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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Virtio vhost-user driver
4 *
5 * Copyright(c) 2019 Intel Corporation
6 *
7 * This driver allows virtio devices to be used over a vhost-user socket.
8 *
9 * Guest devices can be instantiated by kernel module or command line
10 * parameters. One device will be created for each parameter. Syntax:
11 *
12 * virtio_uml.device=<socket>:<virtio_id>[:<platform_id>]
13 * where:
14 * <socket> := vhost-user socket path to connect
15 * <virtio_id> := virtio device id (as in virtio_ids.h)
16 * <platform_id> := (optional) platform device id
17 *
18 * example:
19 * virtio_uml.device=/var/uml.socket:1
20 *
21 * Based on Virtio MMIO driver by Pawel Moll, copyright 2011-2014, ARM Ltd.
22 */
23#include <linux/module.h>
24#include <linux/platform_device.h>
25#include <linux/slab.h>
26#include <linux/virtio.h>
27#include <linux/virtio_config.h>
28#include <linux/virtio_ring.h>
29#include <linux/time-internal.h>
30#include <shared/as-layout.h>
31#include <irq_kern.h>
32#include <init.h>
33#include <os.h>
34#include "vhost_user.h"
35
36/* Workaround due to a conflict between irq_user.h and irqreturn.h */
37#ifdef IRQ_NONE
38#undef IRQ_NONE
39#endif
40
41#define MAX_SUPPORTED_QUEUE_SIZE 256
42
43#define to_virtio_uml_device(_vdev) \
44 container_of(_vdev, struct virtio_uml_device, vdev)
45
46struct virtio_uml_platform_data {
47 u32 virtio_device_id;
48 const char *socket_path;
49 struct work_struct conn_broken_wk;
50 struct platform_device *pdev;
51};
52
53struct virtio_uml_device {
54 struct virtio_device vdev;
55 struct platform_device *pdev;
56
57 spinlock_t sock_lock;
58 int sock, req_fd;
59 u64 features;
60 u64 protocol_features;
61 u8 status;
62 u8 registered:1;
63};
64
65struct virtio_uml_vq_info {
66 int kick_fd, call_fd;
67 char name[32];
68#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
69 struct virtqueue *vq;
70 vq_callback_t *callback;
71 struct time_travel_event defer;
72#endif
73};
74
75extern unsigned long long physmem_size, highmem;
76
77#define vu_err(vu_dev, ...) dev_err(&(vu_dev)->pdev->dev, ##__VA_ARGS__)
78
79/* Vhost-user protocol */
80
81static int full_sendmsg_fds(int fd, const void *buf, unsigned int len,
82 const int *fds, unsigned int fds_num)
83{
84 int rc;
85
86 do {
87 rc = os_sendmsg_fds(fd, buf, len, fds, fds_num);
88 if (rc > 0) {
89 buf += rc;
90 len -= rc;
91 fds = NULL;
92 fds_num = 0;
93 }
94 } while (len && (rc >= 0 || rc == -EINTR));
95
96 if (rc < 0)
97 return rc;
98 return 0;
99}
100
101static int full_read(int fd, void *buf, int len, bool abortable)
102{
103 int rc;
104
105 do {
106 rc = os_read_file(fd, buf, len);
107 if (rc > 0) {
108 buf += rc;
109 len -= rc;
110 }
111 } while (len && (rc > 0 || rc == -EINTR || (!abortable && rc == -EAGAIN)));
112
113 if (rc < 0)
114 return rc;
115 if (rc == 0)
116 return -ECONNRESET;
117 return 0;
118}
119
120static int vhost_user_recv_header(int fd, struct vhost_user_msg *msg)
121{
122 return full_read(fd, msg, sizeof(msg->header), true);
123}
124
125static int vhost_user_recv(struct virtio_uml_device *vu_dev,
126 int fd, struct vhost_user_msg *msg,
127 size_t max_payload_size, bool wait)
128{
129 size_t size;
130 int rc;
131
132 /*
133 * In virtio time-travel mode, we're handling all the vhost-user
134 * FDs by polling them whenever appropriate. However, we may get
135 * into a situation where we're sending out an interrupt message
136 * to a device (e.g. a net device) and need to handle a simulation
137 * time message while doing so, e.g. one that tells us to update
138 * our idea of how long we can run without scheduling.
139 *
140 * Thus, we need to not just read() from the given fd, but need
141 * to also handle messages for the simulation time - this function
142 * does that for us while waiting for the given fd to be readable.
143 */
144 if (wait)
145 time_travel_wait_readable(fd);
146
147 rc = vhost_user_recv_header(fd, msg);
148
149 if (rc == -ECONNRESET && vu_dev->registered) {
150 struct virtio_uml_platform_data *pdata;
151
152 pdata = vu_dev->pdev->dev.platform_data;
153
154 virtio_break_device(&vu_dev->vdev);
155 schedule_work(&pdata->conn_broken_wk);
156 }
157 if (rc)
158 return rc;
159 size = msg->header.size;
160 if (size > max_payload_size)
161 return -EPROTO;
162 return full_read(fd, &msg->payload, size, false);
163}
164
165static int vhost_user_recv_resp(struct virtio_uml_device *vu_dev,
166 struct vhost_user_msg *msg,
167 size_t max_payload_size)
168{
169 int rc = vhost_user_recv(vu_dev, vu_dev->sock, msg,
170 max_payload_size, true);
171
172 if (rc)
173 return rc;
174
175 if (msg->header.flags != (VHOST_USER_FLAG_REPLY | VHOST_USER_VERSION))
176 return -EPROTO;
177
178 return 0;
179}
180
181static int vhost_user_recv_u64(struct virtio_uml_device *vu_dev,
182 u64 *value)
183{
184 struct vhost_user_msg msg;
185 int rc = vhost_user_recv_resp(vu_dev, &msg,
186 sizeof(msg.payload.integer));
187
188 if (rc)
189 return rc;
190 if (msg.header.size != sizeof(msg.payload.integer))
191 return -EPROTO;
192 *value = msg.payload.integer;
193 return 0;
194}
195
196static int vhost_user_recv_req(struct virtio_uml_device *vu_dev,
197 struct vhost_user_msg *msg,
198 size_t max_payload_size)
199{
200 int rc = vhost_user_recv(vu_dev, vu_dev->req_fd, msg,
201 max_payload_size, false);
202
203 if (rc)
204 return rc;
205
206 if ((msg->header.flags & ~VHOST_USER_FLAG_NEED_REPLY) !=
207 VHOST_USER_VERSION)
208 return -EPROTO;
209
210 return 0;
211}
212
213static int vhost_user_send(struct virtio_uml_device *vu_dev,
214 bool need_response, struct vhost_user_msg *msg,
215 int *fds, size_t num_fds)
216{
217 size_t size = sizeof(msg->header) + msg->header.size;
218 unsigned long flags;
219 bool request_ack;
220 int rc;
221
222 msg->header.flags |= VHOST_USER_VERSION;
223
224 /*
225 * The need_response flag indicates that we already need a response,
226 * e.g. to read the features. In these cases, don't request an ACK as
227 * it is meaningless. Also request an ACK only if supported.
228 */
229 request_ack = !need_response;
230 if (!(vu_dev->protocol_features &
231 BIT_ULL(VHOST_USER_PROTOCOL_F_REPLY_ACK)))
232 request_ack = false;
233
234 if (request_ack)
235 msg->header.flags |= VHOST_USER_FLAG_NEED_REPLY;
236
237 spin_lock_irqsave(&vu_dev->sock_lock, flags);
238 rc = full_sendmsg_fds(vu_dev->sock, msg, size, fds, num_fds);
239 if (rc < 0)
240 goto out;
241
242 if (request_ack) {
243 uint64_t status;
244
245 rc = vhost_user_recv_u64(vu_dev, &status);
246 if (rc)
247 goto out;
248
249 if (status) {
250 vu_err(vu_dev, "slave reports error: %llu\n", status);
251 rc = -EIO;
252 goto out;
253 }
254 }
255
256out:
257 spin_unlock_irqrestore(&vu_dev->sock_lock, flags);
258 return rc;
259}
260
261static int vhost_user_send_no_payload(struct virtio_uml_device *vu_dev,
262 bool need_response, u32 request)
263{
264 struct vhost_user_msg msg = {
265 .header.request = request,
266 };
267
268 return vhost_user_send(vu_dev, need_response, &msg, NULL, 0);
269}
270
271static int vhost_user_send_no_payload_fd(struct virtio_uml_device *vu_dev,
272 u32 request, int fd)
273{
274 struct vhost_user_msg msg = {
275 .header.request = request,
276 };
277
278 return vhost_user_send(vu_dev, false, &msg, &fd, 1);
279}
280
281static int vhost_user_send_u64(struct virtio_uml_device *vu_dev,
282 u32 request, u64 value)
283{
284 struct vhost_user_msg msg = {
285 .header.request = request,
286 .header.size = sizeof(msg.payload.integer),
287 .payload.integer = value,
288 };
289
290 return vhost_user_send(vu_dev, false, &msg, NULL, 0);
291}
292
293static int vhost_user_set_owner(struct virtio_uml_device *vu_dev)
294{
295 return vhost_user_send_no_payload(vu_dev, false, VHOST_USER_SET_OWNER);
296}
297
298static int vhost_user_get_features(struct virtio_uml_device *vu_dev,
299 u64 *features)
300{
301 int rc = vhost_user_send_no_payload(vu_dev, true,
302 VHOST_USER_GET_FEATURES);
303
304 if (rc)
305 return rc;
306 return vhost_user_recv_u64(vu_dev, features);
307}
308
309static int vhost_user_set_features(struct virtio_uml_device *vu_dev,
310 u64 features)
311{
312 return vhost_user_send_u64(vu_dev, VHOST_USER_SET_FEATURES, features);
313}
314
315static int vhost_user_get_protocol_features(struct virtio_uml_device *vu_dev,
316 u64 *protocol_features)
317{
318 int rc = vhost_user_send_no_payload(vu_dev, true,
319 VHOST_USER_GET_PROTOCOL_FEATURES);
320
321 if (rc)
322 return rc;
323 return vhost_user_recv_u64(vu_dev, protocol_features);
324}
325
326static int vhost_user_set_protocol_features(struct virtio_uml_device *vu_dev,
327 u64 protocol_features)
328{
329 return vhost_user_send_u64(vu_dev, VHOST_USER_SET_PROTOCOL_FEATURES,
330 protocol_features);
331}
332
333static void vhost_user_reply(struct virtio_uml_device *vu_dev,
334 struct vhost_user_msg *msg, int response)
335{
336 struct vhost_user_msg reply = {
337 .payload.integer = response,
338 };
339 size_t size = sizeof(reply.header) + sizeof(reply.payload.integer);
340 int rc;
341
342 reply.header = msg->header;
343 reply.header.flags &= ~VHOST_USER_FLAG_NEED_REPLY;
344 reply.header.flags |= VHOST_USER_FLAG_REPLY;
345 reply.header.size = sizeof(reply.payload.integer);
346
347 rc = full_sendmsg_fds(vu_dev->req_fd, &reply, size, NULL, 0);
348
349 if (rc)
350 vu_err(vu_dev,
351 "sending reply to slave request failed: %d (size %zu)\n",
352 rc, size);
353}
354
355static irqreturn_t vu_req_interrupt(int irq, void *data)
356{
357 struct virtio_uml_device *vu_dev = data;
358 struct virtqueue *vq;
359 int response = 1;
360 struct {
361 struct vhost_user_msg msg;
362 u8 extra_payload[512];
363 } msg;
364 int rc;
365
366 rc = vhost_user_recv_req(vu_dev, &msg.msg,
367 sizeof(msg.msg.payload) +
368 sizeof(msg.extra_payload));
369
370 if (rc)
371 return IRQ_NONE;
372
373 switch (msg.msg.header.request) {
374 case VHOST_USER_SLAVE_CONFIG_CHANGE_MSG:
375 virtio_config_changed(&vu_dev->vdev);
376 response = 0;
377 break;
378 case VHOST_USER_SLAVE_VRING_CALL:
379 virtio_device_for_each_vq((&vu_dev->vdev), vq) {
380 if (vq->index == msg.msg.payload.vring_state.index) {
381 response = 0;
382 vring_interrupt(0 /* ignored */, vq);
383 break;
384 }
385 }
386 break;
387 case VHOST_USER_SLAVE_IOTLB_MSG:
388 /* not supported - VIRTIO_F_ACCESS_PLATFORM */
389 case VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG:
390 /* not supported - VHOST_USER_PROTOCOL_F_HOST_NOTIFIER */
391 default:
392 vu_err(vu_dev, "unexpected slave request %d\n",
393 msg.msg.header.request);
394 }
395
396 if (msg.msg.header.flags & VHOST_USER_FLAG_NEED_REPLY)
397 vhost_user_reply(vu_dev, &msg.msg, response);
398
399 return IRQ_HANDLED;
400}
401
402static int vhost_user_init_slave_req(struct virtio_uml_device *vu_dev)
403{
404 int rc, req_fds[2];
405
406 /* Use a pipe for slave req fd, SIGIO is not supported for eventfd */
407 rc = os_pipe(req_fds, true, true);
408 if (rc < 0)
409 return rc;
410 vu_dev->req_fd = req_fds[0];
411
412 rc = um_request_irq(VIRTIO_IRQ, vu_dev->req_fd, IRQ_READ,
413 vu_req_interrupt, IRQF_SHARED,
414 vu_dev->pdev->name, vu_dev);
415 if (rc)
416 goto err_close;
417
418 rc = vhost_user_send_no_payload_fd(vu_dev, VHOST_USER_SET_SLAVE_REQ_FD,
419 req_fds[1]);
420 if (rc)
421 goto err_free_irq;
422
423 goto out;
424
425err_free_irq:
426 um_free_irq(VIRTIO_IRQ, vu_dev);
427err_close:
428 os_close_file(req_fds[0]);
429out:
430 /* Close unused write end of request fds */
431 os_close_file(req_fds[1]);
432 return rc;
433}
434
435static int vhost_user_init(struct virtio_uml_device *vu_dev)
436{
437 int rc = vhost_user_set_owner(vu_dev);
438
439 if (rc)
440 return rc;
441 rc = vhost_user_get_features(vu_dev, &vu_dev->features);
442 if (rc)
443 return rc;
444
445 if (vu_dev->features & BIT_ULL(VHOST_USER_F_PROTOCOL_FEATURES)) {
446 rc = vhost_user_get_protocol_features(vu_dev,
447 &vu_dev->protocol_features);
448 if (rc)
449 return rc;
450 vu_dev->protocol_features &= VHOST_USER_SUPPORTED_PROTOCOL_F;
451 rc = vhost_user_set_protocol_features(vu_dev,
452 vu_dev->protocol_features);
453 if (rc)
454 return rc;
455 }
456
457 if (vu_dev->protocol_features &
458 BIT_ULL(VHOST_USER_PROTOCOL_F_SLAVE_REQ)) {
459 rc = vhost_user_init_slave_req(vu_dev);
460 if (rc)
461 return rc;
462 }
463
464 return 0;
465}
466
467static void vhost_user_get_config(struct virtio_uml_device *vu_dev,
468 u32 offset, void *buf, u32 len)
469{
470 u32 cfg_size = offset + len;
471 struct vhost_user_msg *msg;
472 size_t payload_size = sizeof(msg->payload.config) + cfg_size;
473 size_t msg_size = sizeof(msg->header) + payload_size;
474 int rc;
475
476 if (!(vu_dev->protocol_features &
477 BIT_ULL(VHOST_USER_PROTOCOL_F_CONFIG)))
478 return;
479
480 msg = kzalloc(msg_size, GFP_KERNEL);
481 if (!msg)
482 return;
483 msg->header.request = VHOST_USER_GET_CONFIG;
484 msg->header.size = payload_size;
485 msg->payload.config.offset = 0;
486 msg->payload.config.size = cfg_size;
487
488 rc = vhost_user_send(vu_dev, true, msg, NULL, 0);
489 if (rc) {
490 vu_err(vu_dev, "sending VHOST_USER_GET_CONFIG failed: %d\n",
491 rc);
492 goto free;
493 }
494
495 rc = vhost_user_recv_resp(vu_dev, msg, msg_size);
496 if (rc) {
497 vu_err(vu_dev,
498 "receiving VHOST_USER_GET_CONFIG response failed: %d\n",
499 rc);
500 goto free;
501 }
502
503 if (msg->header.size != payload_size ||
504 msg->payload.config.size != cfg_size) {
505 rc = -EPROTO;
506 vu_err(vu_dev,
507 "Invalid VHOST_USER_GET_CONFIG sizes (payload %d expected %zu, config %u expected %u)\n",
508 msg->header.size, payload_size,
509 msg->payload.config.size, cfg_size);
510 goto free;
511 }
512 memcpy(buf, msg->payload.config.payload + offset, len);
513
514free:
515 kfree(msg);
516}
517
518static void vhost_user_set_config(struct virtio_uml_device *vu_dev,
519 u32 offset, const void *buf, u32 len)
520{
521 struct vhost_user_msg *msg;
522 size_t payload_size = sizeof(msg->payload.config) + len;
523 size_t msg_size = sizeof(msg->header) + payload_size;
524 int rc;
525
526 if (!(vu_dev->protocol_features &
527 BIT_ULL(VHOST_USER_PROTOCOL_F_CONFIG)))
528 return;
529
530 msg = kzalloc(msg_size, GFP_KERNEL);
531 if (!msg)
532 return;
533 msg->header.request = VHOST_USER_SET_CONFIG;
534 msg->header.size = payload_size;
535 msg->payload.config.offset = offset;
536 msg->payload.config.size = len;
537 memcpy(msg->payload.config.payload, buf, len);
538
539 rc = vhost_user_send(vu_dev, false, msg, NULL, 0);
540 if (rc)
541 vu_err(vu_dev, "sending VHOST_USER_SET_CONFIG failed: %d\n",
542 rc);
543
544 kfree(msg);
545}
546
547static int vhost_user_init_mem_region(u64 addr, u64 size, int *fd_out,
548 struct vhost_user_mem_region *region_out)
549{
550 unsigned long long mem_offset;
551 int rc = phys_mapping(addr, &mem_offset);
552
553 if (WARN(rc < 0, "phys_mapping of 0x%llx returned %d\n", addr, rc))
554 return -EFAULT;
555 *fd_out = rc;
556 region_out->guest_addr = addr;
557 region_out->user_addr = addr;
558 region_out->size = size;
559 region_out->mmap_offset = mem_offset;
560
561 /* Ensure mapping is valid for the entire region */
562 rc = phys_mapping(addr + size - 1, &mem_offset);
563 if (WARN(rc != *fd_out, "phys_mapping of 0x%llx failed: %d != %d\n",
564 addr + size - 1, rc, *fd_out))
565 return -EFAULT;
566 return 0;
567}
568
569static int vhost_user_set_mem_table(struct virtio_uml_device *vu_dev)
570{
571 struct vhost_user_msg msg = {
572 .header.request = VHOST_USER_SET_MEM_TABLE,
573 .header.size = sizeof(msg.payload.mem_regions),
574 .payload.mem_regions.num = 1,
575 };
576 unsigned long reserved = uml_reserved - uml_physmem;
577 int fds[2];
578 int rc;
579
580 /*
581 * This is a bit tricky, see also the comment with setup_physmem().
582 *
583 * Essentially, setup_physmem() uses a file to mmap() our physmem,
584 * but the code and data we *already* have is omitted. To us, this
585 * is no difference, since they both become part of our address
586 * space and memory consumption. To somebody looking in from the
587 * outside, however, it is different because the part of our memory
588 * consumption that's already part of the binary (code/data) is not
589 * mapped from the file, so it's not visible to another mmap from
590 * the file descriptor.
591 *
592 * Thus, don't advertise this space to the vhost-user slave. This
593 * means that the slave will likely abort or similar when we give
594 * it an address from the hidden range, since it's not marked as
595 * a valid address, but at least that way we detect the issue and
596 * don't just have the slave read an all-zeroes buffer from the
597 * shared memory file, or write something there that we can never
598 * see (depending on the direction of the virtqueue traffic.)
599 *
600 * Since we usually don't want to use .text for virtio buffers,
601 * this effectively means that you cannot use
602 * 1) global variables, which are in the .bss and not in the shm
603 * file-backed memory
604 * 2) the stack in some processes, depending on where they have
605 * their stack (or maybe only no interrupt stack?)
606 *
607 * The stack is already not typically valid for DMA, so this isn't
608 * much of a restriction, but global variables might be encountered.
609 *
610 * It might be possible to fix it by copying around the data that's
611 * between bss_start and where we map the file now, but it's not
612 * something that you typically encounter with virtio drivers, so
613 * it didn't seem worthwhile.
614 */
615 rc = vhost_user_init_mem_region(reserved, physmem_size - reserved,
616 &fds[0],
617 &msg.payload.mem_regions.regions[0]);
618
619 if (rc < 0)
620 return rc;
621 if (highmem) {
622 msg.payload.mem_regions.num++;
623 rc = vhost_user_init_mem_region(__pa(end_iomem), highmem,
624 &fds[1], &msg.payload.mem_regions.regions[1]);
625 if (rc < 0)
626 return rc;
627 }
628
629 return vhost_user_send(vu_dev, false, &msg, fds,
630 msg.payload.mem_regions.num);
631}
632
633static int vhost_user_set_vring_state(struct virtio_uml_device *vu_dev,
634 u32 request, u32 index, u32 num)
635{
636 struct vhost_user_msg msg = {
637 .header.request = request,
638 .header.size = sizeof(msg.payload.vring_state),
639 .payload.vring_state.index = index,
640 .payload.vring_state.num = num,
641 };
642
643 return vhost_user_send(vu_dev, false, &msg, NULL, 0);
644}
645
646static int vhost_user_set_vring_num(struct virtio_uml_device *vu_dev,
647 u32 index, u32 num)
648{
649 return vhost_user_set_vring_state(vu_dev, VHOST_USER_SET_VRING_NUM,
650 index, num);
651}
652
653static int vhost_user_set_vring_base(struct virtio_uml_device *vu_dev,
654 u32 index, u32 offset)
655{
656 return vhost_user_set_vring_state(vu_dev, VHOST_USER_SET_VRING_BASE,
657 index, offset);
658}
659
660static int vhost_user_set_vring_addr(struct virtio_uml_device *vu_dev,
661 u32 index, u64 desc, u64 used, u64 avail,
662 u64 log)
663{
664 struct vhost_user_msg msg = {
665 .header.request = VHOST_USER_SET_VRING_ADDR,
666 .header.size = sizeof(msg.payload.vring_addr),
667 .payload.vring_addr.index = index,
668 .payload.vring_addr.desc = desc,
669 .payload.vring_addr.used = used,
670 .payload.vring_addr.avail = avail,
671 .payload.vring_addr.log = log,
672 };
673
674 return vhost_user_send(vu_dev, false, &msg, NULL, 0);
675}
676
677static int vhost_user_set_vring_fd(struct virtio_uml_device *vu_dev,
678 u32 request, int index, int fd)
679{
680 struct vhost_user_msg msg = {
681 .header.request = request,
682 .header.size = sizeof(msg.payload.integer),
683 .payload.integer = index,
684 };
685
686 if (index & ~VHOST_USER_VRING_INDEX_MASK)
687 return -EINVAL;
688 if (fd < 0) {
689 msg.payload.integer |= VHOST_USER_VRING_POLL_MASK;
690 return vhost_user_send(vu_dev, false, &msg, NULL, 0);
691 }
692 return vhost_user_send(vu_dev, false, &msg, &fd, 1);
693}
694
695static int vhost_user_set_vring_call(struct virtio_uml_device *vu_dev,
696 int index, int fd)
697{
698 return vhost_user_set_vring_fd(vu_dev, VHOST_USER_SET_VRING_CALL,
699 index, fd);
700}
701
702static int vhost_user_set_vring_kick(struct virtio_uml_device *vu_dev,
703 int index, int fd)
704{
705 return vhost_user_set_vring_fd(vu_dev, VHOST_USER_SET_VRING_KICK,
706 index, fd);
707}
708
709static int vhost_user_set_vring_enable(struct virtio_uml_device *vu_dev,
710 u32 index, bool enable)
711{
712 if (!(vu_dev->features & BIT_ULL(VHOST_USER_F_PROTOCOL_FEATURES)))
713 return 0;
714
715 return vhost_user_set_vring_state(vu_dev, VHOST_USER_SET_VRING_ENABLE,
716 index, enable);
717}
718
719
720/* Virtio interface */
721
722static bool vu_notify(struct virtqueue *vq)
723{
724 struct virtio_uml_vq_info *info = vq->priv;
725 const uint64_t n = 1;
726 int rc;
727
728 time_travel_propagate_time();
729
730 if (info->kick_fd < 0) {
731 struct virtio_uml_device *vu_dev;
732
733 vu_dev = to_virtio_uml_device(vq->vdev);
734
735 return vhost_user_set_vring_state(vu_dev, VHOST_USER_VRING_KICK,
736 vq->index, 0) == 0;
737 }
738
739 do {
740 rc = os_write_file(info->kick_fd, &n, sizeof(n));
741 } while (rc == -EINTR);
742 return !WARN(rc != sizeof(n), "write returned %d\n", rc);
743}
744
745static irqreturn_t vu_interrupt(int irq, void *opaque)
746{
747 struct virtqueue *vq = opaque;
748 struct virtio_uml_vq_info *info = vq->priv;
749 uint64_t n;
750 int rc;
751 irqreturn_t ret = IRQ_NONE;
752
753 do {
754 rc = os_read_file(info->call_fd, &n, sizeof(n));
755 if (rc == sizeof(n))
756 ret |= vring_interrupt(irq, vq);
757 } while (rc == sizeof(n) || rc == -EINTR);
758 WARN(rc != -EAGAIN, "read returned %d\n", rc);
759 return ret;
760}
761
762
763static void vu_get(struct virtio_device *vdev, unsigned offset,
764 void *buf, unsigned len)
765{
766 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
767
768 vhost_user_get_config(vu_dev, offset, buf, len);
769}
770
771static void vu_set(struct virtio_device *vdev, unsigned offset,
772 const void *buf, unsigned len)
773{
774 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
775
776 vhost_user_set_config(vu_dev, offset, buf, len);
777}
778
779static u8 vu_get_status(struct virtio_device *vdev)
780{
781 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
782
783 return vu_dev->status;
784}
785
786static void vu_set_status(struct virtio_device *vdev, u8 status)
787{
788 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
789
790 vu_dev->status = status;
791}
792
793static void vu_reset(struct virtio_device *vdev)
794{
795 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
796
797 vu_dev->status = 0;
798}
799
800static void vu_del_vq(struct virtqueue *vq)
801{
802 struct virtio_uml_vq_info *info = vq->priv;
803
804 if (info->call_fd >= 0) {
805 um_free_irq(VIRTIO_IRQ, vq);
806 os_close_file(info->call_fd);
807 }
808
809 if (info->kick_fd >= 0)
810 os_close_file(info->kick_fd);
811
812 vring_del_virtqueue(vq);
813 kfree(info);
814}
815
816static void vu_del_vqs(struct virtio_device *vdev)
817{
818 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
819 struct virtqueue *vq, *n;
820 u64 features;
821
822 /* Note: reverse order as a workaround to a decoding bug in snabb */
823 list_for_each_entry_reverse(vq, &vdev->vqs, list)
824 WARN_ON(vhost_user_set_vring_enable(vu_dev, vq->index, false));
825
826 /* Ensure previous messages have been processed */
827 WARN_ON(vhost_user_get_features(vu_dev, &features));
828
829 list_for_each_entry_safe(vq, n, &vdev->vqs, list)
830 vu_del_vq(vq);
831}
832
833static int vu_setup_vq_call_fd(struct virtio_uml_device *vu_dev,
834 struct virtqueue *vq)
835{
836 struct virtio_uml_vq_info *info = vq->priv;
837 int call_fds[2];
838 int rc;
839
840 /* no call FD needed/desired in this case */
841 if (vu_dev->protocol_features &
842 BIT_ULL(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS) &&
843 vu_dev->protocol_features &
844 BIT_ULL(VHOST_USER_PROTOCOL_F_SLAVE_REQ)) {
845 info->call_fd = -1;
846 return 0;
847 }
848
849 /* Use a pipe for call fd, since SIGIO is not supported for eventfd */
850 rc = os_pipe(call_fds, true, true);
851 if (rc < 0)
852 return rc;
853
854 info->call_fd = call_fds[0];
855 rc = um_request_irq(VIRTIO_IRQ, info->call_fd, IRQ_READ,
856 vu_interrupt, IRQF_SHARED, info->name, vq);
857 if (rc)
858 goto close_both;
859
860 rc = vhost_user_set_vring_call(vu_dev, vq->index, call_fds[1]);
861 if (rc)
862 goto release_irq;
863
864 goto out;
865
866release_irq:
867 um_free_irq(VIRTIO_IRQ, vq);
868close_both:
869 os_close_file(call_fds[0]);
870out:
871 /* Close (unused) write end of call fds */
872 os_close_file(call_fds[1]);
873
874 return rc;
875}
876
877#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
878static void vu_defer_irq_handle(struct time_travel_event *d)
879{
880 struct virtio_uml_vq_info *info;
881
882 info = container_of(d, struct virtio_uml_vq_info, defer);
883 info->callback(info->vq);
884}
885
886static void vu_defer_irq_callback(struct virtqueue *vq)
887{
888 struct virtio_uml_vq_info *info = vq->priv;
889
890 time_travel_add_irq_event(&info->defer);
891}
892#endif
893
894static struct virtqueue *vu_setup_vq(struct virtio_device *vdev,
895 unsigned index, vq_callback_t *callback,
896 const char *name, bool ctx)
897{
898 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
899 struct platform_device *pdev = vu_dev->pdev;
900 struct virtio_uml_vq_info *info;
901 struct virtqueue *vq;
902 int num = MAX_SUPPORTED_QUEUE_SIZE;
903 int rc;
904
905 info = kzalloc(sizeof(*info), GFP_KERNEL);
906 if (!info) {
907 rc = -ENOMEM;
908 goto error_kzalloc;
909 }
910 snprintf(info->name, sizeof(info->name), "%s.%d-%s", pdev->name,
911 pdev->id, name);
912
913#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
914 /*
915 * When we get an interrupt, we must bounce it through the simulation
916 * calendar (the simtime device), except for the simtime device itself
917 * since that's part of the simulation control.
918 */
919 if (time_travel_mode == TT_MODE_EXTERNAL && callback) {
920 info->callback = callback;
921 callback = vu_defer_irq_callback;
922 time_travel_set_event_fn(&info->defer, vu_defer_irq_handle);
923 }
924#endif
925
926 vq = vring_create_virtqueue(index, num, PAGE_SIZE, vdev, true, true,
927 ctx, vu_notify, callback, info->name);
928 if (!vq) {
929 rc = -ENOMEM;
930 goto error_create;
931 }
932 vq->priv = info;
933 num = virtqueue_get_vring_size(vq);
934#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
935 info->vq = vq;
936#endif
937
938 if (vu_dev->protocol_features &
939 BIT_ULL(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS)) {
940 info->kick_fd = -1;
941 } else {
942 rc = os_eventfd(0, 0);
943 if (rc < 0)
944 goto error_kick;
945 info->kick_fd = rc;
946 }
947
948 rc = vu_setup_vq_call_fd(vu_dev, vq);
949 if (rc)
950 goto error_call;
951
952 rc = vhost_user_set_vring_num(vu_dev, index, num);
953 if (rc)
954 goto error_setup;
955
956 rc = vhost_user_set_vring_base(vu_dev, index, 0);
957 if (rc)
958 goto error_setup;
959
960 rc = vhost_user_set_vring_addr(vu_dev, index,
961 virtqueue_get_desc_addr(vq),
962 virtqueue_get_used_addr(vq),
963 virtqueue_get_avail_addr(vq),
964 (u64) -1);
965 if (rc)
966 goto error_setup;
967
968 return vq;
969
970error_setup:
971 if (info->call_fd >= 0) {
972 um_free_irq(VIRTIO_IRQ, vq);
973 os_close_file(info->call_fd);
974 }
975error_call:
976 if (info->kick_fd >= 0)
977 os_close_file(info->kick_fd);
978error_kick:
979 vring_del_virtqueue(vq);
980error_create:
981 kfree(info);
982error_kzalloc:
983 return ERR_PTR(rc);
984}
985
986static int vu_find_vqs(struct virtio_device *vdev, unsigned nvqs,
987 struct virtqueue *vqs[], vq_callback_t *callbacks[],
988 const char * const names[], const bool *ctx,
989 struct irq_affinity *desc)
990{
991 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
992 int i, queue_idx = 0, rc;
993 struct virtqueue *vq;
994
995 rc = vhost_user_set_mem_table(vu_dev);
996 if (rc)
997 return rc;
998
999 for (i = 0; i < nvqs; ++i) {
1000 if (!names[i]) {
1001 vqs[i] = NULL;
1002 continue;
1003 }
1004
1005 vqs[i] = vu_setup_vq(vdev, queue_idx++, callbacks[i], names[i],
1006 ctx ? ctx[i] : false);
1007 if (IS_ERR(vqs[i])) {
1008 rc = PTR_ERR(vqs[i]);
1009 goto error_setup;
1010 }
1011 }
1012
1013 list_for_each_entry(vq, &vdev->vqs, list) {
1014 struct virtio_uml_vq_info *info = vq->priv;
1015
1016 if (info->kick_fd >= 0) {
1017 rc = vhost_user_set_vring_kick(vu_dev, vq->index,
1018 info->kick_fd);
1019 if (rc)
1020 goto error_setup;
1021 }
1022
1023 rc = vhost_user_set_vring_enable(vu_dev, vq->index, true);
1024 if (rc)
1025 goto error_setup;
1026 }
1027
1028 return 0;
1029
1030error_setup:
1031 vu_del_vqs(vdev);
1032 return rc;
1033}
1034
1035static u64 vu_get_features(struct virtio_device *vdev)
1036{
1037 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
1038
1039 return vu_dev->features;
1040}
1041
1042static int vu_finalize_features(struct virtio_device *vdev)
1043{
1044 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
1045 u64 supported = vdev->features & VHOST_USER_SUPPORTED_F;
1046
1047 vring_transport_features(vdev);
1048 vu_dev->features = vdev->features | supported;
1049
1050 return vhost_user_set_features(vu_dev, vu_dev->features);
1051}
1052
1053static const char *vu_bus_name(struct virtio_device *vdev)
1054{
1055 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
1056
1057 return vu_dev->pdev->name;
1058}
1059
1060static const struct virtio_config_ops virtio_uml_config_ops = {
1061 .get = vu_get,
1062 .set = vu_set,
1063 .get_status = vu_get_status,
1064 .set_status = vu_set_status,
1065 .reset = vu_reset,
1066 .find_vqs = vu_find_vqs,
1067 .del_vqs = vu_del_vqs,
1068 .get_features = vu_get_features,
1069 .finalize_features = vu_finalize_features,
1070 .bus_name = vu_bus_name,
1071};
1072
1073static void virtio_uml_release_dev(struct device *d)
1074{
1075 struct virtio_device *vdev =
1076 container_of(d, struct virtio_device, dev);
1077 struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
1078
1079 /* might not have been opened due to not negotiating the feature */
1080 if (vu_dev->req_fd >= 0) {
1081 um_free_irq(VIRTIO_IRQ, vu_dev);
1082 os_close_file(vu_dev->req_fd);
1083 }
1084
1085 os_close_file(vu_dev->sock);
1086}
1087
1088/* Platform device */
1089
1090static int virtio_uml_probe(struct platform_device *pdev)
1091{
1092 struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
1093 struct virtio_uml_device *vu_dev;
1094 int rc;
1095
1096 if (!pdata)
1097 return -EINVAL;
1098
1099 vu_dev = devm_kzalloc(&pdev->dev, sizeof(*vu_dev), GFP_KERNEL);
1100 if (!vu_dev)
1101 return -ENOMEM;
1102
1103 vu_dev->vdev.dev.parent = &pdev->dev;
1104 vu_dev->vdev.dev.release = virtio_uml_release_dev;
1105 vu_dev->vdev.config = &virtio_uml_config_ops;
1106 vu_dev->vdev.id.device = pdata->virtio_device_id;
1107 vu_dev->vdev.id.vendor = VIRTIO_DEV_ANY_ID;
1108 vu_dev->pdev = pdev;
1109 vu_dev->req_fd = -1;
1110
1111 do {
1112 rc = os_connect_socket(pdata->socket_path);
1113 } while (rc == -EINTR);
1114 if (rc < 0)
1115 return rc;
1116 vu_dev->sock = rc;
1117
1118 spin_lock_init(&vu_dev->sock_lock);
1119
1120 rc = vhost_user_init(vu_dev);
1121 if (rc)
1122 goto error_init;
1123
1124 platform_set_drvdata(pdev, vu_dev);
1125
1126 rc = register_virtio_device(&vu_dev->vdev);
1127 if (rc)
1128 put_device(&vu_dev->vdev.dev);
1129 vu_dev->registered = 1;
1130 return rc;
1131
1132error_init:
1133 os_close_file(vu_dev->sock);
1134 return rc;
1135}
1136
1137static int virtio_uml_remove(struct platform_device *pdev)
1138{
1139 struct virtio_uml_device *vu_dev = platform_get_drvdata(pdev);
1140
1141 unregister_virtio_device(&vu_dev->vdev);
1142 return 0;
1143}
1144
1145/* Command line device list */
1146
1147static void vu_cmdline_release_dev(struct device *d)
1148{
1149}
1150
1151static struct device vu_cmdline_parent = {
1152 .init_name = "virtio-uml-cmdline",
1153 .release = vu_cmdline_release_dev,
1154};
1155
1156static bool vu_cmdline_parent_registered;
1157static int vu_cmdline_id;
1158
1159static int vu_unregister_cmdline_device(struct device *dev, void *data)
1160{
1161 struct platform_device *pdev = to_platform_device(dev);
1162 struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
1163
1164 kfree(pdata->socket_path);
1165 platform_device_unregister(pdev);
1166 return 0;
1167}
1168
1169static void vu_conn_broken(struct work_struct *wk)
1170{
1171 struct virtio_uml_platform_data *pdata;
1172
1173 pdata = container_of(wk, struct virtio_uml_platform_data, conn_broken_wk);
1174 vu_unregister_cmdline_device(&pdata->pdev->dev, NULL);
1175}
1176
1177static int vu_cmdline_set(const char *device, const struct kernel_param *kp)
1178{
1179 const char *ids = strchr(device, ':');
1180 unsigned int virtio_device_id;
1181 int processed, consumed, err;
1182 char *socket_path;
1183 struct virtio_uml_platform_data pdata, *ppdata;
1184 struct platform_device *pdev;
1185
1186 if (!ids || ids == device)
1187 return -EINVAL;
1188
1189 processed = sscanf(ids, ":%u%n:%d%n",
1190 &virtio_device_id, &consumed,
1191 &vu_cmdline_id, &consumed);
1192
1193 if (processed < 1 || ids[consumed])
1194 return -EINVAL;
1195
1196 if (!vu_cmdline_parent_registered) {
1197 err = device_register(&vu_cmdline_parent);
1198 if (err) {
1199 pr_err("Failed to register parent device!\n");
1200 put_device(&vu_cmdline_parent);
1201 return err;
1202 }
1203 vu_cmdline_parent_registered = true;
1204 }
1205
1206 socket_path = kmemdup_nul(device, ids - device, GFP_KERNEL);
1207 if (!socket_path)
1208 return -ENOMEM;
1209
1210 pdata.virtio_device_id = (u32) virtio_device_id;
1211 pdata.socket_path = socket_path;
1212
1213 pr_info("Registering device virtio-uml.%d id=%d at %s\n",
1214 vu_cmdline_id, virtio_device_id, socket_path);
1215
1216 pdev = platform_device_register_data(&vu_cmdline_parent, "virtio-uml",
1217 vu_cmdline_id++, &pdata,
1218 sizeof(pdata));
1219 err = PTR_ERR_OR_ZERO(pdev);
1220 if (err)
1221 goto free;
1222
1223 ppdata = pdev->dev.platform_data;
1224 ppdata->pdev = pdev;
1225 INIT_WORK(&ppdata->conn_broken_wk, vu_conn_broken);
1226
1227 return 0;
1228
1229free:
1230 kfree(socket_path);
1231 return err;
1232}
1233
1234static int vu_cmdline_get_device(struct device *dev, void *data)
1235{
1236 struct platform_device *pdev = to_platform_device(dev);
1237 struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
1238 char *buffer = data;
1239 unsigned int len = strlen(buffer);
1240
1241 snprintf(buffer + len, PAGE_SIZE - len, "%s:%d:%d\n",
1242 pdata->socket_path, pdata->virtio_device_id, pdev->id);
1243 return 0;
1244}
1245
1246static int vu_cmdline_get(char *buffer, const struct kernel_param *kp)
1247{
1248 buffer[0] = '\0';
1249 if (vu_cmdline_parent_registered)
1250 device_for_each_child(&vu_cmdline_parent, buffer,
1251 vu_cmdline_get_device);
1252 return strlen(buffer) + 1;
1253}
1254
1255static const struct kernel_param_ops vu_cmdline_param_ops = {
1256 .set = vu_cmdline_set,
1257 .get = vu_cmdline_get,
1258};
1259
1260device_param_cb(device, &vu_cmdline_param_ops, NULL, S_IRUSR);
1261__uml_help(vu_cmdline_param_ops,
1262"virtio_uml.device=<socket>:<virtio_id>[:<platform_id>]\n"
1263" Configure a virtio device over a vhost-user socket.\n"
1264" See virtio_ids.h for a list of possible virtio device id values.\n"
1265" Optionally use a specific platform_device id.\n\n"
1266);
1267
1268
1269static void vu_unregister_cmdline_devices(void)
1270{
1271 if (vu_cmdline_parent_registered) {
1272 device_for_each_child(&vu_cmdline_parent, NULL,
1273 vu_unregister_cmdline_device);
1274 device_unregister(&vu_cmdline_parent);
1275 vu_cmdline_parent_registered = false;
1276 }
1277}
1278
1279/* Platform driver */
1280
1281static const struct of_device_id virtio_uml_match[] = {
1282 { .compatible = "virtio,uml", },
1283 { }
1284};
1285MODULE_DEVICE_TABLE(of, virtio_uml_match);
1286
1287static struct platform_driver virtio_uml_driver = {
1288 .probe = virtio_uml_probe,
1289 .remove = virtio_uml_remove,
1290 .driver = {
1291 .name = "virtio-uml",
1292 .of_match_table = virtio_uml_match,
1293 },
1294};
1295
1296static int __init virtio_uml_init(void)
1297{
1298 return platform_driver_register(&virtio_uml_driver);
1299}
1300
1301static void __exit virtio_uml_exit(void)
1302{
1303 platform_driver_unregister(&virtio_uml_driver);
1304 vu_unregister_cmdline_devices();
1305}
1306
1307module_init(virtio_uml_init);
1308module_exit(virtio_uml_exit);
1309__uml_exitcall(virtio_uml_exit);
1310
1311MODULE_DESCRIPTION("UML driver for vhost-user virtio devices");
1312MODULE_LICENSE("GPL");