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/sizes.h>
  12 #include <asm/pci_dma.h>
  13
  14 /*
  15  * Physically contiguous memory regions can be mapped with 4 KiB alignment,
  16  * we allow all page sizes that are an order of 4KiB (no special large page
  17  * support so far).
  18  */
  19 #define S390_IOMMU_PGSIZES      (~0xFFFUL)
  20
  21 struct s390_domain {
  22         struct iommu_domain     domain;
  23         struct list_head        devices;
  24         unsigned long           *dma_table;
  25         spinlock_t              dma_table_lock;
  26         spinlock_t              list_lock;
  27 };
  28
  29 struct s390_domain_device {
  30         struct list_head        list;
  31         struct zpci_dev         *zdev;
  32 };
  33
  34 static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
  35 {
  36         return container_of(dom, struct s390_domain, domain);
  37 }
  38
  39 static bool s390_iommu_capable(enum iommu_cap cap)
  40 {
  41         switch (cap) {
  42         case IOMMU_CAP_CACHE_COHERENCY:
  43                 return true;
  44         case IOMMU_CAP_INTR_REMAP:
  45                 return true;
  46         default:
  47                 return false;
  48         }
  49 }
  50
  51 static struct iommu_domain *s390_domain_alloc(unsigned domain_type)
  52 {
  53         struct s390_domain *s390_domain;
  54
  55         if (domain_type != IOMMU_DOMAIN_UNMANAGED)
  56                 return NULL;
  57
  58         s390_domain = kzalloc(sizeof(*s390_domain), GFP_KERNEL);
  59         if (!s390_domain)
  60                 return NULL;
  61
  62         s390_domain->dma_table = dma_alloc_cpu_table();
  63         if (!s390_domain->dma_table) {
  64                 kfree(s390_domain);
  65                 return NULL;
  66         }
  67
  68         spin_lock_init(&s390_domain->dma_table_lock);
  69         spin_lock_init(&s390_domain->list_lock);
  70         INIT_LIST_HEAD(&s390_domain->devices);
  71
  72         return &s390_domain->domain;
  73 }
  74
  75 static void s390_domain_free(struct iommu_domain *domain)
  76 {
  77         struct s390_domain *s390_domain = to_s390_domain(domain);
  78
  79         dma_cleanup_tables(s390_domain->dma_table);
  80         kfree(s390_domain);
  81 }
  82
  83 static int s390_iommu_attach_device(struct iommu_domain *domain,
  84                                     struct device *dev)
  85 {
  86         struct s390_domain *s390_domain = to_s390_domain(domain);
  87         struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
  88         struct s390_domain_device *domain_device;
  89         unsigned long flags;
  90         int rc;
  91
  92         if (!zdev)
  93                 return -ENODEV;
  94
  95         domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
  96         if (!domain_device)
  97                 return -ENOMEM;
  98
  99         if (zdev->dma_table)
 100                 zpci_dma_exit_device(zdev);
 101
 102         zdev->dma_table = s390_domain->dma_table;
 103         rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 104                                 (u64) zdev->dma_table);
 105         if (rc)
 106                 goto out_restore;
 107
 108         spin_lock_irqsave(&s390_domain->list_lock, flags);
 109         /* First device defines the DMA range limits */
 110         if (list_empty(&s390_domain->devices)) {
 111                 domain->geometry.aperture_start = zdev->start_dma;
 112                 domain->geometry.aperture_end = zdev->end_dma;
 113                 domain->geometry.force_aperture = true;
 114         /* Allow only devices with identical DMA range limits */
 115         } else if (domain->geometry.aperture_start != zdev->start_dma ||
 116                    domain->geometry.aperture_end != zdev->end_dma) {
 117                 rc = -EINVAL;
 118                 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 119                 goto out_restore;
 120         }
 121         domain_device->zdev = zdev;
 122         zdev->s390_domain = s390_domain;
 123         list_add(&domain_device->list, &s390_domain->devices);
 124         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 125
 126         return 0;
 127
 128 out_restore:
 129         zpci_dma_init_device(zdev);
 130         kfree(domain_device);
 131
 132         return rc;
 133 }
 134
 135 static void s390_iommu_detach_device(struct iommu_domain *domain,
 136                                      struct device *dev)
 137 {
 138         struct s390_domain *s390_domain = to_s390_domain(domain);
 139         struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
 140         struct s390_domain_device *domain_device, *tmp;
 141         unsigned long flags;
 142         int found = 0;
 143
 144         if (!zdev)
 145                 return;
 146
 147         spin_lock_irqsave(&s390_domain->list_lock, flags);
 148         list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
 149                                  list) {
 150                 if (domain_device->zdev == zdev) {
 151                         list_del(&domain_device->list);
 152                         kfree(domain_device);
 153                         found = 1;
 154                         break;
 155                 }
 156         }
 157         spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 158
 159         if (found) {
 160                 zdev->s390_domain = NULL;
 161                 zpci_unregister_ioat(zdev, 0);
 162                 zpci_dma_init_device(zdev);
 163         }
 164 }
 165
 166 static int s390_iommu_add_device(struct device *dev)
 167 {
 168         struct iommu_group *group;
 169         int rc;
 170
 171         group = iommu_group_get(dev);
 172         if (!group) {
 173                 group = iommu_group_alloc();
 174                 if (IS_ERR(group))
 175                         return PTR_ERR(group);
 176         }
 177
 178         rc = iommu_group_add_device(group, dev);
 179         iommu_group_put(group);
 180
 181         return rc;
 182 }
 183
 184 static void s390_iommu_remove_device(struct device *dev)
 185 {
 186         struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
 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 remove_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         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 {
 319         struct s390_domain *s390_domain = to_s390_domain(domain);
 320         int flags = ZPCI_PTE_INVALID;
 321         phys_addr_t paddr;
 322         int rc;
 323
 324         paddr = s390_iommu_iova_to_phys(domain, iova);
 325         if (!paddr)
 326                 return 0;
 327
 328         rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
 329                                      size, flags);
 330         if (rc)
 331                 return 0;
 332
 333         return size;
 334 }
 335
 336 static struct iommu_ops s390_iommu_ops = {
 337         .capable = s390_iommu_capable,
 338         .domain_alloc = s390_domain_alloc,
 339         .domain_free = s390_domain_free,
 340         .attach_dev = s390_iommu_attach_device,
 341         .detach_dev = s390_iommu_detach_device,
 342         .map = s390_iommu_map,
 343         .unmap = s390_iommu_unmap,
 344         .iova_to_phys = s390_iommu_iova_to_phys,
 345         .add_device = s390_iommu_add_device,
 346         .remove_device = s390_iommu_remove_device,
 347         .pgsize_bitmap = S390_IOMMU_PGSIZES,
 348 };
 349
 350 static int __init s390_iommu_init(void)
 351 {
 352         return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
 353 }
 354 subsys_initcall(s390_iommu_init);