xref: /dpdk/drivers/net/virtio/virtqueue.h (revision 89f0711f9ddfb5822da9d34f384b92f72a61c4dc)
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 
14 #include "virtio_pci.h"
15 #include "virtio_ring.h"
16 #include "virtio_logs.h"
17 #include "virtio_rxtx.h"
18 
19 struct rte_mbuf;
20 
21 /*
22  * Per virtio_config.h in Linux.
23  *     For virtio_pci on SMP, we don't need to order with respect to MMIO
24  *     accesses through relaxed memory I/O windows, so smp_mb() et al are
25  *     sufficient.
26  *
27  */
28 #define virtio_mb()	rte_smp_mb()
29 #define virtio_rmb()	rte_smp_rmb()
30 #define virtio_wmb()	rte_smp_wmb()
31 
32 #ifdef RTE_PMD_PACKET_PREFETCH
33 #define rte_packet_prefetch(p)  rte_prefetch1(p)
34 #else
35 #define rte_packet_prefetch(p)  do {} while(0)
36 #endif
37 
38 #define VIRTQUEUE_MAX_NAME_SZ 32
39 
40 #ifdef RTE_VIRTIO_USER
41 /**
42  * Return the physical address (or virtual address in case of
43  * virtio-user) of mbuf data buffer.
44  *
45  * The address is firstly casted to the word size (sizeof(uintptr_t))
46  * before casting it to uint64_t. This is to make it work with different
47  * combination of word size (64 bit and 32 bit) and virtio device
48  * (virtio-pci and virtio-user).
49  */
50 #define VIRTIO_MBUF_ADDR(mb, vq) \
51 	((uint64_t)(*(uintptr_t *)((uintptr_t)(mb) + (vq)->offset)))
52 #else
53 #define VIRTIO_MBUF_ADDR(mb, vq) ((mb)->buf_iova)
54 #endif
55 
56 /**
57  * Return the physical address (or virtual address in case of
58  * virtio-user) of mbuf data buffer, taking care of mbuf data offset
59  */
60 #define VIRTIO_MBUF_DATA_DMA_ADDR(mb, vq) \
61 	(VIRTIO_MBUF_ADDR(mb, vq) + (mb)->data_off)
62 
63 #define VTNET_SQ_RQ_QUEUE_IDX 0
64 #define VTNET_SQ_TQ_QUEUE_IDX 1
65 #define VTNET_SQ_CQ_QUEUE_IDX 2
66 
67 enum { VTNET_RQ = 0, VTNET_TQ = 1, VTNET_CQ = 2 };
68 /**
69  * The maximum virtqueue size is 2^15. Use that value as the end of
70  * descriptor chain terminator since it will never be a valid index
71  * in the descriptor table. This is used to verify we are correctly
72  * handling vq_free_cnt.
73  */
74 #define VQ_RING_DESC_CHAIN_END 32768
75 
76 /**
77  * Control the RX mode, ie. promiscuous, allmulti, etc...
78  * All commands require an "out" sg entry containing a 1 byte
79  * state value, zero = disable, non-zero = enable.  Commands
80  * 0 and 1 are supported with the VIRTIO_NET_F_CTRL_RX feature.
81  * Commands 2-5 are added with VIRTIO_NET_F_CTRL_RX_EXTRA.
82  */
83 #define VIRTIO_NET_CTRL_RX              0
84 #define VIRTIO_NET_CTRL_RX_PROMISC      0
85 #define VIRTIO_NET_CTRL_RX_ALLMULTI     1
86 #define VIRTIO_NET_CTRL_RX_ALLUNI       2
87 #define VIRTIO_NET_CTRL_RX_NOMULTI      3
88 #define VIRTIO_NET_CTRL_RX_NOUNI        4
89 #define VIRTIO_NET_CTRL_RX_NOBCAST      5
90 
91 /**
92  * Control the MAC
93  *
94  * The MAC filter table is managed by the hypervisor, the guest should
95  * assume the size is infinite.  Filtering should be considered
96  * non-perfect, ie. based on hypervisor resources, the guest may
97  * received packets from sources not specified in the filter list.
98  *
99  * In addition to the class/cmd header, the TABLE_SET command requires
100  * two out scatterlists.  Each contains a 4 byte count of entries followed
101  * by a concatenated byte stream of the ETH_ALEN MAC addresses.  The
102  * first sg list contains unicast addresses, the second is for multicast.
103  * This functionality is present if the VIRTIO_NET_F_CTRL_RX feature
104  * is available.
105  *
106  * The ADDR_SET command requests one out scatterlist, it contains a
107  * 6 bytes MAC address. This functionality is present if the
108  * VIRTIO_NET_F_CTRL_MAC_ADDR feature is available.
109  */
110 struct virtio_net_ctrl_mac {
111 	uint32_t entries;
112 	uint8_t macs[][ETHER_ADDR_LEN];
113 } __attribute__((__packed__));
114 
115 #define VIRTIO_NET_CTRL_MAC    1
116 #define VIRTIO_NET_CTRL_MAC_TABLE_SET        0
117 #define VIRTIO_NET_CTRL_MAC_ADDR_SET         1
118 
119 /**
120  * Control VLAN filtering
121  *
122  * The VLAN filter table is controlled via a simple ADD/DEL interface.
123  * VLAN IDs not added may be filtered by the hypervisor.  Del is the
124  * opposite of add.  Both commands expect an out entry containing a 2
125  * byte VLAN ID.  VLAN filtering is available with the
126  * VIRTIO_NET_F_CTRL_VLAN feature bit.
127  */
128 #define VIRTIO_NET_CTRL_VLAN     2
129 #define VIRTIO_NET_CTRL_VLAN_ADD 0
130 #define VIRTIO_NET_CTRL_VLAN_DEL 1
131 
132 /*
133  * Control link announce acknowledgement
134  *
135  * The command VIRTIO_NET_CTRL_ANNOUNCE_ACK is used to indicate that
136  * driver has recevied the notification; device would clear the
137  * VIRTIO_NET_S_ANNOUNCE bit in the status field after it receives
138  * this command.
139  */
140 #define VIRTIO_NET_CTRL_ANNOUNCE     3
141 #define VIRTIO_NET_CTRL_ANNOUNCE_ACK 0
142 
143 struct virtio_net_ctrl_hdr {
144 	uint8_t class;
145 	uint8_t cmd;
146 } __attribute__((packed));
147 
148 typedef uint8_t virtio_net_ctrl_ack;
149 
150 #define VIRTIO_NET_OK     0
151 #define VIRTIO_NET_ERR    1
152 
153 #define VIRTIO_MAX_CTRL_DATA 2048
154 
155 struct virtio_pmd_ctrl {
156 	struct virtio_net_ctrl_hdr hdr;
157 	virtio_net_ctrl_ack status;
158 	uint8_t data[VIRTIO_MAX_CTRL_DATA];
159 };
160 
161 struct vq_desc_extra {
162 	void *cookie;
163 	uint16_t ndescs;
164 };
165 
166 struct virtqueue {
167 	struct virtio_hw  *hw; /**< virtio_hw structure pointer. */
168 	struct vring vq_ring;  /**< vring keeping desc, used and avail */
169 	/**
170 	 * Last consumed descriptor in the used table,
171 	 * trails vq_ring.used->idx.
172 	 */
173 	uint16_t vq_used_cons_idx;
174 	uint16_t vq_nentries;  /**< vring desc numbers */
175 	uint16_t vq_free_cnt;  /**< num of desc available */
176 	uint16_t vq_avail_idx; /**< sync until needed */
177 	uint16_t vq_free_thresh; /**< free threshold */
178 
179 	void *vq_ring_virt_mem;  /**< linear address of vring*/
180 	unsigned int vq_ring_size;
181 
182 	union {
183 		struct virtnet_rx rxq;
184 		struct virtnet_tx txq;
185 		struct virtnet_ctl cq;
186 	};
187 
188 	rte_iova_t vq_ring_mem; /**< physical address of vring,
189 	                         * or virtual address for virtio_user. */
190 
191 	/**
192 	 * Head of the free chain in the descriptor table. If
193 	 * there are no free descriptors, this will be set to
194 	 * VQ_RING_DESC_CHAIN_END.
195 	 */
196 	uint16_t  vq_desc_head_idx;
197 	uint16_t  vq_desc_tail_idx;
198 	uint16_t  vq_queue_index;   /**< PCI queue index */
199 	uint16_t offset; /**< relative offset to obtain addr in mbuf */
200 	uint16_t  *notify_addr;
201 	struct rte_mbuf **sw_ring;  /**< RX software ring. */
202 	struct vq_desc_extra vq_descx[0];
203 };
204 
205 /* If multiqueue is provided by host, then we suppport it. */
206 #define VIRTIO_NET_CTRL_MQ   4
207 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET        0
208 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN        1
209 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX        0x8000
210 
211 /**
212  * This is the first element of the scatter-gather list.  If you don't
213  * specify GSO or CSUM features, you can simply ignore the header.
214  */
215 struct virtio_net_hdr {
216 #define VIRTIO_NET_HDR_F_NEEDS_CSUM 1    /**< Use csum_start,csum_offset*/
217 #define VIRTIO_NET_HDR_F_DATA_VALID 2    /**< Checksum is valid */
218 	uint8_t flags;
219 #define VIRTIO_NET_HDR_GSO_NONE     0    /**< Not a GSO frame */
220 #define VIRTIO_NET_HDR_GSO_TCPV4    1    /**< GSO frame, IPv4 TCP (TSO) */
221 #define VIRTIO_NET_HDR_GSO_UDP      3    /**< GSO frame, IPv4 UDP (UFO) */
222 #define VIRTIO_NET_HDR_GSO_TCPV6    4    /**< GSO frame, IPv6 TCP */
223 #define VIRTIO_NET_HDR_GSO_ECN      0x80 /**< TCP has ECN set */
224 	uint8_t gso_type;
225 	uint16_t hdr_len;     /**< Ethernet + IP + tcp/udp hdrs */
226 	uint16_t gso_size;    /**< Bytes to append to hdr_len per frame */
227 	uint16_t csum_start;  /**< Position to start checksumming from */
228 	uint16_t csum_offset; /**< Offset after that to place checksum */
229 };
230 
231 /**
232  * This is the version of the header to use when the MRG_RXBUF
233  * feature has been negotiated.
234  */
235 struct virtio_net_hdr_mrg_rxbuf {
236 	struct   virtio_net_hdr hdr;
237 	uint16_t num_buffers; /**< Number of merged rx buffers */
238 };
239 
240 /* Region reserved to allow for transmit header and indirect ring */
241 #define VIRTIO_MAX_TX_INDIRECT 8
242 struct virtio_tx_region {
243 	struct virtio_net_hdr_mrg_rxbuf tx_hdr;
244 	struct vring_desc tx_indir[VIRTIO_MAX_TX_INDIRECT]
245 			   __attribute__((__aligned__(16)));
246 };
247 
248 /* Chain all the descriptors in the ring with an END */
249 static inline void
250 vring_desc_init(struct vring_desc *dp, uint16_t n)
251 {
252 	uint16_t i;
253 
254 	for (i = 0; i < n - 1; i++)
255 		dp[i].next = (uint16_t)(i + 1);
256 	dp[i].next = VQ_RING_DESC_CHAIN_END;
257 }
258 
259 /**
260  * Tell the backend not to interrupt us.
261  */
262 static inline void
263 virtqueue_disable_intr(struct virtqueue *vq)
264 {
265 	vq->vq_ring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
266 }
267 
268 /**
269  * Tell the backend to interrupt us.
270  */
271 static inline void
272 virtqueue_enable_intr(struct virtqueue *vq)
273 {
274 	vq->vq_ring.avail->flags &= (~VRING_AVAIL_F_NO_INTERRUPT);
275 }
276 
277 /**
278  *  Dump virtqueue internal structures, for debug purpose only.
279  */
280 void virtqueue_dump(struct virtqueue *vq);
281 /**
282  *  Get all mbufs to be freed.
283  */
284 struct rte_mbuf *virtqueue_detach_unused(struct virtqueue *vq);
285 
286 /* Flush the elements in the used ring. */
287 void virtqueue_rxvq_flush(struct virtqueue *vq);
288 
289 static inline int
290 virtqueue_full(const struct virtqueue *vq)
291 {
292 	return vq->vq_free_cnt == 0;
293 }
294 
295 static inline int
296 virtio_get_queue_type(struct virtio_hw *hw, uint16_t vtpci_queue_idx)
297 {
298 	if (vtpci_queue_idx == hw->max_queue_pairs * 2)
299 		return VTNET_CQ;
300 	else if (vtpci_queue_idx % 2 == 0)
301 		return VTNET_RQ;
302 	else
303 		return VTNET_TQ;
304 }
305 
306 #define VIRTQUEUE_NUSED(vq) ((uint16_t)((vq)->vq_ring.used->idx - (vq)->vq_used_cons_idx))
307 
308 void vq_ring_free_chain(struct virtqueue *vq, uint16_t desc_idx);
309 
310 static inline void
311 vq_update_avail_idx(struct virtqueue *vq)
312 {
313 	virtio_wmb();
314 	vq->vq_ring.avail->idx = vq->vq_avail_idx;
315 }
316 
317 static inline void
318 vq_update_avail_ring(struct virtqueue *vq, uint16_t desc_idx)
319 {
320 	uint16_t avail_idx;
321 	/*
322 	 * Place the head of the descriptor chain into the next slot and make
323 	 * it usable to the host. The chain is made available now rather than
324 	 * deferring to virtqueue_notify() in the hopes that if the host is
325 	 * currently running on another CPU, we can keep it processing the new
326 	 * descriptor.
327 	 */
328 	avail_idx = (uint16_t)(vq->vq_avail_idx & (vq->vq_nentries - 1));
329 	if (unlikely(vq->vq_ring.avail->ring[avail_idx] != desc_idx))
330 		vq->vq_ring.avail->ring[avail_idx] = desc_idx;
331 	vq->vq_avail_idx++;
332 }
333 
334 static inline int
335 virtqueue_kick_prepare(struct virtqueue *vq)
336 {
337 	return !(vq->vq_ring.used->flags & VRING_USED_F_NO_NOTIFY);
338 }
339 
340 static inline void
341 virtqueue_notify(struct virtqueue *vq)
342 {
343 	/*
344 	 * Ensure updated avail->idx is visible to host.
345 	 * For virtio on IA, the notificaiton is through io port operation
346 	 * which is a serialization instruction itself.
347 	 */
348 	VTPCI_OPS(vq->hw)->notify_queue(vq->hw, vq);
349 }
350 
351 #ifdef RTE_LIBRTE_VIRTIO_DEBUG_DUMP
352 #define VIRTQUEUE_DUMP(vq) do { \
353 	uint16_t used_idx, nused; \
354 	used_idx = (vq)->vq_ring.used->idx; \
355 	nused = (uint16_t)(used_idx - (vq)->vq_used_cons_idx); \
356 	PMD_INIT_LOG(DEBUG, \
357 	  "VQ: - size=%d; free=%d; used=%d; desc_head_idx=%d;" \
358 	  " avail.idx=%d; used_cons_idx=%d; used.idx=%d;" \
359 	  " avail.flags=0x%x; used.flags=0x%x", \
360 	  (vq)->vq_nentries, (vq)->vq_free_cnt, nused, \
361 	  (vq)->vq_desc_head_idx, (vq)->vq_ring.avail->idx, \
362 	  (vq)->vq_used_cons_idx, (vq)->vq_ring.used->idx, \
363 	  (vq)->vq_ring.avail->flags, (vq)->vq_ring.used->flags); \
364 } while (0)
365 #else
366 #define VIRTQUEUE_DUMP(vq) do { } while (0)
367 #endif
368 
369 #endif /* _VIRTQUEUE_H_ */
370