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s390x/sclp: properly guard pci-specific functions
[qemu.git] / contrib / libvhost-user / libvhost-user.c
blob35fa0c5e566c50f836dabec16b9832299e2dbe18
1 /*
2 * Vhost User library
3 *
4 * Copyright IBM, Corp. 2007
5 * Copyright (c) 2016 Red Hat, Inc.
6 *
7 * Authors:
8 * Anthony Liguori <aliguori@us.ibm.com>
9 * Marc-André Lureau <mlureau@redhat.com>
10 * Victor Kaplansky <victork@redhat.com>
11 *
12 * This work is licensed under the terms of the GNU GPL, version 2 or
13 * later. See the COPYING file in the top-level directory.
14 */
15
16 #include <qemu/osdep.h>
17 #include <sys/eventfd.h>
18 #include <linux/vhost.h>
19
20 #include "qemu/atomic.h"
21
22 #include "libvhost-user.h"
23
24 #define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
25
26 /* The version of the protocol we support */
27 #define VHOST_USER_VERSION 1
28 #define LIBVHOST_USER_DEBUG 0
29
30 #define DPRINT(...) \
31 do { \
32 if (LIBVHOST_USER_DEBUG) { \
33 fprintf(stderr, __VA_ARGS__); \
34 } \
35 } while (0)
36
37 static const char *
38 vu_request_to_string(int req)
39 {
40 #define REQ(req) [req] = #req
41 static const char *vu_request_str[] = {
42 REQ(VHOST_USER_NONE),
43 REQ(VHOST_USER_GET_FEATURES),
44 REQ(VHOST_USER_SET_FEATURES),
45 REQ(VHOST_USER_NONE),
46 REQ(VHOST_USER_GET_FEATURES),
47 REQ(VHOST_USER_SET_FEATURES),
48 REQ(VHOST_USER_SET_OWNER),
49 REQ(VHOST_USER_RESET_OWNER),
50 REQ(VHOST_USER_SET_MEM_TABLE),
51 REQ(VHOST_USER_SET_LOG_BASE),
52 REQ(VHOST_USER_SET_LOG_FD),
53 REQ(VHOST_USER_SET_VRING_NUM),
54 REQ(VHOST_USER_SET_VRING_ADDR),
55 REQ(VHOST_USER_SET_VRING_BASE),
56 REQ(VHOST_USER_GET_VRING_BASE),
57 REQ(VHOST_USER_SET_VRING_KICK),
58 REQ(VHOST_USER_SET_VRING_CALL),
59 REQ(VHOST_USER_SET_VRING_ERR),
60 REQ(VHOST_USER_GET_PROTOCOL_FEATURES),
61 REQ(VHOST_USER_SET_PROTOCOL_FEATURES),
62 REQ(VHOST_USER_GET_QUEUE_NUM),
63 REQ(VHOST_USER_SET_VRING_ENABLE),
64 REQ(VHOST_USER_SEND_RARP),
65 REQ(VHOST_USER_INPUT_GET_CONFIG),
66 REQ(VHOST_USER_MAX),
67 };
68 #undef REQ
69
70 if (req < VHOST_USER_MAX) {
71 return vu_request_str[req];
72 } else {
73 return "unknown";
74 }
75 }
76
77 static void
78 vu_panic(VuDev *dev, const char *msg, ...)
79 {
80 char *buf = NULL;
81 va_list ap;
82
83 va_start(ap, msg);
84 buf = g_strdup_vprintf(msg, ap);
85 va_end(ap);
86
87 dev->broken = true;
88 dev->panic(dev, buf);
89 free(buf);
90
91 /* FIXME: find a way to call virtio_error? */
92 }
93
94 /* Translate guest physical address to our virtual address. */
95 void *
96 vu_gpa_to_va(VuDev *dev, uint64_t guest_addr)
97 {
98 int i;
99
100 /* Find matching memory region. */
101 for (i = 0; i < dev->nregions; i++) {
102 VuDevRegion *r = &dev->regions[i];
103
104 if ((guest_addr >= r->gpa) && (guest_addr < (r->gpa + r->size))) {
105 return (void *)(uintptr_t)
106 guest_addr - r->gpa + r->mmap_addr + r->mmap_offset;
107 }
108 }
109
110 return NULL;
111 }
112
113 /* Translate qemu virtual address to our virtual address. */
114 static void *
115 qva_to_va(VuDev *dev, uint64_t qemu_addr)
116 {
117 int i;
118
119 /* Find matching memory region. */
120 for (i = 0; i < dev->nregions; i++) {
121 VuDevRegion *r = &dev->regions[i];
122
123 if ((qemu_addr >= r->qva) && (qemu_addr < (r->qva + r->size))) {
124 return (void *)(uintptr_t)
125 qemu_addr - r->qva + r->mmap_addr + r->mmap_offset;
126 }
127 }
128
129 return NULL;
130 }
131
132 static void
133 vmsg_close_fds(VhostUserMsg *vmsg)
134 {
135 int i;
136
137 for (i = 0; i < vmsg->fd_num; i++) {
138 close(vmsg->fds[i]);
139 }
140 }
141
142 static bool
143 vu_message_read(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
144 {
145 char control[CMSG_SPACE(VHOST_MEMORY_MAX_NREGIONS * sizeof(int))] = { };
146 struct iovec iov = {
147 .iov_base = (char *)vmsg,
148 .iov_len = VHOST_USER_HDR_SIZE,
149 };
150 struct msghdr msg = {
151 .msg_iov = &iov,
152 .msg_iovlen = 1,
153 .msg_control = control,
154 .msg_controllen = sizeof(control),
155 };
156 size_t fd_size;
157 struct cmsghdr *cmsg;
158 int rc;
159
160 do {
161 rc = recvmsg(conn_fd, &msg, 0);
162 } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
163
164 if (rc < 0) {
165 vu_panic(dev, "Error while recvmsg: %s", strerror(errno));
166 return false;
167 }
168
169 vmsg->fd_num = 0;
170 for (cmsg = CMSG_FIRSTHDR(&msg);
171 cmsg != NULL;
172 cmsg = CMSG_NXTHDR(&msg, cmsg))
173 {
174 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
175 fd_size = cmsg->cmsg_len - CMSG_LEN(0);
176 vmsg->fd_num = fd_size / sizeof(int);
177 memcpy(vmsg->fds, CMSG_DATA(cmsg), fd_size);
178 break;
179 }
180 }
181
182 if (vmsg->size > sizeof(vmsg->payload)) {
183 vu_panic(dev,
184 "Error: too big message request: %d, size: vmsg->size: %u, "
185 "while sizeof(vmsg->payload) = %zu\n",
186 vmsg->request, vmsg->size, sizeof(vmsg->payload));
187 goto fail;
188 }
189
190 if (vmsg->size) {
191 do {
192 rc = read(conn_fd, &vmsg->payload, vmsg->size);
193 } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
194
195 if (rc <= 0) {
196 vu_panic(dev, "Error while reading: %s", strerror(errno));
197 goto fail;
198 }
199
200 assert(rc == vmsg->size);
201 }
202
203 return true;
204
205 fail:
206 vmsg_close_fds(vmsg);
207
208 return false;
209 }
210
211 static bool
212 vu_message_write(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
213 {
214 int rc;
215 uint8_t *p = (uint8_t *)vmsg;
216
217 /* Set the version in the flags when sending the reply */
218 vmsg->flags &= ~VHOST_USER_VERSION_MASK;
219 vmsg->flags |= VHOST_USER_VERSION;
220 vmsg->flags |= VHOST_USER_REPLY_MASK;
221
222 do {
223 rc = write(conn_fd, p, VHOST_USER_HDR_SIZE);
224 } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
225
226 do {
227 if (vmsg->data) {
228 rc = write(conn_fd, vmsg->data, vmsg->size);
229 } else {
230 rc = write(conn_fd, p + VHOST_USER_HDR_SIZE, vmsg->size);
231 }
232 } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
233
234 if (rc <= 0) {
235 vu_panic(dev, "Error while writing: %s", strerror(errno));
236 return false;
237 }
238
239 return true;
240 }
241
242 /* Kick the log_call_fd if required. */
243 static void
244 vu_log_kick(VuDev *dev)
245 {
246 if (dev->log_call_fd != -1) {
247 DPRINT("Kicking the QEMU's log...\n");
248 if (eventfd_write(dev->log_call_fd, 1) < 0) {
249 vu_panic(dev, "Error writing eventfd: %s", strerror(errno));
250 }
251 }
252 }
253
254 static void
255 vu_log_page(uint8_t *log_table, uint64_t page)
256 {
257 DPRINT("Logged dirty guest page: %"PRId64"\n", page);
258 atomic_or(&log_table[page / 8], 1 << (page % 8));
259 }
260
261 static void
262 vu_log_write(VuDev *dev, uint64_t address, uint64_t length)
263 {
264 uint64_t page;
265
266 if (!(dev->features & (1ULL << VHOST_F_LOG_ALL)) ||
267 !dev->log_table || !length) {
268 return;
269 }
270
271 assert(dev->log_size > ((address + length - 1) / VHOST_LOG_PAGE / 8));
272
273 page = address / VHOST_LOG_PAGE;
274 while (page * VHOST_LOG_PAGE < address + length) {
275 vu_log_page(dev->log_table, page);
276 page += VHOST_LOG_PAGE;
277 }
278
279 vu_log_kick(dev);
280 }
281
282 static void
283 vu_kick_cb(VuDev *dev, int condition, void *data)
284 {
285 int index = (intptr_t)data;
286 VuVirtq *vq = &dev->vq[index];
287 int sock = vq->kick_fd;
288 eventfd_t kick_data;
289 ssize_t rc;
290
291 rc = eventfd_read(sock, &kick_data);
292 if (rc == -1) {
293 vu_panic(dev, "kick eventfd_read(): %s", strerror(errno));
294 dev->remove_watch(dev, dev->vq[index].kick_fd);
295 } else {
296 DPRINT("Got kick_data: %016"PRIx64" handler:%p idx:%d\n",
297 kick_data, vq->handler, index);
298 if (vq->handler) {
299 vq->handler(dev, index);
300 }
301 }
302 }
303
304 static bool
305 vu_get_features_exec(VuDev *dev, VhostUserMsg *vmsg)
306 {
307 vmsg->payload.u64 =
308 1ULL << VHOST_F_LOG_ALL |
309 1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
310
311 if (dev->iface->get_features) {
312 vmsg->payload.u64 |= dev->iface->get_features(dev);
313 }
314
315 vmsg->size = sizeof(vmsg->payload.u64);
316
317 DPRINT("Sending back to guest u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
318
319 return true;
320 }
321
322 static void
323 vu_set_enable_all_rings(VuDev *dev, bool enabled)
324 {
325 int i;
326
327 for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {
328 dev->vq[i].enable = enabled;
329 }
330 }
331
332 static bool
333 vu_set_features_exec(VuDev *dev, VhostUserMsg *vmsg)
334 {
335 DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
336
337 dev->features = vmsg->payload.u64;
338
339 if (!(dev->features & VHOST_USER_F_PROTOCOL_FEATURES)) {
340 vu_set_enable_all_rings(dev, true);
341 }
342
343 if (dev->iface->set_features) {
344 dev->iface->set_features(dev, dev->features);
345 }
346
347 return false;
348 }
349
350 static bool
351 vu_set_owner_exec(VuDev *dev, VhostUserMsg *vmsg)
352 {
353 return false;
354 }
355
356 static void
357 vu_close_log(VuDev *dev)
358 {
359 if (dev->log_table) {
360 if (munmap(dev->log_table, dev->log_size) != 0) {
361 perror("close log munmap() error");
362 }
363
364 dev->log_table = NULL;
365 }
366 if (dev->log_call_fd != -1) {
367 close(dev->log_call_fd);
368 dev->log_call_fd = -1;
369 }
370 }
371
372 static bool
373 vu_reset_device_exec(VuDev *dev, VhostUserMsg *vmsg)
374 {
375 vu_set_enable_all_rings(dev, false);
376
377 return false;
378 }
379
380 static bool
381 vu_set_mem_table_exec(VuDev *dev, VhostUserMsg *vmsg)
382 {
383 int i;
384 VhostUserMemory *memory = &vmsg->payload.memory;
385 dev->nregions = memory->nregions;
386
387 DPRINT("Nregions: %d\n", memory->nregions);
388 for (i = 0; i < dev->nregions; i++) {
389 void *mmap_addr;
390 VhostUserMemoryRegion *msg_region = &memory->regions[i];
391 VuDevRegion *dev_region = &dev->regions[i];
392
393 DPRINT("Region %d\n", i);
394 DPRINT(" guest_phys_addr: 0x%016"PRIx64"\n",
395 msg_region->guest_phys_addr);
396 DPRINT(" memory_size: 0x%016"PRIx64"\n",
397 msg_region->memory_size);
398 DPRINT(" userspace_addr 0x%016"PRIx64"\n",
399 msg_region->userspace_addr);
400 DPRINT(" mmap_offset 0x%016"PRIx64"\n",
401 msg_region->mmap_offset);
402
403 dev_region->gpa = msg_region->guest_phys_addr;
404 dev_region->size = msg_region->memory_size;
405 dev_region->qva = msg_region->userspace_addr;
406 dev_region->mmap_offset = msg_region->mmap_offset;
407
408 /* We don't use offset argument of mmap() since the
409 * mapped address has to be page aligned, and we use huge
410 * pages. */
411 mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset,
412 PROT_READ | PROT_WRITE, MAP_SHARED,
413 vmsg->fds[i], 0);
414
415 if (mmap_addr == MAP_FAILED) {
416 vu_panic(dev, "region mmap error: %s", strerror(errno));
417 } else {
418 dev_region->mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
419 DPRINT(" mmap_addr: 0x%016"PRIx64"\n",
420 dev_region->mmap_addr);
421 }
422
423 close(vmsg->fds[i]);
424 }
425
426 return false;
427 }
428
429 static bool
430 vu_set_log_base_exec(VuDev *dev, VhostUserMsg *vmsg)
431 {
432 int fd;
433 uint64_t log_mmap_size, log_mmap_offset;
434 void *rc;
435
436 if (vmsg->fd_num != 1 ||
437 vmsg->size != sizeof(vmsg->payload.log)) {
438 vu_panic(dev, "Invalid log_base message");
439 return true;
440 }
441
442 fd = vmsg->fds[0];
443 log_mmap_offset = vmsg->payload.log.mmap_offset;
444 log_mmap_size = vmsg->payload.log.mmap_size;
445 DPRINT("Log mmap_offset: %"PRId64"\n", log_mmap_offset);
446 DPRINT("Log mmap_size: %"PRId64"\n", log_mmap_size);
447
448 rc = mmap(0, log_mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
449 log_mmap_offset);
450 if (rc == MAP_FAILED) {
451 perror("log mmap error");
452 }
453 dev->log_table = rc;
454 dev->log_size = log_mmap_size;
455
456 vmsg->size = sizeof(vmsg->payload.u64);
457
458 return true;
459 }
460
461 static bool
462 vu_set_log_fd_exec(VuDev *dev, VhostUserMsg *vmsg)
463 {
464 if (vmsg->fd_num != 1) {
465 vu_panic(dev, "Invalid log_fd message");
466 return false;
467 }
468
469 if (dev->log_call_fd != -1) {
470 close(dev->log_call_fd);
471 }
472 dev->log_call_fd = vmsg->fds[0];
473 DPRINT("Got log_call_fd: %d\n", vmsg->fds[0]);
474
475 return false;
476 }
477
478 static bool
479 vu_set_vring_num_exec(VuDev *dev, VhostUserMsg *vmsg)
480 {
481 unsigned int index = vmsg->payload.state.index;
482 unsigned int num = vmsg->payload.state.num;
483
484 DPRINT("State.index: %d\n", index);
485 DPRINT("State.num: %d\n", num);
486 dev->vq[index].vring.num = num;
487
488 return false;
489 }
490
491 static bool
492 vu_set_vring_addr_exec(VuDev *dev, VhostUserMsg *vmsg)
493 {
494 struct vhost_vring_addr *vra = &vmsg->payload.addr;
495 unsigned int index = vra->index;
496 VuVirtq *vq = &dev->vq[index];
497
498 DPRINT("vhost_vring_addr:\n");
499 DPRINT(" index: %d\n", vra->index);
500 DPRINT(" flags: %d\n", vra->flags);
501 DPRINT(" desc_user_addr: 0x%016llx\n", vra->desc_user_addr);
502 DPRINT(" used_user_addr: 0x%016llx\n", vra->used_user_addr);
503 DPRINT(" avail_user_addr: 0x%016llx\n", vra->avail_user_addr);
504 DPRINT(" log_guest_addr: 0x%016llx\n", vra->log_guest_addr);
505
506 vq->vring.flags = vra->flags;
507 vq->vring.desc = qva_to_va(dev, vra->desc_user_addr);
508 vq->vring.used = qva_to_va(dev, vra->used_user_addr);
509 vq->vring.avail = qva_to_va(dev, vra->avail_user_addr);
510 vq->vring.log_guest_addr = vra->log_guest_addr;
511
512 DPRINT("Setting virtq addresses:\n");
513 DPRINT(" vring_desc at %p\n", vq->vring.desc);
514 DPRINT(" vring_used at %p\n", vq->vring.used);
515 DPRINT(" vring_avail at %p\n", vq->vring.avail);
516
517 if (!(vq->vring.desc && vq->vring.used && vq->vring.avail)) {
518 vu_panic(dev, "Invalid vring_addr message");
519 return false;
520 }
521
522 vq->used_idx = vq->vring.used->idx;
523
524 return false;
525 }
526
527 static bool
528 vu_set_vring_base_exec(VuDev *dev, VhostUserMsg *vmsg)
529 {
530 unsigned int index = vmsg->payload.state.index;
531 unsigned int num = vmsg->payload.state.num;
532
533 DPRINT("State.index: %d\n", index);
534 DPRINT("State.num: %d\n", num);
535 dev->vq[index].shadow_avail_idx = dev->vq[index].last_avail_idx = num;
536
537 return false;
538 }
539
540 static bool
541 vu_get_vring_base_exec(VuDev *dev, VhostUserMsg *vmsg)
542 {
543 unsigned int index = vmsg->payload.state.index;
544
545 DPRINT("State.index: %d\n", index);
546 vmsg->payload.state.num = dev->vq[index].last_avail_idx;
547 vmsg->size = sizeof(vmsg->payload.state);
548
549 dev->vq[index].started = false;
550 if (dev->iface->queue_set_started) {
551 dev->iface->queue_set_started(dev, index, false);
552 }
553
554 if (dev->vq[index].call_fd != -1) {
555 close(dev->vq[index].call_fd);
556 dev->vq[index].call_fd = -1;
557 }
558 if (dev->vq[index].kick_fd != -1) {
559 dev->remove_watch(dev, dev->vq[index].kick_fd);
560 close(dev->vq[index].kick_fd);
561 dev->vq[index].kick_fd = -1;
562 }
563
564 return true;
565 }
566
567 static bool
568 vu_check_queue_msg_file(VuDev *dev, VhostUserMsg *vmsg)
569 {
570 int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
571
572 if (index >= VHOST_MAX_NR_VIRTQUEUE) {
573 vmsg_close_fds(vmsg);
574 vu_panic(dev, "Invalid queue index: %u", index);
575 return false;
576 }
577
578 if (vmsg->payload.u64 & VHOST_USER_VRING_NOFD_MASK ||
579 vmsg->fd_num != 1) {
580 vmsg_close_fds(vmsg);
581 vu_panic(dev, "Invalid fds in request: %d", vmsg->request);
582 return false;
583 }
584
585 return true;
586 }
587
588 static bool
589 vu_set_vring_kick_exec(VuDev *dev, VhostUserMsg *vmsg)
590 {
591 int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
592
593 DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
594
595 if (!vu_check_queue_msg_file(dev, vmsg)) {
596 return false;
597 }
598
599 if (dev->vq[index].kick_fd != -1) {
600 dev->remove_watch(dev, dev->vq[index].kick_fd);
601 close(dev->vq[index].kick_fd);
602 dev->vq[index].kick_fd = -1;
603 }
604
605 if (!(vmsg->payload.u64 & VHOST_USER_VRING_NOFD_MASK)) {
606 dev->vq[index].kick_fd = vmsg->fds[0];
607 DPRINT("Got kick_fd: %d for vq: %d\n", vmsg->fds[0], index);
608 }
609
610 dev->vq[index].started = true;
611 if (dev->iface->queue_set_started) {
612 dev->iface->queue_set_started(dev, index, true);
613 }
614
615 if (dev->vq[index].kick_fd != -1 && dev->vq[index].handler) {
616 dev->set_watch(dev, dev->vq[index].kick_fd, VU_WATCH_IN,
617 vu_kick_cb, (void *)(long)index);
618
619 DPRINT("Waiting for kicks on fd: %d for vq: %d\n",
620 dev->vq[index].kick_fd, index);
621 }
622
623 return false;
624 }
625
626 void vu_set_queue_handler(VuDev *dev, VuVirtq *vq,
627 vu_queue_handler_cb handler)
628 {
629 int qidx = vq - dev->vq;
630
631 vq->handler = handler;
632 if (vq->kick_fd >= 0) {
633 if (handler) {
634 dev->set_watch(dev, vq->kick_fd, VU_WATCH_IN,
635 vu_kick_cb, (void *)(long)qidx);
636 } else {
637 dev->remove_watch(dev, vq->kick_fd);
638 }
639 }
640 }
641
642 static bool
643 vu_set_vring_call_exec(VuDev *dev, VhostUserMsg *vmsg)
644 {
645 int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
646
647 DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
648
649 if (!vu_check_queue_msg_file(dev, vmsg)) {
650 return false;
651 }
652
653 if (dev->vq[index].call_fd != -1) {
654 close(dev->vq[index].call_fd);
655 dev->vq[index].call_fd = -1;
656 }
657
658 if (!(vmsg->payload.u64 & VHOST_USER_VRING_NOFD_MASK)) {
659 dev->vq[index].call_fd = vmsg->fds[0];
660 }
661
662 DPRINT("Got call_fd: %d for vq: %d\n", vmsg->fds[0], index);
663
664 return false;
665 }
666
667 static bool
668 vu_set_vring_err_exec(VuDev *dev, VhostUserMsg *vmsg)
669 {
670 int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
671
672 DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
673
674 if (!vu_check_queue_msg_file(dev, vmsg)) {
675 return false;
676 }
677
678 if (dev->vq[index].err_fd != -1) {
679 close(dev->vq[index].err_fd);
680 dev->vq[index].err_fd = -1;
681 }
682
683 if (!(vmsg->payload.u64 & VHOST_USER_VRING_NOFD_MASK)) {
684 dev->vq[index].err_fd = vmsg->fds[0];
685 }
686
687 return false;
688 }
689
690 static bool
691 vu_get_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg)
692 {
693 uint64_t features = 1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD;
694
695 if (dev->iface->get_protocol_features) {
696 features |= dev->iface->get_protocol_features(dev);
697 }
698
699 vmsg->payload.u64 = features;
700 vmsg->size = sizeof(vmsg->payload.u64);
701
702 return true;
703 }
704
705 static bool
706 vu_set_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg)
707 {
708 uint64_t features = vmsg->payload.u64;
709
710 DPRINT("u64: 0x%016"PRIx64"\n", features);
711
712 dev->protocol_features = vmsg->payload.u64;
713
714 if (dev->iface->set_protocol_features) {
715 dev->iface->set_protocol_features(dev, features);
716 }
717
718 return false;
719 }
720
721 static bool
722 vu_get_queue_num_exec(VuDev *dev, VhostUserMsg *vmsg)
723 {
724 DPRINT("Function %s() not implemented yet.\n", __func__);
725 return false;
726 }
727
728 static bool
729 vu_set_vring_enable_exec(VuDev *dev, VhostUserMsg *vmsg)
730 {
731 unsigned int index = vmsg->payload.state.index;
732 unsigned int enable = vmsg->payload.state.num;
733
734 DPRINT("State.index: %d\n", index);
735 DPRINT("State.enable: %d\n", enable);
736
737 if (index >= VHOST_MAX_NR_VIRTQUEUE) {
738 vu_panic(dev, "Invalid vring_enable index: %u", index);
739 return false;
740 }
741
742 dev->vq[index].enable = enable;
743 return false;
744 }
745
746 static bool
747 vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
748 {
749 int do_reply = 0;
750
751 /* Print out generic part of the request. */
752 DPRINT("================ Vhost user message ================\n");
753 DPRINT("Request: %s (%d)\n", vu_request_to_string(vmsg->request),
754 vmsg->request);
755 DPRINT("Flags: 0x%x\n", vmsg->flags);
756 DPRINT("Size: %d\n", vmsg->size);
757
758 if (vmsg->fd_num) {
759 int i;
760 DPRINT("Fds:");
761 for (i = 0; i < vmsg->fd_num; i++) {
762 DPRINT(" %d", vmsg->fds[i]);
763 }
764 DPRINT("\n");
765 }
766
767 if (dev->iface->process_msg &&
768 dev->iface->process_msg(dev, vmsg, &do_reply)) {
769 return do_reply;
770 }
771
772 switch (vmsg->request) {
773 case VHOST_USER_GET_FEATURES:
774 return vu_get_features_exec(dev, vmsg);
775 case VHOST_USER_SET_FEATURES:
776 return vu_set_features_exec(dev, vmsg);
777 case VHOST_USER_GET_PROTOCOL_FEATURES:
778 return vu_get_protocol_features_exec(dev, vmsg);
779 case VHOST_USER_SET_PROTOCOL_FEATURES:
780 return vu_set_protocol_features_exec(dev, vmsg);
781 case VHOST_USER_SET_OWNER:
782 return vu_set_owner_exec(dev, vmsg);
783 case VHOST_USER_RESET_OWNER:
784 return vu_reset_device_exec(dev, vmsg);
785 case VHOST_USER_SET_MEM_TABLE:
786 return vu_set_mem_table_exec(dev, vmsg);
787 case VHOST_USER_SET_LOG_BASE:
788 return vu_set_log_base_exec(dev, vmsg);
789 case VHOST_USER_SET_LOG_FD:
790 return vu_set_log_fd_exec(dev, vmsg);
791 case VHOST_USER_SET_VRING_NUM:
792 return vu_set_vring_num_exec(dev, vmsg);
793 case VHOST_USER_SET_VRING_ADDR:
794 return vu_set_vring_addr_exec(dev, vmsg);
795 case VHOST_USER_SET_VRING_BASE:
796 return vu_set_vring_base_exec(dev, vmsg);
797 case VHOST_USER_GET_VRING_BASE:
798 return vu_get_vring_base_exec(dev, vmsg);
799 case VHOST_USER_SET_VRING_KICK:
800 return vu_set_vring_kick_exec(dev, vmsg);
801 case VHOST_USER_SET_VRING_CALL:
802 return vu_set_vring_call_exec(dev, vmsg);
803 case VHOST_USER_SET_VRING_ERR:
804 return vu_set_vring_err_exec(dev, vmsg);
805 case VHOST_USER_GET_QUEUE_NUM:
806 return vu_get_queue_num_exec(dev, vmsg);
807 case VHOST_USER_SET_VRING_ENABLE:
808 return vu_set_vring_enable_exec(dev, vmsg);
809 case VHOST_USER_NONE:
810 break;
811 default:
812 vmsg_close_fds(vmsg);
813 vu_panic(dev, "Unhandled request: %d", vmsg->request);
814 }
815
816 return false;
817 }
818
819 bool
820 vu_dispatch(VuDev *dev)
821 {
822 VhostUserMsg vmsg = { 0, };
823 int reply_requested;
824 bool success = false;
825
826 if (!vu_message_read(dev, dev->sock, &vmsg)) {
827 goto end;
828 }
829
830 reply_requested = vu_process_message(dev, &vmsg);
831 if (!reply_requested) {
832 success = true;
833 goto end;
834 }
835
836 if (!vu_message_write(dev, dev->sock, &vmsg)) {
837 goto end;
838 }
839
840 success = true;
841
842 end:
843 g_free(vmsg.data);
844 return success;
845 }
846
847 void
848 vu_deinit(VuDev *dev)
849 {
850 int i;
851
852 for (i = 0; i < dev->nregions; i++) {
853 VuDevRegion *r = &dev->regions[i];
854 void *m = (void *) (uintptr_t) r->mmap_addr;
855 if (m != MAP_FAILED) {
856 munmap(m, r->size + r->mmap_offset);
857 }
858 }
859 dev->nregions = 0;
860
861 for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {
862 VuVirtq *vq = &dev->vq[i];
863
864 if (vq->call_fd != -1) {
865 close(vq->call_fd);
866 vq->call_fd = -1;
867 }
868
869 if (vq->kick_fd != -1) {
870 close(vq->kick_fd);
871 vq->kick_fd = -1;
872 }
873
874 if (vq->err_fd != -1) {
875 close(vq->err_fd);
876 vq->err_fd = -1;
877 }
878 }
879
880
881 vu_close_log(dev);
882
883 if (dev->sock != -1) {
884 close(dev->sock);
885 }
886 }
887
888 void
889 vu_init(VuDev *dev,
890 int socket,
891 vu_panic_cb panic,
892 vu_set_watch_cb set_watch,
893 vu_remove_watch_cb remove_watch,
894 const VuDevIface *iface)
895 {
896 int i;
897
898 assert(socket >= 0);
899 assert(set_watch);
900 assert(remove_watch);
901 assert(iface);
902 assert(panic);
903
904 memset(dev, 0, sizeof(*dev));
905
906 dev->sock = socket;
907 dev->panic = panic;
908 dev->set_watch = set_watch;
909 dev->remove_watch = remove_watch;
910 dev->iface = iface;
911 dev->log_call_fd = -1;
912 for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {
913 dev->vq[i] = (VuVirtq) {
914 .call_fd = -1, .kick_fd = -1, .err_fd = -1,
915 .notification = true,
916 };
917 }
918 }
919
920 VuVirtq *
921 vu_get_queue(VuDev *dev, int qidx)
922 {
923 assert(qidx < VHOST_MAX_NR_VIRTQUEUE);
924 return &dev->vq[qidx];
925 }
926
927 bool
928 vu_queue_enabled(VuDev *dev, VuVirtq *vq)
929 {
930 return vq->enable;
931 }
932
933 static inline uint16_t
934 vring_avail_flags(VuVirtq *vq)
935 {
936 return vq->vring.avail->flags;
937 }
938
939 static inline uint16_t
940 vring_avail_idx(VuVirtq *vq)
941 {
942 vq->shadow_avail_idx = vq->vring.avail->idx;
943
944 return vq->shadow_avail_idx;
945 }
946
947 static inline uint16_t
948 vring_avail_ring(VuVirtq *vq, int i)
949 {
950 return vq->vring.avail->ring[i];
951 }
952
953 static inline uint16_t
954 vring_get_used_event(VuVirtq *vq)
955 {
956 return vring_avail_ring(vq, vq->vring.num);
957 }
958
959 static int
960 virtqueue_num_heads(VuDev *dev, VuVirtq *vq, unsigned int idx)
961 {
962 uint16_t num_heads = vring_avail_idx(vq) - idx;
963
964 /* Check it isn't doing very strange things with descriptor numbers. */
965 if (num_heads > vq->vring.num) {
966 vu_panic(dev, "Guest moved used index from %u to %u",
967 idx, vq->shadow_avail_idx);
968 return -1;
969 }
970 if (num_heads) {
971 /* On success, callers read a descriptor at vq->last_avail_idx.
972 * Make sure descriptor read does not bypass avail index read. */
973 smp_rmb();
974 }
975
976 return num_heads;
977 }
978
979 static bool
980 virtqueue_get_head(VuDev *dev, VuVirtq *vq,
981 unsigned int idx, unsigned int *head)
982 {
983 /* Grab the next descriptor number they're advertising, and increment
984 * the index we've seen. */
985 *head = vring_avail_ring(vq, idx % vq->vring.num);
986
987 /* If their number is silly, that's a fatal mistake. */
988 if (*head >= vq->vring.num) {
989 vu_panic(dev, "Guest says index %u is available", head);
990 return false;
991 }
992
993 return true;
994 }
995
996 enum {
997 VIRTQUEUE_READ_DESC_ERROR = -1,
998 VIRTQUEUE_READ_DESC_DONE = 0, /* end of chain */
999 VIRTQUEUE_READ_DESC_MORE = 1, /* more buffers in chain */
1000 };
1001
1002 static int
1003 virtqueue_read_next_desc(VuDev *dev, struct vring_desc *desc,
1004 int i, unsigned int max, unsigned int *next)
1005 {
1006 /* If this descriptor says it doesn't chain, we're done. */
1007 if (!(desc[i].flags & VRING_DESC_F_NEXT)) {
1008 return VIRTQUEUE_READ_DESC_DONE;
1009 }
1010
1011 /* Check they're not leading us off end of descriptors. */
1012 *next = desc[i].next;
1013 /* Make sure compiler knows to grab that: we don't want it changing! */
1014 smp_wmb();
1015
1016 if (*next >= max) {
1017 vu_panic(dev, "Desc next is %u", next);
1018 return VIRTQUEUE_READ_DESC_ERROR;
1019 }
1020
1021 return VIRTQUEUE_READ_DESC_MORE;
1022 }
1023
1024 void
1025 vu_queue_get_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int *in_bytes,
1026 unsigned int *out_bytes,
1027 unsigned max_in_bytes, unsigned max_out_bytes)
1028 {
1029 unsigned int idx;
1030 unsigned int total_bufs, in_total, out_total;
1031 int rc;
1032
1033 idx = vq->last_avail_idx;
1034
1035 total_bufs = in_total = out_total = 0;
1036 if (unlikely(dev->broken) ||
1037 unlikely(!vq->vring.avail)) {
1038 goto done;
1039 }
1040
1041 while ((rc = virtqueue_num_heads(dev, vq, idx)) > 0) {
1042 unsigned int max, num_bufs, indirect = 0;
1043 struct vring_desc *desc;
1044 unsigned int i;
1045
1046 max = vq->vring.num;
1047 num_bufs = total_bufs;
1048 if (!virtqueue_get_head(dev, vq, idx++, &i)) {
1049 goto err;
1050 }
1051 desc = vq->vring.desc;
1052
1053 if (desc[i].flags & VRING_DESC_F_INDIRECT) {
1054 if (desc[i].len % sizeof(struct vring_desc)) {
1055 vu_panic(dev, "Invalid size for indirect buffer table");
1056 goto err;
1057 }
1058
1059 /* If we've got too many, that implies a descriptor loop. */
1060 if (num_bufs >= max) {
1061 vu_panic(dev, "Looped descriptor");
1062 goto err;
1063 }
1064
1065 /* loop over the indirect descriptor table */
1066 indirect = 1;
1067 max = desc[i].len / sizeof(struct vring_desc);
1068 desc = vu_gpa_to_va(dev, desc[i].addr);
1069 num_bufs = i = 0;
1070 }
1071
1072 do {
1073 /* If we've got too many, that implies a descriptor loop. */
1074 if (++num_bufs > max) {
1075 vu_panic(dev, "Looped descriptor");
1076 goto err;
1077 }
1078
1079 if (desc[i].flags & VRING_DESC_F_WRITE) {
1080 in_total += desc[i].len;
1081 } else {
1082 out_total += desc[i].len;
1083 }
1084 if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
1085 goto done;
1086 }
1087 rc = virtqueue_read_next_desc(dev, desc, i, max, &i);
1088 } while (rc == VIRTQUEUE_READ_DESC_MORE);
1089
1090 if (rc == VIRTQUEUE_READ_DESC_ERROR) {
1091 goto err;
1092 }
1093
1094 if (!indirect) {
1095 total_bufs = num_bufs;
1096 } else {
1097 total_bufs++;
1098 }
1099 }
1100 if (rc < 0) {
1101 goto err;
1102 }
1103 done:
1104 if (in_bytes) {
1105 *in_bytes = in_total;
1106 }
1107 if (out_bytes) {
1108 *out_bytes = out_total;
1109 }
1110 return;
1111
1112 err:
1113 in_total = out_total = 0;
1114 goto done;
1115 }
1116
1117 bool
1118 vu_queue_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int in_bytes,
1119 unsigned int out_bytes)
1120 {
1121 unsigned int in_total, out_total;
1122
1123 vu_queue_get_avail_bytes(dev, vq, &in_total, &out_total,
1124 in_bytes, out_bytes);
1125
1126 return in_bytes <= in_total && out_bytes <= out_total;
1127 }
1128
1129 /* Fetch avail_idx from VQ memory only when we really need to know if
1130 * guest has added some buffers. */
1131 bool
1132 vu_queue_empty(VuDev *dev, VuVirtq *vq)
1133 {
1134 if (unlikely(dev->broken) ||
1135 unlikely(!vq->vring.avail)) {
1136 return true;
1137 }
1138
1139 if (vq->shadow_avail_idx != vq->last_avail_idx) {
1140 return false;
1141 }
1142
1143 return vring_avail_idx(vq) == vq->last_avail_idx;
1144 }
1145
1146 static inline
1147 bool has_feature(uint64_t features, unsigned int fbit)
1148 {
1149 assert(fbit < 64);
1150 return !!(features & (1ULL << fbit));
1151 }
1152
1153 static inline
1154 bool vu_has_feature(VuDev *dev,
1155 unsigned int fbit)
1156 {
1157 return has_feature(dev->features, fbit);
1158 }
1159
1160 static bool
1161 vring_notify(VuDev *dev, VuVirtq *vq)
1162 {
1163 uint16_t old, new;
1164 bool v;
1165
1166 /* We need to expose used array entries before checking used event. */
1167 smp_mb();
1168
1169 /* Always notify when queue is empty (when feature acknowledge) */
1170 if (vu_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
1171 !vq->inuse && vu_queue_empty(dev, vq)) {
1172 return true;
1173 }
1174
1175 if (!vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
1176 return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
1177 }
1178
1179 v = vq->signalled_used_valid;
1180 vq->signalled_used_valid = true;
1181 old = vq->signalled_used;
1182 new = vq->signalled_used = vq->used_idx;
1183 return !v || vring_need_event(vring_get_used_event(vq), new, old);
1184 }
1185
1186 void
1187 vu_queue_notify(VuDev *dev, VuVirtq *vq)
1188 {
1189 if (unlikely(dev->broken) ||
1190 unlikely(!vq->vring.avail)) {
1191 return;
1192 }
1193
1194 if (!vring_notify(dev, vq)) {
1195 DPRINT("skipped notify...\n");
1196 return;
1197 }
1198
1199 if (eventfd_write(vq->call_fd, 1) < 0) {
1200 vu_panic(dev, "Error writing eventfd: %s", strerror(errno));
1201 }
1202 }
1203
1204 static inline void
1205 vring_used_flags_set_bit(VuVirtq *vq, int mask)
1206 {
1207 uint16_t *flags;
1208
1209 flags = (uint16_t *)((char*)vq->vring.used +
1210 offsetof(struct vring_used, flags));
1211 *flags |= mask;
1212 }
1213
1214 static inline void
1215 vring_used_flags_unset_bit(VuVirtq *vq, int mask)
1216 {
1217 uint16_t *flags;
1218
1219 flags = (uint16_t *)((char*)vq->vring.used +
1220 offsetof(struct vring_used, flags));
1221 *flags &= ~mask;
1222 }
1223
1224 static inline void
1225 vring_set_avail_event(VuVirtq *vq, uint16_t val)
1226 {
1227 if (!vq->notification) {
1228 return;
1229 }
1230
1231 *((uint16_t *) &vq->vring.used->ring[vq->vring.num]) = val;
1232 }
1233
1234 void
1235 vu_queue_set_notification(VuDev *dev, VuVirtq *vq, int enable)
1236 {
1237 vq->notification = enable;
1238 if (vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
1239 vring_set_avail_event(vq, vring_avail_idx(vq));
1240 } else if (enable) {
1241 vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
1242 } else {
1243 vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
1244 }
1245 if (enable) {
1246 /* Expose avail event/used flags before caller checks the avail idx. */
1247 smp_mb();
1248 }
1249 }
1250
1251 static void
1252 virtqueue_map_desc(VuDev *dev,
1253 unsigned int *p_num_sg, struct iovec *iov,
1254 unsigned int max_num_sg, bool is_write,
1255 uint64_t pa, size_t sz)
1256 {
1257 unsigned num_sg = *p_num_sg;
1258
1259 assert(num_sg <= max_num_sg);
1260
1261 if (!sz) {
1262 vu_panic(dev, "virtio: zero sized buffers are not allowed");
1263 return;
1264 }
1265
1266 iov[num_sg].iov_base = vu_gpa_to_va(dev, pa);
1267 iov[num_sg].iov_len = sz;
1268 num_sg++;
1269
1270 *p_num_sg = num_sg;
1271 }
1272
1273 /* Round number down to multiple */
1274 #define ALIGN_DOWN(n, m) ((n) / (m) * (m))
1275
1276 /* Round number up to multiple */
1277 #define ALIGN_UP(n, m) ALIGN_DOWN((n) + (m) - 1, (m))
1278
1279 static void *
1280 virtqueue_alloc_element(size_t sz,
1281 unsigned out_num, unsigned in_num)
1282 {
1283 VuVirtqElement *elem;
1284 size_t in_sg_ofs = ALIGN_UP(sz, __alignof__(elem->in_sg[0]));
1285 size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]);
1286 size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]);
1287
1288 assert(sz >= sizeof(VuVirtqElement));
1289 elem = malloc(out_sg_end);
1290 elem->out_num = out_num;
1291 elem->in_num = in_num;
1292 elem->in_sg = (void *)elem + in_sg_ofs;
1293 elem->out_sg = (void *)elem + out_sg_ofs;
1294 return elem;
1295 }
1296
1297 void *
1298 vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz)
1299 {
1300 unsigned int i, head, max;
1301 VuVirtqElement *elem;
1302 unsigned out_num, in_num;
1303 struct iovec iov[VIRTQUEUE_MAX_SIZE];
1304 struct vring_desc *desc;
1305 int rc;
1306
1307 if (unlikely(dev->broken) ||
1308 unlikely(!vq->vring.avail)) {
1309 return NULL;
1310 }
1311
1312 if (vu_queue_empty(dev, vq)) {
1313 return NULL;
1314 }
1315 /* Needed after virtio_queue_empty(), see comment in
1316 * virtqueue_num_heads(). */
1317 smp_rmb();
1318
1319 /* When we start there are none of either input nor output. */
1320 out_num = in_num = 0;
1321
1322 max = vq->vring.num;
1323 if (vq->inuse >= vq->vring.num) {
1324 vu_panic(dev, "Virtqueue size exceeded");
1325 return NULL;
1326 }
1327
1328 if (!virtqueue_get_head(dev, vq, vq->last_avail_idx++, &head)) {
1329 return NULL;
1330 }
1331
1332 if (vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
1333 vring_set_avail_event(vq, vq->last_avail_idx);
1334 }
1335
1336 i = head;
1337 desc = vq->vring.desc;
1338 if (desc[i].flags & VRING_DESC_F_INDIRECT) {
1339 if (desc[i].len % sizeof(struct vring_desc)) {
1340 vu_panic(dev, "Invalid size for indirect buffer table");
1341 }
1342
1343 /* loop over the indirect descriptor table */
1344 max = desc[i].len / sizeof(struct vring_desc);
1345 desc = vu_gpa_to_va(dev, desc[i].addr);
1346 i = 0;
1347 }
1348
1349 /* Collect all the descriptors */
1350 do {
1351 if (desc[i].flags & VRING_DESC_F_WRITE) {
1352 virtqueue_map_desc(dev, &in_num, iov + out_num,
1353 VIRTQUEUE_MAX_SIZE - out_num, true,
1354 desc[i].addr, desc[i].len);
1355 } else {
1356 if (in_num) {
1357 vu_panic(dev, "Incorrect order for descriptors");
1358 return NULL;
1359 }
1360 virtqueue_map_desc(dev, &out_num, iov,
1361 VIRTQUEUE_MAX_SIZE, false,
1362 desc[i].addr, desc[i].len);
1363 }
1364
1365 /* If we've got too many, that implies a descriptor loop. */
1366 if ((in_num + out_num) > max) {
1367 vu_panic(dev, "Looped descriptor");
1368 }
1369 rc = virtqueue_read_next_desc(dev, desc, i, max, &i);
1370 } while (rc == VIRTQUEUE_READ_DESC_MORE);
1371
1372 if (rc == VIRTQUEUE_READ_DESC_ERROR) {
1373 return NULL;
1374 }
1375
1376 /* Now copy what we have collected and mapped */
1377 elem = virtqueue_alloc_element(sz, out_num, in_num);
1378 elem->index = head;
1379 for (i = 0; i < out_num; i++) {
1380 elem->out_sg[i] = iov[i];
1381 }
1382 for (i = 0; i < in_num; i++) {
1383 elem->in_sg[i] = iov[out_num + i];
1384 }
1385
1386 vq->inuse++;
1387
1388 return elem;
1389 }
1390
1391 bool
1392 vu_queue_rewind(VuDev *dev, VuVirtq *vq, unsigned int num)
1393 {
1394 if (num > vq->inuse) {
1395 return false;
1396 }
1397 vq->last_avail_idx -= num;
1398 vq->inuse -= num;
1399 return true;
1400 }
1401
1402 static inline
1403 void vring_used_write(VuDev *dev, VuVirtq *vq,
1404 struct vring_used_elem *uelem, int i)
1405 {
1406 struct vring_used *used = vq->vring.used;
1407
1408 used->ring[i] = *uelem;
1409 vu_log_write(dev, vq->vring.log_guest_addr +
1410 offsetof(struct vring_used, ring[i]),
1411 sizeof(used->ring[i]));
1412 }
1413
1414
1415 static void
1416 vu_log_queue_fill(VuDev *dev, VuVirtq *vq,
1417 const VuVirtqElement *elem,
1418 unsigned int len)
1419 {
1420 struct vring_desc *desc = vq->vring.desc;
1421 unsigned int i, max, min;
1422 unsigned num_bufs = 0;
1423
1424 max = vq->vring.num;
1425 i = elem->index;
1426
1427 if (desc[i].flags & VRING_DESC_F_INDIRECT) {
1428 if (desc[i].len % sizeof(struct vring_desc)) {
1429 vu_panic(dev, "Invalid size for indirect buffer table");
1430 }
1431
1432 /* loop over the indirect descriptor table */
1433 max = desc[i].len / sizeof(struct vring_desc);
1434 desc = vu_gpa_to_va(dev, desc[i].addr);
1435 i = 0;
1436 }
1437
1438 do {
1439 if (++num_bufs > max) {
1440 vu_panic(dev, "Looped descriptor");
1441 return;
1442 }
1443
1444 if (desc[i].flags & VRING_DESC_F_WRITE) {
1445 min = MIN(desc[i].len, len);
1446 vu_log_write(dev, desc[i].addr, min);
1447 len -= min;
1448 }
1449
1450 } while (len > 0 &&
1451 (virtqueue_read_next_desc(dev, desc, i, max, &i)
1452 == VIRTQUEUE_READ_DESC_MORE));
1453 }
1454
1455 void
1456 vu_queue_fill(VuDev *dev, VuVirtq *vq,
1457 const VuVirtqElement *elem,
1458 unsigned int len, unsigned int idx)
1459 {
1460 struct vring_used_elem uelem;
1461
1462 if (unlikely(dev->broken) ||
1463 unlikely(!vq->vring.avail)) {
1464 return;
1465 }
1466
1467 vu_log_queue_fill(dev, vq, elem, len);
1468
1469 idx = (idx + vq->used_idx) % vq->vring.num;
1470
1471 uelem.id = elem->index;
1472 uelem.len = len;
1473 vring_used_write(dev, vq, &uelem, idx);
1474 }
1475
1476 static inline
1477 void vring_used_idx_set(VuDev *dev, VuVirtq *vq, uint16_t val)
1478 {
1479 vq->vring.used->idx = val;
1480 vu_log_write(dev,
1481 vq->vring.log_guest_addr + offsetof(struct vring_used, idx),
1482 sizeof(vq->vring.used->idx));
1483
1484 vq->used_idx = val;
1485 }
1486
1487 void
1488 vu_queue_flush(VuDev *dev, VuVirtq *vq, unsigned int count)
1489 {
1490 uint16_t old, new;
1491
1492 if (unlikely(dev->broken) ||
1493 unlikely(!vq->vring.avail)) {
1494 return;
1495 }
1496
1497 /* Make sure buffer is written before we update index. */
1498 smp_wmb();
1499
1500 old = vq->used_idx;
1501 new = old + count;
1502 vring_used_idx_set(dev, vq, new);
1503 vq->inuse -= count;
1504 if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old))) {
1505 vq->signalled_used_valid = false;
1506 }
1507 }
1508
1509 void
1510 vu_queue_push(VuDev *dev, VuVirtq *vq,
1511 const VuVirtqElement *elem, unsigned int len)
1512 {
1513 vu_queue_fill(dev, vq, elem, len, 0);
1514 vu_queue_flush(dev, vq, 1);
1515 }
QEmu