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 = iommu_group_get_for_dev(dev);
 169
 170         if (IS_ERR(group))
 171                 return PTR_ERR(group);
 172
 173         iommu_group_put(group);
 174
 175         return 0;
 176 }
 177
 178 static void s390_iommu_remove_device(struct device *dev)
 179 {
 180         struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
 181         struct iommu_domain *domain;
 182
 183         /*
 184          * This is a workaround for a scenario where the IOMMU API common code
 185          * "forgets" to call the detach_dev callback: After binding a device
 186          * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
 187          * the attach_dev), removing the device via
 188          * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
 189          * only remove_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
 190          * notifier.
 191          *
 192          * So let's call detach_dev from here if it hasn't been called before.
 193          */
 194         if (zdev && zdev->s390_domain) {
 195                 domain = iommu_get_domain_for_dev(dev);
 196                 if (domain)
 197                         s390_iommu_detach_device(domain, dev);
 198         }
 199
 200         iommu_group_remove_device(dev);
 201 }
 202
 203 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 204                                    unsigned long pa, dma_addr_t dma_addr,
 205                                    size_t size, int flags)
 206 {
 207         struct s390_domain_device *domain_device;
 208         u8 *page_addr = (u8 *) (pa & PAGE_MASK);
 209         dma_addr_t start_dma_addr = dma_addr;
 210         unsigned long irq_flags, nr_pages, i;
 211         unsigned long *entry;
 212         int rc = 0;
 213
 214         if (dma_addr < s390_domain->domain.geometry.aperture_start ||
 215             dma_addr + size > s390_domain->domain.geometry.aperture_end)
 216                 return -EINVAL;
 217
 218         nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 219         if (!nr_pages)
 220                 return 0;
 221
 222         spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
 223         for (i = 0; i < nr_pages; i++) {
 224                 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
 225                 if (!entry) {
 226                         rc = -ENOMEM;
 227                         goto undo_cpu_trans;
 228                 }
 229                 dma_update_cpu_trans(entry, page_addr, flags);
 230                 page_addr += PAGE_SIZE;
 231                 dma_addr += PAGE_SIZE;
 232         }
 233
 234         spin_lock(&s390_domain->list_lock);
 235         list_for_each_entry(domain_device, &s390_domain->devices, list) {
 236                 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
 237                                         start_dma_addr, nr_pages * PAGE_SIZE);
 238                 if (rc)
 239                         break;
 240         }
 241         spin_unlock(&s390_domain->list_lock);
 242
 243 undo_cpu_trans:
 244         if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
 245                 flags = ZPCI_PTE_INVALID;
 246                 while (i-- > 0) {
 247                         page_addr -= PAGE_SIZE;
 248                         dma_addr -= PAGE_SIZE;
 249                         entry = dma_walk_cpu_trans(s390_domain->dma_table,
 250                                                    dma_addr);
 251                         if (!entry)
 252                                 break;
 253                         dma_update_cpu_trans(entry, page_addr, flags);
 254                 }
 255         }
 256         spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
 257
 258         return rc;
 259 }
 260
 261 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
 262                           phys_addr_t paddr, size_t size, int prot)
 263 {
 264         struct s390_domain *s390_domain = to_s390_domain(domain);
 265         int flags = ZPCI_PTE_VALID, rc = 0;
 266
 267         if (!(prot & IOMMU_READ))
 268                 return -EINVAL;
 269
 270         if (!(prot & IOMMU_WRITE))
 271                 flags |= ZPCI_TABLE_PROTECTED;
 272
 273         rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
 274                                      size, flags);
 275
 276         return rc;
 277 }
 278
 279 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
 280                                            dma_addr_t iova)
 281 {
 282         struct s390_domain *s390_domain = to_s390_domain(domain);
 283         unsigned long *sto, *pto, *rto, flags;
 284         unsigned int rtx, sx, px;
 285         phys_addr_t phys = 0;
 286
 287         if (iova < domain->geometry.aperture_start ||
 288             iova > domain->geometry.aperture_end)
 289                 return 0;
 290
 291         rtx = calc_rtx(iova);
 292         sx = calc_sx(iova);
 293         px = calc_px(iova);
 294         rto = s390_domain->dma_table;
 295
 296         spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
 297         if (rto && reg_entry_isvalid(rto[rtx])) {
 298                 sto = get_rt_sto(rto[rtx]);
 299                 if (sto && reg_entry_isvalid(sto[sx])) {
 300                         pto = get_st_pto(sto[sx]);
 301                         if (pto && pt_entry_isvalid(pto[px]))
 302                                 phys = pto[px] & ZPCI_PTE_ADDR_MASK;
 303                 }
 304         }
 305         spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
 306
 307         return phys;
 308 }
 309
 310 static size_t s390_iommu_unmap(struct iommu_domain *domain,
 311                                unsigned long iova, size_t size)
 312 {
 313         struct s390_domain *s390_domain = to_s390_domain(domain);
 314         int flags = ZPCI_PTE_INVALID;
 315         phys_addr_t paddr;
 316         int rc;
 317
 318         paddr = s390_iommu_iova_to_phys(domain, iova);
 319         if (!paddr)
 320                 return 0;
 321
 322         rc = s390_iommu_update_trans(s390_domain, (unsigned long) paddr, iova,
 323                                      size, flags);
 324         if (rc)
 325                 return 0;
 326
 327         return size;
 328 }
 329
 330 static struct iommu_ops s390_iommu_ops = {
 331         .capable = s390_iommu_capable,
 332         .domain_alloc = s390_domain_alloc,
 333         .domain_free = s390_domain_free,
 334         .attach_dev = s390_iommu_attach_device,
 335         .detach_dev = s390_iommu_detach_device,
 336         .map = s390_iommu_map,
 337         .unmap = s390_iommu_unmap,
 338         .iova_to_phys = s390_iommu_iova_to_phys,
 339         .add_device = s390_iommu_add_device,
 340         .remove_device = s390_iommu_remove_device,
 341         .device_group = generic_device_group,
 342         .pgsize_bitmap = S390_IOMMU_PGSIZES,
 343 };
 344
 345 static int __init s390_iommu_init(void)
 346 {
 347         return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
 348 }
 349 subsys_initcall(s390_iommu_init);