drivers/iommu/s390-iommu.c

   1 /*
   2  * IOMMU API for s390 PCI devices
   3  *
   4  * Copyright IBM Corp. 2015
   5  * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
   6  */
   7
   8 #include <linux/pci.h>
   9 #include <linux/iommu.h>
  10 #include <linux/iommu-helper.h>
  11 #include <linux/pci.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 struct s390_domain {
  23         struct iommu_domain     domain;
  24         struct list_head        devices;
  25         unsigned long           *dma_table;
  26         spinlock_t              dma_table_lock;
  27         spinlock_t              list_lock;
  28 };
  29
  30 struct s390_domain_device {
  31         struct list_head        list;
  32         struct zpci_dev         *zdev;
  33 };
  34
  35 static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
  36 {
  37         return container_of(dom, struct s390_domain, domain);
  38 }
  39
  40 static bool s390_iommu_capable(enum iommu_cap cap)
  41 {
  42         switch (cap) {
  43         case IOMMU_CAP_CACHE_COHERENCY:
  44                 return true;
  45         case IOMMU_CAP_INTR_REMAP:
  46                 return true;
  47         default:
  48                 return false;
  49         }
  50 }
  51
  52 static struct iommu_domain *s390_domain_alloc(unsigned domain_type)
  53 {
  54         struct s390_domain *s390_domain;
  55
  56         if (domain_type != IOMMU_DOMAIN_UNMANAGED)
  57                 return NULL;
  58
  59         s390_domain = kzalloc(sizeof(*s390_domain), GFP_KERNEL);
  60         if (!s390_domain)
  61                 return NULL;
  62
  63         s390_domain->dma_table = dma_alloc_cpu_table();
  64         if (!s390_domain->dma_table) {
  65                 kfree(s390_domain);
  66                 return NULL;
  67         }
  68
  69         spin_lock_init(&s390_domain->dma_table_lock);
  70         spin_lock_init(&s390_domain->list_lock);
  71         INIT_LIST_HEAD(&s390_domain->devices);
  72
  73         return &s390_domain->domain;
  74 }
  75
  76 static void s390_domain_free(struct iommu_domain *domain)
  77 {
  78         struct s390_domain *s390_domain = to_s390_domain(domain);
  79
  80         dma_cleanup_tables(s390_domain->dma_table);
  81         kfree(s390_domain);
  82 }
  83
  84 static int s390_iommu_attach_device(struct iommu_domain *domain,
  85                                     struct device *dev)
  86 {
  87         struct s390_domain *s390_domain = to_s390_domain(domain);
  88         struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
  89         struct s390_domain_device *domain_device;
  90         unsigned long flags;
  91         int rc;
  92
  93         if (!zdev)
  94                 return -ENODEV;
  95
  96         domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
  97         if (!domain_device)
  98                 return -ENOMEM;
  99
 100         if (zdev->dma_table)
 101                 zpci_dma_exit_device(zdev);
 102
 103         zdev->dma_table = s390_domain->dma_table;
 104         rc = zpci_register_ioat(zdev, 0, zdev->start_dma + PAGE_OFFSET,
 105                                 zdev->start_dma + zdev->iommu_size - 1,
 106                                 (u64) zdev->dma_table);
 107         if (rc)
 108                 goto out_restore;
 109
 110         spin_lock_irqsave(&s390_domain->list_lock, flags);
 111         /* First device defines the DMA range limits */
 112         if (list_empty(&s390_domain->devices)) {
 113                 domain->geometry.aperture_start = zdev->start_dma;
 114                 domain->geometry.aperture_end = zdev->end_dma;
 115                 domain->geometry.force_aperture = true;
 116         /* Allow only devices with identical DMA range limits */
 117         } else if (domain->geometry.aperture_start != zdev->start_dma ||
 118                    domain->geometry.aperture_end != zdev->end_dma) {
 119                 rc = -EINVAL;
 120                 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 121                 goto out_restore;
 122         }
 123         domain_device->zdev = zdev;
 124         zdev->s390_domain = s390_domain;
 125         list_add(&domain_device->list, &s390_domain->devices);
 126         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 127
 128         return 0;
 129
 130 out_restore:
 131         zpci_dma_init_device(zdev);
 132         kfree(domain_device);
 133
 134         return rc;
 135 }
 136
 137 static void s390_iommu_detach_device(struct iommu_domain *domain,
 138                                      struct device *dev)
 139 {
 140         struct s390_domain *s390_domain = to_s390_domain(domain);
 141         struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
 142         struct s390_domain_device *domain_device, *tmp;
 143         unsigned long flags;
 144         int found = 0;
 145
 146         if (!zdev)
 147                 return;
 148
 149         spin_lock_irqsave(&s390_domain->list_lock, flags);
 150         list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
 151                                  list) {
 152                 if (domain_device->zdev == zdev) {
 153                         list_del(&domain_device->list);
 154                         kfree(domain_device);
 155                         found = 1;
 156                         break;
 157                 }
 158         }
 159         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 160
 161         if (found) {
 162                 zdev->s390_domain = NULL;
 163                 zpci_unregister_ioat(zdev, 0);
 164                 zpci_dma_init_device(zdev);
 165         }
 166 }
 167
 168 static int s390_iommu_add_device(struct device *dev)
 169 {
 170         struct iommu_group *group;
 171         int rc;
 172
 173         group = iommu_group_get(dev);
 174         if (!group) {
 175                 group = iommu_group_alloc();
 176                 if (IS_ERR(group))
 177                         return PTR_ERR(group);
 178         }
 179
 180         rc = iommu_group_add_device(group, dev);
 181         iommu_group_put(group);
 182
 183         return rc;
 184 }
 185
 186 static void s390_iommu_remove_device(struct device *dev)
 187 {
 188         struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
 189         struct iommu_domain *domain;
 190
 191         /*
 192          * This is a workaround for a scenario where the IOMMU API common code
 193          * "forgets" to call the detach_dev callback: After binding a device
 194          * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
 195          * the attach_dev), removing the device via
 196          * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
 197          * only remove_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
 198          * notifier.
 199          *
 200          * So let's call detach_dev from here if it hasn't been called before.
 201          */
 202         if (zdev && zdev->s390_domain) {
 203                 domain = iommu_get_domain_for_dev(dev);
 204                 if (domain)
 205                         s390_iommu_detach_device(domain, dev);
 206         }
 207
 208         iommu_group_remove_device(dev);
 209 }
 210
 211 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 212                                    unsigned long pa, dma_addr_t dma_addr,
 213                                    size_t size, int flags)
 214 {
 215         struct s390_domain_device *domain_device;
 216         u8 *page_addr = (u8 *) (pa & PAGE_MASK);
 217         dma_addr_t start_dma_addr = dma_addr;
 218         unsigned long irq_flags, nr_pages, i;
 219         unsigned long *entry;
 220         int rc = 0;
 221
 222         if (dma_addr < s390_domain->domain.geometry.aperture_start ||
 223             dma_addr + size > s390_domain->domain.geometry.aperture_end)
 224                 return -EINVAL;
 225
 226         nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 227         if (!nr_pages)
 228                 return 0;
 229
 230         spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
 231         for (i = 0; i < nr_pages; i++) {
 232                 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
 233                 if (!entry) {
 234                         rc = -ENOMEM;
 235                         goto undo_cpu_trans;
 236                 }
 237                 dma_update_cpu_trans(entry, page_addr, flags);
 238                 page_addr += PAGE_SIZE;
 239                 dma_addr += PAGE_SIZE;
 240         }
 241
 242         spin_lock(&s390_domain->list_lock);
 243         list_for_each_entry(domain_device, &s390_domain->devices, list) {
 244                 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
 245                                         start_dma_addr, nr_pages * PAGE_SIZE);
 246                 if (rc)
 247                         break;
 248         }
 249         spin_unlock(&s390_domain->list_lock);
 250
 251 undo_cpu_trans:
 252         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
 253                 flags = ZPCI_PTE_INVALID;
 254                 while (i-- > 0) {
 255                         page_addr -= PAGE_SIZE;
 256                         dma_addr -= PAGE_SIZE;
 257                         entry = dma_walk_cpu_trans(s390_domain->dma_table,
 258                                                    dma_addr);
 259                         if (!entry)
 260                                 break;
 261                         dma_update_cpu_trans(entry, page_addr, flags);
 262                 }
 263         }
 264         spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
 265
 266         return rc;
 267 }
 268
 269 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
 270                           phys_addr_t paddr, size_t size, int prot)
 271 {
 272         struct s390_domain *s390_domain = to_s390_domain(domain);
 273         int flags = ZPCI_PTE_VALID, rc = 0;
 274
 275         if (!(prot & IOMMU_READ))
 276                 return -EINVAL;
 277
 278         if (!(prot & IOMMU_WRITE))
 279                 flags |= ZPCI_TABLE_PROTECTED;
 280
 281         rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
 282                                      size, flags);
 283
 284         return rc;
 285 }
 286
 287 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
 288                                            dma_addr_t iova)
 289 {
 290         struct s390_domain *s390_domain = to_s390_domain(domain);
 291         unsigned long *sto, *pto, *rto, flags;
 292         unsigned int rtx, sx, px;
 293         phys_addr_t phys = 0;
 294
 295         if (iova < domain->geometry.aperture_start ||
 296             iova > domain->geometry.aperture_end)
 297                 return 0;
 298
 299         rtx = calc_rtx(iova);
 300         sx = calc_sx(iova);
 301         px = calc_px(iova);
 302         rto = s390_domain->dma_table;
 303
 304         spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
 305         if (rto && reg_entry_isvalid(rto[rtx])) {
 306                 sto = get_rt_sto(rto[rtx]);
 307                 if (sto && reg_entry_isvalid(sto[sx])) {
 308                         pto = get_st_pto(sto[sx]);
 309                         if (pto && pt_entry_isvalid(pto[px]))
 310                                 phys = pto[px] & ZPCI_PTE_ADDR_MASK;
 311                 }
 312         }
 313         spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
 314
 315         return phys;
 316 }
 317
 318 static size_t s390_iommu_unmap(struct iommu_domain *domain,
 319                                unsigned long iova, size_t size)
 320 {
 321         struct s390_domain *s390_domain = to_s390_domain(domain);
 322         int flags = ZPCI_PTE_INVALID;
 323         phys_addr_t paddr;
 324         int rc;
 325
 326         paddr = s390_iommu_iova_to_phys(domain, iova);
 327         if (!paddr)
 328                 return 0;
 329
 330         rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
 331                                      size, flags);
 332         if (rc)
 333                 return 0;
 334
 335         return size;
 336 }
 337
 338 static struct iommu_ops s390_iommu_ops = {
 339         .capable = s390_iommu_capable,
 340         .domain_alloc = s390_domain_alloc,
 341         .domain_free = s390_domain_free,
 342         .attach_dev = s390_iommu_attach_device,
 343         .detach_dev = s390_iommu_detach_device,
 344         .map = s390_iommu_map,
 345         .unmap = s390_iommu_unmap,
 346         .iova_to_phys = s390_iommu_iova_to_phys,
 347         .add_device = s390_iommu_add_device,
 348         .remove_device = s390_iommu_remove_device,
 349         .pgsize_bitmap = S390_IOMMU_PGSIZES,
 350 };
 351
 352 static int __init s390_iommu_init(void)
 353 {
 354         return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
 355 }
 356 subsys_initcall(s390_iommu_init);