drivers/vdpa/vdpa_sim/vdpa_sim.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * VDPA networking device simulator.
   4  *
   5  * Copyright (c) 2020, Red Hat Inc. All rights reserved.
   6  *     Author: Jason Wang <jasowang@redhat.com>
   7  *
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/device.h>
  13 #include <linux/kernel.h>
  14 #include <linux/fs.h>
  15 #include <linux/poll.h>
  16 #include <linux/slab.h>
  17 #include <linux/sched.h>
  18 #include <linux/wait.h>
  19 #include <linux/uuid.h>
  20 #include <linux/iommu.h>
  21 #include <linux/dma-mapping.h>
  22 #include <linux/sysfs.h>
  23 #include <linux/file.h>
  24 #include <linux/etherdevice.h>
  25 #include <linux/vringh.h>
  26 #include <linux/vdpa.h>
  27 #include <linux/vhost_iotlb.h>
  28 #include <uapi/linux/virtio_config.h>
  29 #include <uapi/linux/virtio_net.h>
  30
  31 #define DRV_VERSION  "0.1"
  32 #define DRV_AUTHOR   "Jason Wang <jasowang@redhat.com>"
  33 #define DRV_DESC     "vDPA Device Simulator"
  34 #define DRV_LICENSE  "GPL v2"
  35
  36 struct vdpasim_virtqueue {
  37         struct vringh vring;
  38         struct vringh_kiov iov;
  39         unsigned short head;
  40         bool ready;
  41         u64 desc_addr;
  42         u64 device_addr;
  43         u64 driver_addr;
  44         u32 num;
  45         void *private;
  46         irqreturn_t (*cb)(void *data);
  47 };
  48
  49 #define VDPASIM_QUEUE_ALIGN PAGE_SIZE
  50 #define VDPASIM_QUEUE_MAX 256
  51 #define VDPASIM_DEVICE_ID 0x1
  52 #define VDPASIM_VENDOR_ID 0
  53 #define VDPASIM_VQ_NUM 0x2
  54 #define VDPASIM_NAME "vdpasim-netdev"
  55
  56 static u64 vdpasim_features = (1ULL << VIRTIO_F_ANY_LAYOUT) |
  57                               (1ULL << VIRTIO_F_VERSION_1)  |
  58                               (1ULL << VIRTIO_F_IOMMU_PLATFORM);
  59
  60 /* State of each vdpasim device */
  61 struct vdpasim {
  62         struct vdpa_device vdpa;
  63         struct vdpasim_virtqueue vqs[2];
  64         struct work_struct work;
  65         /* spinlock to synchronize virtqueue state */
  66         spinlock_t lock;
  67         struct virtio_net_config config;
  68         struct vhost_iotlb *iommu;
  69         void *buffer;
  70         u32 status;
  71         u32 generation;
  72         u64 features;
  73 };
  74
  75 static struct vdpasim *vdpasim_dev;
  76
  77 static struct vdpasim *vdpa_to_sim(struct vdpa_device *vdpa)
  78 {
  79         return container_of(vdpa, struct vdpasim, vdpa);
  80 }
  81
  82 static struct vdpasim *dev_to_sim(struct device *dev)
  83 {
  84         struct vdpa_device *vdpa = dev_to_vdpa(dev);
  85
  86         return vdpa_to_sim(vdpa);
  87 }
  88
  89 static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
  90 {
  91         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
  92
  93         vringh_init_iotlb(&vq->vring, vdpasim_features,
  94                           VDPASIM_QUEUE_MAX, false,
  95                           (struct vring_desc *)(uintptr_t)vq->desc_addr,
  96                           (struct vring_avail *)
  97                           (uintptr_t)vq->driver_addr,
  98                           (struct vring_used *)
  99                           (uintptr_t)vq->device_addr);
 100 }
 101
 102 static void vdpasim_vq_reset(struct vdpasim_virtqueue *vq)
 103 {
 104         vq->ready = 0;
 105         vq->desc_addr = 0;
 106         vq->driver_addr = 0;
 107         vq->device_addr = 0;
 108         vq->cb = NULL;
 109         vq->private = NULL;
 110         vringh_init_iotlb(&vq->vring, vdpasim_features, VDPASIM_QUEUE_MAX,
 111                           false, NULL, NULL, NULL);
 112 }
 113
 114 static void vdpasim_reset(struct vdpasim *vdpasim)
 115 {
 116         int i;
 117
 118         for (i = 0; i < VDPASIM_VQ_NUM; i++)
 119                 vdpasim_vq_reset(&vdpasim->vqs[i]);
 120
 121         vhost_iotlb_reset(vdpasim->iommu);
 122
 123         vdpasim->features = 0;
 124         vdpasim->status = 0;
 125         ++vdpasim->generation;
 126 }
 127
 128 static void vdpasim_work(struct work_struct *work)
 129 {
 130         struct vdpasim *vdpasim = container_of(work, struct
 131                                                  vdpasim, work);
 132         struct vdpasim_virtqueue *txq = &vdpasim->vqs[1];
 133         struct vdpasim_virtqueue *rxq = &vdpasim->vqs[0];
 134         size_t read, write, total_write;
 135         int err;
 136         int pkts = 0;
 137
 138         spin_lock(&vdpasim->lock);
 139
 140         if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
 141                 goto out;
 142
 143         if (!txq->ready || !rxq->ready)
 144                 goto out;
 145
 146         while (true) {
 147                 total_write = 0;
 148                 err = vringh_getdesc_iotlb(&txq->vring, &txq->iov, NULL,
 149                                            &txq->head, GFP_ATOMIC);
 150                 if (err <= 0)
 151                         break;
 152
 153                 err = vringh_getdesc_iotlb(&rxq->vring, NULL, &rxq->iov,
 154                                            &rxq->head, GFP_ATOMIC);
 155                 if (err <= 0) {
 156                         vringh_complete_iotlb(&txq->vring, txq->head, 0);
 157                         break;
 158                 }
 159
 160                 while (true) {
 161                         read = vringh_iov_pull_iotlb(&txq->vring, &txq->iov,
 162                                                      vdpasim->buffer,
 163                                                      PAGE_SIZE);
 164                         if (read <= 0)
 165                                 break;
 166
 167                         write = vringh_iov_push_iotlb(&rxq->vring, &rxq->iov,
 168                                                       vdpasim->buffer, read);
 169                         if (write <= 0)
 170                                 break;
 171
 172                         total_write += write;
 173                 }
 174
 175                 /* Make sure data is wrote before advancing index */
 176                 smp_wmb();
 177
 178                 vringh_complete_iotlb(&txq->vring, txq->head, 0);
 179                 vringh_complete_iotlb(&rxq->vring, rxq->head, total_write);
 180
 181                 /* Make sure used is visible before rasing the interrupt. */
 182                 smp_wmb();
 183
 184                 local_bh_disable();
 185                 if (txq->cb)
 186                         txq->cb(txq->private);
 187                 if (rxq->cb)
 188                         rxq->cb(rxq->private);
 189                 local_bh_enable();
 190
 191                 if (++pkts > 4) {
 192                         schedule_work(&vdpasim->work);
 193                         goto out;
 194                 }
 195         }
 196
 197 out:
 198         spin_unlock(&vdpasim->lock);
 199 }
 200
 201 static int dir_to_perm(enum dma_data_direction dir)
 202 {
 203         int perm = -EFAULT;
 204
 205         switch (dir) {
 206         case DMA_FROM_DEVICE:
 207                 perm = VHOST_MAP_WO;
 208                 break;
 209         case DMA_TO_DEVICE:
 210                 perm = VHOST_MAP_RO;
 211                 break;
 212         case DMA_BIDIRECTIONAL:
 213                 perm = VHOST_MAP_RW;
 214                 break;
 215         default:
 216                 break;
 217         }
 218
 219         return perm;
 220 }
 221
 222 static dma_addr_t vdpasim_map_page(struct device *dev, struct page *page,
 223                                    unsigned long offset, size_t size,
 224                                    enum dma_data_direction dir,
 225                                    unsigned long attrs)
 226 {
 227         struct vdpasim *vdpasim = dev_to_sim(dev);
 228         struct vhost_iotlb *iommu = vdpasim->iommu;
 229         u64 pa = (page_to_pfn(page) << PAGE_SHIFT) + offset;
 230         int ret, perm = dir_to_perm(dir);
 231
 232         if (perm < 0)
 233                 return DMA_MAPPING_ERROR;
 234
 235         /* For simplicity, use identical mapping to avoid e.g iova
 236          * allocator.
 237          */
 238         ret = vhost_iotlb_add_range(iommu, pa, pa + size - 1,
 239                                     pa, dir_to_perm(dir));
 240         if (ret)
 241                 return DMA_MAPPING_ERROR;
 242
 243         return (dma_addr_t)(pa);
 244 }
 245
 246 static void vdpasim_unmap_page(struct device *dev, dma_addr_t dma_addr,
 247                                size_t size, enum dma_data_direction dir,
 248                                unsigned long attrs)
 249 {
 250         struct vdpasim *vdpasim = dev_to_sim(dev);
 251         struct vhost_iotlb *iommu = vdpasim->iommu;
 252
 253         vhost_iotlb_del_range(iommu, (u64)dma_addr,
 254                               (u64)dma_addr + size - 1);
 255 }
 256
 257 static void *vdpasim_alloc_coherent(struct device *dev, size_t size,
 258                                     dma_addr_t *dma_addr, gfp_t flag,
 259                                     unsigned long attrs)
 260 {
 261         struct vdpasim *vdpasim = dev_to_sim(dev);
 262         struct vhost_iotlb *iommu = vdpasim->iommu;
 263         void *addr = kmalloc(size, flag);
 264         int ret;
 265
 266         if (!addr)
 267                 *dma_addr = DMA_MAPPING_ERROR;
 268         else {
 269                 u64 pa = virt_to_phys(addr);
 270
 271                 ret = vhost_iotlb_add_range(iommu, (u64)pa,
 272                                             (u64)pa + size - 1,
 273                                             pa, VHOST_MAP_RW);
 274                 if (ret) {
 275                         *dma_addr = DMA_MAPPING_ERROR;
 276                         kfree(addr);
 277                         addr = NULL;
 278                 } else
 279                         *dma_addr = (dma_addr_t)pa;
 280         }
 281
 282         return addr;
 283 }
 284
 285 static void vdpasim_free_coherent(struct device *dev, size_t size,
 286                                   void *vaddr, dma_addr_t dma_addr,
 287                                   unsigned long attrs)
 288 {
 289         struct vdpasim *vdpasim = dev_to_sim(dev);
 290         struct vhost_iotlb *iommu = vdpasim->iommu;
 291
 292         vhost_iotlb_del_range(iommu, (u64)dma_addr,
 293                               (u64)dma_addr + size - 1);
 294         kfree(phys_to_virt((uintptr_t)dma_addr));
 295 }
 296
 297 static const struct dma_map_ops vdpasim_dma_ops = {
 298         .map_page = vdpasim_map_page,
 299         .unmap_page = vdpasim_unmap_page,
 300         .alloc = vdpasim_alloc_coherent,
 301         .free = vdpasim_free_coherent,
 302 };
 303
 304 static const struct vdpa_config_ops vdpasim_net_config_ops;
 305
 306 static struct vdpasim *vdpasim_create(void)
 307 {
 308         struct virtio_net_config *config;
 309         struct vdpasim *vdpasim;
 310         struct device *dev;
 311         int ret = -ENOMEM;
 312
 313         vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL,
 314                                     &vdpasim_net_config_ops);
 315         if (!vdpasim)
 316                 goto err_alloc;
 317
 318         INIT_WORK(&vdpasim->work, vdpasim_work);
 319         spin_lock_init(&vdpasim->lock);
 320
 321         dev = &vdpasim->vdpa.dev;
 322         dev->coherent_dma_mask = DMA_BIT_MASK(64);
 323         set_dma_ops(dev, &vdpasim_dma_ops);
 324
 325         vdpasim->iommu = vhost_iotlb_alloc(2048, 0);
 326         if (!vdpasim->iommu)
 327                 goto err_iommu;
 328
 329         vdpasim->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
 330         if (!vdpasim->buffer)
 331                 goto err_iommu;
 332
 333         config = &vdpasim->config;
 334         config->mtu = 1500;
 335         config->status = VIRTIO_NET_S_LINK_UP;
 336         eth_random_addr(config->mac);
 337
 338         vringh_set_iotlb(&vdpasim->vqs[0].vring, vdpasim->iommu);
 339         vringh_set_iotlb(&vdpasim->vqs[1].vring, vdpasim->iommu);
 340
 341         vdpasim->vdpa.dma_dev = dev;
 342         ret = vdpa_register_device(&vdpasim->vdpa);
 343         if (ret)
 344                 goto err_iommu;
 345
 346         return vdpasim;
 347
 348 err_iommu:
 349         put_device(dev);
 350 err_alloc:
 351         return ERR_PTR(ret);
 352 }
 353
 354 static int vdpasim_set_vq_address(struct vdpa_device *vdpa, u16 idx,
 355                                   u64 desc_area, u64 driver_area,
 356                                   u64 device_area)
 357 {
 358         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 359         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 360
 361         vq->desc_addr = desc_area;
 362         vq->driver_addr = driver_area;
 363         vq->device_addr = device_area;
 364
 365         return 0;
 366 }
 367
 368 static void vdpasim_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num)
 369 {
 370         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 371         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 372
 373         vq->num = num;
 374 }
 375
 376 static void vdpasim_kick_vq(struct vdpa_device *vdpa, u16 idx)
 377 {
 378         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 379         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 380
 381         if (vq->ready)
 382                 schedule_work(&vdpasim->work);
 383 }
 384
 385 static void vdpasim_set_vq_cb(struct vdpa_device *vdpa, u16 idx,
 386                               struct vdpa_callback *cb)
 387 {
 388         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 389         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 390
 391         vq->cb = cb->callback;
 392         vq->private = cb->private;
 393 }
 394
 395 static void vdpasim_set_vq_ready(struct vdpa_device *vdpa, u16 idx, bool ready)
 396 {
 397         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 398         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 399
 400         spin_lock(&vdpasim->lock);
 401         vq->ready = ready;
 402         if (vq->ready)
 403                 vdpasim_queue_ready(vdpasim, idx);
 404         spin_unlock(&vdpasim->lock);
 405 }
 406
 407 static bool vdpasim_get_vq_ready(struct vdpa_device *vdpa, u16 idx)
 408 {
 409         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 410         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 411
 412         return vq->ready;
 413 }
 414
 415 static int vdpasim_set_vq_state(struct vdpa_device *vdpa, u16 idx, u64 state)
 416 {
 417         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 418         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 419         struct vringh *vrh = &vq->vring;
 420
 421         spin_lock(&vdpasim->lock);
 422         vrh->last_avail_idx = state;
 423         spin_unlock(&vdpasim->lock);
 424
 425         return 0;
 426 }
 427
 428 static u64 vdpasim_get_vq_state(struct vdpa_device *vdpa, u16 idx)
 429 {
 430         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 431         struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 432         struct vringh *vrh = &vq->vring;
 433
 434         return vrh->last_avail_idx;
 435 }
 436
 437 static u32 vdpasim_get_vq_align(struct vdpa_device *vdpa)
 438 {
 439         return VDPASIM_QUEUE_ALIGN;
 440 }
 441
 442 static u64 vdpasim_get_features(struct vdpa_device *vdpa)
 443 {
 444         return vdpasim_features;
 445 }
 446
 447 static int vdpasim_set_features(struct vdpa_device *vdpa, u64 features)
 448 {
 449         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 450
 451         /* DMA mapping must be done by driver */
 452         if (!(features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)))
 453                 return -EINVAL;
 454
 455         vdpasim->features = features & vdpasim_features;
 456
 457         return 0;
 458 }
 459
 460 static void vdpasim_set_config_cb(struct vdpa_device *vdpa,
 461                                   struct vdpa_callback *cb)
 462 {
 463         /* We don't support config interrupt */
 464 }
 465
 466 static u16 vdpasim_get_vq_num_max(struct vdpa_device *vdpa)
 467 {
 468         return VDPASIM_QUEUE_MAX;
 469 }
 470
 471 static u32 vdpasim_get_device_id(struct vdpa_device *vdpa)
 472 {
 473         return VDPASIM_DEVICE_ID;
 474 }
 475
 476 static u32 vdpasim_get_vendor_id(struct vdpa_device *vdpa)
 477 {
 478         return VDPASIM_VENDOR_ID;
 479 }
 480
 481 static u8 vdpasim_get_status(struct vdpa_device *vdpa)
 482 {
 483         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 484         u8 status;
 485
 486         spin_lock(&vdpasim->lock);
 487         status = vdpasim->status;
 488         spin_unlock(&vdpasim->lock);
 489
 490         return status;
 491 }
 492
 493 static void vdpasim_set_status(struct vdpa_device *vdpa, u8 status)
 494 {
 495         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 496
 497         spin_lock(&vdpasim->lock);
 498         vdpasim->status = status;
 499         if (status == 0)
 500                 vdpasim_reset(vdpasim);
 501         spin_unlock(&vdpasim->lock);
 502 }
 503
 504 static void vdpasim_get_config(struct vdpa_device *vdpa, unsigned int offset,
 505                              void *buf, unsigned int len)
 506 {
 507         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 508
 509         if (offset + len < sizeof(struct virtio_net_config))
 510                 memcpy(buf, &vdpasim->config + offset, len);
 511 }
 512
 513 static void vdpasim_set_config(struct vdpa_device *vdpa, unsigned int offset,
 514                              const void *buf, unsigned int len)
 515 {
 516         /* No writable config supportted by vdpasim */
 517 }
 518
 519 static u32 vdpasim_get_generation(struct vdpa_device *vdpa)
 520 {
 521         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 522
 523         return vdpasim->generation;
 524 }
 525
 526 static int vdpasim_set_map(struct vdpa_device *vdpa,
 527                            struct vhost_iotlb *iotlb)
 528 {
 529         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 530         struct vhost_iotlb_map *map;
 531         u64 start = 0ULL, last = 0ULL - 1;
 532         int ret;
 533
 534         vhost_iotlb_reset(vdpasim->iommu);
 535
 536         for (map = vhost_iotlb_itree_first(iotlb, start, last); map;
 537              map = vhost_iotlb_itree_next(map, start, last)) {
 538                 ret = vhost_iotlb_add_range(vdpasim->iommu, map->start,
 539                                             map->last, map->addr, map->perm);
 540                 if (ret)
 541                         goto err;
 542         }
 543         return 0;
 544
 545 err:
 546         vhost_iotlb_reset(vdpasim->iommu);
 547         return ret;
 548 }
 549
 550 static int vdpasim_dma_map(struct vdpa_device *vdpa, u64 iova, u64 size,
 551                            u64 pa, u32 perm)
 552 {
 553         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 554
 555         return vhost_iotlb_add_range(vdpasim->iommu, iova,
 556                                      iova + size - 1, pa, perm);
 557 }
 558
 559 static int vdpasim_dma_unmap(struct vdpa_device *vdpa, u64 iova, u64 size)
 560 {
 561         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 562
 563         vhost_iotlb_del_range(vdpasim->iommu, iova, iova + size - 1);
 564
 565         return 0;
 566 }
 567
 568 static void vdpasim_free(struct vdpa_device *vdpa)
 569 {
 570         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 571
 572         cancel_work_sync(&vdpasim->work);
 573         kfree(vdpasim->buffer);
 574         if (vdpasim->iommu)
 575                 vhost_iotlb_free(vdpasim->iommu);
 576 }
 577
 578 static const struct vdpa_config_ops vdpasim_net_config_ops = {
 579         .set_vq_address         = vdpasim_set_vq_address,
 580         .set_vq_num             = vdpasim_set_vq_num,
 581         .kick_vq                = vdpasim_kick_vq,
 582         .set_vq_cb              = vdpasim_set_vq_cb,
 583         .set_vq_ready           = vdpasim_set_vq_ready,
 584         .get_vq_ready           = vdpasim_get_vq_ready,
 585         .set_vq_state           = vdpasim_set_vq_state,
 586         .get_vq_state           = vdpasim_get_vq_state,
 587         .get_vq_align           = vdpasim_get_vq_align,
 588         .get_features           = vdpasim_get_features,
 589         .set_features           = vdpasim_set_features,
 590         .set_config_cb          = vdpasim_set_config_cb,
 591         .get_vq_num_max         = vdpasim_get_vq_num_max,
 592         .get_device_id          = vdpasim_get_device_id,
 593         .get_vendor_id          = vdpasim_get_vendor_id,
 594         .get_status             = vdpasim_get_status,
 595         .set_status             = vdpasim_set_status,
 596         .get_config             = vdpasim_get_config,
 597         .set_config             = vdpasim_set_config,
 598         .get_generation         = vdpasim_get_generation,
 599         .set_map                = vdpasim_set_map,
 600         .dma_map                = vdpasim_dma_map,
 601         .dma_unmap              = vdpasim_dma_unmap,
 602         .free                   = vdpasim_free,
 603 };
 604
 605 static int __init vdpasim_dev_init(void)
 606 {
 607         vdpasim_dev = vdpasim_create();
 608
 609         if (!IS_ERR(vdpasim_dev))
 610                 return 0;
 611
 612         return PTR_ERR(vdpasim_dev);
 613 }
 614
 615 static void __exit vdpasim_dev_exit(void)
 616 {
 617         struct vdpa_device *vdpa = &vdpasim_dev->vdpa;
 618
 619         vdpa_unregister_device(vdpa);
 620 }
 621
 622 module_init(vdpasim_dev_init)
 623 module_exit(vdpasim_dev_exit)
 624
 625 MODULE_VERSION(DRV_VERSION);
 626 MODULE_LICENSE(DRV_LICENSE);
 627 MODULE_AUTHOR(DRV_AUTHOR);
 628 MODULE_DESCRIPTION(DRV_DESC);