linux/drivers/iommu/s390-iommu.c
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   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
  22static const struct iommu_ops s390_iommu_ops;
  23
  24struct 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
  32struct s390_domain_device {
  33        struct list_head        list;
  34        struct zpci_dev         *zdev;
  35};
  36
  37static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
  38{
  39        return container_of(dom, struct s390_domain, domain);
  40}
  41
  42static 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
  54static 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
  78static 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
  86static 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_pci_dev(dev)->sysdata;
  91        struct s390_domain_device *domain_device;
  92        unsigned long flags;
  93        int 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                zpci_dma_exit_device(zdev);
 104
 105        zdev->dma_table = s390_domain->dma_table;
 106        rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 107                                (u64) zdev->dma_table);
 108        if (rc)
 109                goto out_restore;
 110
 111        spin_lock_irqsave(&s390_domain->list_lock, flags);
 112        /* First device defines the DMA range limits */
 113        if (list_empty(&s390_domain->devices)) {
 114                domain->geometry.aperture_start = zdev->start_dma;
 115                domain->geometry.aperture_end = zdev->end_dma;
 116                domain->geometry.force_aperture = true;
 117        /* Allow only devices with identical DMA range limits */
 118        } else if (domain->geometry.aperture_start != zdev->start_dma ||
 119                   domain->geometry.aperture_end != zdev->end_dma) {
 120                rc = -EINVAL;
 121                spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 122                goto out_restore;
 123        }
 124        domain_device->zdev = zdev;
 125        zdev->s390_domain = s390_domain;
 126        list_add(&domain_device->list, &s390_domain->devices);
 127        spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 128
 129        return 0;
 130
 131out_restore:
 132        zpci_dma_init_device(zdev);
 133        kfree(domain_device);
 134
 135        return rc;
 136}
 137
 138static void s390_iommu_detach_device(struct iommu_domain *domain,
 139                                     struct device *dev)
 140{
 141        struct s390_domain *s390_domain = to_s390_domain(domain);
 142        struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
 143        struct s390_domain_device *domain_device, *tmp;
 144        unsigned long flags;
 145        int found = 0;
 146
 147        if (!zdev)
 148                return;
 149
 150        spin_lock_irqsave(&s390_domain->list_lock, flags);
 151        list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
 152                                 list) {
 153                if (domain_device->zdev == zdev) {
 154                        list_del(&domain_device->list);
 155                        kfree(domain_device);
 156                        found = 1;
 157                        break;
 158                }
 159        }
 160        spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 161
 162        if (found) {
 163                zdev->s390_domain = NULL;
 164                zpci_unregister_ioat(zdev, 0);
 165                zpci_dma_init_device(zdev);
 166        }
 167}
 168
 169static int s390_iommu_add_device(struct device *dev)
 170{
 171        struct iommu_group *group = iommu_group_get_for_dev(dev);
 172        struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
 173
 174        if (IS_ERR(group))
 175                return PTR_ERR(group);
 176
 177        iommu_group_put(group);
 178        iommu_device_link(&zdev->iommu_dev, dev);
 179
 180        return 0;
 181}
 182
 183static void s390_iommu_remove_device(struct device *dev)
 184{
 185        struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
 186        struct iommu_domain *domain;
 187
 188        /*
 189         * This is a workaround for a scenario where the IOMMU API common code
 190         * "forgets" to call the detach_dev callback: After binding a device
 191         * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
 192         * the attach_dev), removing the device via
 193         * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
 194         * only remove_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
 195         * notifier.
 196         *
 197         * So let's call detach_dev from here if it hasn't been called before.
 198         */
 199        if (zdev && zdev->s390_domain) {
 200                domain = iommu_get_domain_for_dev(dev);
 201                if (domain)
 202                        s390_iommu_detach_device(domain, dev);
 203        }
 204
 205        iommu_device_unlink(&zdev->iommu_dev, dev);
 206        iommu_group_remove_device(dev);
 207}
 208
 209static 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
 249undo_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
 267static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
 268                          phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
 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
 285static 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
 316static size_t s390_iommu_unmap(struct iommu_domain *domain,
 317                               unsigned long iova, size_t size,
 318                               struct iommu_iotlb_gather *gather)
 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
 337int zpci_init_iommu(struct zpci_dev *zdev)
 338{
 339        int rc = 0;
 340
 341        rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
 342                                    "s390-iommu.%08x", zdev->fid);
 343        if (rc)
 344                goto out_err;
 345
 346        iommu_device_set_ops(&zdev->iommu_dev, &s390_iommu_ops);
 347
 348        rc = iommu_device_register(&zdev->iommu_dev);
 349        if (rc)
 350                goto out_sysfs;
 351
 352        return 0;
 353
 354out_sysfs:
 355        iommu_device_sysfs_remove(&zdev->iommu_dev);
 356
 357out_err:
 358        return rc;
 359}
 360
 361void zpci_destroy_iommu(struct zpci_dev *zdev)
 362{
 363        iommu_device_unregister(&zdev->iommu_dev);
 364        iommu_device_sysfs_remove(&zdev->iommu_dev);
 365}
 366
 367static const struct iommu_ops s390_iommu_ops = {
 368        .capable = s390_iommu_capable,
 369        .domain_alloc = s390_domain_alloc,
 370        .domain_free = s390_domain_free,
 371        .attach_dev = s390_iommu_attach_device,
 372        .detach_dev = s390_iommu_detach_device,
 373        .map = s390_iommu_map,
 374        .unmap = s390_iommu_unmap,
 375        .iova_to_phys = s390_iommu_iova_to_phys,
 376        .add_device = s390_iommu_add_device,
 377        .remove_device = s390_iommu_remove_device,
 378        .device_group = generic_device_group,
 379        .pgsize_bitmap = S390_IOMMU_PGSIZES,
 380};
 381
 382static int __init s390_iommu_init(void)
 383{
 384        return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
 385}
 386subsys_initcall(s390_iommu_init);
 387