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