xref: /dpdk/drivers/net/virtio/virtio_pci.c (revision bd03d3f1e4f1734c70bf6be32cdeb5e3ae6fa611)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2014 Intel Corporation
3  */
4 #include <stdint.h>
5 
6 #ifdef RTE_EXEC_ENV_LINUXAPP
7  #include <dirent.h>
8  #include <fcntl.h>
9 #endif
10 
11 #include <rte_io.h>
12 #include <rte_bus.h>
13 
14 #include "virtio_pci.h"
15 #include "virtio_logs.h"
16 #include "virtqueue.h"
17 
18 /*
19  * Following macros are derived from linux/pci_regs.h, however,
20  * we can't simply include that header here, as there is no such
21  * file for non-Linux platform.
22  */
23 #define PCI_CAPABILITY_LIST	0x34
24 #define PCI_CAP_ID_VNDR		0x09
25 #define PCI_CAP_ID_MSIX		0x11
26 
27 /*
28  * The remaining space is defined by each driver as the per-driver
29  * configuration space.
30  */
31 #define VIRTIO_PCI_CONFIG(hw) \
32 		(((hw)->use_msix == VIRTIO_MSIX_ENABLED) ? 24 : 20)
33 
34 static inline int
35 check_vq_phys_addr_ok(struct virtqueue *vq)
36 {
37 	/* Virtio PCI device VIRTIO_PCI_QUEUE_PF register is 32bit,
38 	 * and only accepts 32 bit page frame number.
39 	 * Check if the allocated physical memory exceeds 16TB.
40 	 */
41 	if ((vq->vq_ring_mem + vq->vq_ring_size - 1) >>
42 			(VIRTIO_PCI_QUEUE_ADDR_SHIFT + 32)) {
43 		PMD_INIT_LOG(ERR, "vring address shouldn't be above 16TB!");
44 		return 0;
45 	}
46 
47 	return 1;
48 }
49 
50 /*
51  * Since we are in legacy mode:
52  * http://ozlabs.org/~rusty/virtio-spec/virtio-0.9.5.pdf
53  *
54  * "Note that this is possible because while the virtio header is PCI (i.e.
55  * little) endian, the device-specific region is encoded in the native endian of
56  * the guest (where such distinction is applicable)."
57  *
58  * For powerpc which supports both, qemu supposes that cpu is big endian and
59  * enforces this for the virtio-net stuff.
60  */
61 static void
62 legacy_read_dev_config(struct virtio_hw *hw, size_t offset,
63 		       void *dst, int length)
64 {
65 #ifdef RTE_ARCH_PPC_64
66 	int size;
67 
68 	while (length > 0) {
69 		if (length >= 4) {
70 			size = 4;
71 			rte_pci_ioport_read(VTPCI_IO(hw), dst, size,
72 				VIRTIO_PCI_CONFIG(hw) + offset);
73 			*(uint32_t *)dst = rte_be_to_cpu_32(*(uint32_t *)dst);
74 		} else if (length >= 2) {
75 			size = 2;
76 			rte_pci_ioport_read(VTPCI_IO(hw), dst, size,
77 				VIRTIO_PCI_CONFIG(hw) + offset);
78 			*(uint16_t *)dst = rte_be_to_cpu_16(*(uint16_t *)dst);
79 		} else {
80 			size = 1;
81 			rte_pci_ioport_read(VTPCI_IO(hw), dst, size,
82 				VIRTIO_PCI_CONFIG(hw) + offset);
83 		}
84 
85 		dst = (char *)dst + size;
86 		offset += size;
87 		length -= size;
88 	}
89 #else
90 	rte_pci_ioport_read(VTPCI_IO(hw), dst, length,
91 		VIRTIO_PCI_CONFIG(hw) + offset);
92 #endif
93 }
94 
95 static void
96 legacy_write_dev_config(struct virtio_hw *hw, size_t offset,
97 			const void *src, int length)
98 {
99 #ifdef RTE_ARCH_PPC_64
100 	union {
101 		uint32_t u32;
102 		uint16_t u16;
103 	} tmp;
104 	int size;
105 
106 	while (length > 0) {
107 		if (length >= 4) {
108 			size = 4;
109 			tmp.u32 = rte_cpu_to_be_32(*(const uint32_t *)src);
110 			rte_pci_ioport_write(VTPCI_IO(hw), &tmp.u32, size,
111 				VIRTIO_PCI_CONFIG(hw) + offset);
112 		} else if (length >= 2) {
113 			size = 2;
114 			tmp.u16 = rte_cpu_to_be_16(*(const uint16_t *)src);
115 			rte_pci_ioport_write(VTPCI_IO(hw), &tmp.u16, size,
116 				VIRTIO_PCI_CONFIG(hw) + offset);
117 		} else {
118 			size = 1;
119 			rte_pci_ioport_write(VTPCI_IO(hw), src, size,
120 				VIRTIO_PCI_CONFIG(hw) + offset);
121 		}
122 
123 		src = (const char *)src + size;
124 		offset += size;
125 		length -= size;
126 	}
127 #else
128 	rte_pci_ioport_write(VTPCI_IO(hw), src, length,
129 		VIRTIO_PCI_CONFIG(hw) + offset);
130 #endif
131 }
132 
133 static uint64_t
134 legacy_get_features(struct virtio_hw *hw)
135 {
136 	uint32_t dst;
137 
138 	rte_pci_ioport_read(VTPCI_IO(hw), &dst, 4, VIRTIO_PCI_HOST_FEATURES);
139 	return dst;
140 }
141 
142 static void
143 legacy_set_features(struct virtio_hw *hw, uint64_t features)
144 {
145 	if ((features >> 32) != 0) {
146 		PMD_DRV_LOG(ERR,
147 			"only 32 bit features are allowed for legacy virtio!");
148 		return;
149 	}
150 	rte_pci_ioport_write(VTPCI_IO(hw), &features, 4,
151 		VIRTIO_PCI_GUEST_FEATURES);
152 }
153 
154 static uint8_t
155 legacy_get_status(struct virtio_hw *hw)
156 {
157 	uint8_t dst;
158 
159 	rte_pci_ioport_read(VTPCI_IO(hw), &dst, 1, VIRTIO_PCI_STATUS);
160 	return dst;
161 }
162 
163 static void
164 legacy_set_status(struct virtio_hw *hw, uint8_t status)
165 {
166 	rte_pci_ioport_write(VTPCI_IO(hw), &status, 1, VIRTIO_PCI_STATUS);
167 }
168 
169 static uint8_t
170 legacy_get_isr(struct virtio_hw *hw)
171 {
172 	uint8_t dst;
173 
174 	rte_pci_ioport_read(VTPCI_IO(hw), &dst, 1, VIRTIO_PCI_ISR);
175 	return dst;
176 }
177 
178 /* Enable one vector (0) for Link State Intrerrupt */
179 static uint16_t
180 legacy_set_config_irq(struct virtio_hw *hw, uint16_t vec)
181 {
182 	uint16_t dst;
183 
184 	rte_pci_ioport_write(VTPCI_IO(hw), &vec, 2, VIRTIO_MSI_CONFIG_VECTOR);
185 	rte_pci_ioport_read(VTPCI_IO(hw), &dst, 2, VIRTIO_MSI_CONFIG_VECTOR);
186 	return dst;
187 }
188 
189 static uint16_t
190 legacy_set_queue_irq(struct virtio_hw *hw, struct virtqueue *vq, uint16_t vec)
191 {
192 	uint16_t dst;
193 
194 	rte_pci_ioport_write(VTPCI_IO(hw), &vq->vq_queue_index, 2,
195 		VIRTIO_PCI_QUEUE_SEL);
196 	rte_pci_ioport_write(VTPCI_IO(hw), &vec, 2, VIRTIO_MSI_QUEUE_VECTOR);
197 	rte_pci_ioport_read(VTPCI_IO(hw), &dst, 2, VIRTIO_MSI_QUEUE_VECTOR);
198 	return dst;
199 }
200 
201 static uint16_t
202 legacy_get_queue_num(struct virtio_hw *hw, uint16_t queue_id)
203 {
204 	uint16_t dst;
205 
206 	rte_pci_ioport_write(VTPCI_IO(hw), &queue_id, 2, VIRTIO_PCI_QUEUE_SEL);
207 	rte_pci_ioport_read(VTPCI_IO(hw), &dst, 2, VIRTIO_PCI_QUEUE_NUM);
208 	return dst;
209 }
210 
211 static int
212 legacy_setup_queue(struct virtio_hw *hw, struct virtqueue *vq)
213 {
214 	uint32_t src;
215 
216 	if (!check_vq_phys_addr_ok(vq))
217 		return -1;
218 
219 	rte_pci_ioport_write(VTPCI_IO(hw), &vq->vq_queue_index, 2,
220 		VIRTIO_PCI_QUEUE_SEL);
221 	src = vq->vq_ring_mem >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
222 	rte_pci_ioport_write(VTPCI_IO(hw), &src, 4, VIRTIO_PCI_QUEUE_PFN);
223 
224 	return 0;
225 }
226 
227 static void
228 legacy_del_queue(struct virtio_hw *hw, struct virtqueue *vq)
229 {
230 	uint32_t src = 0;
231 
232 	rte_pci_ioport_write(VTPCI_IO(hw), &vq->vq_queue_index, 2,
233 		VIRTIO_PCI_QUEUE_SEL);
234 	rte_pci_ioport_write(VTPCI_IO(hw), &src, 4, VIRTIO_PCI_QUEUE_PFN);
235 }
236 
237 static void
238 legacy_notify_queue(struct virtio_hw *hw, struct virtqueue *vq)
239 {
240 	rte_pci_ioport_write(VTPCI_IO(hw), &vq->vq_queue_index, 2,
241 		VIRTIO_PCI_QUEUE_NOTIFY);
242 }
243 
244 const struct virtio_pci_ops legacy_ops = {
245 	.read_dev_cfg	= legacy_read_dev_config,
246 	.write_dev_cfg	= legacy_write_dev_config,
247 	.get_status	= legacy_get_status,
248 	.set_status	= legacy_set_status,
249 	.get_features	= legacy_get_features,
250 	.set_features	= legacy_set_features,
251 	.get_isr	= legacy_get_isr,
252 	.set_config_irq	= legacy_set_config_irq,
253 	.set_queue_irq  = legacy_set_queue_irq,
254 	.get_queue_num	= legacy_get_queue_num,
255 	.setup_queue	= legacy_setup_queue,
256 	.del_queue	= legacy_del_queue,
257 	.notify_queue	= legacy_notify_queue,
258 };
259 
260 static inline void
261 io_write64_twopart(uint64_t val, uint32_t *lo, uint32_t *hi)
262 {
263 	rte_write32(val & ((1ULL << 32) - 1), lo);
264 	rte_write32(val >> 32,		     hi);
265 }
266 
267 static void
268 modern_read_dev_config(struct virtio_hw *hw, size_t offset,
269 		       void *dst, int length)
270 {
271 	int i;
272 	uint8_t *p;
273 	uint8_t old_gen, new_gen;
274 
275 	do {
276 		old_gen = rte_read8(&hw->common_cfg->config_generation);
277 
278 		p = dst;
279 		for (i = 0;  i < length; i++)
280 			*p++ = rte_read8((uint8_t *)hw->dev_cfg + offset + i);
281 
282 		new_gen = rte_read8(&hw->common_cfg->config_generation);
283 	} while (old_gen != new_gen);
284 }
285 
286 static void
287 modern_write_dev_config(struct virtio_hw *hw, size_t offset,
288 			const void *src, int length)
289 {
290 	int i;
291 	const uint8_t *p = src;
292 
293 	for (i = 0;  i < length; i++)
294 		rte_write8((*p++), (((uint8_t *)hw->dev_cfg) + offset + i));
295 }
296 
297 static uint64_t
298 modern_get_features(struct virtio_hw *hw)
299 {
300 	uint32_t features_lo, features_hi;
301 
302 	rte_write32(0, &hw->common_cfg->device_feature_select);
303 	features_lo = rte_read32(&hw->common_cfg->device_feature);
304 
305 	rte_write32(1, &hw->common_cfg->device_feature_select);
306 	features_hi = rte_read32(&hw->common_cfg->device_feature);
307 
308 	return ((uint64_t)features_hi << 32) | features_lo;
309 }
310 
311 static void
312 modern_set_features(struct virtio_hw *hw, uint64_t features)
313 {
314 	rte_write32(0, &hw->common_cfg->guest_feature_select);
315 	rte_write32(features & ((1ULL << 32) - 1),
316 		    &hw->common_cfg->guest_feature);
317 
318 	rte_write32(1, &hw->common_cfg->guest_feature_select);
319 	rte_write32(features >> 32,
320 		    &hw->common_cfg->guest_feature);
321 }
322 
323 static uint8_t
324 modern_get_status(struct virtio_hw *hw)
325 {
326 	return rte_read8(&hw->common_cfg->device_status);
327 }
328 
329 static void
330 modern_set_status(struct virtio_hw *hw, uint8_t status)
331 {
332 	rte_write8(status, &hw->common_cfg->device_status);
333 }
334 
335 static uint8_t
336 modern_get_isr(struct virtio_hw *hw)
337 {
338 	return rte_read8(hw->isr);
339 }
340 
341 static uint16_t
342 modern_set_config_irq(struct virtio_hw *hw, uint16_t vec)
343 {
344 	rte_write16(vec, &hw->common_cfg->msix_config);
345 	return rte_read16(&hw->common_cfg->msix_config);
346 }
347 
348 static uint16_t
349 modern_set_queue_irq(struct virtio_hw *hw, struct virtqueue *vq, uint16_t vec)
350 {
351 	rte_write16(vq->vq_queue_index, &hw->common_cfg->queue_select);
352 	rte_write16(vec, &hw->common_cfg->queue_msix_vector);
353 	return rte_read16(&hw->common_cfg->queue_msix_vector);
354 }
355 
356 static uint16_t
357 modern_get_queue_num(struct virtio_hw *hw, uint16_t queue_id)
358 {
359 	rte_write16(queue_id, &hw->common_cfg->queue_select);
360 	return rte_read16(&hw->common_cfg->queue_size);
361 }
362 
363 static int
364 modern_setup_queue(struct virtio_hw *hw, struct virtqueue *vq)
365 {
366 	uint64_t desc_addr, avail_addr, used_addr;
367 	uint16_t notify_off;
368 
369 	if (!check_vq_phys_addr_ok(vq))
370 		return -1;
371 
372 	desc_addr = vq->vq_ring_mem;
373 	avail_addr = desc_addr + vq->vq_nentries * sizeof(struct vring_desc);
374 	used_addr = RTE_ALIGN_CEIL(avail_addr + offsetof(struct vring_avail,
375 							 ring[vq->vq_nentries]),
376 				   VIRTIO_PCI_VRING_ALIGN);
377 
378 	rte_write16(vq->vq_queue_index, &hw->common_cfg->queue_select);
379 
380 	io_write64_twopart(desc_addr, &hw->common_cfg->queue_desc_lo,
381 				      &hw->common_cfg->queue_desc_hi);
382 	io_write64_twopart(avail_addr, &hw->common_cfg->queue_avail_lo,
383 				       &hw->common_cfg->queue_avail_hi);
384 	io_write64_twopart(used_addr, &hw->common_cfg->queue_used_lo,
385 				      &hw->common_cfg->queue_used_hi);
386 
387 	notify_off = rte_read16(&hw->common_cfg->queue_notify_off);
388 	vq->notify_addr = (void *)((uint8_t *)hw->notify_base +
389 				notify_off * hw->notify_off_multiplier);
390 
391 	rte_write16(1, &hw->common_cfg->queue_enable);
392 
393 	PMD_INIT_LOG(DEBUG, "queue %u addresses:", vq->vq_queue_index);
394 	PMD_INIT_LOG(DEBUG, "\t desc_addr: %" PRIx64, desc_addr);
395 	PMD_INIT_LOG(DEBUG, "\t aval_addr: %" PRIx64, avail_addr);
396 	PMD_INIT_LOG(DEBUG, "\t used_addr: %" PRIx64, used_addr);
397 	PMD_INIT_LOG(DEBUG, "\t notify addr: %p (notify offset: %u)",
398 		vq->notify_addr, notify_off);
399 
400 	return 0;
401 }
402 
403 static void
404 modern_del_queue(struct virtio_hw *hw, struct virtqueue *vq)
405 {
406 	rte_write16(vq->vq_queue_index, &hw->common_cfg->queue_select);
407 
408 	io_write64_twopart(0, &hw->common_cfg->queue_desc_lo,
409 				  &hw->common_cfg->queue_desc_hi);
410 	io_write64_twopart(0, &hw->common_cfg->queue_avail_lo,
411 				  &hw->common_cfg->queue_avail_hi);
412 	io_write64_twopart(0, &hw->common_cfg->queue_used_lo,
413 				  &hw->common_cfg->queue_used_hi);
414 
415 	rte_write16(0, &hw->common_cfg->queue_enable);
416 }
417 
418 static void
419 modern_notify_queue(struct virtio_hw *hw __rte_unused, struct virtqueue *vq)
420 {
421 	rte_write16(vq->vq_queue_index, vq->notify_addr);
422 }
423 
424 const struct virtio_pci_ops modern_ops = {
425 	.read_dev_cfg	= modern_read_dev_config,
426 	.write_dev_cfg	= modern_write_dev_config,
427 	.get_status	= modern_get_status,
428 	.set_status	= modern_set_status,
429 	.get_features	= modern_get_features,
430 	.set_features	= modern_set_features,
431 	.get_isr	= modern_get_isr,
432 	.set_config_irq	= modern_set_config_irq,
433 	.set_queue_irq  = modern_set_queue_irq,
434 	.get_queue_num	= modern_get_queue_num,
435 	.setup_queue	= modern_setup_queue,
436 	.del_queue	= modern_del_queue,
437 	.notify_queue	= modern_notify_queue,
438 };
439 
440 
441 void
442 vtpci_read_dev_config(struct virtio_hw *hw, size_t offset,
443 		      void *dst, int length)
444 {
445 	VTPCI_OPS(hw)->read_dev_cfg(hw, offset, dst, length);
446 }
447 
448 void
449 vtpci_write_dev_config(struct virtio_hw *hw, size_t offset,
450 		       const void *src, int length)
451 {
452 	VTPCI_OPS(hw)->write_dev_cfg(hw, offset, src, length);
453 }
454 
455 uint64_t
456 vtpci_negotiate_features(struct virtio_hw *hw, uint64_t host_features)
457 {
458 	uint64_t features;
459 
460 	/*
461 	 * Limit negotiated features to what the driver, virtqueue, and
462 	 * host all support.
463 	 */
464 	features = host_features & hw->guest_features;
465 	VTPCI_OPS(hw)->set_features(hw, features);
466 
467 	return features;
468 }
469 
470 void
471 vtpci_reset(struct virtio_hw *hw)
472 {
473 	VTPCI_OPS(hw)->set_status(hw, VIRTIO_CONFIG_STATUS_RESET);
474 	/* flush status write */
475 	VTPCI_OPS(hw)->get_status(hw);
476 }
477 
478 void
479 vtpci_reinit_complete(struct virtio_hw *hw)
480 {
481 	vtpci_set_status(hw, VIRTIO_CONFIG_STATUS_DRIVER_OK);
482 }
483 
484 void
485 vtpci_set_status(struct virtio_hw *hw, uint8_t status)
486 {
487 	if (status != VIRTIO_CONFIG_STATUS_RESET)
488 		status |= VTPCI_OPS(hw)->get_status(hw);
489 
490 	VTPCI_OPS(hw)->set_status(hw, status);
491 }
492 
493 uint8_t
494 vtpci_get_status(struct virtio_hw *hw)
495 {
496 	return VTPCI_OPS(hw)->get_status(hw);
497 }
498 
499 uint8_t
500 vtpci_isr(struct virtio_hw *hw)
501 {
502 	return VTPCI_OPS(hw)->get_isr(hw);
503 }
504 
505 static void *
506 get_cfg_addr(struct rte_pci_device *dev, struct virtio_pci_cap *cap)
507 {
508 	uint8_t  bar    = cap->bar;
509 	uint32_t length = cap->length;
510 	uint32_t offset = cap->offset;
511 	uint8_t *base;
512 
513 	if (bar >= PCI_MAX_RESOURCE) {
514 		PMD_INIT_LOG(ERR, "invalid bar: %u", bar);
515 		return NULL;
516 	}
517 
518 	if (offset + length < offset) {
519 		PMD_INIT_LOG(ERR, "offset(%u) + length(%u) overflows",
520 			offset, length);
521 		return NULL;
522 	}
523 
524 	if (offset + length > dev->mem_resource[bar].len) {
525 		PMD_INIT_LOG(ERR,
526 			"invalid cap: overflows bar space: %u > %" PRIu64,
527 			offset + length, dev->mem_resource[bar].len);
528 		return NULL;
529 	}
530 
531 	base = dev->mem_resource[bar].addr;
532 	if (base == NULL) {
533 		PMD_INIT_LOG(ERR, "bar %u base addr is NULL", bar);
534 		return NULL;
535 	}
536 
537 	return base + offset;
538 }
539 
540 #define PCI_MSIX_ENABLE 0x8000
541 
542 static int
543 virtio_read_caps(struct rte_pci_device *dev, struct virtio_hw *hw)
544 {
545 	uint8_t pos;
546 	struct virtio_pci_cap cap;
547 	int ret;
548 
549 	if (rte_pci_map_device(dev)) {
550 		PMD_INIT_LOG(DEBUG, "failed to map pci device!");
551 		return -1;
552 	}
553 
554 	ret = rte_pci_read_config(dev, &pos, 1, PCI_CAPABILITY_LIST);
555 	if (ret != 1) {
556 		PMD_INIT_LOG(DEBUG,
557 			     "failed to read pci capability list, ret %d", ret);
558 		return -1;
559 	}
560 
561 	while (pos) {
562 		ret = rte_pci_read_config(dev, &cap, 2, pos);
563 		if (ret != 2) {
564 			PMD_INIT_LOG(DEBUG,
565 				     "failed to read pci cap at pos: %x ret %d",
566 				     pos, ret);
567 			break;
568 		}
569 
570 		if (cap.cap_vndr == PCI_CAP_ID_MSIX) {
571 			/* Transitional devices would also have this capability,
572 			 * that's why we also check if msix is enabled.
573 			 * 1st byte is cap ID; 2nd byte is the position of next
574 			 * cap; next two bytes are the flags.
575 			 */
576 			uint16_t flags;
577 
578 			ret = rte_pci_read_config(dev, &flags, sizeof(flags),
579 					pos + 2);
580 			if (ret != sizeof(flags)) {
581 				PMD_INIT_LOG(DEBUG,
582 					     "failed to read pci cap at pos:"
583 					     " %x ret %d", pos + 2, ret);
584 				break;
585 			}
586 
587 			if (flags & PCI_MSIX_ENABLE)
588 				hw->use_msix = VIRTIO_MSIX_ENABLED;
589 			else
590 				hw->use_msix = VIRTIO_MSIX_DISABLED;
591 		}
592 
593 		if (cap.cap_vndr != PCI_CAP_ID_VNDR) {
594 			PMD_INIT_LOG(DEBUG,
595 				"[%2x] skipping non VNDR cap id: %02x",
596 				pos, cap.cap_vndr);
597 			goto next;
598 		}
599 
600 		ret = rte_pci_read_config(dev, &cap, sizeof(cap), pos);
601 		if (ret != sizeof(cap)) {
602 			PMD_INIT_LOG(DEBUG,
603 				     "failed to read pci cap at pos: %x ret %d",
604 				     pos, ret);
605 			break;
606 		}
607 
608 		PMD_INIT_LOG(DEBUG,
609 			"[%2x] cfg type: %u, bar: %u, offset: %04x, len: %u",
610 			pos, cap.cfg_type, cap.bar, cap.offset, cap.length);
611 
612 		switch (cap.cfg_type) {
613 		case VIRTIO_PCI_CAP_COMMON_CFG:
614 			hw->common_cfg = get_cfg_addr(dev, &cap);
615 			break;
616 		case VIRTIO_PCI_CAP_NOTIFY_CFG:
617 			ret = rte_pci_read_config(dev,
618 					&hw->notify_off_multiplier,
619 					4, pos + sizeof(cap));
620 			if (ret != 4)
621 				PMD_INIT_LOG(DEBUG,
622 					"failed to read notify_off_multiplier, ret %d",
623 					ret);
624 			else
625 				hw->notify_base = get_cfg_addr(dev, &cap);
626 			break;
627 		case VIRTIO_PCI_CAP_DEVICE_CFG:
628 			hw->dev_cfg = get_cfg_addr(dev, &cap);
629 			break;
630 		case VIRTIO_PCI_CAP_ISR_CFG:
631 			hw->isr = get_cfg_addr(dev, &cap);
632 			break;
633 		}
634 
635 next:
636 		pos = cap.cap_next;
637 	}
638 
639 	if (hw->common_cfg == NULL || hw->notify_base == NULL ||
640 	    hw->dev_cfg == NULL    || hw->isr == NULL) {
641 		PMD_INIT_LOG(INFO, "no modern virtio pci device found.");
642 		return -1;
643 	}
644 
645 	PMD_INIT_LOG(INFO, "found modern virtio pci device.");
646 
647 	PMD_INIT_LOG(DEBUG, "common cfg mapped at: %p", hw->common_cfg);
648 	PMD_INIT_LOG(DEBUG, "device cfg mapped at: %p", hw->dev_cfg);
649 	PMD_INIT_LOG(DEBUG, "isr cfg mapped at: %p", hw->isr);
650 	PMD_INIT_LOG(DEBUG, "notify base: %p, notify off multiplier: %u",
651 		hw->notify_base, hw->notify_off_multiplier);
652 
653 	return 0;
654 }
655 
656 /*
657  * Return -1:
658  *   if there is error mapping with VFIO/UIO.
659  *   if port map error when driver type is KDRV_NONE.
660  *   if whitelisted but driver type is KDRV_UNKNOWN.
661  * Return 1 if kernel driver is managing the device.
662  * Return 0 on success.
663  */
664 int
665 vtpci_init(struct rte_pci_device *dev, struct virtio_hw *hw)
666 {
667 	/*
668 	 * Try if we can succeed reading virtio pci caps, which exists
669 	 * only on modern pci device. If failed, we fallback to legacy
670 	 * virtio handling.
671 	 */
672 	if (virtio_read_caps(dev, hw) == 0) {
673 		PMD_INIT_LOG(INFO, "modern virtio pci detected.");
674 		virtio_hw_internal[hw->port_id].vtpci_ops = &modern_ops;
675 		hw->modern = 1;
676 		return 0;
677 	}
678 
679 	PMD_INIT_LOG(INFO, "trying with legacy virtio pci.");
680 	if (rte_pci_ioport_map(dev, 0, VTPCI_IO(hw)) < 0) {
681 		if (dev->kdrv == RTE_KDRV_UNKNOWN &&
682 		    (!dev->device.devargs ||
683 		     dev->device.devargs->bus !=
684 		     rte_bus_find_by_name("pci"))) {
685 			PMD_INIT_LOG(INFO,
686 				"skip kernel managed virtio device.");
687 			return 1;
688 		}
689 		return -1;
690 	}
691 
692 	virtio_hw_internal[hw->port_id].vtpci_ops = &legacy_ops;
693 	hw->modern   = 0;
694 
695 	return 0;
696 }
697 
698 enum virtio_msix_status
699 vtpci_msix_detect(struct rte_pci_device *dev)
700 {
701 	uint8_t pos;
702 	int ret;
703 
704 	ret = rte_pci_read_config(dev, &pos, 1, PCI_CAPABILITY_LIST);
705 	if (ret != 1) {
706 		PMD_INIT_LOG(DEBUG,
707 			     "failed to read pci capability list, ret %d", ret);
708 		return VIRTIO_MSIX_NONE;
709 	}
710 
711 	while (pos) {
712 		uint8_t cap[2];
713 
714 		ret = rte_pci_read_config(dev, cap, sizeof(cap), pos);
715 		if (ret != sizeof(cap)) {
716 			PMD_INIT_LOG(DEBUG,
717 				     "failed to read pci cap at pos: %x ret %d",
718 				     pos, ret);
719 			break;
720 		}
721 
722 		if (cap[0] == PCI_CAP_ID_MSIX) {
723 			uint16_t flags;
724 
725 			ret = rte_pci_read_config(dev, &flags, sizeof(flags),
726 					pos + sizeof(cap));
727 			if (ret != sizeof(flags)) {
728 				PMD_INIT_LOG(DEBUG,
729 					     "failed to read pci cap at pos:"
730 					     " %x ret %d", pos + 2, ret);
731 				break;
732 			}
733 
734 			if (flags & PCI_MSIX_ENABLE)
735 				return VIRTIO_MSIX_ENABLED;
736 			else
737 				return VIRTIO_MSIX_DISABLED;
738 		}
739 
740 		pos = cap[1];
741 	}
742 
743 	return VIRTIO_MSIX_NONE;
744 }
745