arch/um/drivers/virtio_uml.c

   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
  46 struct 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
  53 struct 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
  65 struct 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
  75 extern 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
  81 static 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
 101 static 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
 120 static 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
 125 static 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
 165 static 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
 181 static 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
 196 static 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
 213 static 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
 256 out:
 257         spin_unlock_irqrestore(&vu_dev->sock_lock, flags);
 258         return rc;
 259 }
 260
 261 static 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
 271 static 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
 281 static 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
 293 static 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
 298 static 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
 309 static 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
 315 static 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
 326 static 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
 333 static 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
 355 static 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
 402 static 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
 425 err_free_irq:
 426         um_free_irq(VIRTIO_IRQ, vu_dev);
 427 err_close:
 428         os_close_file(req_fds[0]);
 429 out:
 430         /* Close unused write end of request fds */
 431         os_close_file(req_fds[1]);
 432         return rc;
 433 }
 434
 435 static 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
 467 static 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
 514 free:
 515         kfree(msg);
 516 }
 517
 518 static 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
 547 static 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
 569 static 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
 633 static 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
 646 static 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
 653 static 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
 660 static 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
 677 static 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
 695 static 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
 702 static 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
 709 static 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
 722 static 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
 745 static 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
 763 static 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
 771 static 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
 779 static 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
 786 static 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
 793 static 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
 800 static 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
 816 static 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
 833 static 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
 866 release_irq:
 867         um_free_irq(VIRTIO_IRQ, vq);
 868 close_both:
 869         os_close_file(call_fds[0]);
 870 out:
 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
 878 static 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
 886 static 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
 894 static 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
 970 error_setup:
 971         if (info->call_fd >= 0) {
 972                 um_free_irq(VIRTIO_IRQ, vq);
 973                 os_close_file(info->call_fd);
 974         }
 975 error_call:
 976         if (info->kick_fd >= 0)
 977                 os_close_file(info->kick_fd);
 978 error_kick:
 979         vring_del_virtqueue(vq);
 980 error_create:
 981         kfree(info);
 982 error_kzalloc:
 983         return ERR_PTR(rc);
 984 }
 985
 986 static 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
1030 error_setup:
1031         vu_del_vqs(vdev);
1032         return rc;
1033 }
1034
1035 static 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
1042 static 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
1053 static 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
1060 static 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
1073 static 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
1090 static 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
1132 error_init:
1133         os_close_file(vu_dev->sock);
1134         return rc;
1135 }
1136
1137 static 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
1147 static void vu_cmdline_release_dev(struct device *d)
1148 {
1149 }
1150
1151 static struct device vu_cmdline_parent = {
1152         .init_name = "virtio-uml-cmdline",
1153         .release = vu_cmdline_release_dev,
1154 };
1155
1156 static bool vu_cmdline_parent_registered;
1157 static int vu_cmdline_id;
1158
1159 static 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
1169 static 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
1177 static 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
1229 free:
1230         kfree(socket_path);
1231         return err;
1232 }
1233
1234 static 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
1246 static 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
1255 static const struct kernel_param_ops vu_cmdline_param_ops = {
1256         .set = vu_cmdline_set,
1257         .get = vu_cmdline_get,
1258 };
1259
1260 device_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
1269 static 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
1281 static const struct of_device_id virtio_uml_match[] = {
1282         { .compatible = "virtio,uml", },
1283         { }
1284 };
1285 MODULE_DEVICE_TABLE(of, virtio_uml_match);
1286
1287 static 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
1296 static int __init virtio_uml_init(void)
1297 {
1298         return platform_driver_register(&virtio_uml_driver);
1299 }
1300
1301 static void __exit virtio_uml_exit(void)
1302 {
1303         platform_driver_unregister(&virtio_uml_driver);
1304         vu_unregister_cmdline_devices();
1305 }
1306
1307 module_init(virtio_uml_init);
1308 module_exit(virtio_uml_exit);
1309 __uml_exitcall(virtio_uml_exit);
1310
1311 MODULE_DESCRIPTION("UML driver for vhost-user virtio devices");
1312 MODULE_LICENSE("GPL");