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(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 = to_zpci_dev(dev);
 189
 190         return &zdev->iommu_dev;
 191 }
 192
 193 static void s390_iommu_release_device(struct device *dev)
 194 {
 195         struct zpci_dev *zdev = to_zpci_dev(dev);
 196         struct iommu_domain *domain;
 197
 198         /*
 199          * This is a workaround for a scenario where the IOMMU API common code
 200          * "forgets" to call the detach_dev callback: After binding a device
 201          * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
 202          * the attach_dev), removing the device via
 203          * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
 204          * only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
 205          * notifier.
 206          *
 207          * So let's call detach_dev from here if it hasn't been called before.
 208          */
 209         if (zdev && zdev->s390_domain) {
 210                 domain = iommu_get_domain_for_dev(dev);
 211                 if (domain)
 212                         s390_iommu_detach_device(domain, dev);
 213         }
 214 }
 215
 216 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 217                                    phys_addr_t pa, dma_addr_t dma_addr,
 218                                    size_t size, int flags)
 219 {
 220         struct s390_domain_device *domain_device;
 221         phys_addr_t page_addr = pa & PAGE_MASK;
 222         dma_addr_t start_dma_addr = dma_addr;
 223         unsigned long irq_flags, nr_pages, i;
 224         unsigned long *entry;
 225         int rc = 0;
 226
 227         if (dma_addr < s390_domain->domain.geometry.aperture_start ||
 228             dma_addr + size > s390_domain->domain.geometry.aperture_end)
 229                 return -EINVAL;
 230
 231         nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 232         if (!nr_pages)
 233                 return 0;
 234
 235         spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
 236         for (i = 0; i < nr_pages; i++) {
 237                 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
 238                 if (!entry) {
 239                         rc = -ENOMEM;
 240                         goto undo_cpu_trans;
 241                 }
 242                 dma_update_cpu_trans(entry, page_addr, flags);
 243                 page_addr += PAGE_SIZE;
 244                 dma_addr += PAGE_SIZE;
 245         }
 246
 247         spin_lock(&s390_domain->list_lock);
 248         list_for_each_entry(domain_device, &s390_domain->devices, list) {
 249                 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
 250                                         start_dma_addr, nr_pages * PAGE_SIZE);
 251                 if (rc)
 252                         break;
 253         }
 254         spin_unlock(&s390_domain->list_lock);
 255
 256 undo_cpu_trans:
 257         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
 258                 flags = ZPCI_PTE_INVALID;
 259                 while (i-- > 0) {
 260                         page_addr -= PAGE_SIZE;
 261                         dma_addr -= PAGE_SIZE;
 262                         entry = dma_walk_cpu_trans(s390_domain->dma_table,
 263                                                    dma_addr);
 264                         if (!entry)
 265                                 break;
 266                         dma_update_cpu_trans(entry, page_addr, flags);
 267                 }
 268         }
 269         spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
 270
 271         return rc;
 272 }
 273
 274 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
 275                           phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
 276 {
 277         struct s390_domain *s390_domain = to_s390_domain(domain);
 278         int flags = ZPCI_PTE_VALID, rc = 0;
 279
 280         if (!(prot & IOMMU_READ))
 281                 return -EINVAL;
 282
 283         if (!(prot & IOMMU_WRITE))
 284                 flags |= ZPCI_TABLE_PROTECTED;
 285
 286         rc = s390_iommu_update_trans(s390_domain, paddr, iova,
 287                                      size, flags);
 288
 289         return rc;
 290 }
 291
 292 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
 293                                            dma_addr_t iova)
 294 {
 295         struct s390_domain *s390_domain = to_s390_domain(domain);
 296         unsigned long *sto, *pto, *rto, flags;
 297         unsigned int rtx, sx, px;
 298         phys_addr_t phys = 0;
 299
 300         if (iova < domain->geometry.aperture_start ||
 301             iova > domain->geometry.aperture_end)
 302                 return 0;
 303
 304         rtx = calc_rtx(iova);
 305         sx = calc_sx(iova);
 306         px = calc_px(iova);
 307         rto = s390_domain->dma_table;
 308
 309         spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
 310         if (rto && reg_entry_isvalid(rto[rtx])) {
 311                 sto = get_rt_sto(rto[rtx]);
 312                 if (sto && reg_entry_isvalid(sto[sx])) {
 313                         pto = get_st_pto(sto[sx]);
 314                         if (pto && pt_entry_isvalid(pto[px]))
 315                                 phys = pto[px] & ZPCI_PTE_ADDR_MASK;
 316                 }
 317         }
 318         spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
 319
 320         return phys;
 321 }
 322
 323 static size_t s390_iommu_unmap(struct iommu_domain *domain,
 324                                unsigned long iova, size_t size,
 325                                struct iommu_iotlb_gather *gather)
 326 {
 327         struct s390_domain *s390_domain = to_s390_domain(domain);
 328         int flags = ZPCI_PTE_INVALID;
 329         phys_addr_t paddr;
 330         int rc;
 331
 332         paddr = s390_iommu_iova_to_phys(domain, iova);
 333         if (!paddr)
 334                 return 0;
 335
 336         rc = s390_iommu_update_trans(s390_domain, paddr, iova,
 337                                      size, flags);
 338         if (rc)
 339                 return 0;
 340
 341         return size;
 342 }
 343
 344 int zpci_init_iommu(struct zpci_dev *zdev)
 345 {
 346         int rc = 0;
 347
 348         rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
 349                                     "s390-iommu.%08x", zdev->fid);
 350         if (rc)
 351                 goto out_err;
 352
 353         rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL);
 354         if (rc)
 355                 goto out_sysfs;
 356
 357         return 0;
 358
 359 out_sysfs:
 360         iommu_device_sysfs_remove(&zdev->iommu_dev);
 361
 362 out_err:
 363         return rc;
 364 }
 365
 366 void zpci_destroy_iommu(struct zpci_dev *zdev)
 367 {
 368         iommu_device_unregister(&zdev->iommu_dev);
 369         iommu_device_sysfs_remove(&zdev->iommu_dev);
 370 }
 371
 372 static const struct iommu_ops s390_iommu_ops = {
 373         .capable = s390_iommu_capable,
 374         .domain_alloc = s390_domain_alloc,
 375         .probe_device = s390_iommu_probe_device,
 376         .release_device = s390_iommu_release_device,
 377         .device_group = generic_device_group,
 378         .pgsize_bitmap = S390_IOMMU_PGSIZES,
 379         .default_domain_ops = &(const struct iommu_domain_ops) {
 380                 .attach_dev     = s390_iommu_attach_device,
 381                 .detach_dev     = s390_iommu_detach_device,
 382                 .map            = s390_iommu_map,
 383                 .unmap          = s390_iommu_unmap,
 384                 .iova_to_phys   = s390_iommu_iova_to_phys,
 385                 .free           = s390_domain_free,
 386         }
 387 };
 388
 389 static int __init s390_iommu_init(void)
 390 {
 391         return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
 392 }
 393 subsys_initcall(s390_iommu_init);