drivers/iommu/s390-iommu.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * IOMMU API for s390 PCI devices
   4  *
   5  * Copyright IBM Corp. 2015
   6  * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
   7  */
   8
   9 #include <linux/pci.h>
  10 #include <linux/iommu.h>
  11 #include <linux/iommu-helper.h>
  12 #include <linux/sizes.h>
  13 #include <asm/pci_dma.h>
  14
  15 /*
  16  * Physically contiguous memory regions can be mapped with 4 KiB alignment,
  17  * we allow all page sizes that are an order of 4KiB (no special large page
  18  * support so far).
  19  */
  20 #define S390_IOMMU_PGSIZES      (~0xFFFUL)
  21
  22 static const struct iommu_ops s390_iommu_ops;
  23
  24 struct s390_domain {
  25         struct iommu_domain     domain;
  26         struct list_head        devices;
  27         unsigned long           *dma_table;
  28         spinlock_t              dma_table_lock;
  29         spinlock_t              list_lock;
  30 };
  31
  32 struct s390_domain_device {
  33         struct list_head        list;
  34         struct zpci_dev         *zdev;
  35 };
  36
  37 static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
  38 {
  39         return container_of(dom, struct s390_domain, domain);
  40 }
  41
  42 static bool s390_iommu_capable(struct device *dev, enum iommu_cap cap)
  43 {
  44         switch (cap) {
  45         case IOMMU_CAP_CACHE_COHERENCY:
  46                 return true;
  47         case IOMMU_CAP_INTR_REMAP:
  48                 return true;
  49         default:
  50                 return false;
  51         }
  52 }
  53
  54 static struct iommu_domain *s390_domain_alloc(unsigned domain_type)
  55 {
  56         struct s390_domain *s390_domain;
  57
  58         if (domain_type != IOMMU_DOMAIN_UNMANAGED)
  59                 return NULL;
  60
  61         s390_domain = kzalloc(sizeof(*s390_domain), GFP_KERNEL);
  62         if (!s390_domain)
  63                 return NULL;
  64
  65         s390_domain->dma_table = dma_alloc_cpu_table();
  66         if (!s390_domain->dma_table) {
  67                 kfree(s390_domain);
  68                 return NULL;
  69         }
  70
  71         spin_lock_init(&s390_domain->dma_table_lock);
  72         spin_lock_init(&s390_domain->list_lock);
  73         INIT_LIST_HEAD(&s390_domain->devices);
  74
  75         return &s390_domain->domain;
  76 }
  77
  78 static void s390_domain_free(struct iommu_domain *domain)
  79 {
  80         struct s390_domain *s390_domain = to_s390_domain(domain);
  81
  82         dma_cleanup_tables(s390_domain->dma_table);
  83         kfree(s390_domain);
  84 }
  85
  86 static int s390_iommu_attach_device(struct iommu_domain *domain,
  87                                     struct device *dev)
  88 {
  89         struct s390_domain *s390_domain = to_s390_domain(domain);
  90         struct zpci_dev *zdev = to_zpci_dev(dev);
  91         struct s390_domain_device *domain_device;
  92         unsigned long flags;
  93         int cc, rc;
  94
  95         if (!zdev)
  96                 return -ENODEV;
  97
  98         domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
  99         if (!domain_device)
 100                 return -ENOMEM;
 101
 102         if (zdev->dma_table && !zdev->s390_domain) {
 103                 cc = zpci_dma_exit_device(zdev);
 104                 if (cc) {
 105                         rc = -EIO;
 106                         goto out_free;
 107                 }
 108         }
 109
 110         if (zdev->s390_domain)
 111                 zpci_unregister_ioat(zdev, 0);
 112
 113         zdev->dma_table = s390_domain->dma_table;
 114         cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 115                                 virt_to_phys(zdev->dma_table));
 116         if (cc) {
 117                 rc = -EIO;
 118                 goto out_restore;
 119         }
 120
 121         spin_lock_irqsave(&s390_domain->list_lock, flags);
 122         /* First device defines the DMA range limits */
 123         if (list_empty(&s390_domain->devices)) {
 124                 domain->geometry.aperture_start = zdev->start_dma;
 125                 domain->geometry.aperture_end = zdev->end_dma;
 126                 domain->geometry.force_aperture = true;
 127         /* Allow only devices with identical DMA range limits */
 128         } else if (domain->geometry.aperture_start != zdev->start_dma ||
 129                    domain->geometry.aperture_end != zdev->end_dma) {
 130                 rc = -EINVAL;
 131                 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 132                 goto out_restore;
 133         }
 134         domain_device->zdev = zdev;
 135         zdev->s390_domain = s390_domain;
 136         list_add(&domain_device->list, &s390_domain->devices);
 137         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 138
 139         return 0;
 140
 141 out_restore:
 142         if (!zdev->s390_domain) {
 143                 zpci_dma_init_device(zdev);
 144         } else {
 145                 zdev->dma_table = zdev->s390_domain->dma_table;
 146                 zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 147                                    virt_to_phys(zdev->dma_table));
 148         }
 149 out_free:
 150         kfree(domain_device);
 151
 152         return rc;
 153 }
 154
 155 static void s390_iommu_detach_device(struct iommu_domain *domain,
 156                                      struct device *dev)
 157 {
 158         struct s390_domain *s390_domain = to_s390_domain(domain);
 159         struct zpci_dev *zdev = to_zpci_dev(dev);
 160         struct s390_domain_device *domain_device, *tmp;
 161         unsigned long flags;
 162         int found = 0;
 163
 164         if (!zdev)
 165                 return;
 166
 167         spin_lock_irqsave(&s390_domain->list_lock, flags);
 168         list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
 169                                  list) {
 170                 if (domain_device->zdev == zdev) {
 171                         list_del(&domain_device->list);
 172                         kfree(domain_device);
 173                         found = 1;
 174                         break;
 175                 }
 176         }
 177         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 178
 179         if (found && (zdev->s390_domain == s390_domain)) {
 180                 zdev->s390_domain = NULL;
 181                 zpci_unregister_ioat(zdev, 0);
 182                 zpci_dma_init_device(zdev);
 183         }
 184 }
 185
 186 static struct iommu_device *s390_iommu_probe_device(struct device *dev)
 187 {
 188         struct zpci_dev *zdev;
 189
 190         if (!dev_is_pci(dev))
 191                 return ERR_PTR(-ENODEV);
 192
 193         zdev = to_zpci_dev(dev);
 194
 195         return &zdev->iommu_dev;
 196 }
 197
 198 static void s390_iommu_release_device(struct device *dev)
 199 {
 200         struct zpci_dev *zdev = to_zpci_dev(dev);
 201         struct iommu_domain *domain;
 202
 203         /*
 204          * This is a workaround for a scenario where the IOMMU API common code
 205          * "forgets" to call the detach_dev callback: After binding a device
 206          * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
 207          * the attach_dev), removing the device via
 208          * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
 209          * only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
 210          * notifier.
 211          *
 212          * So let's call detach_dev from here if it hasn't been called before.
 213          */
 214         if (zdev && zdev->s390_domain) {
 215                 domain = iommu_get_domain_for_dev(dev);
 216                 if (domain)
 217                         s390_iommu_detach_device(domain, dev);
 218         }
 219 }
 220
 221 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 222                                    phys_addr_t pa, dma_addr_t dma_addr,
 223                                    size_t size, int flags)
 224 {
 225         struct s390_domain_device *domain_device;
 226         phys_addr_t page_addr = pa & PAGE_MASK;
 227         dma_addr_t start_dma_addr = dma_addr;
 228         unsigned long irq_flags, nr_pages, i;
 229         unsigned long *entry;
 230         int rc = 0;
 231
 232         if (dma_addr < s390_domain->domain.geometry.aperture_start ||
 233             dma_addr + size > s390_domain->domain.geometry.aperture_end)
 234                 return -EINVAL;
 235
 236         nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 237         if (!nr_pages)
 238                 return 0;
 239
 240         spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
 241         for (i = 0; i < nr_pages; i++) {
 242                 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
 243                 if (!entry) {
 244                         rc = -ENOMEM;
 245                         goto undo_cpu_trans;
 246                 }
 247                 dma_update_cpu_trans(entry, page_addr, flags);
 248                 page_addr += PAGE_SIZE;
 249                 dma_addr += PAGE_SIZE;
 250         }
 251
 252         spin_lock(&s390_domain->list_lock);
 253         list_for_each_entry(domain_device, &s390_domain->devices, list) {
 254                 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
 255                                         start_dma_addr, nr_pages * PAGE_SIZE);
 256                 if (rc)
 257                         break;
 258         }
 259         spin_unlock(&s390_domain->list_lock);
 260
 261 undo_cpu_trans:
 262         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
 263                 flags = ZPCI_PTE_INVALID;
 264                 while (i-- > 0) {
 265                         page_addr -= PAGE_SIZE;
 266                         dma_addr -= PAGE_SIZE;
 267                         entry = dma_walk_cpu_trans(s390_domain->dma_table,
 268                                                    dma_addr);
 269                         if (!entry)
 270                                 break;
 271                         dma_update_cpu_trans(entry, page_addr, flags);
 272                 }
 273         }
 274         spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
 275
 276         return rc;
 277 }
 278
 279 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
 280                           phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
 281 {
 282         struct s390_domain *s390_domain = to_s390_domain(domain);
 283         int flags = ZPCI_PTE_VALID, rc = 0;
 284
 285         if (!(prot & IOMMU_READ))
 286                 return -EINVAL;
 287
 288         if (!(prot & IOMMU_WRITE))
 289                 flags |= ZPCI_TABLE_PROTECTED;
 290
 291         rc = s390_iommu_update_trans(s390_domain, paddr, iova,
 292                                      size, flags);
 293
 294         return rc;
 295 }
 296
 297 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
 298                                            dma_addr_t iova)
 299 {
 300         struct s390_domain *s390_domain = to_s390_domain(domain);
 301         unsigned long *sto, *pto, *rto, flags;
 302         unsigned int rtx, sx, px;
 303         phys_addr_t phys = 0;
 304
 305         if (iova < domain->geometry.aperture_start ||
 306             iova > domain->geometry.aperture_end)
 307                 return 0;
 308
 309         rtx = calc_rtx(iova);
 310         sx = calc_sx(iova);
 311         px = calc_px(iova);
 312         rto = s390_domain->dma_table;
 313
 314         spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
 315         if (rto && reg_entry_isvalid(rto[rtx])) {
 316                 sto = get_rt_sto(rto[rtx]);
 317                 if (sto && reg_entry_isvalid(sto[sx])) {
 318                         pto = get_st_pto(sto[sx]);
 319                         if (pto && pt_entry_isvalid(pto[px]))
 320                                 phys = pto[px] & ZPCI_PTE_ADDR_MASK;
 321                 }
 322         }
 323         spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
 324
 325         return phys;
 326 }
 327
 328 static size_t s390_iommu_unmap(struct iommu_domain *domain,
 329                                unsigned long iova, size_t size,
 330                                struct iommu_iotlb_gather *gather)
 331 {
 332         struct s390_domain *s390_domain = to_s390_domain(domain);
 333         int flags = ZPCI_PTE_INVALID;
 334         phys_addr_t paddr;
 335         int rc;
 336
 337         paddr = s390_iommu_iova_to_phys(domain, iova);
 338         if (!paddr)
 339                 return 0;
 340
 341         rc = s390_iommu_update_trans(s390_domain, paddr, iova,
 342                                      size, flags);
 343         if (rc)
 344                 return 0;
 345
 346         return size;
 347 }
 348
 349 int zpci_init_iommu(struct zpci_dev *zdev)
 350 {
 351         int rc = 0;
 352
 353         rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
 354                                     "s390-iommu.%08x", zdev->fid);
 355         if (rc)
 356                 goto out_err;
 357
 358         rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL);
 359         if (rc)
 360                 goto out_sysfs;
 361
 362         return 0;
 363
 364 out_sysfs:
 365         iommu_device_sysfs_remove(&zdev->iommu_dev);
 366
 367 out_err:
 368         return rc;
 369 }
 370
 371 void zpci_destroy_iommu(struct zpci_dev *zdev)
 372 {
 373         iommu_device_unregister(&zdev->iommu_dev);
 374         iommu_device_sysfs_remove(&zdev->iommu_dev);
 375 }
 376
 377 static const struct iommu_ops s390_iommu_ops = {
 378         .capable = s390_iommu_capable,
 379         .domain_alloc = s390_domain_alloc,
 380         .probe_device = s390_iommu_probe_device,
 381         .release_device = s390_iommu_release_device,
 382         .device_group = generic_device_group,
 383         .pgsize_bitmap = S390_IOMMU_PGSIZES,
 384         .default_domain_ops = &(const struct iommu_domain_ops) {
 385                 .attach_dev     = s390_iommu_attach_device,
 386                 .detach_dev     = s390_iommu_detach_device,
 387                 .map            = s390_iommu_map,
 388                 .unmap          = s390_iommu_unmap,
 389                 .iova_to_phys   = s390_iommu_iova_to_phys,
 390                 .free           = s390_domain_free,
 391         }
 392 };