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