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
to_s390_domain(struct iommu_domain * dom)37 static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
38 {
39 return container_of(dom, struct s390_domain, domain);
40 }
41
s390_iommu_capable(enum iommu_cap cap)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
s390_domain_alloc(unsigned domain_type)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
s390_domain_free(struct iommu_domain * domain)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
s390_iommu_attach_device(struct iommu_domain * domain,struct device * dev)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 && !zdev->s390_domain) {
103 cc = zpci_dma_exit_device(zdev);
104 if (cc) {
105 rc = -EIO;
106 goto out_free;
107 }
108 }
109
110 if (zdev->s390_domain)
111 zpci_unregister_ioat(zdev, 0);
112
113 zdev->dma_table = s390_domain->dma_table;
114 cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
115 virt_to_phys(zdev->dma_table));
116 if (cc) {
117 rc = -EIO;
118 goto out_restore;
119 }
120
121 spin_lock_irqsave(&s390_domain->list_lock, flags);
122 /* First device defines the DMA range limits */
123 if (list_empty(&s390_domain->devices)) {
124 domain->geometry.aperture_start = zdev->start_dma;
125 domain->geometry.aperture_end = zdev->end_dma;
126 domain->geometry.force_aperture = true;
127 /* Allow only devices with identical DMA range limits */
128 } else if (domain->geometry.aperture_start != zdev->start_dma ||
129 domain->geometry.aperture_end != zdev->end_dma) {
130 rc = -EINVAL;
131 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
132 goto out_restore;
133 }
134 domain_device->zdev = zdev;
135 zdev->s390_domain = s390_domain;
136 list_add(&domain_device->list, &s390_domain->devices);
137 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
138
139 return 0;
140
141 out_restore:
142 if (!zdev->s390_domain) {
143 zpci_dma_init_device(zdev);
144 } else {
145 zdev->dma_table = zdev->s390_domain->dma_table;
146 zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
147 virt_to_phys(zdev->dma_table));
148 }
149 out_free:
150 kfree(domain_device);
151
152 return rc;
153 }
154
s390_iommu_detach_device(struct iommu_domain * domain,struct device * dev)155 static void s390_iommu_detach_device(struct iommu_domain *domain,
156 struct device *dev)
157 {
158 struct s390_domain *s390_domain = to_s390_domain(domain);
159 struct zpci_dev *zdev = to_zpci_dev(dev);
160 struct s390_domain_device *domain_device, *tmp;
161 unsigned long flags;
162 int found = 0;
163
164 if (!zdev)
165 return;
166
167 spin_lock_irqsave(&s390_domain->list_lock, flags);
168 list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
169 list) {
170 if (domain_device->zdev == zdev) {
171 list_del(&domain_device->list);
172 kfree(domain_device);
173 found = 1;
174 break;
175 }
176 }
177 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
178
179 if (found && (zdev->s390_domain == s390_domain)) {
180 zdev->s390_domain = NULL;
181 zpci_unregister_ioat(zdev, 0);
182 zpci_dma_init_device(zdev);
183 }
184 }
185
s390_iommu_probe_device(struct device * dev)186 static struct iommu_device *s390_iommu_probe_device(struct device *dev)
187 {
188 struct zpci_dev *zdev = to_zpci_dev(dev);
189
190 return &zdev->iommu_dev;
191 }
192
s390_iommu_release_device(struct device * dev)193 static void s390_iommu_release_device(struct device *dev)
194 {
195 struct zpci_dev *zdev = to_zpci_dev(dev);
196 struct iommu_domain *domain;
197
198 /*
199 * This is a workaround for a scenario where the IOMMU API common code
200 * "forgets" to call the detach_dev callback: After binding a device
201 * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
202 * the attach_dev), removing the device via
203 * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
204 * only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
205 * notifier.
206 *
207 * So let's call detach_dev from here if it hasn't been called before.
208 */
209 if (zdev && zdev->s390_domain) {
210 domain = iommu_get_domain_for_dev(dev);
211 if (domain)
212 s390_iommu_detach_device(domain, dev);
213 }
214 }
215
s390_iommu_update_trans(struct s390_domain * s390_domain,phys_addr_t pa,dma_addr_t dma_addr,size_t size,int flags)216 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
217 phys_addr_t pa, dma_addr_t dma_addr,
218 size_t size, int flags)
219 {
220 struct s390_domain_device *domain_device;
221 phys_addr_t page_addr = pa & PAGE_MASK;
222 dma_addr_t start_dma_addr = dma_addr;
223 unsigned long irq_flags, nr_pages, i;
224 unsigned long *entry;
225 int rc = 0;
226
227 if (dma_addr < s390_domain->domain.geometry.aperture_start ||
228 dma_addr + size > s390_domain->domain.geometry.aperture_end)
229 return -EINVAL;
230
231 nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
232 if (!nr_pages)
233 return 0;
234
235 spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
236 for (i = 0; i < nr_pages; i++) {
237 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
238 if (!entry) {
239 rc = -ENOMEM;
240 goto undo_cpu_trans;
241 }
242 dma_update_cpu_trans(entry, page_addr, flags);
243 page_addr += PAGE_SIZE;
244 dma_addr += PAGE_SIZE;
245 }
246
247 spin_lock(&s390_domain->list_lock);
248 list_for_each_entry(domain_device, &s390_domain->devices, list) {
249 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
250 start_dma_addr, nr_pages * PAGE_SIZE);
251 if (rc)
252 break;
253 }
254 spin_unlock(&s390_domain->list_lock);
255
256 undo_cpu_trans:
257 if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
258 flags = ZPCI_PTE_INVALID;
259 while (i-- > 0) {
260 page_addr -= PAGE_SIZE;
261 dma_addr -= PAGE_SIZE;
262 entry = dma_walk_cpu_trans(s390_domain->dma_table,
263 dma_addr);
264 if (!entry)
265 break;
266 dma_update_cpu_trans(entry, page_addr, flags);
267 }
268 }
269 spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
270
271 return rc;
272 }
273
s390_iommu_map(struct iommu_domain * domain,unsigned long iova,phys_addr_t paddr,size_t size,int prot,gfp_t gfp)274 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
275 phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
276 {
277 struct s390_domain *s390_domain = to_s390_domain(domain);
278 int flags = ZPCI_PTE_VALID, rc = 0;
279
280 if (!(prot & IOMMU_READ))
281 return -EINVAL;
282
283 if (!(prot & IOMMU_WRITE))
284 flags |= ZPCI_TABLE_PROTECTED;
285
286 rc = s390_iommu_update_trans(s390_domain, paddr, iova,
287 size, flags);
288
289 return rc;
290 }
291
s390_iommu_iova_to_phys(struct iommu_domain * domain,dma_addr_t iova)292 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
293 dma_addr_t iova)
294 {
295 struct s390_domain *s390_domain = to_s390_domain(domain);
296 unsigned long *sto, *pto, *rto, flags;
297 unsigned int rtx, sx, px;
298 phys_addr_t phys = 0;
299
300 if (iova < domain->geometry.aperture_start ||
301 iova > domain->geometry.aperture_end)
302 return 0;
303
304 rtx = calc_rtx(iova);
305 sx = calc_sx(iova);
306 px = calc_px(iova);
307 rto = s390_domain->dma_table;
308
309 spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
310 if (rto && reg_entry_isvalid(rto[rtx])) {
311 sto = get_rt_sto(rto[rtx]);
312 if (sto && reg_entry_isvalid(sto[sx])) {
313 pto = get_st_pto(sto[sx]);
314 if (pto && pt_entry_isvalid(pto[px]))
315 phys = pto[px] & ZPCI_PTE_ADDR_MASK;
316 }
317 }
318 spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
319
320 return phys;
321 }
322
s390_iommu_unmap(struct iommu_domain * domain,unsigned long iova,size_t size,struct iommu_iotlb_gather * gather)323 static size_t s390_iommu_unmap(struct iommu_domain *domain,
324 unsigned long iova, size_t size,
325 struct iommu_iotlb_gather *gather)
326 {
327 struct s390_domain *s390_domain = to_s390_domain(domain);
328 int flags = ZPCI_PTE_INVALID;
329 phys_addr_t paddr;
330 int rc;
331
332 paddr = s390_iommu_iova_to_phys(domain, iova);
333 if (!paddr)
334 return 0;
335
336 rc = s390_iommu_update_trans(s390_domain, paddr, iova,
337 size, flags);
338 if (rc)
339 return 0;
340
341 return size;
342 }
343
zpci_init_iommu(struct zpci_dev * zdev)344 int zpci_init_iommu(struct zpci_dev *zdev)
345 {
346 int rc = 0;
347
348 rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
349 "s390-iommu.%08x", zdev->fid);
350 if (rc)
351 goto out_err;
352
353 rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL);
354 if (rc)
355 goto out_sysfs;
356
357 return 0;
358
359 out_sysfs:
360 iommu_device_sysfs_remove(&zdev->iommu_dev);
361
362 out_err:
363 return rc;
364 }
365
zpci_destroy_iommu(struct zpci_dev * zdev)366 void zpci_destroy_iommu(struct zpci_dev *zdev)
367 {
368 iommu_device_unregister(&zdev->iommu_dev);
369 iommu_device_sysfs_remove(&zdev->iommu_dev);
370 }
371
372 static const struct iommu_ops s390_iommu_ops = {
373 .capable = s390_iommu_capable,
374 .domain_alloc = s390_domain_alloc,
375 .probe_device = s390_iommu_probe_device,
376 .release_device = s390_iommu_release_device,
377 .device_group = generic_device_group,
378 .pgsize_bitmap = S390_IOMMU_PGSIZES,
379 .default_domain_ops = &(const struct iommu_domain_ops) {
380 .attach_dev = s390_iommu_attach_device,
381 .detach_dev = s390_iommu_detach_device,
382 .map = s390_iommu_map,
383 .unmap = s390_iommu_unmap,
384 .iova_to_phys = s390_iommu_iova_to_phys,
385 .free = s390_domain_free,
386 }
387 };
388
s390_iommu_init(void)389 static int __init s390_iommu_init(void)
390 {
391 return bus_set_iommu(&pci_bus_type, &s390_iommu_ops);
392 }
393 subsys_initcall(s390_iommu_init);
394