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_pci_dev(dev)->sysdata;
  91         struct s390_domain_device *domain_device;
  92         unsigned long flags;
  93         int 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)
 103                 zpci_dma_exit_device(zdev);
 104
 105         zdev->dma_table = s390_domain->dma_table;
 106         rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 107                                 (u64) zdev->dma_table);
 108         if (rc)
 109                 goto out_restore;
 110
 111         spin_lock_irqsave(&s390_domain->list_lock, flags);
 112         /* First device defines the DMA range limits */
 113         if (list_empty(&s390_domain->devices)) {
 114                 domain->geometry.aperture_start = zdev->start_dma;
 115                 domain->geometry.aperture_end = zdev->end_dma;
 116                 domain->geometry.force_aperture = true;
 117         /* Allow only devices with identical DMA range limits */
 118         } else if (domain->geometry.aperture_start != zdev->start_dma ||
 119                    domain->geometry.aperture_end != zdev->end_dma) {
 120                 rc = -EINVAL;
 121                 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 122                 goto out_restore;
 123         }
 124         domain_device->zdev = zdev;
 125         zdev->s390_domain = s390_domain;
 126         list_add(&domain_device->list, &s390_domain->devices);
 127         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 128
 129         return 0;
 130
 131 out_restore:
 132         zpci_dma_init_device(zdev);
 133         kfree(domain_device);
 134
 135         return rc;
 136 }
 137
 138 static void s390_iommu_detach_device(struct iommu_domain *domain,
 139                                      struct device *dev)
 140 {
 141         struct s390_domain *s390_domain = to_s390_domain(domain);
 142         struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
 143         struct s390_domain_device *domain_device, *tmp;
 144         unsigned long flags;
 145         int found = 0;
 146
 147         if (!zdev)
 148                 return;
 149
 150         spin_lock_irqsave(&s390_domain->list_lock, flags);
 151         list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
 152                                  list) {
 153                 if (domain_device->zdev == zdev) {
 154                         list_del(&domain_device->list);
 155                         kfree(domain_device);
 156                         found = 1;
 157                         break;
 158                 }
 159         }
 160         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 161
 162         if (found) {
 163                 zdev->s390_domain = NULL;
 164                 zpci_unregister_ioat(zdev, 0);
 165                 zpci_dma_init_device(zdev);
 166         }
 167 }
 168
 169 static int s390_iommu_add_device(struct device *dev)
 170 {
 171         struct iommu_group *group = iommu_group_get_for_dev(dev);
 172         struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
 173
 174         if (IS_ERR(group))
 175                 return PTR_ERR(group);
 176
 177         iommu_group_put(group);
 178         iommu_device_link(&zdev->iommu_dev, dev);
 179
 180         return 0;
 181 }
 182
 183 static void s390_iommu_remove_device(struct device *dev)
 184 {
 185         struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
 186         struct iommu_domain *domain;
 187
 188         /*
 189          * This is a workaround for a scenario where the IOMMU API common code
 190          * "forgets" to call the detach_dev callback: After binding a device
 191          * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
 192          * the attach_dev), removing the device via
 193          * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
 194          * only remove_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
 195          * notifier.
 196          *
 197          * So let's call detach_dev from here if it hasn't been called before.
 198          */
 199         if (zdev && zdev->s390_domain) {
 200                 domain = iommu_get_domain_for_dev(dev);
 201                 if (domain)
 202                         s390_iommu_detach_device(domain, dev);
 203         }
 204
 205         iommu_device_unlink(&zdev->iommu_dev, dev);
 206         iommu_group_remove_device(dev);
 207 }
 208
 209 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 210                                    unsigned long pa, dma_addr_t dma_addr,
 211                                    size_t size, int flags)
 212 {
 213         struct s390_domain_device *domain_device;
 214         u8 *page_addr = (u8 *) (pa & PAGE_MASK);
 215         dma_addr_t start_dma_addr = dma_addr;
 216         unsigned long irq_flags, nr_pages, i;
 217         unsigned long *entry;
 218         int rc = 0;
 219
 220         if (dma_addr < s390_domain->domain.geometry.aperture_start ||
 221             dma_addr + size > s390_domain->domain.geometry.aperture_end)
 222                 return -EINVAL;
 223
 224         nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 225         if (!nr_pages)
 226                 return 0;
 227
 228         spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
 229         for (i = 0; i < nr_pages; i++) {
 230                 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
 231                 if (!entry) {
 232                         rc = -ENOMEM;
 233                         goto undo_cpu_trans;
 234                 }
 235                 dma_update_cpu_trans(entry, page_addr, flags);
 236                 page_addr += PAGE_SIZE;
 237                 dma_addr += PAGE_SIZE;
 238         }
 239
 240         spin_lock(&s390_domain->list_lock);
 241         list_for_each_entry(domain_device, &s390_domain->devices, list) {
 242                 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
 243                                         start_dma_addr, nr_pages * PAGE_SIZE);
 244                 if (rc)
 245                         break;
 246         }
 247         spin_unlock(&s390_domain->list_lock);
 248
 249 undo_cpu_trans:
 250         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
 251                 flags = ZPCI_PTE_INVALID;
 252                 while (i-- > 0) {
 253                         page_addr -= PAGE_SIZE;
 254                         dma_addr -= PAGE_SIZE;
 255                         entry = dma_walk_cpu_trans(s390_domain->dma_table,
 256                                                    dma_addr);
 257                         if (!entry)
 258                                 break;
 259                         dma_update_cpu_trans(entry, page_addr, flags);
 260                 }
 261         }
 262         spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
 263
 264         return rc;
 265 }
 266
 267 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
 268                           phys_addr_t paddr, size_t size, int prot)
 269 {
 270         struct s390_domain *s390_domain = to_s390_domain(domain);
 271         int flags = ZPCI_PTE_VALID, rc = 0;
 272
 273         if (!(prot & IOMMU_READ))
 274                 return -EINVAL;
 275
 276         if (!(prot & IOMMU_WRITE))
 277                 flags |= ZPCI_TABLE_PROTECTED;
 278
 279         rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
 280                                      size, flags);
 281
 282         return rc;
 283 }
 284
 285 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
 286                                            dma_addr_t iova)
 287 {
 288         struct s390_domain *s390_domain = to_s390_domain(domain);
 289         unsigned long *sto, *pto, *rto, flags;
 290         unsigned int rtx, sx, px;
 291         phys_addr_t phys = 0;
 292
 293         if (iova < domain->geometry.aperture_start ||
 294             iova > domain->geometry.aperture_end)
 295                 return 0;
 296
 297         rtx = calc_rtx(iova);
 298         sx = calc_sx(iova);
 299         px = calc_px(iova);
 300         rto = s390_domain->dma_table;
 301
 302         spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
 303         if (rto && reg_entry_isvalid(rto[rtx])) {
 304                 sto = get_rt_sto(rto[rtx]);
 305                 if (sto && reg_entry_isvalid(sto[sx])) {
 306                         pto = get_st_pto(sto[sx]);
 307                         if (pto && pt_entry_isvalid(pto[px]))
 308                                 phys = pto[px] & ZPCI_PTE_ADDR_MASK;
 309                 }
 310         }
 311         spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
 312
 313         return phys;
 314 }
 315
 316 static size_t s390_iommu_unmap(struct iommu_domain *domain,
 317                                unsigned long iova, size_t size,
 318                                struct iommu_iotlb_gather *gather)
 319 {
 320         struct s390_domain *s390_domain = to_s390_domain(domain);
 321         int flags = ZPCI_PTE_INVALID;
 322         phys_addr_t paddr;
 323         int rc;
 324
 325         paddr = s390_iommu_iova_to_phys(domain, iova);
 326         if (!paddr)
 327                 return 0;
 328
 329         rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
 330                                      size, flags);
 331         if (rc)
 332                 return 0;
 333
 334         return size;
 335 }
 336
 337 int zpci_init_iommu(struct zpci_dev *zdev)
 338 {
 339         int rc = 0;
 340
 341         rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
 342                                     "s390-iommu.%08x", zdev->fid);
 343         if (rc)
 344                 goto out_err;
 345
 346         iommu_device_set_ops(&zdev->iommu_dev, &s390_iommu_ops);
 347
 348         rc = iommu_device_register(&zdev->iommu_dev);
 349         if (rc)
 350                 goto out_sysfs;
 351
 352         return 0;
 353
 354 out_sysfs:
 355         iommu_device_sysfs_remove(&zdev->iommu_dev);
 356
 357 out_err:
 358         return rc;
 359 }
 360
 361 void zpci_destroy_iommu(struct zpci_dev *zdev)
 362 {
 363         iommu_device_unregister(&zdev->iommu_dev);
 364         iommu_device_sysfs_remove(&zdev->iommu_dev);
 365 }
 366
 367 static const struct iommu_ops s390_iommu_ops = {
 368         .capable = s390_iommu_capable,
 369         .domain_alloc = s390_domain_alloc,
 370         .domain_free = s390_domain_free,
 371         .attach_dev = s390_iommu_attach_device,
 372         .detach_dev = s390_iommu_detach_device,
 373         .map = s390_iommu_map,
 374         .unmap = s390_iommu_unmap,
 375         .iova_to_phys = s390_iommu_iova_to_phys,
 376         .add_device = s390_iommu_add_device,
 377         .remove_device = s390_iommu_remove_device,
 378         .device_group = generic_device_group,
 379         .pgsize_bitmap = S390_IOMMU_PGSIZES,
 380 };
 381
 382 static int __init s390_iommu_init(void)
 383 {
 384         return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
 385 }
 386 subsys_initcall(s390_iommu_init);