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1/*
2 * Virtio SCSI HBA driver
3 *
4 * Copyright IBM Corp. 2010
5 * Copyright Red Hat, Inc. 2011
6 *
7 * Authors:
8 * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
9 * Paolo Bonzini <pbonzini@redhat.com>
10 *
11 * This work is licensed under the terms of the GNU GPL, version 2 or later.
12 * See the COPYING file in the top-level directory.
13 *
14 */
15
16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/module.h>
19#include <linux/slab.h>
20#include <linux/mempool.h>
21#include <linux/virtio.h>
22#include <linux/virtio_ids.h>
23#include <linux/virtio_config.h>
24#include <linux/virtio_scsi.h>
25#include <linux/cpu.h>
26#include <linux/blkdev.h>
27#include <scsi/scsi_host.h>
28#include <scsi/scsi_device.h>
29#include <scsi/scsi_cmnd.h>
30#include <scsi/scsi_tcq.h>
31#include <linux/seqlock.h>
32
33#define VIRTIO_SCSI_MEMPOOL_SZ 64
34#define VIRTIO_SCSI_EVENT_LEN 8
35#define VIRTIO_SCSI_VQ_BASE 2
36
37/* Command queue element */
38struct virtio_scsi_cmd {
39 struct scsi_cmnd *sc;
40 struct completion *comp;
41 union {
42 struct virtio_scsi_cmd_req cmd;
43 struct virtio_scsi_cmd_req_pi cmd_pi;
44 struct virtio_scsi_ctrl_tmf_req tmf;
45 struct virtio_scsi_ctrl_an_req an;
46 } req;
47 union {
48 struct virtio_scsi_cmd_resp cmd;
49 struct virtio_scsi_ctrl_tmf_resp tmf;
50 struct virtio_scsi_ctrl_an_resp an;
51 struct virtio_scsi_event evt;
52 } resp;
53} ____cacheline_aligned_in_smp;
54
55struct virtio_scsi_event_node {
56 struct virtio_scsi *vscsi;
57 struct virtio_scsi_event event;
58 struct work_struct work;
59};
60
61struct virtio_scsi_vq {
62 /* Protects vq */
63 spinlock_t vq_lock;
64
65 struct virtqueue *vq;
66};
67
68/*
69 * Per-target queue state.
70 *
71 * This struct holds the data needed by the queue steering policy. When a
72 * target is sent multiple requests, we need to drive them to the same queue so
73 * that FIFO processing order is kept. However, if a target was idle, we can
74 * choose a queue arbitrarily. In this case the queue is chosen according to
75 * the current VCPU, so the driver expects the number of request queues to be
76 * equal to the number of VCPUs. This makes it easy and fast to select the
77 * queue, and also lets the driver optimize the IRQ affinity for the virtqueues
78 * (each virtqueue's affinity is set to the CPU that "owns" the queue).
79 *
80 * tgt_seq is held to serialize reading and writing req_vq.
81 *
82 * Decrements of reqs are never concurrent with writes of req_vq: before the
83 * decrement reqs will be != 0; after the decrement the virtqueue completion
84 * routine will not use the req_vq so it can be changed by a new request.
85 * Thus they can happen outside the tgt_seq, provided of course we make reqs
86 * an atomic_t.
87 */
88struct virtio_scsi_target_state {
89 seqcount_t tgt_seq;
90
91 /* Count of outstanding requests. */
92 atomic_t reqs;
93
94 /* Currently active virtqueue for requests sent to this target. */
95 struct virtio_scsi_vq *req_vq;
96};
97
98/* Driver instance state */
99struct virtio_scsi {
100 struct virtio_device *vdev;
101
102 /* Get some buffers ready for event vq */
103 struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
104
105 u32 num_queues;
106
107 /* If the affinity hint is set for virtqueues */
108 bool affinity_hint_set;
109
110 struct hlist_node node;
111 struct hlist_node node_dead;
112
113 /* Protected by event_vq lock */
114 bool stop_events;
115
116 struct virtio_scsi_vq ctrl_vq;
117 struct virtio_scsi_vq event_vq;
118 struct virtio_scsi_vq req_vqs[];
119};
120
121static enum cpuhp_state virtioscsi_online;
122static struct kmem_cache *virtscsi_cmd_cache;
123static mempool_t *virtscsi_cmd_pool;
124
125static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
126{
127 return vdev->priv;
128}
129
130static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
131{
132 if (!resid)
133 return;
134
135 if (!scsi_bidi_cmnd(sc)) {
136 scsi_set_resid(sc, resid);
137 return;
138 }
139
140 scsi_in(sc)->resid = min(resid, scsi_in(sc)->length);
141 scsi_out(sc)->resid = resid - scsi_in(sc)->resid;
142}
143
144/**
145 * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
146 *
147 * Called with vq_lock held.
148 */
149static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
150{
151 struct virtio_scsi_cmd *cmd = buf;
152 struct scsi_cmnd *sc = cmd->sc;
153 struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
154 struct virtio_scsi_target_state *tgt =
155 scsi_target(sc->device)->hostdata;
156
157 dev_dbg(&sc->device->sdev_gendev,
158 "cmd %p response %u status %#02x sense_len %u\n",
159 sc, resp->response, resp->status, resp->sense_len);
160
161 sc->result = resp->status;
162 virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid));
163 switch (resp->response) {
164 case VIRTIO_SCSI_S_OK:
165 set_host_byte(sc, DID_OK);
166 break;
167 case VIRTIO_SCSI_S_OVERRUN:
168 set_host_byte(sc, DID_ERROR);
169 break;
170 case VIRTIO_SCSI_S_ABORTED:
171 set_host_byte(sc, DID_ABORT);
172 break;
173 case VIRTIO_SCSI_S_BAD_TARGET:
174 set_host_byte(sc, DID_BAD_TARGET);
175 break;
176 case VIRTIO_SCSI_S_RESET:
177 set_host_byte(sc, DID_RESET);
178 break;
179 case VIRTIO_SCSI_S_BUSY:
180 set_host_byte(sc, DID_BUS_BUSY);
181 break;
182 case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
183 set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
184 break;
185 case VIRTIO_SCSI_S_TARGET_FAILURE:
186 set_host_byte(sc, DID_TARGET_FAILURE);
187 break;
188 case VIRTIO_SCSI_S_NEXUS_FAILURE:
189 set_host_byte(sc, DID_NEXUS_FAILURE);
190 break;
191 default:
192 scmd_printk(KERN_WARNING, sc, "Unknown response %d",
193 resp->response);
194 /* fall through */
195 case VIRTIO_SCSI_S_FAILURE:
196 set_host_byte(sc, DID_ERROR);
197 break;
198 }
199
200 WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) >
201 VIRTIO_SCSI_SENSE_SIZE);
202 if (sc->sense_buffer) {
203 memcpy(sc->sense_buffer, resp->sense,
204 min_t(u32,
205 virtio32_to_cpu(vscsi->vdev, resp->sense_len),
206 VIRTIO_SCSI_SENSE_SIZE));
207 if (resp->sense_len)
208 set_driver_byte(sc, DRIVER_SENSE);
209 }
210
211 sc->scsi_done(sc);
212
213 atomic_dec(&tgt->reqs);
214}
215
216static void virtscsi_vq_done(struct virtio_scsi *vscsi,
217 struct virtio_scsi_vq *virtscsi_vq,
218 void (*fn)(struct virtio_scsi *vscsi, void *buf))
219{
220 void *buf;
221 unsigned int len;
222 unsigned long flags;
223 struct virtqueue *vq = virtscsi_vq->vq;
224
225 spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
226 do {
227 virtqueue_disable_cb(vq);
228 while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
229 fn(vscsi, buf);
230
231 if (unlikely(virtqueue_is_broken(vq)))
232 break;
233 } while (!virtqueue_enable_cb(vq));
234 spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
235}
236
237static void virtscsi_req_done(struct virtqueue *vq)
238{
239 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
240 struct virtio_scsi *vscsi = shost_priv(sh);
241 int index = vq->index - VIRTIO_SCSI_VQ_BASE;
242 struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
243
244 virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
245};
246
247static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
248{
249 int i, num_vqs;
250
251 num_vqs = vscsi->num_queues;
252 for (i = 0; i < num_vqs; i++)
253 virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
254 virtscsi_complete_cmd);
255}
256
257static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
258{
259 struct virtio_scsi_cmd *cmd = buf;
260
261 if (cmd->comp)
262 complete(cmd->comp);
263}
264
265static void virtscsi_ctrl_done(struct virtqueue *vq)
266{
267 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
268 struct virtio_scsi *vscsi = shost_priv(sh);
269
270 virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
271};
272
273static void virtscsi_handle_event(struct work_struct *work);
274
275static int virtscsi_kick_event(struct virtio_scsi *vscsi,
276 struct virtio_scsi_event_node *event_node)
277{
278 int err;
279 struct scatterlist sg;
280 unsigned long flags;
281
282 INIT_WORK(&event_node->work, virtscsi_handle_event);
283 sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
284
285 spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
286
287 err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
288 GFP_ATOMIC);
289 if (!err)
290 virtqueue_kick(vscsi->event_vq.vq);
291
292 spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
293
294 return err;
295}
296
297static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
298{
299 int i;
300
301 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
302 vscsi->event_list[i].vscsi = vscsi;
303 virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
304 }
305
306 return 0;
307}
308
309static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
310{
311 int i;
312
313 /* Stop scheduling work before calling cancel_work_sync. */
314 spin_lock_irq(&vscsi->event_vq.vq_lock);
315 vscsi->stop_events = true;
316 spin_unlock_irq(&vscsi->event_vq.vq_lock);
317
318 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
319 cancel_work_sync(&vscsi->event_list[i].work);
320}
321
322static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
323 struct virtio_scsi_event *event)
324{
325 struct scsi_device *sdev;
326 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
327 unsigned int target = event->lun[1];
328 unsigned int lun = (event->lun[2] << 8) | event->lun[3];
329
330 switch (virtio32_to_cpu(vscsi->vdev, event->reason)) {
331 case VIRTIO_SCSI_EVT_RESET_RESCAN:
332 scsi_add_device(shost, 0, target, lun);
333 break;
334 case VIRTIO_SCSI_EVT_RESET_REMOVED:
335 sdev = scsi_device_lookup(shost, 0, target, lun);
336 if (sdev) {
337 scsi_remove_device(sdev);
338 scsi_device_put(sdev);
339 } else {
340 pr_err("SCSI device %d 0 %d %d not found\n",
341 shost->host_no, target, lun);
342 }
343 break;
344 default:
345 pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
346 }
347}
348
349static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
350 struct virtio_scsi_event *event)
351{
352 struct scsi_device *sdev;
353 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
354 unsigned int target = event->lun[1];
355 unsigned int lun = (event->lun[2] << 8) | event->lun[3];
356 u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255;
357 u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8;
358
359 sdev = scsi_device_lookup(shost, 0, target, lun);
360 if (!sdev) {
361 pr_err("SCSI device %d 0 %d %d not found\n",
362 shost->host_no, target, lun);
363 return;
364 }
365
366 /* Handle "Parameters changed", "Mode parameters changed", and
367 "Capacity data has changed". */
368 if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
369 scsi_rescan_device(&sdev->sdev_gendev);
370
371 scsi_device_put(sdev);
372}
373
374static void virtscsi_handle_event(struct work_struct *work)
375{
376 struct virtio_scsi_event_node *event_node =
377 container_of(work, struct virtio_scsi_event_node, work);
378 struct virtio_scsi *vscsi = event_node->vscsi;
379 struct virtio_scsi_event *event = &event_node->event;
380
381 if (event->event &
382 cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {
383 event->event &= ~cpu_to_virtio32(vscsi->vdev,
384 VIRTIO_SCSI_T_EVENTS_MISSED);
385 scsi_scan_host(virtio_scsi_host(vscsi->vdev));
386 }
387
388 switch (virtio32_to_cpu(vscsi->vdev, event->event)) {
389 case VIRTIO_SCSI_T_NO_EVENT:
390 break;
391 case VIRTIO_SCSI_T_TRANSPORT_RESET:
392 virtscsi_handle_transport_reset(vscsi, event);
393 break;
394 case VIRTIO_SCSI_T_PARAM_CHANGE:
395 virtscsi_handle_param_change(vscsi, event);
396 break;
397 default:
398 pr_err("Unsupport virtio scsi event %x\n", event->event);
399 }
400 virtscsi_kick_event(vscsi, event_node);
401}
402
403static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
404{
405 struct virtio_scsi_event_node *event_node = buf;
406
407 if (!vscsi->stop_events)
408 queue_work(system_freezable_wq, &event_node->work);
409}
410
411static void virtscsi_event_done(struct virtqueue *vq)
412{
413 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
414 struct virtio_scsi *vscsi = shost_priv(sh);
415
416 virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
417};
418
419/**
420 * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue
421 * @vq : the struct virtqueue we're talking about
422 * @cmd : command structure
423 * @req_size : size of the request buffer
424 * @resp_size : size of the response buffer
425 */
426static int virtscsi_add_cmd(struct virtqueue *vq,
427 struct virtio_scsi_cmd *cmd,
428 size_t req_size, size_t resp_size)
429{
430 struct scsi_cmnd *sc = cmd->sc;
431 struct scatterlist *sgs[6], req, resp;
432 struct sg_table *out, *in;
433 unsigned out_num = 0, in_num = 0;
434
435 out = in = NULL;
436
437 if (sc && sc->sc_data_direction != DMA_NONE) {
438 if (sc->sc_data_direction != DMA_FROM_DEVICE)
439 out = &scsi_out(sc)->table;
440 if (sc->sc_data_direction != DMA_TO_DEVICE)
441 in = &scsi_in(sc)->table;
442 }
443
444 /* Request header. */
445 sg_init_one(&req, &cmd->req, req_size);
446 sgs[out_num++] = &req;
447
448 /* Data-out buffer. */
449 if (out) {
450 /* Place WRITE protection SGLs before Data OUT payload */
451 if (scsi_prot_sg_count(sc))
452 sgs[out_num++] = scsi_prot_sglist(sc);
453 sgs[out_num++] = out->sgl;
454 }
455
456 /* Response header. */
457 sg_init_one(&resp, &cmd->resp, resp_size);
458 sgs[out_num + in_num++] = &resp;
459
460 /* Data-in buffer */
461 if (in) {
462 /* Place READ protection SGLs before Data IN payload */
463 if (scsi_prot_sg_count(sc))
464 sgs[out_num + in_num++] = scsi_prot_sglist(sc);
465 sgs[out_num + in_num++] = in->sgl;
466 }
467
468 return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
469}
470
471static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,
472 struct virtio_scsi_cmd *cmd,
473 size_t req_size, size_t resp_size)
474{
475 unsigned long flags;
476 int err;
477 bool needs_kick = false;
478
479 spin_lock_irqsave(&vq->vq_lock, flags);
480 err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
481 if (!err)
482 needs_kick = virtqueue_kick_prepare(vq->vq);
483
484 spin_unlock_irqrestore(&vq->vq_lock, flags);
485
486 if (needs_kick)
487 virtqueue_notify(vq->vq);
488 return err;
489}
490
491static void virtio_scsi_init_hdr(struct virtio_device *vdev,
492 struct virtio_scsi_cmd_req *cmd,
493 struct scsi_cmnd *sc)
494{
495 cmd->lun[0] = 1;
496 cmd->lun[1] = sc->device->id;
497 cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
498 cmd->lun[3] = sc->device->lun & 0xff;
499 cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc);
500 cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
501 cmd->prio = 0;
502 cmd->crn = 0;
503}
504
505#ifdef CONFIG_BLK_DEV_INTEGRITY
506static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
507 struct virtio_scsi_cmd_req_pi *cmd_pi,
508 struct scsi_cmnd *sc)
509{
510 struct request *rq = sc->request;
511 struct blk_integrity *bi;
512
513 virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
514
515 if (!rq || !scsi_prot_sg_count(sc))
516 return;
517
518 bi = blk_get_integrity(rq->rq_disk);
519
520 if (sc->sc_data_direction == DMA_TO_DEVICE)
521 cmd_pi->pi_bytesout = cpu_to_virtio32(vdev,
522 blk_rq_sectors(rq) *
523 bi->tuple_size);
524 else if (sc->sc_data_direction == DMA_FROM_DEVICE)
525 cmd_pi->pi_bytesin = cpu_to_virtio32(vdev,
526 blk_rq_sectors(rq) *
527 bi->tuple_size);
528}
529#endif
530
531static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
532 struct virtio_scsi_vq *req_vq,
533 struct scsi_cmnd *sc)
534{
535 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
536 struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
537 unsigned long flags;
538 int req_size;
539 int ret;
540
541 BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
542
543 /* TODO: check feature bit and fail if unsupported? */
544 BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
545
546 dev_dbg(&sc->device->sdev_gendev,
547 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
548
549 memset(cmd, 0, sizeof(*cmd));
550 cmd->sc = sc;
551
552 BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
553
554#ifdef CONFIG_BLK_DEV_INTEGRITY
555 if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
556 virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc);
557 memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
558 req_size = sizeof(cmd->req.cmd_pi);
559 } else
560#endif
561 {
562 virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc);
563 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
564 req_size = sizeof(cmd->req.cmd);
565 }
566
567 ret = virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd));
568 if (ret == -EIO) {
569 cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
570 spin_lock_irqsave(&req_vq->vq_lock, flags);
571 virtscsi_complete_cmd(vscsi, cmd);
572 spin_unlock_irqrestore(&req_vq->vq_lock, flags);
573 } else if (ret != 0) {
574 return SCSI_MLQUEUE_HOST_BUSY;
575 }
576 return 0;
577}
578
579static int virtscsi_queuecommand_single(struct Scsi_Host *sh,
580 struct scsi_cmnd *sc)
581{
582 struct virtio_scsi *vscsi = shost_priv(sh);
583 struct virtio_scsi_target_state *tgt =
584 scsi_target(sc->device)->hostdata;
585
586 atomic_inc(&tgt->reqs);
587 return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], sc);
588}
589
590static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
591 struct scsi_cmnd *sc)
592{
593 u32 tag = blk_mq_unique_tag(sc->request);
594 u16 hwq = blk_mq_unique_tag_to_hwq(tag);
595
596 return &vscsi->req_vqs[hwq];
597}
598
599static struct virtio_scsi_vq *virtscsi_pick_vq(struct virtio_scsi *vscsi,
600 struct virtio_scsi_target_state *tgt)
601{
602 struct virtio_scsi_vq *vq;
603 unsigned long flags;
604 u32 queue_num;
605
606 local_irq_save(flags);
607 if (atomic_inc_return(&tgt->reqs) > 1) {
608 unsigned long seq;
609
610 do {
611 seq = read_seqcount_begin(&tgt->tgt_seq);
612 vq = tgt->req_vq;
613 } while (read_seqcount_retry(&tgt->tgt_seq, seq));
614 } else {
615 /* no writes can be concurrent because of atomic_t */
616 write_seqcount_begin(&tgt->tgt_seq);
617
618 /* keep previous req_vq if a reader just arrived */
619 if (unlikely(atomic_read(&tgt->reqs) > 1)) {
620 vq = tgt->req_vq;
621 goto unlock;
622 }
623
624 queue_num = smp_processor_id();
625 while (unlikely(queue_num >= vscsi->num_queues))
626 queue_num -= vscsi->num_queues;
627 tgt->req_vq = vq = &vscsi->req_vqs[queue_num];
628 unlock:
629 write_seqcount_end(&tgt->tgt_seq);
630 }
631 local_irq_restore(flags);
632
633 return vq;
634}
635
636static int virtscsi_queuecommand_multi(struct Scsi_Host *sh,
637 struct scsi_cmnd *sc)
638{
639 struct virtio_scsi *vscsi = shost_priv(sh);
640 struct virtio_scsi_target_state *tgt =
641 scsi_target(sc->device)->hostdata;
642 struct virtio_scsi_vq *req_vq;
643
644 if (shost_use_blk_mq(sh))
645 req_vq = virtscsi_pick_vq_mq(vscsi, sc);
646 else
647 req_vq = virtscsi_pick_vq(vscsi, tgt);
648
649 return virtscsi_queuecommand(vscsi, req_vq, sc);
650}
651
652static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
653{
654 DECLARE_COMPLETION_ONSTACK(comp);
655 int ret = FAILED;
656
657 cmd->comp = ∁
658 if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,
659 sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0)
660 goto out;
661
662 wait_for_completion(&comp);
663 if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
664 cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
665 ret = SUCCESS;
666
667 /*
668 * The spec guarantees that all requests related to the TMF have
669 * been completed, but the callback might not have run yet if
670 * we're using independent interrupts (e.g. MSI). Poll the
671 * virtqueues once.
672 *
673 * In the abort case, sc->scsi_done will do nothing, because
674 * the block layer must have detected a timeout and as a result
675 * REQ_ATOM_COMPLETE has been set.
676 */
677 virtscsi_poll_requests(vscsi);
678
679out:
680 mempool_free(cmd, virtscsi_cmd_pool);
681 return ret;
682}
683
684static int virtscsi_device_reset(struct scsi_cmnd *sc)
685{
686 struct virtio_scsi *vscsi = shost_priv(sc->device->host);
687 struct virtio_scsi_cmd *cmd;
688
689 sdev_printk(KERN_INFO, sc->device, "device reset\n");
690 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
691 if (!cmd)
692 return FAILED;
693
694 memset(cmd, 0, sizeof(*cmd));
695 cmd->sc = sc;
696 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
697 .type = VIRTIO_SCSI_T_TMF,
698 .subtype = cpu_to_virtio32(vscsi->vdev,
699 VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET),
700 .lun[0] = 1,
701 .lun[1] = sc->device->id,
702 .lun[2] = (sc->device->lun >> 8) | 0x40,
703 .lun[3] = sc->device->lun & 0xff,
704 };
705 return virtscsi_tmf(vscsi, cmd);
706}
707
708/**
709 * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
710 * @sdev: Virtscsi target whose queue depth to change
711 * @qdepth: New queue depth
712 */
713static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
714{
715 struct Scsi_Host *shost = sdev->host;
716 int max_depth = shost->cmd_per_lun;
717
718 return scsi_change_queue_depth(sdev, min(max_depth, qdepth));
719}
720
721static int virtscsi_abort(struct scsi_cmnd *sc)
722{
723 struct virtio_scsi *vscsi = shost_priv(sc->device->host);
724 struct virtio_scsi_cmd *cmd;
725
726 scmd_printk(KERN_INFO, sc, "abort\n");
727 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
728 if (!cmd)
729 return FAILED;
730
731 memset(cmd, 0, sizeof(*cmd));
732 cmd->sc = sc;
733 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
734 .type = VIRTIO_SCSI_T_TMF,
735 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
736 .lun[0] = 1,
737 .lun[1] = sc->device->id,
738 .lun[2] = (sc->device->lun >> 8) | 0x40,
739 .lun[3] = sc->device->lun & 0xff,
740 .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc),
741 };
742 return virtscsi_tmf(vscsi, cmd);
743}
744
745static int virtscsi_target_alloc(struct scsi_target *starget)
746{
747 struct Scsi_Host *sh = dev_to_shost(starget->dev.parent);
748 struct virtio_scsi *vscsi = shost_priv(sh);
749
750 struct virtio_scsi_target_state *tgt =
751 kmalloc(sizeof(*tgt), GFP_KERNEL);
752 if (!tgt)
753 return -ENOMEM;
754
755 seqcount_init(&tgt->tgt_seq);
756 atomic_set(&tgt->reqs, 0);
757 tgt->req_vq = &vscsi->req_vqs[0];
758
759 starget->hostdata = tgt;
760 return 0;
761}
762
763static void virtscsi_target_destroy(struct scsi_target *starget)
764{
765 struct virtio_scsi_target_state *tgt = starget->hostdata;
766 kfree(tgt);
767}
768
769static struct scsi_host_template virtscsi_host_template_single = {
770 .module = THIS_MODULE,
771 .name = "Virtio SCSI HBA",
772 .proc_name = "virtio_scsi",
773 .this_id = -1,
774 .cmd_size = sizeof(struct virtio_scsi_cmd),
775 .queuecommand = virtscsi_queuecommand_single,
776 .change_queue_depth = virtscsi_change_queue_depth,
777 .eh_abort_handler = virtscsi_abort,
778 .eh_device_reset_handler = virtscsi_device_reset,
779
780 .can_queue = 1024,
781 .dma_boundary = UINT_MAX,
782 .use_clustering = ENABLE_CLUSTERING,
783 .target_alloc = virtscsi_target_alloc,
784 .target_destroy = virtscsi_target_destroy,
785 .track_queue_depth = 1,
786};
787
788static struct scsi_host_template virtscsi_host_template_multi = {
789 .module = THIS_MODULE,
790 .name = "Virtio SCSI HBA",
791 .proc_name = "virtio_scsi",
792 .this_id = -1,
793 .cmd_size = sizeof(struct virtio_scsi_cmd),
794 .queuecommand = virtscsi_queuecommand_multi,
795 .change_queue_depth = virtscsi_change_queue_depth,
796 .eh_abort_handler = virtscsi_abort,
797 .eh_device_reset_handler = virtscsi_device_reset,
798
799 .can_queue = 1024,
800 .dma_boundary = UINT_MAX,
801 .use_clustering = ENABLE_CLUSTERING,
802 .target_alloc = virtscsi_target_alloc,
803 .target_destroy = virtscsi_target_destroy,
804 .track_queue_depth = 1,
805};
806
807#define virtscsi_config_get(vdev, fld) \
808 ({ \
809 typeof(((struct virtio_scsi_config *)0)->fld) __val; \
810 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
811 __val; \
812 })
813
814#define virtscsi_config_set(vdev, fld, val) \
815 do { \
816 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
817 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
818 } while(0)
819
820static void __virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
821{
822 int i;
823 int cpu;
824
825 /* In multiqueue mode, when the number of cpu is equal
826 * to the number of request queues, we let the qeueues
827 * to be private to one cpu by setting the affinity hint
828 * to eliminate the contention.
829 */
830 if ((vscsi->num_queues == 1 ||
831 vscsi->num_queues != num_online_cpus()) && affinity) {
832 if (vscsi->affinity_hint_set)
833 affinity = false;
834 else
835 return;
836 }
837
838 if (affinity) {
839 i = 0;
840 for_each_online_cpu(cpu) {
841 virtqueue_set_affinity(vscsi->req_vqs[i].vq, cpu);
842 i++;
843 }
844
845 vscsi->affinity_hint_set = true;
846 } else {
847 for (i = 0; i < vscsi->num_queues; i++) {
848 if (!vscsi->req_vqs[i].vq)
849 continue;
850
851 virtqueue_set_affinity(vscsi->req_vqs[i].vq, -1);
852 }
853
854 vscsi->affinity_hint_set = false;
855 }
856}
857
858static void virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
859{
860 get_online_cpus();
861 __virtscsi_set_affinity(vscsi, affinity);
862 put_online_cpus();
863}
864
865static int virtscsi_cpu_online(unsigned int cpu, struct hlist_node *node)
866{
867 struct virtio_scsi *vscsi = hlist_entry_safe(node, struct virtio_scsi,
868 node);
869 __virtscsi_set_affinity(vscsi, true);
870 return 0;
871}
872
873static int virtscsi_cpu_notif_add(struct virtio_scsi *vi)
874{
875 int ret;
876
877 ret = cpuhp_state_add_instance(virtioscsi_online, &vi->node);
878 if (ret)
879 return ret;
880
881 ret = cpuhp_state_add_instance(CPUHP_VIRT_SCSI_DEAD, &vi->node_dead);
882 if (ret)
883 cpuhp_state_remove_instance(virtioscsi_online, &vi->node);
884 return ret;
885}
886
887static void virtscsi_cpu_notif_remove(struct virtio_scsi *vi)
888{
889 cpuhp_state_remove_instance_nocalls(virtioscsi_online, &vi->node);
890 cpuhp_state_remove_instance_nocalls(CPUHP_VIRT_SCSI_DEAD,
891 &vi->node_dead);
892}
893
894static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
895 struct virtqueue *vq)
896{
897 spin_lock_init(&virtscsi_vq->vq_lock);
898 virtscsi_vq->vq = vq;
899}
900
901static void virtscsi_remove_vqs(struct virtio_device *vdev)
902{
903 struct Scsi_Host *sh = virtio_scsi_host(vdev);
904 struct virtio_scsi *vscsi = shost_priv(sh);
905
906 virtscsi_set_affinity(vscsi, false);
907
908 /* Stop all the virtqueues. */
909 vdev->config->reset(vdev);
910
911 vdev->config->del_vqs(vdev);
912}
913
914static int virtscsi_init(struct virtio_device *vdev,
915 struct virtio_scsi *vscsi)
916{
917 int err;
918 u32 i;
919 u32 num_vqs;
920 vq_callback_t **callbacks;
921 const char **names;
922 struct virtqueue **vqs;
923
924 num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
925 vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL);
926 callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL);
927 names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL);
928
929 if (!callbacks || !vqs || !names) {
930 err = -ENOMEM;
931 goto out;
932 }
933
934 callbacks[0] = virtscsi_ctrl_done;
935 callbacks[1] = virtscsi_event_done;
936 names[0] = "control";
937 names[1] = "event";
938 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
939 callbacks[i] = virtscsi_req_done;
940 names[i] = "request";
941 }
942
943 /* Discover virtqueues and write information to configuration. */
944 err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
945 if (err)
946 goto out;
947
948 virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
949 virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
950 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
951 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
952 vqs[i]);
953
954 virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
955 virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
956
957 err = 0;
958
959out:
960 kfree(names);
961 kfree(callbacks);
962 kfree(vqs);
963 if (err)
964 virtscsi_remove_vqs(vdev);
965 return err;
966}
967
968static int virtscsi_probe(struct virtio_device *vdev)
969{
970 struct Scsi_Host *shost;
971 struct virtio_scsi *vscsi;
972 int err;
973 u32 sg_elems, num_targets;
974 u32 cmd_per_lun;
975 u32 num_queues;
976 struct scsi_host_template *hostt;
977
978 if (!vdev->config->get) {
979 dev_err(&vdev->dev, "%s failure: config access disabled\n",
980 __func__);
981 return -EINVAL;
982 }
983
984 /* We need to know how many queues before we allocate. */
985 num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
986
987 num_targets = virtscsi_config_get(vdev, max_target) + 1;
988
989 if (num_queues == 1)
990 hostt = &virtscsi_host_template_single;
991 else
992 hostt = &virtscsi_host_template_multi;
993
994 shost = scsi_host_alloc(hostt,
995 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
996 if (!shost)
997 return -ENOMEM;
998
999 sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
1000 shost->sg_tablesize = sg_elems;
1001 vscsi = shost_priv(shost);
1002 vscsi->vdev = vdev;
1003 vscsi->num_queues = num_queues;
1004 vdev->priv = shost;
1005
1006 err = virtscsi_init(vdev, vscsi);
1007 if (err)
1008 goto virtscsi_init_failed;
1009
1010 err = virtscsi_cpu_notif_add(vscsi);
1011 if (err)
1012 goto scsi_add_host_failed;
1013
1014 cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
1015 shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
1016 shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
1017
1018 /* LUNs > 256 are reported with format 1, so they go in the range
1019 * 16640-32767.
1020 */
1021 shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
1022 shost->max_id = num_targets;
1023 shost->max_channel = 0;
1024 shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
1025 shost->nr_hw_queues = num_queues;
1026
1027#ifdef CONFIG_BLK_DEV_INTEGRITY
1028 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
1029 int host_prot;
1030
1031 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
1032 SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
1033 SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
1034
1035 scsi_host_set_prot(shost, host_prot);
1036 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
1037 }
1038#endif
1039
1040 err = scsi_add_host(shost, &vdev->dev);
1041 if (err)
1042 goto scsi_add_host_failed;
1043
1044 virtio_device_ready(vdev);
1045
1046 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
1047 virtscsi_kick_event_all(vscsi);
1048
1049 scsi_scan_host(shost);
1050 return 0;
1051
1052scsi_add_host_failed:
1053 vdev->config->del_vqs(vdev);
1054virtscsi_init_failed:
1055 scsi_host_put(shost);
1056 return err;
1057}
1058
1059static void virtscsi_remove(struct virtio_device *vdev)
1060{
1061 struct Scsi_Host *shost = virtio_scsi_host(vdev);
1062 struct virtio_scsi *vscsi = shost_priv(shost);
1063
1064 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
1065 virtscsi_cancel_event_work(vscsi);
1066
1067 scsi_remove_host(shost);
1068
1069 virtscsi_cpu_notif_remove(vscsi);
1070
1071 virtscsi_remove_vqs(vdev);
1072 scsi_host_put(shost);
1073}
1074
1075#ifdef CONFIG_PM_SLEEP
1076static int virtscsi_freeze(struct virtio_device *vdev)
1077{
1078 struct Scsi_Host *sh = virtio_scsi_host(vdev);
1079 struct virtio_scsi *vscsi = shost_priv(sh);
1080
1081 virtscsi_cpu_notif_remove(vscsi);
1082 virtscsi_remove_vqs(vdev);
1083 return 0;
1084}
1085
1086static int virtscsi_restore(struct virtio_device *vdev)
1087{
1088 struct Scsi_Host *sh = virtio_scsi_host(vdev);
1089 struct virtio_scsi *vscsi = shost_priv(sh);
1090 int err;
1091
1092 err = virtscsi_init(vdev, vscsi);
1093 if (err)
1094 return err;
1095
1096 err = virtscsi_cpu_notif_add(vscsi);
1097 if (err) {
1098 vdev->config->del_vqs(vdev);
1099 return err;
1100 }
1101 virtio_device_ready(vdev);
1102
1103 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
1104 virtscsi_kick_event_all(vscsi);
1105
1106 return err;
1107}
1108#endif
1109
1110static struct virtio_device_id id_table[] = {
1111 { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
1112 { 0 },
1113};
1114
1115static unsigned int features[] = {
1116 VIRTIO_SCSI_F_HOTPLUG,
1117 VIRTIO_SCSI_F_CHANGE,
1118#ifdef CONFIG_BLK_DEV_INTEGRITY
1119 VIRTIO_SCSI_F_T10_PI,
1120#endif
1121};
1122
1123static struct virtio_driver virtio_scsi_driver = {
1124 .feature_table = features,
1125 .feature_table_size = ARRAY_SIZE(features),
1126 .driver.name = KBUILD_MODNAME,
1127 .driver.owner = THIS_MODULE,
1128 .id_table = id_table,
1129 .probe = virtscsi_probe,
1130#ifdef CONFIG_PM_SLEEP
1131 .freeze = virtscsi_freeze,
1132 .restore = virtscsi_restore,
1133#endif
1134 .remove = virtscsi_remove,
1135};
1136
1137static int __init init(void)
1138{
1139 int ret = -ENOMEM;
1140
1141 virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
1142 if (!virtscsi_cmd_cache) {
1143 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
1144 goto error;
1145 }
1146
1147
1148 virtscsi_cmd_pool =
1149 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
1150 virtscsi_cmd_cache);
1151 if (!virtscsi_cmd_pool) {
1152 pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
1153 goto error;
1154 }
1155 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
1156 "scsi/virtio:online",
1157 virtscsi_cpu_online, NULL);
1158 if (ret < 0)
1159 goto error;
1160 virtioscsi_online = ret;
1161 ret = cpuhp_setup_state_multi(CPUHP_VIRT_SCSI_DEAD, "scsi/virtio:dead",
1162 NULL, virtscsi_cpu_online);
1163 if (ret)
1164 goto error;
1165 ret = register_virtio_driver(&virtio_scsi_driver);
1166 if (ret < 0)
1167 goto error;
1168
1169 return 0;
1170
1171error:
1172 if (virtscsi_cmd_pool) {
1173 mempool_destroy(virtscsi_cmd_pool);
1174 virtscsi_cmd_pool = NULL;
1175 }
1176 if (virtscsi_cmd_cache) {
1177 kmem_cache_destroy(virtscsi_cmd_cache);
1178 virtscsi_cmd_cache = NULL;
1179 }
1180 if (virtioscsi_online)
1181 cpuhp_remove_multi_state(virtioscsi_online);
1182 cpuhp_remove_multi_state(CPUHP_VIRT_SCSI_DEAD);
1183 return ret;
1184}
1185
1186static void __exit fini(void)
1187{
1188 unregister_virtio_driver(&virtio_scsi_driver);
1189 cpuhp_remove_multi_state(virtioscsi_online);
1190 cpuhp_remove_multi_state(CPUHP_VIRT_SCSI_DEAD);
1191 mempool_destroy(virtscsi_cmd_pool);
1192 kmem_cache_destroy(virtscsi_cmd_cache);
1193}
1194module_init(init);
1195module_exit(fini);
1196
1197MODULE_DEVICE_TABLE(virtio, id_table);
1198MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1199MODULE_LICENSE("GPL");
1/*
2 * Virtio SCSI HBA driver
3 *
4 * Copyright IBM Corp. 2010
5 * Copyright Red Hat, Inc. 2011
6 *
7 * Authors:
8 * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
9 * Paolo Bonzini <pbonzini@redhat.com>
10 *
11 * This work is licensed under the terms of the GNU GPL, version 2 or later.
12 * See the COPYING file in the top-level directory.
13 *
14 */
15
16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/module.h>
19#include <linux/slab.h>
20#include <linux/mempool.h>
21#include <linux/interrupt.h>
22#include <linux/virtio.h>
23#include <linux/virtio_ids.h>
24#include <linux/virtio_config.h>
25#include <linux/virtio_scsi.h>
26#include <linux/cpu.h>
27#include <linux/blkdev.h>
28#include <scsi/scsi_host.h>
29#include <scsi/scsi_device.h>
30#include <scsi/scsi_cmnd.h>
31#include <scsi/scsi_tcq.h>
32#include <scsi/scsi_devinfo.h>
33#include <linux/seqlock.h>
34#include <linux/blk-mq-virtio.h>
35
36#define VIRTIO_SCSI_MEMPOOL_SZ 64
37#define VIRTIO_SCSI_EVENT_LEN 8
38#define VIRTIO_SCSI_VQ_BASE 2
39
40/* Command queue element */
41struct virtio_scsi_cmd {
42 struct scsi_cmnd *sc;
43 struct completion *comp;
44 union {
45 struct virtio_scsi_cmd_req cmd;
46 struct virtio_scsi_cmd_req_pi cmd_pi;
47 struct virtio_scsi_ctrl_tmf_req tmf;
48 struct virtio_scsi_ctrl_an_req an;
49 } req;
50 union {
51 struct virtio_scsi_cmd_resp cmd;
52 struct virtio_scsi_ctrl_tmf_resp tmf;
53 struct virtio_scsi_ctrl_an_resp an;
54 struct virtio_scsi_event evt;
55 } resp;
56} ____cacheline_aligned_in_smp;
57
58struct virtio_scsi_event_node {
59 struct virtio_scsi *vscsi;
60 struct virtio_scsi_event event;
61 struct work_struct work;
62};
63
64struct virtio_scsi_vq {
65 /* Protects vq */
66 spinlock_t vq_lock;
67
68 struct virtqueue *vq;
69};
70
71/*
72 * Per-target queue state.
73 *
74 * This struct holds the data needed by the queue steering policy. When a
75 * target is sent multiple requests, we need to drive them to the same queue so
76 * that FIFO processing order is kept. However, if a target was idle, we can
77 * choose a queue arbitrarily. In this case the queue is chosen according to
78 * the current VCPU, so the driver expects the number of request queues to be
79 * equal to the number of VCPUs. This makes it easy and fast to select the
80 * queue, and also lets the driver optimize the IRQ affinity for the virtqueues
81 * (each virtqueue's affinity is set to the CPU that "owns" the queue).
82 *
83 * tgt_seq is held to serialize reading and writing req_vq.
84 *
85 * Decrements of reqs are never concurrent with writes of req_vq: before the
86 * decrement reqs will be != 0; after the decrement the virtqueue completion
87 * routine will not use the req_vq so it can be changed by a new request.
88 * Thus they can happen outside the tgt_seq, provided of course we make reqs
89 * an atomic_t.
90 */
91struct virtio_scsi_target_state {
92 seqcount_t tgt_seq;
93
94 /* Currently active virtqueue for requests sent to this target. */
95 struct virtio_scsi_vq *req_vq;
96};
97
98/* Driver instance state */
99struct virtio_scsi {
100 struct virtio_device *vdev;
101
102 /* Get some buffers ready for event vq */
103 struct virtio_scsi_event_node event_list[VIRTIO_SCSI_EVENT_LEN];
104
105 u32 num_queues;
106
107 /* If the affinity hint is set for virtqueues */
108 bool affinity_hint_set;
109
110 struct hlist_node node;
111
112 /* Protected by event_vq lock */
113 bool stop_events;
114
115 struct virtio_scsi_vq ctrl_vq;
116 struct virtio_scsi_vq event_vq;
117 struct virtio_scsi_vq req_vqs[];
118};
119
120static struct kmem_cache *virtscsi_cmd_cache;
121static mempool_t *virtscsi_cmd_pool;
122
123static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
124{
125 return vdev->priv;
126}
127
128static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
129{
130 if (!resid)
131 return;
132
133 if (!scsi_bidi_cmnd(sc)) {
134 scsi_set_resid(sc, resid);
135 return;
136 }
137
138 scsi_in(sc)->resid = min(resid, scsi_in(sc)->length);
139 scsi_out(sc)->resid = resid - scsi_in(sc)->resid;
140}
141
142/**
143 * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
144 *
145 * Called with vq_lock held.
146 */
147static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
148{
149 struct virtio_scsi_cmd *cmd = buf;
150 struct scsi_cmnd *sc = cmd->sc;
151 struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
152
153 dev_dbg(&sc->device->sdev_gendev,
154 "cmd %p response %u status %#02x sense_len %u\n",
155 sc, resp->response, resp->status, resp->sense_len);
156
157 sc->result = resp->status;
158 virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid));
159 switch (resp->response) {
160 case VIRTIO_SCSI_S_OK:
161 set_host_byte(sc, DID_OK);
162 break;
163 case VIRTIO_SCSI_S_OVERRUN:
164 set_host_byte(sc, DID_ERROR);
165 break;
166 case VIRTIO_SCSI_S_ABORTED:
167 set_host_byte(sc, DID_ABORT);
168 break;
169 case VIRTIO_SCSI_S_BAD_TARGET:
170 set_host_byte(sc, DID_BAD_TARGET);
171 break;
172 case VIRTIO_SCSI_S_RESET:
173 set_host_byte(sc, DID_RESET);
174 break;
175 case VIRTIO_SCSI_S_BUSY:
176 set_host_byte(sc, DID_BUS_BUSY);
177 break;
178 case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
179 set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
180 break;
181 case VIRTIO_SCSI_S_TARGET_FAILURE:
182 set_host_byte(sc, DID_TARGET_FAILURE);
183 break;
184 case VIRTIO_SCSI_S_NEXUS_FAILURE:
185 set_host_byte(sc, DID_NEXUS_FAILURE);
186 break;
187 default:
188 scmd_printk(KERN_WARNING, sc, "Unknown response %d",
189 resp->response);
190 /* fall through */
191 case VIRTIO_SCSI_S_FAILURE:
192 set_host_byte(sc, DID_ERROR);
193 break;
194 }
195
196 WARN_ON(virtio32_to_cpu(vscsi->vdev, resp->sense_len) >
197 VIRTIO_SCSI_SENSE_SIZE);
198 if (sc->sense_buffer) {
199 memcpy(sc->sense_buffer, resp->sense,
200 min_t(u32,
201 virtio32_to_cpu(vscsi->vdev, resp->sense_len),
202 VIRTIO_SCSI_SENSE_SIZE));
203 if (resp->sense_len)
204 set_driver_byte(sc, DRIVER_SENSE);
205 }
206
207 sc->scsi_done(sc);
208}
209
210static void virtscsi_vq_done(struct virtio_scsi *vscsi,
211 struct virtio_scsi_vq *virtscsi_vq,
212 void (*fn)(struct virtio_scsi *vscsi, void *buf))
213{
214 void *buf;
215 unsigned int len;
216 unsigned long flags;
217 struct virtqueue *vq = virtscsi_vq->vq;
218
219 spin_lock_irqsave(&virtscsi_vq->vq_lock, flags);
220 do {
221 virtqueue_disable_cb(vq);
222 while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
223 fn(vscsi, buf);
224
225 if (unlikely(virtqueue_is_broken(vq)))
226 break;
227 } while (!virtqueue_enable_cb(vq));
228 spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
229}
230
231static void virtscsi_req_done(struct virtqueue *vq)
232{
233 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
234 struct virtio_scsi *vscsi = shost_priv(sh);
235 int index = vq->index - VIRTIO_SCSI_VQ_BASE;
236 struct virtio_scsi_vq *req_vq = &vscsi->req_vqs[index];
237
238 virtscsi_vq_done(vscsi, req_vq, virtscsi_complete_cmd);
239};
240
241static void virtscsi_poll_requests(struct virtio_scsi *vscsi)
242{
243 int i, num_vqs;
244
245 num_vqs = vscsi->num_queues;
246 for (i = 0; i < num_vqs; i++)
247 virtscsi_vq_done(vscsi, &vscsi->req_vqs[i],
248 virtscsi_complete_cmd);
249}
250
251static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
252{
253 struct virtio_scsi_cmd *cmd = buf;
254
255 if (cmd->comp)
256 complete(cmd->comp);
257}
258
259static void virtscsi_ctrl_done(struct virtqueue *vq)
260{
261 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
262 struct virtio_scsi *vscsi = shost_priv(sh);
263
264 virtscsi_vq_done(vscsi, &vscsi->ctrl_vq, virtscsi_complete_free);
265};
266
267static void virtscsi_handle_event(struct work_struct *work);
268
269static int virtscsi_kick_event(struct virtio_scsi *vscsi,
270 struct virtio_scsi_event_node *event_node)
271{
272 int err;
273 struct scatterlist sg;
274 unsigned long flags;
275
276 INIT_WORK(&event_node->work, virtscsi_handle_event);
277 sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
278
279 spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);
280
281 err = virtqueue_add_inbuf(vscsi->event_vq.vq, &sg, 1, event_node,
282 GFP_ATOMIC);
283 if (!err)
284 virtqueue_kick(vscsi->event_vq.vq);
285
286 spin_unlock_irqrestore(&vscsi->event_vq.vq_lock, flags);
287
288 return err;
289}
290
291static int virtscsi_kick_event_all(struct virtio_scsi *vscsi)
292{
293 int i;
294
295 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++) {
296 vscsi->event_list[i].vscsi = vscsi;
297 virtscsi_kick_event(vscsi, &vscsi->event_list[i]);
298 }
299
300 return 0;
301}
302
303static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
304{
305 int i;
306
307 /* Stop scheduling work before calling cancel_work_sync. */
308 spin_lock_irq(&vscsi->event_vq.vq_lock);
309 vscsi->stop_events = true;
310 spin_unlock_irq(&vscsi->event_vq.vq_lock);
311
312 for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
313 cancel_work_sync(&vscsi->event_list[i].work);
314}
315
316static void virtscsi_handle_transport_reset(struct virtio_scsi *vscsi,
317 struct virtio_scsi_event *event)
318{
319 struct scsi_device *sdev;
320 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
321 unsigned int target = event->lun[1];
322 unsigned int lun = (event->lun[2] << 8) | event->lun[3];
323
324 switch (virtio32_to_cpu(vscsi->vdev, event->reason)) {
325 case VIRTIO_SCSI_EVT_RESET_RESCAN:
326 scsi_add_device(shost, 0, target, lun);
327 break;
328 case VIRTIO_SCSI_EVT_RESET_REMOVED:
329 sdev = scsi_device_lookup(shost, 0, target, lun);
330 if (sdev) {
331 scsi_remove_device(sdev);
332 scsi_device_put(sdev);
333 } else {
334 pr_err("SCSI device %d 0 %d %d not found\n",
335 shost->host_no, target, lun);
336 }
337 break;
338 default:
339 pr_info("Unsupport virtio scsi event reason %x\n", event->reason);
340 }
341}
342
343static void virtscsi_handle_param_change(struct virtio_scsi *vscsi,
344 struct virtio_scsi_event *event)
345{
346 struct scsi_device *sdev;
347 struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
348 unsigned int target = event->lun[1];
349 unsigned int lun = (event->lun[2] << 8) | event->lun[3];
350 u8 asc = virtio32_to_cpu(vscsi->vdev, event->reason) & 255;
351 u8 ascq = virtio32_to_cpu(vscsi->vdev, event->reason) >> 8;
352
353 sdev = scsi_device_lookup(shost, 0, target, lun);
354 if (!sdev) {
355 pr_err("SCSI device %d 0 %d %d not found\n",
356 shost->host_no, target, lun);
357 return;
358 }
359
360 /* Handle "Parameters changed", "Mode parameters changed", and
361 "Capacity data has changed". */
362 if (asc == 0x2a && (ascq == 0x00 || ascq == 0x01 || ascq == 0x09))
363 scsi_rescan_device(&sdev->sdev_gendev);
364
365 scsi_device_put(sdev);
366}
367
368static void virtscsi_handle_event(struct work_struct *work)
369{
370 struct virtio_scsi_event_node *event_node =
371 container_of(work, struct virtio_scsi_event_node, work);
372 struct virtio_scsi *vscsi = event_node->vscsi;
373 struct virtio_scsi_event *event = &event_node->event;
374
375 if (event->event &
376 cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_EVENTS_MISSED)) {
377 event->event &= ~cpu_to_virtio32(vscsi->vdev,
378 VIRTIO_SCSI_T_EVENTS_MISSED);
379 scsi_scan_host(virtio_scsi_host(vscsi->vdev));
380 }
381
382 switch (virtio32_to_cpu(vscsi->vdev, event->event)) {
383 case VIRTIO_SCSI_T_NO_EVENT:
384 break;
385 case VIRTIO_SCSI_T_TRANSPORT_RESET:
386 virtscsi_handle_transport_reset(vscsi, event);
387 break;
388 case VIRTIO_SCSI_T_PARAM_CHANGE:
389 virtscsi_handle_param_change(vscsi, event);
390 break;
391 default:
392 pr_err("Unsupport virtio scsi event %x\n", event->event);
393 }
394 virtscsi_kick_event(vscsi, event_node);
395}
396
397static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
398{
399 struct virtio_scsi_event_node *event_node = buf;
400
401 if (!vscsi->stop_events)
402 queue_work(system_freezable_wq, &event_node->work);
403}
404
405static void virtscsi_event_done(struct virtqueue *vq)
406{
407 struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
408 struct virtio_scsi *vscsi = shost_priv(sh);
409
410 virtscsi_vq_done(vscsi, &vscsi->event_vq, virtscsi_complete_event);
411};
412
413/**
414 * virtscsi_add_cmd - add a virtio_scsi_cmd to a virtqueue
415 * @vq : the struct virtqueue we're talking about
416 * @cmd : command structure
417 * @req_size : size of the request buffer
418 * @resp_size : size of the response buffer
419 */
420static int virtscsi_add_cmd(struct virtqueue *vq,
421 struct virtio_scsi_cmd *cmd,
422 size_t req_size, size_t resp_size)
423{
424 struct scsi_cmnd *sc = cmd->sc;
425 struct scatterlist *sgs[6], req, resp;
426 struct sg_table *out, *in;
427 unsigned out_num = 0, in_num = 0;
428
429 out = in = NULL;
430
431 if (sc && sc->sc_data_direction != DMA_NONE) {
432 if (sc->sc_data_direction != DMA_FROM_DEVICE)
433 out = &scsi_out(sc)->table;
434 if (sc->sc_data_direction != DMA_TO_DEVICE)
435 in = &scsi_in(sc)->table;
436 }
437
438 /* Request header. */
439 sg_init_one(&req, &cmd->req, req_size);
440 sgs[out_num++] = &req;
441
442 /* Data-out buffer. */
443 if (out) {
444 /* Place WRITE protection SGLs before Data OUT payload */
445 if (scsi_prot_sg_count(sc))
446 sgs[out_num++] = scsi_prot_sglist(sc);
447 sgs[out_num++] = out->sgl;
448 }
449
450 /* Response header. */
451 sg_init_one(&resp, &cmd->resp, resp_size);
452 sgs[out_num + in_num++] = &resp;
453
454 /* Data-in buffer */
455 if (in) {
456 /* Place READ protection SGLs before Data IN payload */
457 if (scsi_prot_sg_count(sc))
458 sgs[out_num + in_num++] = scsi_prot_sglist(sc);
459 sgs[out_num + in_num++] = in->sgl;
460 }
461
462 return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, GFP_ATOMIC);
463}
464
465static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,
466 struct virtio_scsi_cmd *cmd,
467 size_t req_size, size_t resp_size)
468{
469 unsigned long flags;
470 int err;
471 bool needs_kick = false;
472
473 spin_lock_irqsave(&vq->vq_lock, flags);
474 err = virtscsi_add_cmd(vq->vq, cmd, req_size, resp_size);
475 if (!err)
476 needs_kick = virtqueue_kick_prepare(vq->vq);
477
478 spin_unlock_irqrestore(&vq->vq_lock, flags);
479
480 if (needs_kick)
481 virtqueue_notify(vq->vq);
482 return err;
483}
484
485static void virtio_scsi_init_hdr(struct virtio_device *vdev,
486 struct virtio_scsi_cmd_req *cmd,
487 struct scsi_cmnd *sc)
488{
489 cmd->lun[0] = 1;
490 cmd->lun[1] = sc->device->id;
491 cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
492 cmd->lun[3] = sc->device->lun & 0xff;
493 cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc);
494 cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
495 cmd->prio = 0;
496 cmd->crn = 0;
497}
498
499#ifdef CONFIG_BLK_DEV_INTEGRITY
500static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev,
501 struct virtio_scsi_cmd_req_pi *cmd_pi,
502 struct scsi_cmnd *sc)
503{
504 struct request *rq = sc->request;
505 struct blk_integrity *bi;
506
507 virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc);
508
509 if (!rq || !scsi_prot_sg_count(sc))
510 return;
511
512 bi = blk_get_integrity(rq->rq_disk);
513
514 if (sc->sc_data_direction == DMA_TO_DEVICE)
515 cmd_pi->pi_bytesout = cpu_to_virtio32(vdev,
516 blk_rq_sectors(rq) *
517 bi->tuple_size);
518 else if (sc->sc_data_direction == DMA_FROM_DEVICE)
519 cmd_pi->pi_bytesin = cpu_to_virtio32(vdev,
520 blk_rq_sectors(rq) *
521 bi->tuple_size);
522}
523#endif
524
525static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
526 struct scsi_cmnd *sc)
527{
528 u32 tag = blk_mq_unique_tag(sc->request);
529 u16 hwq = blk_mq_unique_tag_to_hwq(tag);
530
531 return &vscsi->req_vqs[hwq];
532}
533
534static int virtscsi_queuecommand(struct Scsi_Host *shost,
535 struct scsi_cmnd *sc)
536{
537 struct virtio_scsi *vscsi = shost_priv(shost);
538 struct virtio_scsi_vq *req_vq = virtscsi_pick_vq_mq(vscsi, sc);
539 struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
540 unsigned long flags;
541 int req_size;
542 int ret;
543
544 BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
545
546 /* TODO: check feature bit and fail if unsupported? */
547 BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
548
549 dev_dbg(&sc->device->sdev_gendev,
550 "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
551
552 cmd->sc = sc;
553
554 BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
555
556#ifdef CONFIG_BLK_DEV_INTEGRITY
557 if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) {
558 virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc);
559 memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
560 req_size = sizeof(cmd->req.cmd_pi);
561 } else
562#endif
563 {
564 virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc);
565 memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
566 req_size = sizeof(cmd->req.cmd);
567 }
568
569 ret = virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd));
570 if (ret == -EIO) {
571 cmd->resp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
572 spin_lock_irqsave(&req_vq->vq_lock, flags);
573 virtscsi_complete_cmd(vscsi, cmd);
574 spin_unlock_irqrestore(&req_vq->vq_lock, flags);
575 } else if (ret != 0) {
576 return SCSI_MLQUEUE_HOST_BUSY;
577 }
578 return 0;
579}
580
581static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
582{
583 DECLARE_COMPLETION_ONSTACK(comp);
584 int ret = FAILED;
585
586 cmd->comp = ∁
587 if (virtscsi_kick_cmd(&vscsi->ctrl_vq, cmd,
588 sizeof cmd->req.tmf, sizeof cmd->resp.tmf) < 0)
589 goto out;
590
591 wait_for_completion(&comp);
592 if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
593 cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
594 ret = SUCCESS;
595
596 /*
597 * The spec guarantees that all requests related to the TMF have
598 * been completed, but the callback might not have run yet if
599 * we're using independent interrupts (e.g. MSI). Poll the
600 * virtqueues once.
601 *
602 * In the abort case, sc->scsi_done will do nothing, because
603 * the block layer must have detected a timeout and as a result
604 * REQ_ATOM_COMPLETE has been set.
605 */
606 virtscsi_poll_requests(vscsi);
607
608out:
609 mempool_free(cmd, virtscsi_cmd_pool);
610 return ret;
611}
612
613static int virtscsi_device_reset(struct scsi_cmnd *sc)
614{
615 struct virtio_scsi *vscsi = shost_priv(sc->device->host);
616 struct virtio_scsi_cmd *cmd;
617
618 sdev_printk(KERN_INFO, sc->device, "device reset\n");
619 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
620 if (!cmd)
621 return FAILED;
622
623 memset(cmd, 0, sizeof(*cmd));
624 cmd->sc = sc;
625 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
626 .type = VIRTIO_SCSI_T_TMF,
627 .subtype = cpu_to_virtio32(vscsi->vdev,
628 VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET),
629 .lun[0] = 1,
630 .lun[1] = sc->device->id,
631 .lun[2] = (sc->device->lun >> 8) | 0x40,
632 .lun[3] = sc->device->lun & 0xff,
633 };
634 return virtscsi_tmf(vscsi, cmd);
635}
636
637static int virtscsi_device_alloc(struct scsi_device *sdevice)
638{
639 /*
640 * Passed through SCSI targets (e.g. with qemu's 'scsi-block')
641 * may have transfer limits which come from the host SCSI
642 * controller or something on the host side other than the
643 * target itself.
644 *
645 * To make this work properly, the hypervisor can adjust the
646 * target's VPD information to advertise these limits. But
647 * for that to work, the guest has to look at the VPD pages,
648 * which we won't do by default if it is an SPC-2 device, even
649 * if it does actually support it.
650 *
651 * So, set the blist to always try to read the VPD pages.
652 */
653 sdevice->sdev_bflags = BLIST_TRY_VPD_PAGES;
654
655 return 0;
656}
657
658
659/**
660 * virtscsi_change_queue_depth() - Change a virtscsi target's queue depth
661 * @sdev: Virtscsi target whose queue depth to change
662 * @qdepth: New queue depth
663 */
664static int virtscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
665{
666 struct Scsi_Host *shost = sdev->host;
667 int max_depth = shost->cmd_per_lun;
668
669 return scsi_change_queue_depth(sdev, min(max_depth, qdepth));
670}
671
672static int virtscsi_abort(struct scsi_cmnd *sc)
673{
674 struct virtio_scsi *vscsi = shost_priv(sc->device->host);
675 struct virtio_scsi_cmd *cmd;
676
677 scmd_printk(KERN_INFO, sc, "abort\n");
678 cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
679 if (!cmd)
680 return FAILED;
681
682 memset(cmd, 0, sizeof(*cmd));
683 cmd->sc = sc;
684 cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
685 .type = VIRTIO_SCSI_T_TMF,
686 .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
687 .lun[0] = 1,
688 .lun[1] = sc->device->id,
689 .lun[2] = (sc->device->lun >> 8) | 0x40,
690 .lun[3] = sc->device->lun & 0xff,
691 .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc),
692 };
693 return virtscsi_tmf(vscsi, cmd);
694}
695
696static int virtscsi_target_alloc(struct scsi_target *starget)
697{
698 struct Scsi_Host *sh = dev_to_shost(starget->dev.parent);
699 struct virtio_scsi *vscsi = shost_priv(sh);
700
701 struct virtio_scsi_target_state *tgt =
702 kmalloc(sizeof(*tgt), GFP_KERNEL);
703 if (!tgt)
704 return -ENOMEM;
705
706 seqcount_init(&tgt->tgt_seq);
707 tgt->req_vq = &vscsi->req_vqs[0];
708
709 starget->hostdata = tgt;
710 return 0;
711}
712
713static void virtscsi_target_destroy(struct scsi_target *starget)
714{
715 struct virtio_scsi_target_state *tgt = starget->hostdata;
716 kfree(tgt);
717}
718
719static int virtscsi_map_queues(struct Scsi_Host *shost)
720{
721 struct virtio_scsi *vscsi = shost_priv(shost);
722
723 return blk_mq_virtio_map_queues(&shost->tag_set, vscsi->vdev, 2);
724}
725
726/*
727 * The host guarantees to respond to each command, although I/O
728 * latencies might be higher than on bare metal. Reset the timer
729 * unconditionally to give the host a chance to perform EH.
730 */
731static enum blk_eh_timer_return virtscsi_eh_timed_out(struct scsi_cmnd *scmnd)
732{
733 return BLK_EH_RESET_TIMER;
734}
735
736static struct scsi_host_template virtscsi_host_template = {
737 .module = THIS_MODULE,
738 .name = "Virtio SCSI HBA",
739 .proc_name = "virtio_scsi",
740 .this_id = -1,
741 .cmd_size = sizeof(struct virtio_scsi_cmd),
742 .queuecommand = virtscsi_queuecommand,
743 .change_queue_depth = virtscsi_change_queue_depth,
744 .eh_abort_handler = virtscsi_abort,
745 .eh_device_reset_handler = virtscsi_device_reset,
746 .eh_timed_out = virtscsi_eh_timed_out,
747 .slave_alloc = virtscsi_device_alloc,
748
749 .dma_boundary = UINT_MAX,
750 .use_clustering = ENABLE_CLUSTERING,
751 .target_alloc = virtscsi_target_alloc,
752 .target_destroy = virtscsi_target_destroy,
753 .map_queues = virtscsi_map_queues,
754 .track_queue_depth = 1,
755 .force_blk_mq = 1,
756};
757
758#define virtscsi_config_get(vdev, fld) \
759 ({ \
760 typeof(((struct virtio_scsi_config *)0)->fld) __val; \
761 virtio_cread(vdev, struct virtio_scsi_config, fld, &__val); \
762 __val; \
763 })
764
765#define virtscsi_config_set(vdev, fld, val) \
766 do { \
767 typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
768 virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
769 } while(0)
770
771static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
772 struct virtqueue *vq)
773{
774 spin_lock_init(&virtscsi_vq->vq_lock);
775 virtscsi_vq->vq = vq;
776}
777
778static void virtscsi_remove_vqs(struct virtio_device *vdev)
779{
780 /* Stop all the virtqueues. */
781 vdev->config->reset(vdev);
782 vdev->config->del_vqs(vdev);
783}
784
785static int virtscsi_init(struct virtio_device *vdev,
786 struct virtio_scsi *vscsi)
787{
788 int err;
789 u32 i;
790 u32 num_vqs;
791 vq_callback_t **callbacks;
792 const char **names;
793 struct virtqueue **vqs;
794 struct irq_affinity desc = { .pre_vectors = 2 };
795
796 num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
797 vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL);
798 callbacks = kmalloc(num_vqs * sizeof(vq_callback_t *), GFP_KERNEL);
799 names = kmalloc(num_vqs * sizeof(char *), GFP_KERNEL);
800
801 if (!callbacks || !vqs || !names) {
802 err = -ENOMEM;
803 goto out;
804 }
805
806 callbacks[0] = virtscsi_ctrl_done;
807 callbacks[1] = virtscsi_event_done;
808 names[0] = "control";
809 names[1] = "event";
810 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++) {
811 callbacks[i] = virtscsi_req_done;
812 names[i] = "request";
813 }
814
815 /* Discover virtqueues and write information to configuration. */
816 err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
817 if (err)
818 goto out;
819
820 virtscsi_init_vq(&vscsi->ctrl_vq, vqs[0]);
821 virtscsi_init_vq(&vscsi->event_vq, vqs[1]);
822 for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
823 virtscsi_init_vq(&vscsi->req_vqs[i - VIRTIO_SCSI_VQ_BASE],
824 vqs[i]);
825
826 virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
827 virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
828
829 err = 0;
830
831out:
832 kfree(names);
833 kfree(callbacks);
834 kfree(vqs);
835 if (err)
836 virtscsi_remove_vqs(vdev);
837 return err;
838}
839
840static int virtscsi_probe(struct virtio_device *vdev)
841{
842 struct Scsi_Host *shost;
843 struct virtio_scsi *vscsi;
844 int err;
845 u32 sg_elems, num_targets;
846 u32 cmd_per_lun;
847 u32 num_queues;
848
849 if (!vdev->config->get) {
850 dev_err(&vdev->dev, "%s failure: config access disabled\n",
851 __func__);
852 return -EINVAL;
853 }
854
855 /* We need to know how many queues before we allocate. */
856 num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;
857
858 num_targets = virtscsi_config_get(vdev, max_target) + 1;
859
860 shost = scsi_host_alloc(&virtscsi_host_template,
861 sizeof(*vscsi) + sizeof(vscsi->req_vqs[0]) * num_queues);
862 if (!shost)
863 return -ENOMEM;
864
865 sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
866 shost->sg_tablesize = sg_elems;
867 vscsi = shost_priv(shost);
868 vscsi->vdev = vdev;
869 vscsi->num_queues = num_queues;
870 vdev->priv = shost;
871
872 err = virtscsi_init(vdev, vscsi);
873 if (err)
874 goto virtscsi_init_failed;
875
876 shost->can_queue = virtqueue_get_vring_size(vscsi->req_vqs[0].vq);
877
878 cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
879 shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
880 shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
881
882 /* LUNs > 256 are reported with format 1, so they go in the range
883 * 16640-32767.
884 */
885 shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1 + 0x4000;
886 shost->max_id = num_targets;
887 shost->max_channel = 0;
888 shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
889 shost->nr_hw_queues = num_queues;
890
891#ifdef CONFIG_BLK_DEV_INTEGRITY
892 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
893 int host_prot;
894
895 host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
896 SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
897 SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
898
899 scsi_host_set_prot(shost, host_prot);
900 scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
901 }
902#endif
903
904 err = scsi_add_host(shost, &vdev->dev);
905 if (err)
906 goto scsi_add_host_failed;
907
908 virtio_device_ready(vdev);
909
910 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
911 virtscsi_kick_event_all(vscsi);
912
913 scsi_scan_host(shost);
914 return 0;
915
916scsi_add_host_failed:
917 vdev->config->del_vqs(vdev);
918virtscsi_init_failed:
919 scsi_host_put(shost);
920 return err;
921}
922
923static void virtscsi_remove(struct virtio_device *vdev)
924{
925 struct Scsi_Host *shost = virtio_scsi_host(vdev);
926 struct virtio_scsi *vscsi = shost_priv(shost);
927
928 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
929 virtscsi_cancel_event_work(vscsi);
930
931 scsi_remove_host(shost);
932 virtscsi_remove_vqs(vdev);
933 scsi_host_put(shost);
934}
935
936#ifdef CONFIG_PM_SLEEP
937static int virtscsi_freeze(struct virtio_device *vdev)
938{
939 virtscsi_remove_vqs(vdev);
940 return 0;
941}
942
943static int virtscsi_restore(struct virtio_device *vdev)
944{
945 struct Scsi_Host *sh = virtio_scsi_host(vdev);
946 struct virtio_scsi *vscsi = shost_priv(sh);
947 int err;
948
949 err = virtscsi_init(vdev, vscsi);
950 if (err)
951 return err;
952
953 virtio_device_ready(vdev);
954
955 if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
956 virtscsi_kick_event_all(vscsi);
957
958 return err;
959}
960#endif
961
962static struct virtio_device_id id_table[] = {
963 { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
964 { 0 },
965};
966
967static unsigned int features[] = {
968 VIRTIO_SCSI_F_HOTPLUG,
969 VIRTIO_SCSI_F_CHANGE,
970#ifdef CONFIG_BLK_DEV_INTEGRITY
971 VIRTIO_SCSI_F_T10_PI,
972#endif
973};
974
975static struct virtio_driver virtio_scsi_driver = {
976 .feature_table = features,
977 .feature_table_size = ARRAY_SIZE(features),
978 .driver.name = KBUILD_MODNAME,
979 .driver.owner = THIS_MODULE,
980 .id_table = id_table,
981 .probe = virtscsi_probe,
982#ifdef CONFIG_PM_SLEEP
983 .freeze = virtscsi_freeze,
984 .restore = virtscsi_restore,
985#endif
986 .remove = virtscsi_remove,
987};
988
989static int __init init(void)
990{
991 int ret = -ENOMEM;
992
993 virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
994 if (!virtscsi_cmd_cache) {
995 pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n");
996 goto error;
997 }
998
999
1000 virtscsi_cmd_pool =
1001 mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
1002 virtscsi_cmd_cache);
1003 if (!virtscsi_cmd_pool) {
1004 pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
1005 goto error;
1006 }
1007 ret = register_virtio_driver(&virtio_scsi_driver);
1008 if (ret < 0)
1009 goto error;
1010
1011 return 0;
1012
1013error:
1014 if (virtscsi_cmd_pool) {
1015 mempool_destroy(virtscsi_cmd_pool);
1016 virtscsi_cmd_pool = NULL;
1017 }
1018 if (virtscsi_cmd_cache) {
1019 kmem_cache_destroy(virtscsi_cmd_cache);
1020 virtscsi_cmd_cache = NULL;
1021 }
1022 return ret;
1023}
1024
1025static void __exit fini(void)
1026{
1027 unregister_virtio_driver(&virtio_scsi_driver);
1028 mempool_destroy(virtscsi_cmd_pool);
1029 kmem_cache_destroy(virtscsi_cmd_cache);
1030}
1031module_init(init);
1032module_exit(fini);
1033
1034MODULE_DEVICE_TABLE(virtio, id_table);
1035MODULE_DESCRIPTION("Virtio SCSI HBA driver");
1036MODULE_LICENSE("GPL");