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); 355