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12#include "qemu/osdep.h"
13#include "block/block.h"
14#include "subprojects/libvhost-user/libvhost-user.h"
15#include "standard-headers/linux/virtio_blk.h"
16#include "qemu/vhost-user-server.h"
17#include "vhost-user-blk-server.h"
18#include "qapi/error.h"
19#include "qom/object_interfaces.h"
20#include "sysemu/block-backend.h"
21#include "util/block-helpers.h"
22
23
24
25
26
27#define VIRTIO_BLK_SECTOR_BITS 9
28#define VIRTIO_BLK_SECTOR_SIZE (1ull << VIRTIO_BLK_SECTOR_BITS)
29
30enum {
31 VHOST_USER_BLK_NUM_QUEUES_DEFAULT = 1,
32 VHOST_USER_BLK_MAX_DISCARD_SECTORS = 32768,
33 VHOST_USER_BLK_MAX_WRITE_ZEROES_SECTORS = 32768,
34};
35struct virtio_blk_inhdr {
36 unsigned char status;
37};
38
39typedef struct VuBlkReq {
40 VuVirtqElement elem;
41 int64_t sector_num;
42 size_t size;
43 struct virtio_blk_inhdr *in;
44 struct virtio_blk_outhdr out;
45 VuServer *server;
46 struct VuVirtq *vq;
47} VuBlkReq;
48
49
50typedef struct {
51 BlockExport export;
52 VuServer vu_server;
53 uint32_t blk_size;
54 QIOChannelSocket *sioc;
55 struct virtio_blk_config blkcfg;
56 bool writable;
57} VuBlkExport;
58
59static void vu_blk_req_complete(VuBlkReq *req)
60{
61 VuDev *vu_dev = &req->server->vu_dev;
62
63
64 vu_queue_push(vu_dev, req->vq, &req->elem, req->size + 1);
65 vu_queue_notify(vu_dev, req->vq);
66
67 free(req);
68}
69
70static bool vu_blk_sect_range_ok(VuBlkExport *vexp, uint64_t sector,
71 size_t size)
72{
73 uint64_t nb_sectors;
74 uint64_t total_sectors;
75
76 if (size % VIRTIO_BLK_SECTOR_SIZE) {
77 return false;
78 }
79
80 nb_sectors = size >> VIRTIO_BLK_SECTOR_BITS;
81
82 QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != VIRTIO_BLK_SECTOR_SIZE);
83 if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
84 return false;
85 }
86 if ((sector << VIRTIO_BLK_SECTOR_BITS) % vexp->blk_size) {
87 return false;
88 }
89 blk_get_geometry(vexp->export.blk, &total_sectors);
90 if (sector > total_sectors || nb_sectors > total_sectors - sector) {
91 return false;
92 }
93 return true;
94}
95
96static int coroutine_fn
97vu_blk_discard_write_zeroes(VuBlkExport *vexp, struct iovec *iov,
98 uint32_t iovcnt, uint32_t type)
99{
100 BlockBackend *blk = vexp->export.blk;
101 struct virtio_blk_discard_write_zeroes desc;
102 ssize_t size;
103 uint64_t sector;
104 uint32_t num_sectors;
105 uint32_t max_sectors;
106 uint32_t flags;
107 int bytes;
108
109
110 if (unlikely(iov_size(iov, iovcnt) > sizeof(desc))) {
111 return VIRTIO_BLK_S_UNSUPP;
112 }
113
114 size = iov_to_buf(iov, iovcnt, 0, &desc, sizeof(desc));
115 if (unlikely(size != sizeof(desc))) {
116 error_report("Invalid size %zd, expected %zu", size, sizeof(desc));
117 return VIRTIO_BLK_S_IOERR;
118 }
119
120 sector = le64_to_cpu(desc.sector);
121 num_sectors = le32_to_cpu(desc.num_sectors);
122 flags = le32_to_cpu(desc.flags);
123 max_sectors = (type == VIRTIO_BLK_T_WRITE_ZEROES) ?
124 VHOST_USER_BLK_MAX_WRITE_ZEROES_SECTORS :
125 VHOST_USER_BLK_MAX_DISCARD_SECTORS;
126
127
128 if (unlikely(num_sectors > max_sectors)) {
129 return VIRTIO_BLK_S_IOERR;
130 }
131
132 bytes = num_sectors << VIRTIO_BLK_SECTOR_BITS;
133
134 if (unlikely(!vu_blk_sect_range_ok(vexp, sector, bytes))) {
135 return VIRTIO_BLK_S_IOERR;
136 }
137
138
139
140
141
142 if (unlikely(flags & ~VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP)) {
143 return VIRTIO_BLK_S_UNSUPP;
144 }
145
146 if (type == VIRTIO_BLK_T_WRITE_ZEROES) {
147 int blk_flags = 0;
148
149 if (flags & VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP) {
150 blk_flags |= BDRV_REQ_MAY_UNMAP;
151 }
152
153 if (blk_co_pwrite_zeroes(blk, sector << VIRTIO_BLK_SECTOR_BITS,
154 bytes, blk_flags) == 0) {
155 return VIRTIO_BLK_S_OK;
156 }
157 } else if (type == VIRTIO_BLK_T_DISCARD) {
158
159
160
161
162 if (unlikely(flags & VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP)) {
163 return VIRTIO_BLK_S_UNSUPP;
164 }
165
166 if (blk_co_pdiscard(blk, sector << VIRTIO_BLK_SECTOR_BITS,
167 bytes) == 0) {
168 return VIRTIO_BLK_S_OK;
169 }
170 }
171
172 return VIRTIO_BLK_S_IOERR;
173}
174
175static void coroutine_fn vu_blk_virtio_process_req(void *opaque)
176{
177 VuBlkReq *req = opaque;
178 VuServer *server = req->server;
179 VuVirtqElement *elem = &req->elem;
180 uint32_t type;
181
182 VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
183 BlockBackend *blk = vexp->export.blk;
184
185 struct iovec *in_iov = elem->in_sg;
186 struct iovec *out_iov = elem->out_sg;
187 unsigned in_num = elem->in_num;
188 unsigned out_num = elem->out_num;
189
190
191 if (elem->out_num < 1 || elem->in_num < 1) {
192 error_report("virtio-blk request missing headers");
193 goto err;
194 }
195
196 if (unlikely(iov_to_buf(out_iov, out_num, 0, &req->out,
197 sizeof(req->out)) != sizeof(req->out))) {
198 error_report("virtio-blk request outhdr too short");
199 goto err;
200 }
201
202 iov_discard_front(&out_iov, &out_num, sizeof(req->out));
203
204 if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) {
205 error_report("virtio-blk request inhdr too short");
206 goto err;
207 }
208
209
210 req->in = (void *)in_iov[in_num - 1].iov_base
211 + in_iov[in_num - 1].iov_len
212 - sizeof(struct virtio_blk_inhdr);
213 iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr));
214
215 type = le32_to_cpu(req->out.type);
216 switch (type & ~VIRTIO_BLK_T_BARRIER) {
217 case VIRTIO_BLK_T_IN:
218 case VIRTIO_BLK_T_OUT: {
219 QEMUIOVector qiov;
220 int64_t offset;
221 ssize_t ret = 0;
222 bool is_write = type & VIRTIO_BLK_T_OUT;
223 req->sector_num = le64_to_cpu(req->out.sector);
224
225 if (is_write && !vexp->writable) {
226 req->in->status = VIRTIO_BLK_S_IOERR;
227 break;
228 }
229
230 if (is_write) {
231 qemu_iovec_init_external(&qiov, out_iov, out_num);
232 } else {
233 qemu_iovec_init_external(&qiov, in_iov, in_num);
234 }
235
236 if (unlikely(!vu_blk_sect_range_ok(vexp,
237 req->sector_num,
238 qiov.size))) {
239 req->in->status = VIRTIO_BLK_S_IOERR;
240 break;
241 }
242
243 offset = req->sector_num << VIRTIO_BLK_SECTOR_BITS;
244
245 if (is_write) {
246 ret = blk_co_pwritev(blk, offset, qiov.size, &qiov, 0);
247 } else {
248 ret = blk_co_preadv(blk, offset, qiov.size, &qiov, 0);
249 }
250 if (ret >= 0) {
251 req->in->status = VIRTIO_BLK_S_OK;
252 } else {
253 req->in->status = VIRTIO_BLK_S_IOERR;
254 }
255 break;
256 }
257 case VIRTIO_BLK_T_FLUSH:
258 if (blk_co_flush(blk) == 0) {
259 req->in->status = VIRTIO_BLK_S_OK;
260 } else {
261 req->in->status = VIRTIO_BLK_S_IOERR;
262 }
263 break;
264 case VIRTIO_BLK_T_GET_ID: {
265 size_t size = MIN(iov_size(&elem->in_sg[0], in_num),
266 VIRTIO_BLK_ID_BYTES);
267 snprintf(elem->in_sg[0].iov_base, size, "%s", "vhost_user_blk");
268 req->in->status = VIRTIO_BLK_S_OK;
269 req->size = elem->in_sg[0].iov_len;
270 break;
271 }
272 case VIRTIO_BLK_T_DISCARD:
273 case VIRTIO_BLK_T_WRITE_ZEROES: {
274 if (!vexp->writable) {
275 req->in->status = VIRTIO_BLK_S_IOERR;
276 break;
277 }
278
279 req->in->status = vu_blk_discard_write_zeroes(vexp, out_iov, out_num,
280 type);
281 break;
282 }
283 default:
284 req->in->status = VIRTIO_BLK_S_UNSUPP;
285 break;
286 }
287
288 vu_blk_req_complete(req);
289 return;
290
291err:
292 free(req);
293}
294
295static void vu_blk_process_vq(VuDev *vu_dev, int idx)
296{
297 VuServer *server = container_of(vu_dev, VuServer, vu_dev);
298 VuVirtq *vq = vu_get_queue(vu_dev, idx);
299
300 while (1) {
301 VuBlkReq *req;
302
303 req = vu_queue_pop(vu_dev, vq, sizeof(VuBlkReq));
304 if (!req) {
305 break;
306 }
307
308 req->server = server;
309 req->vq = vq;
310
311 Coroutine *co =
312 qemu_coroutine_create(vu_blk_virtio_process_req, req);
313 qemu_coroutine_enter(co);
314 }
315}
316
317static void vu_blk_queue_set_started(VuDev *vu_dev, int idx, bool started)
318{
319 VuVirtq *vq;
320
321 assert(vu_dev);
322
323 vq = vu_get_queue(vu_dev, idx);
324 vu_set_queue_handler(vu_dev, vq, started ? vu_blk_process_vq : NULL);
325}
326
327static uint64_t vu_blk_get_features(VuDev *dev)
328{
329 uint64_t features;
330 VuServer *server = container_of(dev, VuServer, vu_dev);
331 VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
332 features = 1ull << VIRTIO_BLK_F_SIZE_MAX |
333 1ull << VIRTIO_BLK_F_SEG_MAX |
334 1ull << VIRTIO_BLK_F_TOPOLOGY |
335 1ull << VIRTIO_BLK_F_BLK_SIZE |
336 1ull << VIRTIO_BLK_F_FLUSH |
337 1ull << VIRTIO_BLK_F_DISCARD |
338 1ull << VIRTIO_BLK_F_WRITE_ZEROES |
339 1ull << VIRTIO_BLK_F_CONFIG_WCE |
340 1ull << VIRTIO_BLK_F_MQ |
341 1ull << VIRTIO_F_VERSION_1 |
342 1ull << VIRTIO_RING_F_INDIRECT_DESC |
343 1ull << VIRTIO_RING_F_EVENT_IDX |
344 1ull << VHOST_USER_F_PROTOCOL_FEATURES;
345
346 if (!vexp->writable) {
347 features |= 1ull << VIRTIO_BLK_F_RO;
348 }
349
350 return features;
351}
352
353static uint64_t vu_blk_get_protocol_features(VuDev *dev)
354{
355 return 1ull << VHOST_USER_PROTOCOL_F_CONFIG;
356}
357
358static int
359vu_blk_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len)
360{
361 VuServer *server = container_of(vu_dev, VuServer, vu_dev);
362 VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
363
364 if (len > sizeof(struct virtio_blk_config)) {
365 return -1;
366 }
367
368 memcpy(config, &vexp->blkcfg, len);
369 return 0;
370}
371
372static int
373vu_blk_set_config(VuDev *vu_dev, const uint8_t *data,
374 uint32_t offset, uint32_t size, uint32_t flags)
375{
376 VuServer *server = container_of(vu_dev, VuServer, vu_dev);
377 VuBlkExport *vexp = container_of(server, VuBlkExport, vu_server);
378 uint8_t wce;
379
380
381 if (flags != VHOST_SET_CONFIG_TYPE_MASTER) {
382 return -EINVAL;
383 }
384
385 if (offset != offsetof(struct virtio_blk_config, wce) ||
386 size != 1) {
387 return -EINVAL;
388 }
389
390 wce = *data;
391 vexp->blkcfg.wce = wce;
392 blk_set_enable_write_cache(vexp->export.blk, wce);
393 return 0;
394}
395
396
397
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400
401
402
403
404static int vu_blk_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
405{
406 if (vmsg->request == VHOST_USER_NONE) {
407 dev->panic(dev, "disconnect");
408 return true;
409 }
410 return false;
411}
412
413static const VuDevIface vu_blk_iface = {
414 .get_features = vu_blk_get_features,
415 .queue_set_started = vu_blk_queue_set_started,
416 .get_protocol_features = vu_blk_get_protocol_features,
417 .get_config = vu_blk_get_config,
418 .set_config = vu_blk_set_config,
419 .process_msg = vu_blk_process_msg,
420};
421
422static void blk_aio_attached(AioContext *ctx, void *opaque)
423{
424 VuBlkExport *vexp = opaque;
425
426 vexp->export.ctx = ctx;
427 vhost_user_server_attach_aio_context(&vexp->vu_server, ctx);
428}
429
430static void blk_aio_detach(void *opaque)
431{
432 VuBlkExport *vexp = opaque;
433
434 vhost_user_server_detach_aio_context(&vexp->vu_server);
435 vexp->export.ctx = NULL;
436}
437
438static void
439vu_blk_initialize_config(BlockDriverState *bs,
440 struct virtio_blk_config *config,
441 uint32_t blk_size,
442 uint16_t num_queues)
443{
444 config->capacity =
445 cpu_to_le64(bdrv_getlength(bs) >> VIRTIO_BLK_SECTOR_BITS);
446 config->blk_size = cpu_to_le32(blk_size);
447 config->size_max = cpu_to_le32(0);
448 config->seg_max = cpu_to_le32(128 - 2);
449 config->min_io_size = cpu_to_le16(1);
450 config->opt_io_size = cpu_to_le32(1);
451 config->num_queues = cpu_to_le16(num_queues);
452 config->max_discard_sectors =
453 cpu_to_le32(VHOST_USER_BLK_MAX_DISCARD_SECTORS);
454 config->max_discard_seg = cpu_to_le32(1);
455 config->discard_sector_alignment =
456 cpu_to_le32(blk_size >> VIRTIO_BLK_SECTOR_BITS);
457 config->max_write_zeroes_sectors
458 = cpu_to_le32(VHOST_USER_BLK_MAX_WRITE_ZEROES_SECTORS);
459 config->max_write_zeroes_seg = cpu_to_le32(1);
460}
461
462static void vu_blk_exp_request_shutdown(BlockExport *exp)
463{
464 VuBlkExport *vexp = container_of(exp, VuBlkExport, export);
465
466 vhost_user_server_stop(&vexp->vu_server);
467}
468
469static int vu_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
470 Error **errp)
471{
472 VuBlkExport *vexp = container_of(exp, VuBlkExport, export);
473 BlockExportOptionsVhostUserBlk *vu_opts = &opts->u.vhost_user_blk;
474 Error *local_err = NULL;
475 uint64_t logical_block_size;
476 uint16_t num_queues = VHOST_USER_BLK_NUM_QUEUES_DEFAULT;
477
478 vexp->writable = opts->writable;
479 vexp->blkcfg.wce = 0;
480
481 if (vu_opts->has_logical_block_size) {
482 logical_block_size = vu_opts->logical_block_size;
483 } else {
484 logical_block_size = VIRTIO_BLK_SECTOR_SIZE;
485 }
486 check_block_size(exp->id, "logical-block-size", logical_block_size,
487 &local_err);
488 if (local_err) {
489 error_propagate(errp, local_err);
490 return -EINVAL;
491 }
492 vexp->blk_size = logical_block_size;
493 blk_set_guest_block_size(exp->blk, logical_block_size);
494
495 if (vu_opts->has_num_queues) {
496 num_queues = vu_opts->num_queues;
497 }
498 if (num_queues == 0) {
499 error_setg(errp, "num-queues must be greater than 0");
500 return -EINVAL;
501 }
502
503 vu_blk_initialize_config(blk_bs(exp->blk), &vexp->blkcfg,
504 logical_block_size, num_queues);
505
506 blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
507 vexp);
508
509 if (!vhost_user_server_start(&vexp->vu_server, vu_opts->addr, exp->ctx,
510 num_queues, &vu_blk_iface, errp)) {
511 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
512 blk_aio_detach, vexp);
513 return -EADDRNOTAVAIL;
514 }
515
516 return 0;
517}
518
519static void vu_blk_exp_delete(BlockExport *exp)
520{
521 VuBlkExport *vexp = container_of(exp, VuBlkExport, export);
522
523 blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
524 vexp);
525}
526
527const BlockExportDriver blk_exp_vhost_user_blk = {
528 .type = BLOCK_EXPORT_TYPE_VHOST_USER_BLK,
529 .instance_size = sizeof(VuBlkExport),
530 .create = vu_blk_exp_create,
531 .delete = vu_blk_exp_delete,
532 .request_shutdown = vu_blk_exp_request_shutdown,
533};
534
