addr.function);
355 				rte_errno = errno;
356 				failed++;
357 			}
358 			ret = 0;
359 		}
360 	}
361 
362 	return (probed && probed == failed) ? -1 : 0;
363 }
364 
365 /* dump one device */
366 static int
367 pci_dump_one_device(FILE *f, struct rte_pci_device *dev)
368 {
369 	int i;
370 
371 	fprintf(f, PCI_PRI_FMT, dev->addr.domain, dev->addr.bus,
372 	       dev->addr.devid, dev->addr.function);
373 	fprintf(f, " - vendor:%x device:%x\n", dev->id.vendor_id,
374 	       dev->id.device_id);
375 
376 	for (i = 0; i != sizeof(dev->mem_resource) /
377 		sizeof(dev->mem_resource[0]); i++) {
378 		fprintf(f, "   %16.16"PRIx64" %16.16"PRIx64"\n",
379 			dev->mem_resource[i].phys_addr,
380 			dev->mem_resource[i].len);
381 	}
382 	return 0;
383 }
384 
385 /* dump devices on the bus */
386 void
387 rte_pci_dump(FILE *f)
388 {
389 	struct rte_pci_device *dev = NULL;
390 
391 	FOREACH_DEVICE_ON_PCIBUS(dev) {
392 		pci_dump_one_device(f, dev);
393 	}
394 }
395 
396 static int
397 pci_parse(const char *name, void *addr)
398 {
399 	struct rte_pci_addr *out = addr;
400 	struct rte_pci_addr pci_addr;
401 	bool parse;
402 
403 	parse = (rte_pci_addr_parse(name, &pci_addr) == 0);
404 	if (parse && addr != NULL)
405 		*out = pci_addr;
406 	return parse == false;
407 }
408 
409 /* register a driver */
410 void
411 rte_pci_register(struct rte_pci_driver *driver)
412 {
413 	TAILQ_INSERT_TAIL(&rte_pci_bus.driver_list, driver, next);
414 	driver->bus = &rte_pci_bus;
415 }
416 
417 /* unregister a driver */
418 void
419 rte_pci_unregister(struct rte_pci_driver *driver)
420 {
421 	TAILQ_REMOVE(&rte_pci_bus.driver_list, driver, next);
422 	driver->bus = NULL;
423 }
424 
425 /* Add a device to PCI bus */
426 void
427 rte_pci_add_device(struct rte_pci_device *pci_dev)
428 {
429 	TAILQ_INSERT_TAIL(&rte_pci_bus.device_list, pci_dev, next);
430 }
431 
432 /* Insert a device into a predefined position in PCI bus */
433 void
434 rte_pci_insert_device(struct rte_pci_device *exist_pci_dev,
435 		      struct rte_pci_device *new_pci_dev)
436 {
437 	TAILQ_INSERT_BEFORE(exist_pci_dev, new_pci_dev, next);
438 }
439 
440 /* Remove a device from PCI bus */
441 static void
442 rte_pci_remove_device(struct rte_pci_device *pci_dev)
443 {
444 	TAILQ_REMOVE(&rte_pci_bus.device_list, pci_dev, next);
445 }
446 
447 static struct rte_device *
448 pci_find_device(const struct rte_device *start, rte_dev_cmp_t cmp,
449 		const void *data)
450 {
451 	const struct rte_pci_device *pstart;
452 	struct rte_pci_device *pdev;
453 
454 	if (start != NULL) {
455 		pstart = RTE_DEV_TO_PCI_CONST(start);
456 		pdev = TAILQ_NEXT(pstart, next);
457 	} else {
458 		pdev = TAILQ_FIRST(&rte_pci_bus.device_list);
459 	}
460 	while (pdev != NULL) {
461 		if (cmp(&pdev->device, data) == 0)
462 			return &pdev->device;
463 		pdev = TAILQ_NEXT(pdev, next);
464 	}
465 	return NULL;
466 }
467 
468 /*
469  * find the device which encounter the failure, by iterate over all device on
470  * PCI bus to check if the memory failure address is located in the range
471  * of the BARs of the device.
472  */
473 static struct rte_pci_device *
474 pci_find_device_by_addr(const void *failure_addr)
475 {
476 	struct rte_pci_device *pdev = NULL;
477 	uint64_t check_point, start, end, len;
478 	int i;
479 
480 	check_point = (uint64_t)(uintptr_t)failure_addr;
481 
482 	FOREACH_DEVICE_ON_PCIBUS(pdev) {
483 		for (i = 0; i != RTE_DIM(pdev->mem_resource); i++) {
484 			start = (uint64_t)(uintptr_t)pdev->mem_resource[i].addr;
485 			len = pdev->mem_resource[i].len;
486 			end = start + len;
487 			if (check_point >= start && check_point < end) {
488 				RTE_LOG(DEBUG, EAL, "Failure address %16.16"
489 					PRIx64" belongs to device %s!\n",
490 					check_point, pdev->device.name);
491 				return pdev;
492 			}
493 		}
494 	}
495 	return NULL;
496 }
497 
498 static int
499 pci_hot_unplug_handler(struct rte_device *dev)
500 {
501 	struct rte_pci_device *pdev = NULL;
502 	int ret = 0;
503 
504 	pdev = RTE_DEV_TO_PCI(dev);
505 	if (!pdev)
506 		return -1;
507 
508 	switch (pdev->kdrv) {
509 #ifdef HAVE_VFIO_DEV_REQ_INTERFACE
510 	case RTE_PCI_KDRV_VFIO:
511 		/*
512 		 * vfio kernel module guaranty the pci device would not be
513 		 * deleted until the user space release the resource, so no
514 		 * need to remap BARs resource here, just directly notify
515 		 * the req event to the user space to handle it.
516 		 */
517 		rte_dev_event_callback_process(dev->name,
518 					       RTE_DEV_EVENT_REMOVE);
519 		break;
520 #endif
521 	case RTE_PCI_KDRV_IGB_UIO:
522 	case RTE_PCI_KDRV_UIO_GENERIC:
523 	case RTE_PCI_KDRV_NIC_UIO:
524 		/* BARs resource is invalid, remap it to be safe. */
525 		ret = pci_uio_remap_resource(pdev);
526 		break;
527 	default:
528 		RTE_LOG(DEBUG, EAL,
529 			"Not managed by a supported kernel driver, skipped\n");
530 		ret = -1;
531 		break;
532 	}
533 
534 	return ret;
535 }
536 
537 static int
538 pci_sigbus_handler(const void *failure_addr)
539 {
540 	struct rte_pci_device *pdev = NULL;
541 	int ret = 0;
542 
543 	pdev = pci_find_device_by_addr(failure_addr);
544 	if (!pdev) {
545 		/* It is a generic sigbus error, no bus would handle it. */
546 		ret = 1;
547 	} else {
548 		/* The sigbus error is caused of hot-unplug. */
549 		ret = pci_hot_unplug_handler(&pdev->device);
550 		if (ret) {
551 			RTE_LOG(ERR, EAL,
552 				"Failed to handle hot-unplug for device %s",
553 				pdev->name);
554 			ret = -1;
555 		}
556 	}
557 	return ret;
558 }
559 
560 static int
561 pci_plug(struct rte_device *dev)
562 {
563 	return pci_probe_all_drivers(RTE_DEV_TO_PCI(dev));
564 }
565 
566 static int
567 pci_unplug(struct rte_device *dev)
568 {
569 	struct rte_pci_device *pdev;
570 	int ret;
571 
572 	pdev = RTE_DEV_TO_PCI(dev);
573 	ret = rte_pci_detach_dev(pdev);
574 	if (ret == 0) {
575 		rte_pci_remove_device(pdev);
576 		rte_devargs_remove(dev->devargs);
577 		free(pdev);
578 	}
579 	return ret;
580 }
581 
582 static int
583 pci_dma_map(struct rte_device *dev, void *addr, uint64_t iova, size_t len)
584 {
585 	struct rte_pci_device *pdev = RTE_DEV_TO_PCI(dev);
586 
587 	if (!pdev || !pdev->driver) {
588 		rte_errno = EINVAL;
589 		return -1;
590 	}
591 	if (pdev->driver->dma_map)
592 		return pdev->driver->dma_map(pdev, addr, iova, len);
593 	/**
594 	 *  In case driver don't provides any specific mapping
595 	 *  try fallback to VFIO.
596 	 */
597 	if (pdev->kdrv == RTE_PCI_KDRV_VFIO)
598 		return rte_vfio_container_dma_map
599 				(RTE_VFIO_DEFAULT_CONTAINER_FD, (uintptr_t)addr,
600 				 iova, len);
601 	rte_errno = ENOTSUP;
602 	return -1;
603 }
604 
605 static int
606 pci_dma_unmap(struct rte_device *dev, void *addr, uint64_t iova, size_t len)
607 {
608 	struct rte_pci_device *pdev = RTE_DEV_TO_PCI(dev);
609 
610 	if (!pdev || !pdev->driver) {
611 		rte_errno = EINVAL;
612 		return -1;
613 	}
614 	if (pdev->driver->dma_unmap)
615 		return pdev->driver->dma_unmap(pdev, addr, iova, len);
616 	/**
617 	 *  In case driver don't provides any specific mapping
618 	 *  try fallback to VFIO.
619 	 */
620 	if (pdev->kdrv == RTE_PCI_KDRV_VFIO)
621 		return rte_vfio_container_dma_unmap
622 				(RTE_VFIO_DEFAULT_CONTAINER_FD, (uintptr_t)addr,
623 				 iova, len);
624 	rte_errno = ENOTSUP;
625 	return -1;
626 }
627 
628 bool
629 rte_pci_ignore_device(const struct rte_pci_addr *pci_addr)
630 {
631 	struct rte_devargs *devargs = pci_devargs_lookup(pci_addr);
632 
633 	switch (rte_pci_bus.bus.conf.scan_mode) {
634 	case RTE_BUS_SCAN_ALLOWLIST:
635 		if (devargs && devargs->policy == RTE_DEV_ALLOWED)
636 			return false;
637 		break;
638 	case RTE_BUS_SCAN_UNDEFINED:
639 	case RTE_BUS_SCAN_BLOCKLIST:
640 		if (devargs == NULL || devargs->policy != RTE_DEV_BLOCKED)
641 			return false;
642 		break;
643 	}
644 	return true;
645 }
646 
647 enum rte_iova_mode
648 rte_pci_get_iommu_class(void)
649 {
650 	enum rte_iova_mode iova_mode = RTE_IOVA_DC;
651 	const struct rte_pci_device *dev;
652 	const struct rte_pci_driver *drv;
653 	bool devices_want_va = false;
654 	bool devices_want_pa = false;
655 	int iommu_no_va = -1;
656 
657 	FOREACH_DEVICE_ON_PCIBUS(dev) {
658 		/*
659 		 * We can check this only once, because the IOMMU hardware is
660 		 * the same for all of them.
661 		 */
662 		if (iommu_no_va == -1)
663 			iommu_no_va = pci_device_iommu_support_va(dev)
664 					? 0 : 1;
665 
666 		if (dev->kdrv == RTE_PCI_KDRV_UNKNOWN ||
667 		    dev->kdrv == RTE_PCI_KDRV_NONE)
668 			continue;
669 		FOREACH_DRIVER_ON_PCIBUS(drv) {
670 			enum rte_iova_mode dev_iova_mode;
671 
672 			if (!rte_pci_match(drv, dev))
673 				continue;
674 
675 			dev_iova_mode = pci_device_iova_mode(drv, dev);
676 			RTE_LOG(DEBUG, EAL, "PCI driver %s for device "
677 				PCI_PRI_FMT " wants IOVA as '%s'\n",
678 				drv->driver.name,
679 				dev->addr.domain, dev->addr.bus,
680 				dev->addr.devid, dev->addr.function,
681 				dev_iova_mode == RTE_IOVA_DC ? "DC" :
682 				(dev_iova_mode == RTE_IOVA_PA ? "PA" : "VA"));
683 			if (dev_iova_mode == RTE_IOVA_PA)
684 				devices_want_pa = true;
685 			else if (dev_iova_mode == RTE_IOVA_VA)
686 				devices_want_va = true;
687 		}
688 	}
689 	if (iommu_no_va == 1) {
690 		iova_mode = RTE_IOVA_PA;
691 		if (devices_want_va) {
692 			RTE_LOG(WARNING, EAL, "Some devices want 'VA' but IOMMU does not support 'VA'.\n");
693 			RTE_LOG(WARNING, EAL, "The devices that want 'VA' won't initialize.\n");
694 		}
695 	} else if (devices_want_va && !devices_want_pa) {
696 		iova_mode = RTE_IOVA_VA;
697 	} else if (devices_want_pa && !devices_want_va) {
698 		iova_mode = RTE_IOVA_PA;
699 	} else {
700 		iova_mode = RTE_IOVA_DC;
701 		if (devices_want_va) {
702 			RTE_LOG(WARNING, EAL, "Some devices want 'VA' but forcing 'DC' because other devices want 'PA'.\n");
703 			RTE_LOG(WARNING, EAL, "Depending on the final decision by the EAL, not all devices may be able to initialize.\n");
704 		}
705 	}
706 	return iova_mode;
707 }
708 
709 off_t
710 rte_pci_find_ext_capability(struct rte_pci_device *dev, uint32_t cap)
711 {
712 	off_t offset = RTE_PCI_CFG_SPACE_SIZE;
713 	uint32_t header;
714 	int ttl;
715 
716 	/* minimum 8 bytes per capability */
717 	ttl = (RTE_PCI_CFG_SPACE_EXP_SIZE - RTE_PCI_CFG_SPACE_SIZE) / 8;
718 
719 	if (rte_pci_read_config(dev, &header, 4, offset) < 0) {
720 		RTE_LOG(ERR, EAL, "error in reading extended capabilities\n");
721 		return -1;
722 	}
723 
724 	/*
725 	 * If we have no capabilities, this is indicated by cap ID,
726 	 * cap version and next pointer all being 0.
727 	 */
728 	if (header == 0)
729 		return 0;
730 
731 	while (ttl != 0) {
732 		if (RTE_PCI_EXT_CAP_ID(header) == cap)
733 			return offset;
734 
735 		offset = RTE_PCI_EXT_CAP_NEXT(header);
736 
737 		if (offset < RTE_PCI_CFG_SPACE_SIZE)
738 			break;
739 
740 		if (rte_pci_read_config(dev, &header, 4, offset) < 0) {
741 			RTE_LOG(ERR, EAL,
742 				"error in reading extended capabilities\n");
743 			return -1;
744 		}
745 
746 		ttl--;
747 	}
748 
749 	return 0;
750 }
751 
752 int
753 rte_pci_set_bus_master(struct rte_pci_device *dev, bool enable)
754 {
755 	uint16_t old_cmd, cmd;
756 
757 	if (rte_pci_read_config(dev, &old_cmd, sizeof(old_cmd),
758 				RTE_PCI_COMMAND) < 0) {
759 		RTE_LOG(ERR, EAL, "error in reading PCI command register\n");
760 		return -1;
761 	}
762 
763 	if (enable)
764 		cmd = old_cmd | RTE_PCI_COMMAND_MASTER;
765 	else
766 		cmd = old_cmd & ~RTE_PCI_COMMAND_MASTER;
767 
768 	if (cmd == old_cmd)
769 		return 0;
770 
771 	if (rte_pci_write_config(dev, &cmd, sizeof(cmd),
772 				 RTE_PCI_COMMAND) < 0) {
773 		RTE_LOG(ERR, EAL, "error in writing PCI command register\n");
774 		return -1;
775 	}
776 
777 	return 0;
778 }
779 
780 struct rte_pci_bus rte_pci_bus = {
781 	.bus = {
782 		.scan = rte_pci_scan,
783 		.probe = pci_probe,
784 		.find_device = pci_find_device,
785 		.plug = pci_plug,
786 		.unplug = pci_unplug,
787 		.parse = pci_parse,
788 		.devargs_parse = rte_pci_devargs_parse,
789 		.dma_map = pci_dma_map,
790 		.dma_unmap = pci_dma_unmap,
791 		.get_iommu_class = rte_pci_get_iommu_class,
792 		.dev_iterate = rte_pci_dev_iterate,
793 		.hot_unplug_handler = pci_hot_unplug_handler,
794 		.sigbus_handler = pci_sigbus_handler,
795 	},
796 	.device_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.device_list),
797 	.driver_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.driver_list),
798 };
799 
800 RTE_REGISTER_BUS(pci, rte_pci_bus.bus);
801