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 22 static const struct iommu_ops s390_iommu_ops; 23 24 struct 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 32 struct s390_domain_device { 33 struct list_head list; 34 struct zpci_dev *zdev; 35 }; 36 37 static struct s390_domain *to_s390_domain(struct iommu_domain *dom) 38 { 39 return container_of(dom, struct s390_domain, domain); 40 } 41 42 static 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 54 static 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 78 static 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 86 static 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_zpci_dev(dev); 91 struct s390_domain_device *domain_device; 92 unsigned long flags; 93 int cc, 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 cc = zpci_dma_exit_device(zdev); 104 if (cc) { 105 rc = -EIO; 106 goto out_free; 107 } 108 } 109 110 zdev->dma_table = s390_domain->dma_table; 111 cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma, 112 virt_to_phys(zdev->dma_table)); 113 if (cc) { 114 rc = -EIO; 115 goto out_restore; 116 } 117 118 spin_lock_irqsave(&s390_domain->list_lock, flags); 119 /* First device defines the DMA range limits */ 120 if (list_empty(&s390_domain->devices)) { 121 domain->geometry.aperture_start = zdev->start_dma; 122 domain->geometry.aperture_end = zdev->end_dma; 123 domain->geometry.force_aperture = true; 124 /* Allow only devices with identical DMA range limits */ 125 } else if (domain->geometry.aperture_start != zdev->start_dma || 126 domain->geometry.aperture_end != zdev->end_dma) { 127 rc = -EINVAL; 128 spin_unlock_irqrestore(&s390_domain->list_lock, flags); 129 goto out_restore; 130 } 131 domain_device->zdev = zdev; 132 zdev->s390_domain = s390_domain; 133 list_add(&domain_device->list, &s390_domain->devices); 134 spin_unlock_irqrestore(&s390_domain->list_lock, flags); 135 136 return 0; 137 138 out_restore: 139 zpci_dma_init_device(zdev); 140 out_free: 141 kfree(domain_device); 142 143 return rc; 144 } 145 146 static void s390_iommu_detach_device(struct iommu_domain *domain, 147 struct device *dev) 148 { 149 struct s390_domain *s390_domain = to_s390_domain(domain); 150 struct zpci_dev *zdev = to_zpci_dev(dev); 151 struct s390_domain_device *domain_device, *tmp; 152 unsigned long flags; 153 int found = 0; 154 155 if (!zdev) 156 return; 157 158 spin_lock_irqsave(&s390_domain->list_lock, flags); 159 list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices, 160 list) { 161 if (domain_device->zdev == zdev) { 162 list_del(&domain_device->list); 163 kfree(domain_device); 164 found = 1; 165 break; 166 } 167 } 168 spin_unlock_irqrestore(&s390_domain->list_lock, flags); 169 170 if (found) { 171 zdev->s390_domain = NULL; 172 zpci_unregister_ioat(zdev, 0); 173 zpci_dma_init_device(zdev); 174 } 175 } 176 177 static struct iommu_device *s390_iommu_probe_device(struct device *dev) 178 { 179 struct zpci_dev *zdev = to_zpci_dev(dev); 180 181 return &zdev->iommu_dev; 182 } 183 184 static void s390_iommu_release_device(struct device *dev) 185 { 186 struct zpci_dev *zdev = to_zpci_dev(dev); 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 release_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 } 206 207 static int s390_iommu_update_trans(struct s390_domain *s390_domain, 208 phys_addr_t pa, dma_addr_t dma_addr, 209 size_t size, int flags) 210 { 211 struct s390_domain_device *domain_device; 212 phys_addr_t page_addr = pa & PAGE_MASK; 213 dma_addr_t start_dma_addr = dma_addr; 214 unsigned long irq_flags, nr_pages, i; 215 unsigned long *entry; 216 int rc = 0; 217 218 if (dma_addr < s390_domain->domain.geometry.aperture_start || 219 dma_addr + size > s390_domain->domain.geometry.aperture_end) 220 return -EINVAL; 221 222 nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; 223 if (!nr_pages) 224 return 0; 225 226 spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags); 227 for (i = 0; i < nr_pages; i++) { 228 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr); 229 if (!entry) { 230 rc = -ENOMEM; 231 goto undo_cpu_trans; 232 } 233 dma_update_cpu_trans(entry, page_addr, flags); 234 page_addr += PAGE_SIZE; 235 dma_addr += PAGE_SIZE; 236 } 237 238 spin_lock(&s390_domain->list_lock); 239 list_for_each_entry(domain_device, &s390_domain->devices, list) { 240 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32, 241 start_dma_addr, nr_pages * PAGE_SIZE); 242 if (rc) 243 break; 244 } 245 spin_unlock(&s390_domain->list_lock); 246 247 undo_cpu_trans: 248 if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) { 249 flags = ZPCI_PTE_INVALID; 250 while (i-- > 0) { 251 page_addr -= PAGE_SIZE; 252 dma_addr -= PAGE_SIZE; 253 entry = dma_walk_cpu_trans(s390_domain->dma_table, 254 dma_addr); 255 if (!entry) 256 break; 257 dma_update_cpu_trans(entry, page_addr, flags); 258 } 259 } 260 spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags); 261 262 return rc; 263 } 264 265 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova, 266 phys_addr_t paddr, size_t size, int prot, gfp_t gfp) 267 { 268 struct s390_domain *s390_domain = to_s390_domain(domain); 269 int flags = ZPCI_PTE_VALID, rc = 0; 270 271 if (!(prot & IOMMU_READ)) 272 return -EINVAL; 273 274 if (!(prot & IOMMU_WRITE)) 275 flags |= ZPCI_TABLE_PROTECTED; 276 277 rc = s390_iommu_update_trans(s390_domain, paddr, iova, 278 size, flags); 279 280 return rc; 281 } 282 283 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain, 284 dma_addr_t iova) 285 { 286 struct s390_domain *s390_domain = to_s390_domain(domain); 287 unsigned long *sto, *pto, *rto, flags; 288 unsigned int rtx, sx, px; 289 phys_addr_t phys = 0; 290 291 if (iova < domain->geometry.aperture_start || 292 iova > domain->geometry.aperture_end) 293 return 0; 294 295 rtx = calc_rtx(iova); 296 sx = calc_sx(iova); 297 px = calc_px(iova); 298 rto = s390_domain->dma_table; 299 300 spin_lock_irqsave(&s390_domain->dma_table_lock, flags); 301 if (rto && reg_entry_isvalid(rto[rtx])) { 302 sto = get_rt_sto(rto[rtx]); 303 if (sto && reg_entry_isvalid(sto[sx])) { 304 pto = get_st_pto(sto[sx]); 305 if (pto && pt_entry_isvalid(pto[px])) 306 phys = pto[px] & ZPCI_PTE_ADDR_MASK; 307 } 308 } 309 spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags); 310 311 return phys; 312 } 313 314 static size_t s390_iommu_unmap(struct iommu_domain *domain, 315 unsigned long iova, size_t size, 316 struct iommu_iotlb_gather *gather) 317 { 318 struct s390_domain *s390_domain = to_s390_domain(domain); 319 int flags = ZPCI_PTE_INVALID; 320 phys_addr_t paddr; 321 int rc; 322 323 paddr = s390_iommu_iova_to_phys(domain, iova); 324 if (!paddr) 325 return 0; 326 327 rc = s390_iommu_update_trans(s390_domain, paddr, iova, 328 size, flags); 329 if (rc) 330 return 0; 331 332 return size; 333 } 334 335 int zpci_init_iommu(struct zpci_dev *zdev) 336 { 337 int rc = 0; 338 339 rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL, 340 "s390-iommu.%08x", zdev->fid); 341 if (rc) 342 goto out_err; 343 344 rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL); 345 if (rc) 346 goto out_sysfs; 347 348 return 0; 349 350 out_sysfs: 351 iommu_device_sysfs_remove(&zdev->iommu_dev); 352 353 out_err: 354 return rc; 355 } 356 357 void zpci_destroy_iommu(struct zpci_dev *zdev) 358 { 359 iommu_device_unregister(&zdev->iommu_dev); 360 iommu_device_sysfs_remove(&zdev->iommu_dev); 361 } 362 363 static const struct iommu_ops s390_iommu_ops = { 364 .capable = s390_iommu_capable, 365 .domain_alloc = s390_domain_alloc, 366 .domain_free = s390_domain_free, 367 .attach_dev = s390_iommu_attach_device, 368 .detach_dev = s390_iommu_detach_device, 369 .map = s390_iommu_map, 370 .unmap = s390_iommu_unmap, 371 .iova_to_phys = s390_iommu_iova_to_phys, 372 .probe_device = s390_iommu_probe_device, 373 .release_device = s390_iommu_release_device, 374 .device_group = generic_device_group, 375 .pgsize_bitmap = S390_IOMMU_PGSIZES, 376 }; 377 378 static int __init s390_iommu_init(void) 379 { 380 return bus_set_iommu(&pci_bus_type, &s390_iommu_ops); 381 } 382 subsys_initcall(s390_iommu_init); 383