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) {
 103                 cc = zpci_dma_exit_device(zdev);
 104                 if (cc) {
 105                         rc = -EIO;
 106                         goto out_free;
 107                 }
 108         }
 109
 110         zdev->dma_table = s390_domain->dma_table;
 111         cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 112                                 (u64) zdev->dma_table);
 113         if (cc) {
 114                 rc = -EIO;
 115                 goto out_restore;
 116         }
 117
 118         spin_lock_irqsave(&s390_domain->list_lock, flags);
 119         /* First device defines the DMA range limits */
 120         if (list_empty(&s390_domain->devices)) {
 121                 domain->geometry.aperture_start = zdev->start_dma;
 122                 domain->geometry.aperture_end = zdev->end_dma;
 123                 domain->geometry.force_aperture = true;
 124         /* Allow only devices with identical DMA range limits */
 125         } else if (domain->geometry.aperture_start != zdev->start_dma ||
 126                    domain->geometry.aperture_end != zdev->end_dma) {
 127                 rc = -EINVAL;
 128                 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 129                 goto out_restore;
 130         }
 131         domain_device->zdev = zdev;
 132         zdev->s390_domain = s390_domain;
 133         list_add(&domain_device->list, &s390_domain->devices);
 134         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 135
 136         return 0;
 137
 138 out_restore:
 139         zpci_dma_init_device(zdev);
 140 out_free:
 141         kfree(domain_device);
 142
 143         return rc;
 144 }
 145
 146 static void s390_iommu_detach_device(struct iommu_domain *domain,
 147                                      struct device *dev)
 148 {
 149         struct s390_domain *s390_domain = to_s390_domain(domain);
 150         struct zpci_dev *zdev = to_zpci_dev(dev);
 151         struct s390_domain_device *domain_device, *tmp;
 152         unsigned long flags;
 153         int found = 0;
 154
 155         if (!zdev)
 156                 return;
 157
 158         spin_lock_irqsave(&s390_domain->list_lock, flags);
 159         list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
 160                                  list) {
 161                 if (domain_device->zdev == zdev) {
 162                         list_del(&domain_device->list);
 163                         kfree(domain_device);
 164                         found = 1;
 165                         break;
 166                 }
 167         }
 168         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 169
 170         if (found) {
 171                 zdev->s390_domain = NULL;
 172                 zpci_unregister_ioat(zdev, 0);
 173                 zpci_dma_init_device(zdev);
 174         }
 175 }
 176
 177 static struct iommu_device *s390_iommu_probe_device(struct device *dev)
 178 {
 179         struct zpci_dev *zdev = to_zpci_dev(dev);
 180
 181         return &zdev->iommu_dev;
 182 }
 183
 184 static void s390_iommu_release_device(struct device *dev)
 185 {
 186         struct zpci_dev *zdev = to_zpci_dev(dev);
 187         struct iommu_domain *domain;
 188
 189         /*
 190          * This is a workaround for a scenario where the IOMMU API common code
 191          * "forgets" to call the detach_dev callback: After binding a device
 192          * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
 193          * the attach_dev), removing the device via
 194          * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
 195          * only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
 196          * notifier.
 197          *
 198          * So let's call detach_dev from here if it hasn't been called before.
 199          */
 200         if (zdev && zdev->s390_domain) {
 201                 domain = iommu_get_domain_for_dev(dev);
 202                 if (domain)
 203                         s390_iommu_detach_device(domain, dev);
 204         }
 205 }
 206
 207 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 208                                    unsigned long pa, dma_addr_t dma_addr,
 209                                    size_t size, int flags)
 210 {
 211         struct s390_domain_device *domain_device;
 212         u8 *page_addr = (u8 *) (pa & PAGE_MASK);
 213         dma_addr_t start_dma_addr = dma_addr;
 214         unsigned long irq_flags, nr_pages, i;
 215         unsigned long *entry;
 216         int rc = 0;
 217
 218         if (dma_addr < s390_domain->domain.geometry.aperture_start ||
 219             dma_addr + size > s390_domain->domain.geometry.aperture_end)
 220                 return -EINVAL;
 221
 222         nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 223         if (!nr_pages)
 224                 return 0;
 225
 226         spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
 227         for (i = 0; i < nr_pages; i++) {
 228                 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
 229                 if (!entry) {
 230                         rc = -ENOMEM;
 231                         goto undo_cpu_trans;
 232                 }
 233                 dma_update_cpu_trans(entry, page_addr, flags);
 234                 page_addr += PAGE_SIZE;
 235                 dma_addr += PAGE_SIZE;
 236         }
 237
 238         spin_lock(&s390_domain->list_lock);
 239         list_for_each_entry(domain_device, &s390_domain->devices, list) {
 240                 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
 241                                         start_dma_addr, nr_pages * PAGE_SIZE);
 242                 if (rc)
 243                         break;
 244         }
 245         spin_unlock(&s390_domain->list_lock);
 246
 247 undo_cpu_trans:
 248         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
 249                 flags = ZPCI_PTE_INVALID;
 250                 while (i-- > 0) {
 251                         page_addr -= PAGE_SIZE;
 252                         dma_addr -= PAGE_SIZE;
 253                         entry = dma_walk_cpu_trans(s390_domain->dma_table,
 254                                                    dma_addr);
 255                         if (!entry)
 256                                 break;
 257                         dma_update_cpu_trans(entry, page_addr, flags);
 258                 }
 259         }
 260         spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
 261
 262         return rc;
 263 }
 264
 265 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
 266                           phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
 267 {
 268         struct s390_domain *s390_domain = to_s390_domain(domain);
 269         int flags = ZPCI_PTE_VALID, rc = 0;
 270
 271         if (!(prot & IOMMU_READ))
 272                 return -EINVAL;
 273
 274         if (!(prot & IOMMU_WRITE))
 275                 flags |= ZPCI_TABLE_PROTECTED;
 276
 277         rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
 278                                      size, flags);
 279
 280         return rc;
 281 }
 282
 283 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
 284                                            dma_addr_t iova)
 285 {
 286         struct s390_domain *s390_domain = to_s390_domain(domain);
 287         unsigned long *sto, *pto, *rto, flags;
 288         unsigned int rtx, sx, px;
 289         phys_addr_t phys = 0;
 290
 291         if (iova < domain->geometry.aperture_start ||
 292             iova > domain->geometry.aperture_end)
 293                 return 0;
 294
 295         rtx = calc_rtx(iova);
 296         sx = calc_sx(iova);
 297         px = calc_px(iova);
 298         rto = s390_domain->dma_table;
 299
 300         spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
 301         if (rto && reg_entry_isvalid(rto[rtx])) {
 302                 sto = get_rt_sto(rto[rtx]);
 303                 if (sto && reg_entry_isvalid(sto[sx])) {
 304                         pto = get_st_pto(sto[sx]);
 305                         if (pto && pt_entry_isvalid(pto[px]))
 306                                 phys = pto[px] & ZPCI_PTE_ADDR_MASK;
 307                 }
 308         }
 309         spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
 310
 311         return phys;
 312 }
 313
 314 static size_t s390_iommu_unmap(struct iommu_domain *domain,
 315                                unsigned long iova, size_t size,
 316                                struct iommu_iotlb_gather *gather)
 317 {
 318         struct s390_domain *s390_domain = to_s390_domain(domain);
 319         int flags = ZPCI_PTE_INVALID;
 320         phys_addr_t paddr;
 321         int rc;
 322
 323         paddr = s390_iommu_iova_to_phys(domain, iova);
 324         if (!paddr)
 325                 return 0;
 326
 327         rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
 328                                      size, flags);
 329         if (rc)
 330                 return 0;
 331
 332         return size;
 333 }
 334
 335 int zpci_init_iommu(struct zpci_dev *zdev)
 336 {
 337         int rc = 0;
 338
 339         rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
 340                                     "s390-iommu.%08x", zdev->fid);
 341         if (rc)
 342                 goto out_err;
 343
 344         rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL);
 345         if (rc)
 346                 goto out_sysfs;
 347
 348         return 0;
 349
 350 out_sysfs:
 351         iommu_device_sysfs_remove(&zdev->iommu_dev);
 352
 353 out_err:
 354         return rc;
 355 }
 356
 357 void zpci_destroy_iommu(struct zpci_dev *zdev)
 358 {
 359         iommu_device_unregister(&zdev->iommu_dev);
 360         iommu_device_sysfs_remove(&zdev->iommu_dev);
 361 }
 362
 363 static const struct iommu_ops s390_iommu_ops = {
 364         .capable = s390_iommu_capable,
 365         .domain_alloc = s390_domain_alloc,
 366         .domain_free = s390_domain_free,
 367         .attach_dev = s390_iommu_attach_device,
 368         .detach_dev = s390_iommu_detach_device,
 369         .map = s390_iommu_map,
 370         .unmap = s390_iommu_unmap,
 371         .iova_to_phys = s390_iommu_iova_to_phys,
 372         .probe_device = s390_iommu_probe_device,
 373         .release_device = s390_iommu_release_device,
 374         .device_group = generic_device_group,
 375         .pgsize_bitmap = S390_IOMMU_PGSIZES,
 376 };
 377
 378 static int __init s390_iommu_init(void)
 379 {
 380         return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
 381 }
 382 subsys_initcall(s390_iommu_init);