xref: /dpdk/drivers/bus/pci/pci_common.c (revision bbbe38a6d59ccdda25917712701e629d0b10af6f)
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_per_lcore.h>
20 #include <rte_memory.h>
21 #include <rte_eal.h>
22 #include <rte_eal_paging.h>
23 #include <rte_string_fns.h>
24 #include <rte_common.h>
25 #include <rte_devargs.h>
26 #include <rte_vfio.h>
27 
28 #include "private.h"
29 
30 
31 #define SYSFS_PCI_DEVICES "/sys/bus/pci/devices"
32 
33 const char *rte_pci_get_sysfs_path(void)
34 {
35 	const char *path = NULL;
36 
37 #ifdef RTE_EXEC_ENV_LINUX
38 	path = getenv("SYSFS_PCI_DEVICES");
39 	if (path == NULL)
40 		return SYSFS_PCI_DEVICES;
41 #endif
42 
43 	return path;
44 }
45 
46 static struct rte_devargs *
47 pci_devargs_lookup(const struct rte_pci_addr *pci_addr)
48 {
49 	struct rte_devargs *devargs;
50 	struct rte_pci_addr addr;
51 
52 	RTE_EAL_DEVARGS_FOREACH("pci", devargs) {
53 		devargs->bus->parse(devargs->name, &addr);
54 		if (!rte_pci_addr_cmp(pci_addr, &addr))
55 			return devargs;
56 	}
57 	return NULL;
58 }
59 
60 void
61 pci_name_set(struct rte_pci_device *dev)
62 {
63 	struct rte_devargs *devargs;
64 
65 	/* Each device has its internal, canonical name set. */
66 	rte_pci_device_name(&dev->addr,
67 			dev->name, sizeof(dev->name));
68 	devargs = pci_devargs_lookup(&dev->addr);
69 	dev->device.devargs = devargs;
70 
71 	/* When using a blocklist, only blocked devices will have
72 	 * an rte_devargs. Allowed devices won't have one.
73 	 */
74 	if (devargs != NULL)
75 		/* If an rte_devargs exists, the generic rte_device uses the
76 		 * given name as its name.
77 		 */
78 		dev->device.name = dev->device.devargs->name;
79 	else
80 		/* Otherwise, it uses the internal, canonical form. */
81 		dev->device.name = dev->name;
82 }
83 
84 /* map a particular resource from a file */
85 void *
86 pci_map_resource(void *requested_addr, int fd, off_t offset, size_t size,
87 		 int additional_flags)
88 {
89 	void *mapaddr;
90 
91 	/* Map the PCI memory resource of device */
92 	mapaddr = rte_mem_map(requested_addr, size,
93 		RTE_PROT_READ | RTE_PROT_WRITE,
94 		RTE_MAP_SHARED | additional_flags, fd, offset);
95 	if (mapaddr == NULL) {
96 		RTE_LOG(ERR, EAL,
97 			"%s(): cannot map resource(%d, %p, 0x%zx, 0x%llx): %s (%p)\n",
98 			__func__, fd, requested_addr, size,
99 			(unsigned long long)offset,
100 			rte_strerror(rte_errno), mapaddr);
101 	} else
102 		RTE_LOG(DEBUG, EAL, "  PCI memory mapped at %p\n", mapaddr);
103 
104 	return mapaddr;
105 }
106 
107 /* unmap a particular resource */
108 void
109 pci_unmap_resource(void *requested_addr, size_t size)
110 {
111 	if (requested_addr == NULL)
112 		return;
113 
114 	/* Unmap the PCI memory resource of device */
115 	if (rte_mem_unmap(requested_addr, size)) {
116 		RTE_LOG(ERR, EAL, "%s(): cannot mem unmap(%p, %#zx): %s\n",
117 			__func__, requested_addr, size,
118 			rte_strerror(rte_errno));
119 	} else
120 		RTE_LOG(DEBUG, EAL, "  PCI memory unmapped at %p\n",
121 				requested_addr);
122 }
123 /*
124  * Match the PCI Driver and Device using the ID Table
125  */
126 int
127 rte_pci_match(const struct rte_pci_driver *pci_drv,
128 	      const struct rte_pci_device *pci_dev)
129 {
130 	const struct rte_pci_id *id_table;
131 
132 	for (id_table = pci_drv->id_table; id_table->vendor_id != 0;
133 	     id_table++) {
134 		/* check if device's identifiers match the driver's ones */
135 		if (id_table->vendor_id != pci_dev->id.vendor_id &&
136 				id_table->vendor_id != RTE_PCI_ANY_ID)
137 			continue;
138 		if (id_table->device_id != pci_dev->id.device_id &&
139 				id_table->device_id != RTE_PCI_ANY_ID)
140 			continue;
141 		if (id_table->subsystem_vendor_id !=
142 		    pci_dev->id.subsystem_vendor_id &&
143 		    id_table->subsystem_vendor_id != RTE_PCI_ANY_ID)
144 			continue;
145 		if (id_table->subsystem_device_id !=
146 		    pci_dev->id.subsystem_device_id &&
147 		    id_table->subsystem_device_id != RTE_PCI_ANY_ID)
148 			continue;
149 		if (id_table->class_id != pci_dev->id.class_id &&
150 				id_table->class_id != RTE_CLASS_ANY_ID)
151 			continue;
152 
153 		return 1;
154 	}
155 
156 	return 0;
157 }
158 
159 /*
160  * If vendor/device ID match, call the probe() function of the
161  * driver.
162  */
163 static int
164 rte_pci_probe_one_driver(struct rte_pci_driver *dr,
165 			 struct rte_pci_device *dev)
166 {
167 	int ret;
168 	bool already_probed;
169 	struct rte_pci_addr *loc;
170 
171 	if ((dr == NULL) || (dev == NULL))
172 		return -EINVAL;
173 
174 	loc = &dev->addr;
175 
176 	/* The device is not blocked; Check if driver supports it */
177 	if (!rte_pci_match(dr, dev))
178 		/* Match of device and driver failed */
179 		return 1;
180 
181 	RTE_LOG(DEBUG, EAL, "PCI device "PCI_PRI_FMT" on NUMA socket %i\n",
182 			loc->domain, loc->bus, loc->devid, loc->function,
183 			dev->device.numa_node);
184 
185 	/* no initialization when marked as blocked, return without error */
186 	if (dev->device.devargs != NULL &&
187 		dev->device.devargs->policy == RTE_DEV_BLOCKED) {
188 		RTE_LOG(INFO, EAL, "  Device is blocked, not initializing\n");
189 		return 1;
190 	}
191 
192 	if (dev->device.numa_node < 0) {
193 		RTE_LOG(WARNING, EAL, "  Invalid NUMA socket, default to 0\n");
194 		dev->device.numa_node = 0;
195 	}
196 
197 	already_probed = rte_dev_is_probed(&dev->device);
198 	if (already_probed && !(dr->drv_flags & RTE_PCI_DRV_PROBE_AGAIN)) {
199 		RTE_LOG(DEBUG, EAL, "Device %s is already probed\n",
200 				dev->device.name);
201 		return -EEXIST;
202 	}
203 
204 	RTE_LOG(DEBUG, EAL, "  probe driver: %x:%x %s\n", dev->id.vendor_id,
205 		dev->id.device_id, dr->driver.name);
206 
207 	/*
208 	 * reference driver structure
209 	 * This needs to be before rte_pci_map_device(), as it enables to use
210 	 * driver flags for adjusting configuration.
211 	 */
212 	if (!already_probed) {
213 		enum rte_iova_mode dev_iova_mode;
214 		enum rte_iova_mode iova_mode;
215 
216 		dev_iova_mode = pci_device_iova_mode(dr, dev);
217 		iova_mode = rte_eal_iova_mode();
218 		if (dev_iova_mode != RTE_IOVA_DC &&
219 		    dev_iova_mode != iova_mode) {
220 			RTE_LOG(ERR, EAL, "  Expecting '%s' IOVA mode but current mode is '%s', not initializing\n",
221 				dev_iova_mode == RTE_IOVA_PA ? "PA" : "VA",
222 				iova_mode == RTE_IOVA_PA ? "PA" : "VA");
223 			return -EINVAL;
224 		}
225 
226 		dev->driver = dr;
227 	}
228 
229 	if (!already_probed && (dr->drv_flags & RTE_PCI_DRV_NEED_MAPPING)) {
230 		/* map resources for devices that use igb_uio */
231 		ret = rte_pci_map_device(dev);
232 		if (ret != 0) {
233 			dev->driver = NULL;
234 			return ret;
235 		}
236 	}
237 
238 	RTE_LOG(INFO, EAL, "Probe PCI driver: %s (%x:%x) device: "PCI_PRI_FMT" (socket %i)\n",
239 			dr->driver.name, dev->id.vendor_id, dev->id.device_id,
240 			loc->domain, loc->bus, loc->devid, loc->function,
241 			dev->device.numa_node);
242 	/* call the driver probe() function */
243 	ret = dr->probe(dr, dev);
244 	if (already_probed)
245 		return ret; /* no rollback if already succeeded earlier */
246 	if (ret) {
247 		dev->driver = NULL;
248 		if ((dr->drv_flags & RTE_PCI_DRV_NEED_MAPPING) &&
249 			/* Don't unmap if device is unsupported and
250 			 * driver needs mapped resources.
251 			 */
252 			!(ret > 0 &&
253 				(dr->drv_flags & RTE_PCI_DRV_KEEP_MAPPED_RES)))
254 			rte_pci_unmap_device(dev);
255 	} else {
256 		dev->device.driver = &dr->driver;
257 	}
258 
259 	return ret;
260 }
261 
262 /*
263  * If vendor/device ID match, call the remove() function of the
264  * driver.
265  */
266 static int
267 rte_pci_detach_dev(struct rte_pci_device *dev)
268 {
269 	struct rte_pci_addr *loc;
270 	struct rte_pci_driver *dr;
271 	int ret = 0;
272 
273 	if (dev == NULL)
274 		return -EINVAL;
275 
276 	dr = dev->driver;
277 	loc = &dev->addr;
278 
279 	RTE_LOG(DEBUG, EAL, "PCI device "PCI_PRI_FMT" on NUMA socket %i\n",
280 			loc->domain, loc->bus, loc->devid,
281 			loc->function, dev->device.numa_node);
282 
283 	RTE_LOG(DEBUG, EAL, "  remove driver: %x:%x %s\n", dev->id.vendor_id,
284 			dev->id.device_id, dr->driver.name);
285 
286 	if (dr->remove) {
287 		ret = dr->remove(dev);
288 		if (ret < 0)
289 			return ret;
290 	}
291 
292 	/* clear driver structure */
293 	dev->driver = NULL;
294 	dev->device.driver = NULL;
295 
296 	if (dr->drv_flags & RTE_PCI_DRV_NEED_MAPPING)
297 		/* unmap resources for devices that use igb_uio */
298 		rte_pci_unmap_device(dev);
299 
300 	return 0;
301 }
302 
303 /*
304  * If vendor/device ID match, call the probe() function of all
305  * registered driver for the given device. Return < 0 if initialization
306  * failed, return 1 if no driver is found for this device.
307  */
308 static int
309 pci_probe_all_drivers(struct rte_pci_device *dev)
310 {
311 	struct rte_pci_driver *dr = NULL;
312 	int rc = 0;
313 
314 	if (dev == NULL)
315 		return -EINVAL;
316 
317 	FOREACH_DRIVER_ON_PCIBUS(dr) {
318 		rc = rte_pci_probe_one_driver(dr, dev);
319 		if (rc < 0)
320 			/* negative value is an error */
321 			return rc;
322 		if (rc > 0)
323 			/* positive value means driver doesn't support it */
324 			continue;
325 		return 0;
326 	}
327 	return 1;
328 }
329 
330 /*
331  * Scan the content of the PCI bus, and call the probe() function for
332  * all registered drivers that have a matching entry in its id_table
333  * for discovered devices.
334  */
335 static int
336 pci_probe(void)
337 {
338 	struct rte_pci_device *dev = NULL;
339 	size_t probed = 0, failed = 0;
340 	int ret = 0;
341 
342 	FOREACH_DEVICE_ON_PCIBUS(dev) {
343 		probed++;
344 
345 		ret = pci_probe_all_drivers(dev);
346 		if (ret < 0) {
347 			if (ret != -EEXIST) {
348 				RTE_LOG(ERR, EAL, "Requested device "
349 					PCI_PRI_FMT " cannot be used\n",
350 					dev->addr.domain, dev->addr.bus,
351 					dev->addr.devid, dev->addr.function);
352 				rte_errno = errno;
353 				failed++;
354 			}
355 			ret = 0;
356 		}
357 	}
358 
359 	return (probed && probed == failed) ? -1 : 0;
360 }
361 
362 /* dump one device */
363 static int
364 pci_dump_one_device(FILE *f, struct rte_pci_device *dev)
365 {
366 	int i;
367 
368 	fprintf(f, PCI_PRI_FMT, dev->addr.domain, dev->addr.bus,
369 	       dev->addr.devid, dev->addr.function);
370 	fprintf(f, " - vendor:%x device:%x\n", dev->id.vendor_id,
371 	       dev->id.device_id);
372 
373 	for (i = 0; i != sizeof(dev->mem_resource) /
374 		sizeof(dev->mem_resource[0]); i++) {
375 		fprintf(f, "   %16.16"PRIx64" %16.16"PRIx64"\n",
376 			dev->mem_resource[i].phys_addr,
377 			dev->mem_resource[i].len);
378 	}
379 	return 0;
380 }
381 
382 /* dump devices on the bus */
383 void
384 rte_pci_dump(FILE *f)
385 {
386 	struct rte_pci_device *dev = NULL;
387 
388 	FOREACH_DEVICE_ON_PCIBUS(dev) {
389 		pci_dump_one_device(f, dev);
390 	}
391 }
392 
393 static int
394 pci_parse(const char *name, void *addr)
395 {
396 	struct rte_pci_addr *out = addr;
397 	struct rte_pci_addr pci_addr;
398 	bool parse;
399 
400 	parse = (rte_pci_addr_parse(name, &pci_addr) == 0);
401 	if (parse && addr != NULL)
402 		*out = pci_addr;
403 	return parse == false;
404 }
405 
406 /* register a driver */
407 void
408 rte_pci_register(struct rte_pci_driver *driver)
409 {
410 	TAILQ_INSERT_TAIL(&rte_pci_bus.driver_list, driver, next);
411 	driver->bus = &rte_pci_bus;
412 }
413 
414 /* unregister a driver */
415 void
416 rte_pci_unregister(struct rte_pci_driver *driver)
417 {
418 	TAILQ_REMOVE(&rte_pci_bus.driver_list, driver, next);
419 	driver->bus = NULL;
420 }
421 
422 /* Add a device to PCI bus */
423 void
424 rte_pci_add_device(struct rte_pci_device *pci_dev)
425 {
426 	TAILQ_INSERT_TAIL(&rte_pci_bus.device_list, pci_dev, next);
427 }
428 
429 /* Insert a device into a predefined position in PCI bus */
430 void
431 rte_pci_insert_device(struct rte_pci_device *exist_pci_dev,
432 		      struct rte_pci_device *new_pci_dev)
433 {
434 	TAILQ_INSERT_BEFORE(exist_pci_dev, new_pci_dev, next);
435 }
436 
437 /* Remove a device from PCI bus */
438 static void
439 rte_pci_remove_device(struct rte_pci_device *pci_dev)
440 {
441 	TAILQ_REMOVE(&rte_pci_bus.device_list, pci_dev, next);
442 }
443 
444 static struct rte_device *
445 pci_find_device(const struct rte_device *start, rte_dev_cmp_t cmp,
446 		const void *data)
447 {
448 	const struct rte_pci_device *pstart;
449 	struct rte_pci_device *pdev;
450 
451 	if (start != NULL) {
452 		pstart = RTE_DEV_TO_PCI_CONST(start);
453 		pdev = TAILQ_NEXT(pstart, next);
454 	} else {
455 		pdev = TAILQ_FIRST(&rte_pci_bus.device_list);
456 	}
457 	while (pdev != NULL) {
458 		if (cmp(&pdev->device, data) == 0)
459 			return &pdev->device;
460 		pdev = TAILQ_NEXT(pdev, next);
461 	}
462 	return NULL;
463 }
464 
465 /*
466  * find the device which encounter the failure, by iterate over all device on
467  * PCI bus to check if the memory failure address is located in the range
468  * of the BARs of the device.
469  */
470 static struct rte_pci_device *
471 pci_find_device_by_addr(const void *failure_addr)
472 {
473 	struct rte_pci_device *pdev = NULL;
474 	uint64_t check_point, start, end, len;
475 	int i;
476 
477 	check_point = (uint64_t)(uintptr_t)failure_addr;
478 
479 	FOREACH_DEVICE_ON_PCIBUS(pdev) {
480 		for (i = 0; i != RTE_DIM(pdev->mem_resource); i++) {
481 			start = (uint64_t)(uintptr_t)pdev->mem_resource[i].addr;
482 			len = pdev->mem_resource[i].len;
483 			end = start + len;
484 			if (check_point >= start && check_point < end) {
485 				RTE_LOG(DEBUG, EAL, "Failure address %16.16"
486 					PRIx64" belongs to device %s!\n",
487 					check_point, pdev->device.name);
488 				return pdev;
489 			}
490 		}
491 	}
492 	return NULL;
493 }
494 
495 static int
496 pci_hot_unplug_handler(struct rte_device *dev)
497 {
498 	struct rte_pci_device *pdev = NULL;
499 	int ret = 0;
500 
501 	pdev = RTE_DEV_TO_PCI(dev);
502 	if (!pdev)
503 		return -1;
504 
505 	switch (pdev->kdrv) {
506 #ifdef HAVE_VFIO_DEV_REQ_INTERFACE
507 	case RTE_PCI_KDRV_VFIO:
508 		/*
509 		 * vfio kernel module guaranty the pci device would not be
510 		 * deleted until the user space release the resource, so no
511 		 * need to remap BARs resource here, just directly notify
512 		 * the req event to the user space to handle it.
513 		 */
514 		rte_dev_event_callback_process(dev->name,
515 					       RTE_DEV_EVENT_REMOVE);
516 		break;
517 #endif
518 	case RTE_PCI_KDRV_IGB_UIO:
519 	case RTE_PCI_KDRV_UIO_GENERIC:
520 	case RTE_PCI_KDRV_NIC_UIO:
521 		/* BARs resource is invalid, remap it to be safe. */
522 		ret = pci_uio_remap_resource(pdev);
523 		break;
524 	default:
525 		RTE_LOG(DEBUG, EAL,
526 			"Not managed by a supported kernel driver, skipped\n");
527 		ret = -1;
528 		break;
529 	}
530 
531 	return ret;
532 }
533 
534 static int
535 pci_sigbus_handler(const void *failure_addr)
536 {
537 	struct rte_pci_device *pdev = NULL;
538 	int ret = 0;
539 
540 	pdev = pci_find_device_by_addr(failure_addr);
541 	if (!pdev) {
542 		/* It is a generic sigbus error, no bus would handle it. */
543 		ret = 1;
544 	} else {
545 		/* The sigbus error is caused of hot-unplug. */
546 		ret = pci_hot_unplug_handler(&pdev->device);
547 		if (ret) {
548 			RTE_LOG(ERR, EAL,
549 				"Failed to handle hot-unplug for device %s",
550 				pdev->name);
551 			ret = -1;
552 		}
553 	}
554 	return ret;
555 }
556 
557 static int
558 pci_plug(struct rte_device *dev)
559 {
560 	return pci_probe_all_drivers(RTE_DEV_TO_PCI(dev));
561 }
562 
563 static int
564 pci_unplug(struct rte_device *dev)
565 {
566 	struct rte_pci_device *pdev;
567 	int ret;
568 
569 	pdev = RTE_DEV_TO_PCI(dev);
570 	ret = rte_pci_detach_dev(pdev);
571 	if (ret == 0) {
572 		rte_pci_remove_device(pdev);
573 		rte_devargs_remove(dev->devargs);
574 		free(pdev);
575 	}
576 	return ret;
577 }
578 
579 static int
580 pci_dma_map(struct rte_device *dev, void *addr, uint64_t iova, size_t len)
581 {
582 	struct rte_pci_device *pdev = RTE_DEV_TO_PCI(dev);
583 
584 	if (!pdev || !pdev->driver) {
585 		rte_errno = EINVAL;
586 		return -1;
587 	}
588 	if (pdev->driver->dma_map)
589 		return pdev->driver->dma_map(pdev, addr, iova, len);
590 	/**
591 	 *  In case driver don't provides any specific mapping
592 	 *  try fallback to VFIO.
593 	 */
594 	if (pdev->kdrv == RTE_PCI_KDRV_VFIO)
595 		return rte_vfio_container_dma_map
596 				(RTE_VFIO_DEFAULT_CONTAINER_FD, (uintptr_t)addr,
597 				 iova, len);
598 	rte_errno = ENOTSUP;
599 	return -1;
600 }
601 
602 static int
603 pci_dma_unmap(struct rte_device *dev, void *addr, uint64_t iova, size_t len)
604 {
605 	struct rte_pci_device *pdev = RTE_DEV_TO_PCI(dev);
606 
607 	if (!pdev || !pdev->driver) {
608 		rte_errno = EINVAL;
609 		return -1;
610 	}
611 	if (pdev->driver->dma_unmap)
612 		return pdev->driver->dma_unmap(pdev, addr, iova, len);
613 	/**
614 	 *  In case driver don't provides any specific mapping
615 	 *  try fallback to VFIO.
616 	 */
617 	if (pdev->kdrv == RTE_PCI_KDRV_VFIO)
618 		return rte_vfio_container_dma_unmap
619 				(RTE_VFIO_DEFAULT_CONTAINER_FD, (uintptr_t)addr,
620 				 iova, len);
621 	rte_errno = ENOTSUP;
622 	return -1;
623 }
624 
625 bool
626 rte_pci_ignore_device(const struct rte_pci_addr *pci_addr)
627 {
628 	struct rte_devargs *devargs = pci_devargs_lookup(pci_addr);
629 
630 	switch (rte_pci_bus.bus.conf.scan_mode) {
631 	case RTE_BUS_SCAN_ALLOWLIST:
632 		if (devargs && devargs->policy == RTE_DEV_ALLOWED)
633 			return false;
634 		break;
635 	case RTE_BUS_SCAN_UNDEFINED:
636 	case RTE_BUS_SCAN_BLOCKLIST:
637 		if (devargs == NULL || devargs->policy != RTE_DEV_BLOCKED)
638 			return false;
639 		break;
640 	}
641 	return true;
642 }
643 
644 enum rte_iova_mode
645 rte_pci_get_iommu_class(void)
646 {
647 	enum rte_iova_mode iova_mode = RTE_IOVA_DC;
648 	const struct rte_pci_device *dev;
649 	const struct rte_pci_driver *drv;
650 	bool devices_want_va = false;
651 	bool devices_want_pa = false;
652 	int iommu_no_va = -1;
653 
654 	FOREACH_DEVICE_ON_PCIBUS(dev) {
655 		/*
656 		 * We can check this only once, because the IOMMU hardware is
657 		 * the same for all of them.
658 		 */
659 		if (iommu_no_va == -1)
660 			iommu_no_va = pci_device_iommu_support_va(dev)
661 					? 0 : 1;
662 
663 		if (dev->kdrv == RTE_PCI_KDRV_UNKNOWN ||
664 		    dev->kdrv == RTE_PCI_KDRV_NONE)
665 			continue;
666 		FOREACH_DRIVER_ON_PCIBUS(drv) {
667 			enum rte_iova_mode dev_iova_mode;
668 
669 			if (!rte_pci_match(drv, dev))
670 				continue;
671 
672 			dev_iova_mode = pci_device_iova_mode(drv, dev);
673 			RTE_LOG(DEBUG, EAL, "PCI driver %s for device "
674 				PCI_PRI_FMT " wants IOVA as '%s'\n",
675 				drv->driver.name,
676 				dev->addr.domain, dev->addr.bus,
677 				dev->addr.devid, dev->addr.function,
678 				dev_iova_mode == RTE_IOVA_DC ? "DC" :
679 				(dev_iova_mode == RTE_IOVA_PA ? "PA" : "VA"));
680 			if (dev_iova_mode == RTE_IOVA_PA)
681 				devices_want_pa = true;
682 			else if (dev_iova_mode == RTE_IOVA_VA)
683 				devices_want_va = true;
684 		}
685 	}
686 	if (iommu_no_va == 1) {
687 		iova_mode = RTE_IOVA_PA;
688 		if (devices_want_va) {
689 			RTE_LOG(WARNING, EAL, "Some devices want 'VA' but IOMMU does not support 'VA'.\n");
690 			RTE_LOG(WARNING, EAL, "The devices that want 'VA' won't initialize.\n");
691 		}
692 	} else if (devices_want_va && !devices_want_pa) {
693 		iova_mode = RTE_IOVA_VA;
694 	} else if (devices_want_pa && !devices_want_va) {
695 		iova_mode = RTE_IOVA_PA;
696 	} else {
697 		iova_mode = RTE_IOVA_DC;
698 		if (devices_want_va) {
699 			RTE_LOG(WARNING, EAL, "Some devices want 'VA' but forcing 'DC' because other devices want 'PA'.\n");
700 			RTE_LOG(WARNING, EAL, "Depending on the final decision by the EAL, not all devices may be able to initialize.\n");
701 		}
702 	}
703 	return iova_mode;
704 }
705 
706 off_t
707 rte_pci_find_ext_capability(struct rte_pci_device *dev, uint32_t cap)
708 {
709 	off_t offset = RTE_PCI_CFG_SPACE_SIZE;
710 	uint32_t header;
711 	int ttl;
712 
713 	/* minimum 8 bytes per capability */
714 	ttl = (RTE_PCI_CFG_SPACE_EXP_SIZE - RTE_PCI_CFG_SPACE_SIZE) / 8;
715 
716 	if (rte_pci_read_config(dev, &header, 4, offset) < 0) {
717 		RTE_LOG(ERR, EAL, "error in reading extended capabilities\n");
718 		return -1;
719 	}
720 
721 	/*
722 	 * If we have no capabilities, this is indicated by cap ID,
723 	 * cap version and next pointer all being 0.
724 	 */
725 	if (header == 0)
726 		return 0;
727 
728 	while (ttl != 0) {
729 		if (RTE_PCI_EXT_CAP_ID(header) == cap)
730 			return offset;
731 
732 		offset = RTE_PCI_EXT_CAP_NEXT(header);
733 
734 		if (offset < RTE_PCI_CFG_SPACE_SIZE)
735 			break;
736 
737 		if (rte_pci_read_config(dev, &header, 4, offset) < 0) {
738 			RTE_LOG(ERR, EAL,
739 				"error in reading extended capabilities\n");
740 			return -1;
741 		}
742 
743 		ttl--;
744 	}
745 
746 	return 0;
747 }
748 
749 int
750 rte_pci_set_bus_master(struct rte_pci_device *dev, bool enable)
751 {
752 	uint16_t old_cmd, cmd;
753 
754 	if (rte_pci_read_config(dev, &old_cmd, sizeof(old_cmd),
755 				RTE_PCI_COMMAND) < 0) {
756 		RTE_LOG(ERR, EAL, "error in reading PCI command register\n");
757 		return -1;
758 	}
759 
760 	if (enable)
761 		cmd = old_cmd | RTE_PCI_COMMAND_MASTER;
762 	else
763 		cmd = old_cmd & ~RTE_PCI_COMMAND_MASTER;
764 
765 	if (cmd == old_cmd)
766 		return 0;
767 
768 	if (rte_pci_write_config(dev, &cmd, sizeof(cmd),
769 				 RTE_PCI_COMMAND) < 0) {
770 		RTE_LOG(ERR, EAL, "error in writing PCI command register\n");
771 		return -1;
772 	}
773 
774 	return 0;
775 }
776 
777 struct rte_pci_bus rte_pci_bus = {
778 	.bus = {
779 		.scan = rte_pci_scan,
780 		.probe = pci_probe,
781 		.find_device = pci_find_device,
782 		.plug = pci_plug,
783 		.unplug = pci_unplug,
784 		.parse = pci_parse,
785 		.dma_map = pci_dma_map,
786 		.dma_unmap = pci_dma_unmap,
787 		.get_iommu_class = rte_pci_get_iommu_class,
788 		.dev_iterate = rte_pci_dev_iterate,
789 		.hot_unplug_handler = pci_hot_unplug_handler,
790 		.sigbus_handler = pci_sigbus_handler,
791 	},
792 	.device_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.device_list),
793 	.driver_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.driver_list),
794 };
795 
796 RTE_REGISTER_BUS(pci, rte_pci_bus.bus);
797