xref: /dpdk/drivers/net/virtio/virtqueue.h (revision b53d106d34b5c638f5a2cbdfee0da5bd42d4383f)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2014 Intel Corporation
3  */
4 
5 #ifndef _VIRTQUEUE_H_
6 #define _VIRTQUEUE_H_
7 
8 #include <stdint.h>
9 
10 #include <rte_atomic.h>
11 #include <rte_memory.h>
12 #include <rte_mempool.h>
13 #include <rte_net.h>
14 
15 #include "virtio.h"
16 #include "virtio_ring.h"
17 #include "virtio_logs.h"
18 #include "virtio_rxtx.h"
19 
20 struct rte_mbuf;
21 
22 #define DEFAULT_TX_FREE_THRESH 32
23 #define DEFAULT_RX_FREE_THRESH 32
24 
25 #define VIRTIO_MBUF_BURST_SZ 64
26 /*
27  * Per virtio_ring.h in Linux.
28  *     For virtio_pci on SMP, we don't need to order with respect to MMIO
29  *     accesses through relaxed memory I/O windows, so thread_fence is
30  *     sufficient.
31  *
32  *     For using virtio to talk to real devices (eg. vDPA) we do need real
33  *     barriers.
34  */
35 static inline void
36 virtio_mb(uint8_t weak_barriers)
37 {
38 	if (weak_barriers)
39 		rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
40 	else
41 		rte_mb();
42 }
43 
44 static inline void
45 virtio_rmb(uint8_t weak_barriers)
46 {
47 	if (weak_barriers)
48 		rte_atomic_thread_fence(__ATOMIC_ACQUIRE);
49 	else
50 		rte_io_rmb();
51 }
52 
53 static inline void
54 virtio_wmb(uint8_t weak_barriers)
55 {
56 	if (weak_barriers)
57 		rte_atomic_thread_fence(__ATOMIC_RELEASE);
58 	else
59 		rte_io_wmb();
60 }
61 
62 static inline uint16_t
63 virtqueue_fetch_flags_packed(struct vring_packed_desc *dp,
64 			      uint8_t weak_barriers)
65 {
66 	uint16_t flags;
67 
68 	if (weak_barriers) {
69 /* x86 prefers to using rte_io_rmb over __atomic_load_n as it reports
70  * a better perf(~1.5%), which comes from the saved branch by the compiler.
71  * The if and else branch are identical  on the platforms except Arm.
72  */
73 #ifdef RTE_ARCH_ARM
74 		flags = __atomic_load_n(&dp->flags, __ATOMIC_ACQUIRE);
75 #else
76 		flags = dp->flags;
77 		rte_io_rmb();
78 #endif
79 	} else {
80 		flags = dp->flags;
81 		rte_io_rmb();
82 	}
83 
84 	return flags;
85 }
86 
87 static inline void
88 virtqueue_store_flags_packed(struct vring_packed_desc *dp,
89 			      uint16_t flags, uint8_t weak_barriers)
90 {
91 	if (weak_barriers) {
92 /* x86 prefers to using rte_io_wmb over __atomic_store_n as it reports
93  * a better perf(~1.5%), which comes from the saved branch by the compiler.
94  * The if and else branch are identical on the platforms except Arm.
95  */
96 #ifdef RTE_ARCH_ARM
97 		__atomic_store_n(&dp->flags, flags, __ATOMIC_RELEASE);
98 #else
99 		rte_io_wmb();
100 		dp->flags = flags;
101 #endif
102 	} else {
103 		rte_io_wmb();
104 		dp->flags = flags;
105 	}
106 }
107 
108 #ifdef RTE_PMD_PACKET_PREFETCH
109 #define rte_packet_prefetch(p)  rte_prefetch1(p)
110 #else
111 #define rte_packet_prefetch(p)  do {} while(0)
112 #endif
113 
114 #define VIRTQUEUE_MAX_NAME_SZ 32
115 
116 /**
117  * Return the IOVA (or virtual address in case of virtio-user) of mbuf
118  * data buffer.
119  *
120  * The address is firstly casted to the word size (sizeof(uintptr_t))
121  * before casting it to uint64_t. This is to make it work with different
122  * combination of word size (64 bit and 32 bit) and virtio device
123  * (virtio-pci and virtio-user).
124  */
125 #define VIRTIO_MBUF_ADDR(mb, vq) \
126 	((uint64_t)(*(uintptr_t *)((uintptr_t)(mb) + (vq)->mbuf_addr_offset)))
127 
128 /**
129  * Return the physical address (or virtual address in case of
130  * virtio-user) of mbuf data buffer, taking care of mbuf data offset
131  */
132 #define VIRTIO_MBUF_DATA_DMA_ADDR(mb, vq) \
133 	(VIRTIO_MBUF_ADDR(mb, vq) + (mb)->data_off)
134 
135 #define VTNET_SQ_RQ_QUEUE_IDX 0
136 #define VTNET_SQ_TQ_QUEUE_IDX 1
137 #define VTNET_SQ_CQ_QUEUE_IDX 2
138 
139 enum { VTNET_RQ = 0, VTNET_TQ = 1, VTNET_CQ = 2 };
140 /**
141  * The maximum virtqueue size is 2^15. Use that value as the end of
142  * descriptor chain terminator since it will never be a valid index
143  * in the descriptor table. This is used to verify we are correctly
144  * handling vq_free_cnt.
145  */
146 #define VQ_RING_DESC_CHAIN_END 32768
147 
148 /**
149  * Control the RX mode, ie. promiscuous, allmulti, etc...
150  * All commands require an "out" sg entry containing a 1 byte
151  * state value, zero = disable, non-zero = enable.  Commands
152  * 0 and 1 are supported with the VIRTIO_NET_F_CTRL_RX feature.
153  * Commands 2-5 are added with VIRTIO_NET_F_CTRL_RX_EXTRA.
154  */
155 #define VIRTIO_NET_CTRL_RX              0
156 #define VIRTIO_NET_CTRL_RX_PROMISC      0
157 #define VIRTIO_NET_CTRL_RX_ALLMULTI     1
158 #define VIRTIO_NET_CTRL_RX_ALLUNI       2
159 #define VIRTIO_NET_CTRL_RX_NOMULTI      3
160 #define VIRTIO_NET_CTRL_RX_NOUNI        4
161 #define VIRTIO_NET_CTRL_RX_NOBCAST      5
162 
163 /**
164  * Control the MAC
165  *
166  * The MAC filter table is managed by the hypervisor, the guest should
167  * assume the size is infinite.  Filtering should be considered
168  * non-perfect, ie. based on hypervisor resources, the guest may
169  * received packets from sources not specified in the filter list.
170  *
171  * In addition to the class/cmd header, the TABLE_SET command requires
172  * two out scatterlists.  Each contains a 4 byte count of entries followed
173  * by a concatenated byte stream of the ETH_ALEN MAC addresses.  The
174  * first sg list contains unicast addresses, the second is for multicast.
175  * This functionality is present if the VIRTIO_NET_F_CTRL_RX feature
176  * is available.
177  *
178  * The ADDR_SET command requests one out scatterlist, it contains a
179  * 6 bytes MAC address. This functionality is present if the
180  * VIRTIO_NET_F_CTRL_MAC_ADDR feature is available.
181  */
182 struct virtio_net_ctrl_mac {
183 	uint32_t entries;
184 	uint8_t macs[][RTE_ETHER_ADDR_LEN];
185 } __rte_packed;
186 
187 #define VIRTIO_NET_CTRL_MAC    1
188 #define VIRTIO_NET_CTRL_MAC_TABLE_SET        0
189 #define VIRTIO_NET_CTRL_MAC_ADDR_SET         1
190 
191 /**
192  * Control VLAN filtering
193  *
194  * The VLAN filter table is controlled via a simple ADD/DEL interface.
195  * VLAN IDs not added may be filtered by the hypervisor.  Del is the
196  * opposite of add.  Both commands expect an out entry containing a 2
197  * byte VLAN ID.  VLAN filtering is available with the
198  * VIRTIO_NET_F_CTRL_VLAN feature bit.
199  */
200 #define VIRTIO_NET_CTRL_VLAN     2
201 #define VIRTIO_NET_CTRL_VLAN_ADD 0
202 #define VIRTIO_NET_CTRL_VLAN_DEL 1
203 
204 /**
205  * RSS control
206  *
207  * The RSS feature configuration message is sent by the driver when
208  * VIRTIO_NET_F_RSS has been negotiated. It provides the device with
209  * hash types to use, hash key and indirection table. In this
210  * implementation, the driver only supports fixed key length (40B)
211  * and indirection table size (128 entries).
212  */
213 #define VIRTIO_NET_RSS_RETA_SIZE 128
214 #define VIRTIO_NET_RSS_KEY_SIZE 40
215 
216 struct virtio_net_ctrl_rss {
217 	uint32_t hash_types;
218 	uint16_t indirection_table_mask;
219 	uint16_t unclassified_queue;
220 	uint16_t indirection_table[VIRTIO_NET_RSS_RETA_SIZE];
221 	uint16_t max_tx_vq;
222 	uint8_t hash_key_length;
223 	uint8_t hash_key_data[VIRTIO_NET_RSS_KEY_SIZE];
224 };
225 
226 /*
227  * Control link announce acknowledgement
228  *
229  * The command VIRTIO_NET_CTRL_ANNOUNCE_ACK is used to indicate that
230  * driver has recevied the notification; device would clear the
231  * VIRTIO_NET_S_ANNOUNCE bit in the status field after it receives
232  * this command.
233  */
234 #define VIRTIO_NET_CTRL_ANNOUNCE     3
235 #define VIRTIO_NET_CTRL_ANNOUNCE_ACK 0
236 
237 struct virtio_net_ctrl_hdr {
238 	uint8_t class;
239 	uint8_t cmd;
240 } __rte_packed;
241 
242 typedef uint8_t virtio_net_ctrl_ack;
243 
244 #define VIRTIO_NET_OK     0
245 #define VIRTIO_NET_ERR    1
246 
247 #define VIRTIO_MAX_CTRL_DATA 2048
248 
249 struct virtio_pmd_ctrl {
250 	struct virtio_net_ctrl_hdr hdr;
251 	virtio_net_ctrl_ack status;
252 	uint8_t data[VIRTIO_MAX_CTRL_DATA];
253 };
254 
255 struct vq_desc_extra {
256 	void *cookie;
257 	uint16_t ndescs;
258 	uint16_t next;
259 };
260 
261 #define virtnet_rxq_to_vq(rxvq) container_of(rxvq, struct virtqueue, rxq)
262 #define virtnet_txq_to_vq(txvq) container_of(txvq, struct virtqueue, txq)
263 #define virtnet_cq_to_vq(cvq) container_of(cvq, struct virtqueue, cq)
264 
265 struct virtqueue {
266 	struct virtio_hw  *hw; /**< virtio_hw structure pointer. */
267 	union {
268 		struct {
269 			/**< vring keeping desc, used and avail */
270 			struct vring ring;
271 		} vq_split;
272 
273 		struct {
274 			/**< vring keeping descs and events */
275 			struct vring_packed ring;
276 			bool used_wrap_counter;
277 			uint16_t cached_flags; /**< cached flags for descs */
278 			uint16_t event_flags_shadow;
279 		} vq_packed;
280 	};
281 
282 	uint16_t vq_used_cons_idx; /**< last consumed descriptor */
283 	uint16_t vq_nentries;  /**< vring desc numbers */
284 	uint16_t vq_free_cnt;  /**< num of desc available */
285 	uint16_t vq_avail_idx; /**< sync until needed */
286 	uint16_t vq_free_thresh; /**< free threshold */
287 
288 	/**
289 	 * Head of the free chain in the descriptor table. If
290 	 * there are no free descriptors, this will be set to
291 	 * VQ_RING_DESC_CHAIN_END.
292 	 */
293 	uint16_t  vq_desc_head_idx;
294 	uint16_t  vq_desc_tail_idx;
295 	uint16_t  vq_queue_index;   /**< PCI queue index */
296 
297 	void *vq_ring_virt_mem;  /**< linear address of vring*/
298 	unsigned int vq_ring_size;
299 	uint16_t mbuf_addr_offset;
300 
301 	union {
302 		struct virtnet_rx rxq;
303 		struct virtnet_tx txq;
304 		struct virtnet_ctl cq;
305 	};
306 
307 	rte_iova_t vq_ring_mem; /**< physical address of vring,
308 	                         * or virtual address for virtio_user. */
309 
310 	uint16_t  *notify_addr;
311 	struct rte_mbuf **sw_ring;  /**< RX software ring. */
312 	struct vq_desc_extra vq_descx[0];
313 };
314 
315 /* If multiqueue is provided by host, then we suppport it. */
316 #define VIRTIO_NET_CTRL_MQ   4
317 
318 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET        0
319 #define VIRTIO_NET_CTRL_MQ_RSS_CONFIG          1
320 
321 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN        1
322 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX        0x8000
323 
324 /**
325  * This is the first element of the scatter-gather list.  If you don't
326  * specify GSO or CSUM features, you can simply ignore the header.
327  */
328 struct virtio_net_hdr {
329 #define VIRTIO_NET_HDR_F_NEEDS_CSUM 1    /**< Use csum_start,csum_offset*/
330 #define VIRTIO_NET_HDR_F_DATA_VALID 2    /**< Checksum is valid */
331 	uint8_t flags;
332 #define VIRTIO_NET_HDR_GSO_NONE     0    /**< Not a GSO frame */
333 #define VIRTIO_NET_HDR_GSO_TCPV4    1    /**< GSO frame, IPv4 TCP (TSO) */
334 #define VIRTIO_NET_HDR_GSO_UDP      3    /**< GSO frame, IPv4 UDP (UFO) */
335 #define VIRTIO_NET_HDR_GSO_TCPV6    4    /**< GSO frame, IPv6 TCP */
336 #define VIRTIO_NET_HDR_GSO_ECN      0x80 /**< TCP has ECN set */
337 	uint8_t gso_type;
338 	uint16_t hdr_len;     /**< Ethernet + IP + tcp/udp hdrs */
339 	uint16_t gso_size;    /**< Bytes to append to hdr_len per frame */
340 	uint16_t csum_start;  /**< Position to start checksumming from */
341 	uint16_t csum_offset; /**< Offset after that to place checksum */
342 };
343 
344 /**
345  * This is the version of the header to use when the MRG_RXBUF
346  * feature has been negotiated.
347  */
348 struct virtio_net_hdr_mrg_rxbuf {
349 	struct   virtio_net_hdr hdr;
350 	uint16_t num_buffers; /**< Number of merged rx buffers */
351 };
352 
353 /* Region reserved to allow for transmit header and indirect ring */
354 #define VIRTIO_MAX_TX_INDIRECT 8
355 struct virtio_tx_region {
356 	struct virtio_net_hdr_mrg_rxbuf tx_hdr;
357 	union {
358 		struct vring_desc tx_indir[VIRTIO_MAX_TX_INDIRECT];
359 		struct vring_packed_desc
360 			tx_packed_indir[VIRTIO_MAX_TX_INDIRECT];
361 	} __rte_aligned(16);
362 };
363 
364 static inline int
365 desc_is_used(struct vring_packed_desc *desc, struct virtqueue *vq)
366 {
367 	uint16_t used, avail, flags;
368 
369 	flags = virtqueue_fetch_flags_packed(desc, vq->hw->weak_barriers);
370 	used = !!(flags & VRING_PACKED_DESC_F_USED);
371 	avail = !!(flags & VRING_PACKED_DESC_F_AVAIL);
372 
373 	return avail == used && used == vq->vq_packed.used_wrap_counter;
374 }
375 
376 static inline void
377 vring_desc_init_packed(struct virtqueue *vq, int n)
378 {
379 	int i;
380 	for (i = 0; i < n - 1; i++) {
381 		vq->vq_packed.ring.desc[i].id = i;
382 		vq->vq_descx[i].next = i + 1;
383 	}
384 	vq->vq_packed.ring.desc[i].id = i;
385 	vq->vq_descx[i].next = VQ_RING_DESC_CHAIN_END;
386 }
387 
388 /* Chain all the descriptors in the ring with an END */
389 static inline void
390 vring_desc_init_split(struct vring_desc *dp, uint16_t n)
391 {
392 	uint16_t i;
393 
394 	for (i = 0; i < n - 1; i++)
395 		dp[i].next = (uint16_t)(i + 1);
396 	dp[i].next = VQ_RING_DESC_CHAIN_END;
397 }
398 
399 static inline void
400 vring_desc_init_indirect_packed(struct vring_packed_desc *dp, int n)
401 {
402 	int i;
403 	for (i = 0; i < n; i++) {
404 		dp[i].id = (uint16_t)i;
405 		dp[i].flags = VRING_DESC_F_WRITE;
406 	}
407 }
408 
409 /**
410  * Tell the backend not to interrupt us. Implementation for packed virtqueues.
411  */
412 static inline void
413 virtqueue_disable_intr_packed(struct virtqueue *vq)
414 {
415 	if (vq->vq_packed.event_flags_shadow != RING_EVENT_FLAGS_DISABLE) {
416 		vq->vq_packed.event_flags_shadow = RING_EVENT_FLAGS_DISABLE;
417 		vq->vq_packed.ring.driver->desc_event_flags =
418 			vq->vq_packed.event_flags_shadow;
419 	}
420 }
421 
422 /**
423  * Tell the backend not to interrupt us. Implementation for split virtqueues.
424  */
425 static inline void
426 virtqueue_disable_intr_split(struct virtqueue *vq)
427 {
428 	vq->vq_split.ring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
429 }
430 
431 /**
432  * Tell the backend not to interrupt us.
433  */
434 static inline void
435 virtqueue_disable_intr(struct virtqueue *vq)
436 {
437 	if (virtio_with_packed_queue(vq->hw))
438 		virtqueue_disable_intr_packed(vq);
439 	else
440 		virtqueue_disable_intr_split(vq);
441 }
442 
443 /**
444  * Tell the backend to interrupt. Implementation for packed virtqueues.
445  */
446 static inline void
447 virtqueue_enable_intr_packed(struct virtqueue *vq)
448 {
449 	if (vq->vq_packed.event_flags_shadow == RING_EVENT_FLAGS_DISABLE) {
450 		vq->vq_packed.event_flags_shadow = RING_EVENT_FLAGS_ENABLE;
451 		vq->vq_packed.ring.driver->desc_event_flags =
452 			vq->vq_packed.event_flags_shadow;
453 	}
454 }
455 
456 /**
457  * Tell the backend to interrupt. Implementation for split virtqueues.
458  */
459 static inline void
460 virtqueue_enable_intr_split(struct virtqueue *vq)
461 {
462 	vq->vq_split.ring.avail->flags &= (~VRING_AVAIL_F_NO_INTERRUPT);
463 }
464 
465 /**
466  * Tell the backend to interrupt us.
467  */
468 static inline void
469 virtqueue_enable_intr(struct virtqueue *vq)
470 {
471 	if (virtio_with_packed_queue(vq->hw))
472 		virtqueue_enable_intr_packed(vq);
473 	else
474 		virtqueue_enable_intr_split(vq);
475 }
476 
477 /**
478  *  Dump virtqueue internal structures, for debug purpose only.
479  */
480 void virtqueue_dump(struct virtqueue *vq);
481 /**
482  *  Get all mbufs to be freed.
483  */
484 struct rte_mbuf *virtqueue_detach_unused(struct virtqueue *vq);
485 
486 /* Flush the elements in the used ring. */
487 void virtqueue_rxvq_flush(struct virtqueue *vq);
488 
489 int virtqueue_rxvq_reset_packed(struct virtqueue *vq);
490 
491 int virtqueue_txvq_reset_packed(struct virtqueue *vq);
492 
493 static inline int
494 virtqueue_full(const struct virtqueue *vq)
495 {
496 	return vq->vq_free_cnt == 0;
497 }
498 
499 static inline int
500 virtio_get_queue_type(struct virtio_hw *hw, uint16_t vq_idx)
501 {
502 	if (vq_idx == hw->max_queue_pairs * 2)
503 		return VTNET_CQ;
504 	else if (vq_idx % 2 == 0)
505 		return VTNET_RQ;
506 	else
507 		return VTNET_TQ;
508 }
509 
510 /* virtqueue_nused has load-acquire or rte_io_rmb insed */
511 static inline uint16_t
512 virtqueue_nused(const struct virtqueue *vq)
513 {
514 	uint16_t idx;
515 
516 	if (vq->hw->weak_barriers) {
517 	/**
518 	 * x86 prefers to using rte_smp_rmb over __atomic_load_n as it
519 	 * reports a slightly better perf, which comes from the saved
520 	 * branch by the compiler.
521 	 * The if and else branches are identical with the smp and io
522 	 * barriers both defined as compiler barriers on x86.
523 	 */
524 #ifdef RTE_ARCH_X86_64
525 		idx = vq->vq_split.ring.used->idx;
526 		rte_smp_rmb();
527 #else
528 		idx = __atomic_load_n(&(vq)->vq_split.ring.used->idx,
529 				__ATOMIC_ACQUIRE);
530 #endif
531 	} else {
532 		idx = vq->vq_split.ring.used->idx;
533 		rte_io_rmb();
534 	}
535 	return idx - vq->vq_used_cons_idx;
536 }
537 
538 void vq_ring_free_chain(struct virtqueue *vq, uint16_t desc_idx);
539 void vq_ring_free_chain_packed(struct virtqueue *vq, uint16_t used_idx);
540 void vq_ring_free_inorder(struct virtqueue *vq, uint16_t desc_idx,
541 			  uint16_t num);
542 
543 static inline void
544 vq_update_avail_idx(struct virtqueue *vq)
545 {
546 	if (vq->hw->weak_barriers) {
547 	/* x86 prefers to using rte_smp_wmb over __atomic_store_n as
548 	 * it reports a slightly better perf, which comes from the
549 	 * saved branch by the compiler.
550 	 * The if and else branches are identical with the smp and
551 	 * io barriers both defined as compiler barriers on x86.
552 	 */
553 #ifdef RTE_ARCH_X86_64
554 		rte_smp_wmb();
555 		vq->vq_split.ring.avail->idx = vq->vq_avail_idx;
556 #else
557 		__atomic_store_n(&vq->vq_split.ring.avail->idx,
558 				 vq->vq_avail_idx, __ATOMIC_RELEASE);
559 #endif
560 	} else {
561 		rte_io_wmb();
562 		vq->vq_split.ring.avail->idx = vq->vq_avail_idx;
563 	}
564 }
565 
566 static inline void
567 vq_update_avail_ring(struct virtqueue *vq, uint16_t desc_idx)
568 {
569 	uint16_t avail_idx;
570 	/*
571 	 * Place the head of the descriptor chain into the next slot and make
572 	 * it usable to the host. The chain is made available now rather than
573 	 * deferring to virtqueue_notify() in the hopes that if the host is
574 	 * currently running on another CPU, we can keep it processing the new
575 	 * descriptor.
576 	 */
577 	avail_idx = (uint16_t)(vq->vq_avail_idx & (vq->vq_nentries - 1));
578 	if (unlikely(vq->vq_split.ring.avail->ring[avail_idx] != desc_idx))
579 		vq->vq_split.ring.avail->ring[avail_idx] = desc_idx;
580 	vq->vq_avail_idx++;
581 }
582 
583 static inline int
584 virtqueue_kick_prepare(struct virtqueue *vq)
585 {
586 	/*
587 	 * Ensure updated avail->idx is visible to vhost before reading
588 	 * the used->flags.
589 	 */
590 	virtio_mb(vq->hw->weak_barriers);
591 	return !(vq->vq_split.ring.used->flags & VRING_USED_F_NO_NOTIFY);
592 }
593 
594 static inline int
595 virtqueue_kick_prepare_packed(struct virtqueue *vq)
596 {
597 	uint16_t flags;
598 
599 	/*
600 	 * Ensure updated data is visible to vhost before reading the flags.
601 	 */
602 	virtio_mb(vq->hw->weak_barriers);
603 	flags = vq->vq_packed.ring.device->desc_event_flags;
604 
605 	return flags != RING_EVENT_FLAGS_DISABLE;
606 }
607 
608 /*
609  * virtqueue_kick_prepare*() or the virtio_wmb() should be called
610  * before this function to be sure that all the data is visible to vhost.
611  */
612 static inline void
613 virtqueue_notify(struct virtqueue *vq)
614 {
615 	VIRTIO_OPS(vq->hw)->notify_queue(vq->hw, vq);
616 }
617 
618 #ifdef RTE_LIBRTE_VIRTIO_DEBUG_DUMP
619 #define VIRTQUEUE_DUMP(vq) do { \
620 	uint16_t used_idx, nused; \
621 	used_idx = __atomic_load_n(&(vq)->vq_split.ring.used->idx, \
622 				   __ATOMIC_RELAXED); \
623 	nused = (uint16_t)(used_idx - (vq)->vq_used_cons_idx); \
624 	if (virtio_with_packed_queue((vq)->hw)) { \
625 		PMD_INIT_LOG(DEBUG, \
626 		"VQ: - size=%d; free=%d; used_cons_idx=%d; avail_idx=%d;" \
627 		" cached_flags=0x%x; used_wrap_counter=%d", \
628 		(vq)->vq_nentries, (vq)->vq_free_cnt, (vq)->vq_used_cons_idx, \
629 		(vq)->vq_avail_idx, (vq)->vq_packed.cached_flags, \
630 		(vq)->vq_packed.used_wrap_counter); \
631 		break; \
632 	} \
633 	PMD_INIT_LOG(DEBUG, \
634 	  "VQ: - size=%d; free=%d; used=%d; desc_head_idx=%d;" \
635 	  " avail.idx=%d; used_cons_idx=%d; used.idx=%d;" \
636 	  " avail.flags=0x%x; used.flags=0x%x", \
637 	  (vq)->vq_nentries, (vq)->vq_free_cnt, nused, (vq)->vq_desc_head_idx, \
638 	  (vq)->vq_split.ring.avail->idx, (vq)->vq_used_cons_idx, \
639 	  __atomic_load_n(&(vq)->vq_split.ring.used->idx, __ATOMIC_RELAXED), \
640 	  (vq)->vq_split.ring.avail->flags, (vq)->vq_split.ring.used->flags); \
641 } while (0)
642 #else
643 #define VIRTQUEUE_DUMP(vq) do { } while (0)
644 #endif
645 
646 /* avoid write operation when necessary, to lessen cache issues */
647 #define ASSIGN_UNLESS_EQUAL(var, val) do {	\
648 	typeof(var) *const var_ = &(var);	\
649 	typeof(val)  const val_ = (val);	\
650 	if (*var_ != val_)			\
651 		*var_ = val_;			\
652 } while (0)
653 
654 #define virtqueue_clear_net_hdr(hdr) do {		\
655 	typeof(hdr) hdr_ = (hdr);			\
656 	ASSIGN_UNLESS_EQUAL((hdr_)->csum_start, 0);	\
657 	ASSIGN_UNLESS_EQUAL((hdr_)->csum_offset, 0);	\
658 	ASSIGN_UNLESS_EQUAL((hdr_)->flags, 0);		\
659 	ASSIGN_UNLESS_EQUAL((hdr_)->gso_type, 0);	\
660 	ASSIGN_UNLESS_EQUAL((hdr_)->gso_size, 0);	\
661 	ASSIGN_UNLESS_EQUAL((hdr_)->hdr_len, 0);	\
662 } while (0)
663 
664 static inline void
665 virtqueue_xmit_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *cookie)
666 {
667 	uint64_t csum_l4 = cookie->ol_flags & RTE_MBUF_F_TX_L4_MASK;
668 	uint16_t o_l23_len = (cookie->ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK) ?
669 			     cookie->outer_l2_len + cookie->outer_l3_len : 0;
670 
671 	if (cookie->ol_flags & RTE_MBUF_F_TX_TCP_SEG)
672 		csum_l4 |= RTE_MBUF_F_TX_TCP_CKSUM;
673 
674 	switch (csum_l4) {
675 	case RTE_MBUF_F_TX_UDP_CKSUM:
676 		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
677 		hdr->csum_offset = offsetof(struct rte_udp_hdr, dgram_cksum);
678 		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
679 		break;
680 
681 	case RTE_MBUF_F_TX_TCP_CKSUM:
682 		hdr->csum_start = o_l23_len + cookie->l2_len + cookie->l3_len;
683 		hdr->csum_offset = offsetof(struct rte_tcp_hdr, cksum);
684 		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
685 		break;
686 
687 	default:
688 		ASSIGN_UNLESS_EQUAL(hdr->csum_start, 0);
689 		ASSIGN_UNLESS_EQUAL(hdr->csum_offset, 0);
690 		ASSIGN_UNLESS_EQUAL(hdr->flags, 0);
691 		break;
692 	}
693 
694 	/* TCP Segmentation Offload */
695 	if (cookie->ol_flags & RTE_MBUF_F_TX_TCP_SEG) {
696 		hdr->gso_type = (cookie->ol_flags & RTE_MBUF_F_TX_IPV6) ?
697 			VIRTIO_NET_HDR_GSO_TCPV6 :
698 			VIRTIO_NET_HDR_GSO_TCPV4;
699 		hdr->gso_size = cookie->tso_segsz;
700 		hdr->hdr_len = o_l23_len + cookie->l2_len + cookie->l3_len +
701 			       cookie->l4_len;
702 	} else {
703 		ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
704 		ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);
705 		ASSIGN_UNLESS_EQUAL(hdr->hdr_len, 0);
706 	}
707 }
708 
709 static inline void
710 virtqueue_enqueue_xmit_packed(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
711 			      uint16_t needed, int use_indirect, int can_push,
712 			      int in_order)
713 {
714 	struct virtio_tx_region *txr = txvq->virtio_net_hdr_mz->addr;
715 	struct vq_desc_extra *dxp;
716 	struct virtqueue *vq = virtnet_txq_to_vq(txvq);
717 	struct vring_packed_desc *start_dp, *head_dp;
718 	uint16_t idx, id, head_idx, head_flags;
719 	int16_t head_size = vq->hw->vtnet_hdr_size;
720 	struct virtio_net_hdr *hdr;
721 	uint16_t prev;
722 	bool prepend_header = false;
723 	uint16_t seg_num = cookie->nb_segs;
724 
725 	id = in_order ? vq->vq_avail_idx : vq->vq_desc_head_idx;
726 
727 	dxp = &vq->vq_descx[id];
728 	dxp->ndescs = needed;
729 	dxp->cookie = cookie;
730 
731 	head_idx = vq->vq_avail_idx;
732 	idx = head_idx;
733 	prev = head_idx;
734 	start_dp = vq->vq_packed.ring.desc;
735 
736 	head_dp = &vq->vq_packed.ring.desc[idx];
737 	head_flags = cookie->next ? VRING_DESC_F_NEXT : 0;
738 	head_flags |= vq->vq_packed.cached_flags;
739 
740 	if (can_push) {
741 		/* prepend cannot fail, checked by caller */
742 		hdr = rte_pktmbuf_mtod_offset(cookie, struct virtio_net_hdr *,
743 					      -head_size);
744 		prepend_header = true;
745 
746 		/* if offload disabled, it is not zeroed below, do it now */
747 		if (!vq->hw->has_tx_offload)
748 			virtqueue_clear_net_hdr(hdr);
749 	} else if (use_indirect) {
750 		/* setup tx ring slot to point to indirect
751 		 * descriptor list stored in reserved region.
752 		 *
753 		 * the first slot in indirect ring is already preset
754 		 * to point to the header in reserved region
755 		 */
756 		start_dp[idx].addr  = txvq->virtio_net_hdr_mem +
757 			RTE_PTR_DIFF(&txr[idx].tx_packed_indir, txr);
758 		start_dp[idx].len   = (seg_num + 1) *
759 			sizeof(struct vring_packed_desc);
760 		/* Packed descriptor id needs to be restored when inorder. */
761 		if (in_order)
762 			start_dp[idx].id = idx;
763 		/* reset flags for indirect desc */
764 		head_flags = VRING_DESC_F_INDIRECT;
765 		head_flags |= vq->vq_packed.cached_flags;
766 		hdr = (struct virtio_net_hdr *)&txr[idx].tx_hdr;
767 
768 		/* loop below will fill in rest of the indirect elements */
769 		start_dp = txr[idx].tx_packed_indir;
770 		idx = 1;
771 	} else {
772 		/* setup first tx ring slot to point to header
773 		 * stored in reserved region.
774 		 */
775 		start_dp[idx].addr  = txvq->virtio_net_hdr_mem +
776 			RTE_PTR_DIFF(&txr[idx].tx_hdr, txr);
777 		start_dp[idx].len   = vq->hw->vtnet_hdr_size;
778 		hdr = (struct virtio_net_hdr *)&txr[idx].tx_hdr;
779 		idx++;
780 		if (idx >= vq->vq_nentries) {
781 			idx -= vq->vq_nentries;
782 			vq->vq_packed.cached_flags ^=
783 				VRING_PACKED_DESC_F_AVAIL_USED;
784 		}
785 	}
786 
787 	if (vq->hw->has_tx_offload)
788 		virtqueue_xmit_offload(hdr, cookie);
789 
790 	do {
791 		uint16_t flags;
792 
793 		start_dp[idx].addr = VIRTIO_MBUF_DATA_DMA_ADDR(cookie, vq);
794 		start_dp[idx].len  = cookie->data_len;
795 		if (prepend_header) {
796 			start_dp[idx].addr -= head_size;
797 			start_dp[idx].len += head_size;
798 			prepend_header = false;
799 		}
800 
801 		if (likely(idx != head_idx)) {
802 			flags = cookie->next ? VRING_DESC_F_NEXT : 0;
803 			flags |= vq->vq_packed.cached_flags;
804 			start_dp[idx].flags = flags;
805 		}
806 		prev = idx;
807 		idx++;
808 		if (idx >= vq->vq_nentries) {
809 			idx -= vq->vq_nentries;
810 			vq->vq_packed.cached_flags ^=
811 				VRING_PACKED_DESC_F_AVAIL_USED;
812 		}
813 	} while ((cookie = cookie->next) != NULL);
814 
815 	start_dp[prev].id = id;
816 
817 	if (use_indirect) {
818 		idx = head_idx;
819 		if (++idx >= vq->vq_nentries) {
820 			idx -= vq->vq_nentries;
821 			vq->vq_packed.cached_flags ^=
822 				VRING_PACKED_DESC_F_AVAIL_USED;
823 		}
824 	}
825 
826 	vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - needed);
827 	vq->vq_avail_idx = idx;
828 
829 	if (!in_order) {
830 		vq->vq_desc_head_idx = dxp->next;
831 		if (vq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END)
832 			vq->vq_desc_tail_idx = VQ_RING_DESC_CHAIN_END;
833 	}
834 
835 	virtqueue_store_flags_packed(head_dp, head_flags,
836 				     vq->hw->weak_barriers);
837 }
838 
839 static void
840 vq_ring_free_id_packed(struct virtqueue *vq, uint16_t id)
841 {
842 	struct vq_desc_extra *dxp;
843 
844 	dxp = &vq->vq_descx[id];
845 	vq->vq_free_cnt += dxp->ndescs;
846 
847 	if (vq->vq_desc_tail_idx == VQ_RING_DESC_CHAIN_END)
848 		vq->vq_desc_head_idx = id;
849 	else
850 		vq->vq_descx[vq->vq_desc_tail_idx].next = id;
851 
852 	vq->vq_desc_tail_idx = id;
853 	dxp->next = VQ_RING_DESC_CHAIN_END;
854 }
855 
856 static void
857 virtio_xmit_cleanup_inorder_packed(struct virtqueue *vq, uint16_t num)
858 {
859 	uint16_t used_idx, id, curr_id, free_cnt = 0;
860 	uint16_t size = vq->vq_nentries;
861 	struct vring_packed_desc *desc = vq->vq_packed.ring.desc;
862 	struct vq_desc_extra *dxp;
863 	int nb = num;
864 
865 	used_idx = vq->vq_used_cons_idx;
866 	/* desc_is_used has a load-acquire or rte_io_rmb inside
867 	 * and wait for used desc in virtqueue.
868 	 */
869 	while (nb > 0 && desc_is_used(&desc[used_idx], vq)) {
870 		id = desc[used_idx].id;
871 		do {
872 			curr_id = used_idx;
873 			dxp = &vq->vq_descx[used_idx];
874 			used_idx += dxp->ndescs;
875 			free_cnt += dxp->ndescs;
876 			nb -= dxp->ndescs;
877 			if (used_idx >= size) {
878 				used_idx -= size;
879 				vq->vq_packed.used_wrap_counter ^= 1;
880 			}
881 			if (dxp->cookie != NULL) {
882 				rte_pktmbuf_free(dxp->cookie);
883 				dxp->cookie = NULL;
884 			}
885 		} while (curr_id != id);
886 	}
887 	vq->vq_used_cons_idx = used_idx;
888 	vq->vq_free_cnt += free_cnt;
889 }
890 
891 static void
892 virtio_xmit_cleanup_normal_packed(struct virtqueue *vq, uint16_t num)
893 {
894 	uint16_t used_idx, id;
895 	uint16_t size = vq->vq_nentries;
896 	struct vring_packed_desc *desc = vq->vq_packed.ring.desc;
897 	struct vq_desc_extra *dxp;
898 
899 	used_idx = vq->vq_used_cons_idx;
900 	/* desc_is_used has a load-acquire or rte_io_rmb inside
901 	 * and wait for used desc in virtqueue.
902 	 */
903 	while (num-- && desc_is_used(&desc[used_idx], vq)) {
904 		id = desc[used_idx].id;
905 		dxp = &vq->vq_descx[id];
906 		vq->vq_used_cons_idx += dxp->ndescs;
907 		if (vq->vq_used_cons_idx >= size) {
908 			vq->vq_used_cons_idx -= size;
909 			vq->vq_packed.used_wrap_counter ^= 1;
910 		}
911 		vq_ring_free_id_packed(vq, id);
912 		if (dxp->cookie != NULL) {
913 			rte_pktmbuf_free(dxp->cookie);
914 			dxp->cookie = NULL;
915 		}
916 		used_idx = vq->vq_used_cons_idx;
917 	}
918 }
919 
920 /* Cleanup from completed transmits. */
921 static inline void
922 virtio_xmit_cleanup_packed(struct virtqueue *vq, uint16_t num, int in_order)
923 {
924 	if (in_order)
925 		virtio_xmit_cleanup_inorder_packed(vq, num);
926 	else
927 		virtio_xmit_cleanup_normal_packed(vq, num);
928 }
929 
930 static inline void
931 virtio_xmit_cleanup(struct virtqueue *vq, uint16_t num)
932 {
933 	uint16_t i, used_idx, desc_idx;
934 	for (i = 0; i < num; i++) {
935 		struct vring_used_elem *uep;
936 		struct vq_desc_extra *dxp;
937 
938 		used_idx = (uint16_t)(vq->vq_used_cons_idx &
939 				(vq->vq_nentries - 1));
940 		uep = &vq->vq_split.ring.used->ring[used_idx];
941 
942 		desc_idx = (uint16_t)uep->id;
943 		dxp = &vq->vq_descx[desc_idx];
944 		vq->vq_used_cons_idx++;
945 		vq_ring_free_chain(vq, desc_idx);
946 
947 		if (dxp->cookie != NULL) {
948 			rte_pktmbuf_free(dxp->cookie);
949 			dxp->cookie = NULL;
950 		}
951 	}
952 }
953 
954 /* Cleanup from completed inorder transmits. */
955 static __rte_always_inline void
956 virtio_xmit_cleanup_inorder(struct virtqueue *vq, uint16_t num)
957 {
958 	uint16_t i, idx = vq->vq_used_cons_idx;
959 	int16_t free_cnt = 0;
960 	struct vq_desc_extra *dxp = NULL;
961 
962 	if (unlikely(num == 0))
963 		return;
964 
965 	for (i = 0; i < num; i++) {
966 		dxp = &vq->vq_descx[idx++ & (vq->vq_nentries - 1)];
967 		free_cnt += dxp->ndescs;
968 		if (dxp->cookie != NULL) {
969 			rte_pktmbuf_free(dxp->cookie);
970 			dxp->cookie = NULL;
971 		}
972 	}
973 
974 	vq->vq_free_cnt += free_cnt;
975 	vq->vq_used_cons_idx = idx;
976 }
977 #endif /* _VIRTQUEUE_H_ */
978