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 <linux/rculist.h>
14#include <linux/rcupdate.h>
15#include <asm/pci_dma.h>
16
17static const struct iommu_ops s390_iommu_ops;
18
19struct s390_domain {
20 struct iommu_domain domain;
21 struct list_head devices;
22 unsigned long *dma_table;
23 spinlock_t list_lock;
24 struct rcu_head rcu;
25};
26
27static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
28{
29 return container_of(dom, struct s390_domain, domain);
30}
31
32static bool s390_iommu_capable(struct device *dev, enum iommu_cap cap)
33{
34 switch (cap) {
35 case IOMMU_CAP_CACHE_COHERENCY:
36 return true;
37 default:
38 return false;
39 }
40}
41
42static struct iommu_domain *s390_domain_alloc(unsigned domain_type)
43{
44 struct s390_domain *s390_domain;
45
46 if (domain_type != IOMMU_DOMAIN_UNMANAGED)
47 return NULL;
48
49 s390_domain = kzalloc(size: sizeof(*s390_domain), GFP_KERNEL);
50 if (!s390_domain)
51 return NULL;
52
53 s390_domain->dma_table = dma_alloc_cpu_table(GFP_KERNEL);
54 if (!s390_domain->dma_table) {
55 kfree(objp: s390_domain);
56 return NULL;
57 }
58 s390_domain->domain.geometry.force_aperture = true;
59 s390_domain->domain.geometry.aperture_start = 0;
60 s390_domain->domain.geometry.aperture_end = ZPCI_TABLE_SIZE_RT - 1;
61
62 spin_lock_init(&s390_domain->list_lock);
63 INIT_LIST_HEAD_RCU(list: &s390_domain->devices);
64
65 return &s390_domain->domain;
66}
67
68static void s390_iommu_rcu_free_domain(struct rcu_head *head)
69{
70 struct s390_domain *s390_domain = container_of(head, struct s390_domain, rcu);
71
72 dma_cleanup_tables(s390_domain->dma_table);
73 kfree(objp: s390_domain);
74}
75
76static void s390_domain_free(struct iommu_domain *domain)
77{
78 struct s390_domain *s390_domain = to_s390_domain(dom: domain);
79
80 rcu_read_lock();
81 WARN_ON(!list_empty(&s390_domain->devices));
82 rcu_read_unlock();
83
84 call_rcu(head: &s390_domain->rcu, func: s390_iommu_rcu_free_domain);
85}
86
87static void __s390_iommu_detach_device(struct zpci_dev *zdev)
88{
89 struct s390_domain *s390_domain = zdev->s390_domain;
90 unsigned long flags;
91
92 if (!s390_domain)
93 return;
94
95 spin_lock_irqsave(&s390_domain->list_lock, flags);
96 list_del_rcu(entry: &zdev->iommu_list);
97 spin_unlock_irqrestore(lock: &s390_domain->list_lock, flags);
98
99 zpci_unregister_ioat(zdev, 0);
100 zdev->s390_domain = NULL;
101 zdev->dma_table = NULL;
102}
103
104static int s390_iommu_attach_device(struct iommu_domain *domain,
105 struct device *dev)
106{
107 struct s390_domain *s390_domain = to_s390_domain(dom: domain);
108 struct zpci_dev *zdev = to_zpci_dev(dev);
109 unsigned long flags;
110 u8 status;
111 int cc;
112
113 if (!zdev)
114 return -ENODEV;
115
116 if (WARN_ON(domain->geometry.aperture_start > zdev->end_dma ||
117 domain->geometry.aperture_end < zdev->start_dma))
118 return -EINVAL;
119
120 if (zdev->s390_domain)
121 __s390_iommu_detach_device(zdev);
122 else if (zdev->dma_table)
123 zpci_dma_exit_device(zdev);
124
125 cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
126 virt_to_phys(address: s390_domain->dma_table), &status);
127 /*
128 * If the device is undergoing error recovery the reset code
129 * will re-establish the new domain.
130 */
131 if (cc && status != ZPCI_PCI_ST_FUNC_NOT_AVAIL)
132 return -EIO;
133 zdev->dma_table = s390_domain->dma_table;
134
135 zdev->dma_table = s390_domain->dma_table;
136 zdev->s390_domain = s390_domain;
137
138 spin_lock_irqsave(&s390_domain->list_lock, flags);
139 list_add_rcu(new: &zdev->iommu_list, head: &s390_domain->devices);
140 spin_unlock_irqrestore(lock: &s390_domain->list_lock, flags);
141
142 return 0;
143}
144
145static void s390_iommu_set_platform_dma(struct device *dev)
146{
147 struct zpci_dev *zdev = to_zpci_dev(dev);
148
149 __s390_iommu_detach_device(zdev);
150 zpci_dma_init_device(zdev);
151}
152
153static void s390_iommu_get_resv_regions(struct device *dev,
154 struct list_head *list)
155{
156 struct zpci_dev *zdev = to_zpci_dev(dev);
157 struct iommu_resv_region *region;
158
159 if (zdev->start_dma) {
160 region = iommu_alloc_resv_region(start: 0, length: zdev->start_dma, prot: 0,
161 type: IOMMU_RESV_RESERVED, GFP_KERNEL);
162 if (!region)
163 return;
164 list_add_tail(new: &region->list, head: list);
165 }
166
167 if (zdev->end_dma < ZPCI_TABLE_SIZE_RT - 1) {
168 region = iommu_alloc_resv_region(start: zdev->end_dma + 1,
169 length: ZPCI_TABLE_SIZE_RT - zdev->end_dma - 1,
170 prot: 0, type: IOMMU_RESV_RESERVED, GFP_KERNEL);
171 if (!region)
172 return;
173 list_add_tail(new: &region->list, head: list);
174 }
175}
176
177static struct iommu_device *s390_iommu_probe_device(struct device *dev)
178{
179 struct zpci_dev *zdev;
180
181 if (!dev_is_pci(dev))
182 return ERR_PTR(error: -ENODEV);
183
184 zdev = to_zpci_dev(dev);
185
186 if (zdev->start_dma > zdev->end_dma ||
187 zdev->start_dma > ZPCI_TABLE_SIZE_RT - 1)
188 return ERR_PTR(error: -EINVAL);
189
190 if (zdev->end_dma > ZPCI_TABLE_SIZE_RT - 1)
191 zdev->end_dma = ZPCI_TABLE_SIZE_RT - 1;
192
193 return &zdev->iommu_dev;
194}
195
196static void s390_iommu_release_device(struct device *dev)
197{
198 struct zpci_dev *zdev = to_zpci_dev(dev);
199
200 /*
201 * release_device is expected to detach any domain currently attached
202 * to the device, but keep it attached to other devices in the group.
203 */
204 if (zdev)
205 __s390_iommu_detach_device(zdev);
206}
207
208static void s390_iommu_flush_iotlb_all(struct iommu_domain *domain)
209{
210 struct s390_domain *s390_domain = to_s390_domain(dom: domain);
211 struct zpci_dev *zdev;
212
213 rcu_read_lock();
214 list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
215 zpci_refresh_trans((u64)zdev->fh << 32, zdev->start_dma,
216 zdev->end_dma - zdev->start_dma + 1);
217 }
218 rcu_read_unlock();
219}
220
221static void s390_iommu_iotlb_sync(struct iommu_domain *domain,
222 struct iommu_iotlb_gather *gather)
223{
224 struct s390_domain *s390_domain = to_s390_domain(dom: domain);
225 size_t size = gather->end - gather->start + 1;
226 struct zpci_dev *zdev;
227
228 /* If gather was never added to there is nothing to flush */
229 if (!gather->end)
230 return;
231
232 rcu_read_lock();
233 list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
234 zpci_refresh_trans((u64)zdev->fh << 32, gather->start,
235 size);
236 }
237 rcu_read_unlock();
238}
239
240static void s390_iommu_iotlb_sync_map(struct iommu_domain *domain,
241 unsigned long iova, size_t size)
242{
243 struct s390_domain *s390_domain = to_s390_domain(dom: domain);
244 struct zpci_dev *zdev;
245
246 rcu_read_lock();
247 list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
248 if (!zdev->tlb_refresh)
249 continue;
250 zpci_refresh_trans((u64)zdev->fh << 32,
251 iova, size);
252 }
253 rcu_read_unlock();
254}
255
256static int s390_iommu_validate_trans(struct s390_domain *s390_domain,
257 phys_addr_t pa, dma_addr_t dma_addr,
258 unsigned long nr_pages, int flags,
259 gfp_t gfp)
260{
261 phys_addr_t page_addr = pa & PAGE_MASK;
262 unsigned long *entry;
263 unsigned long i;
264 int rc;
265
266 for (i = 0; i < nr_pages; i++) {
267 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr,
268 gfp);
269 if (unlikely(!entry)) {
270 rc = -ENOMEM;
271 goto undo_cpu_trans;
272 }
273 dma_update_cpu_trans(entry, page_addr, flags);
274 page_addr += PAGE_SIZE;
275 dma_addr += PAGE_SIZE;
276 }
277
278 return 0;
279
280undo_cpu_trans:
281 while (i-- > 0) {
282 dma_addr -= PAGE_SIZE;
283 entry = dma_walk_cpu_trans(s390_domain->dma_table,
284 dma_addr, gfp);
285 if (!entry)
286 break;
287 dma_update_cpu_trans(entry, 0, ZPCI_PTE_INVALID);
288 }
289
290 return rc;
291}
292
293static int s390_iommu_invalidate_trans(struct s390_domain *s390_domain,
294 dma_addr_t dma_addr, unsigned long nr_pages)
295{
296 unsigned long *entry;
297 unsigned long i;
298 int rc = 0;
299
300 for (i = 0; i < nr_pages; i++) {
301 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr,
302 GFP_ATOMIC);
303 if (unlikely(!entry)) {
304 rc = -EINVAL;
305 break;
306 }
307 dma_update_cpu_trans(entry, 0, ZPCI_PTE_INVALID);
308 dma_addr += PAGE_SIZE;
309 }
310
311 return rc;
312}
313
314static int s390_iommu_map_pages(struct iommu_domain *domain,
315 unsigned long iova, phys_addr_t paddr,
316 size_t pgsize, size_t pgcount,
317 int prot, gfp_t gfp, size_t *mapped)
318{
319 struct s390_domain *s390_domain = to_s390_domain(dom: domain);
320 size_t size = pgcount << __ffs(pgsize);
321 int flags = ZPCI_PTE_VALID, rc = 0;
322
323 if (pgsize != SZ_4K)
324 return -EINVAL;
325
326 if (iova < s390_domain->domain.geometry.aperture_start ||
327 (iova + size - 1) > s390_domain->domain.geometry.aperture_end)
328 return -EINVAL;
329
330 if (!IS_ALIGNED(iova | paddr, pgsize))
331 return -EINVAL;
332
333 if (!(prot & IOMMU_READ))
334 return -EINVAL;
335
336 if (!(prot & IOMMU_WRITE))
337 flags |= ZPCI_TABLE_PROTECTED;
338
339 rc = s390_iommu_validate_trans(s390_domain, pa: paddr, dma_addr: iova,
340 nr_pages: pgcount, flags, gfp);
341 if (!rc)
342 *mapped = size;
343
344 return rc;
345}
346
347static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
348 dma_addr_t iova)
349{
350 struct s390_domain *s390_domain = to_s390_domain(dom: domain);
351 unsigned long *rto, *sto, *pto;
352 unsigned long ste, pte, rte;
353 unsigned int rtx, sx, px;
354 phys_addr_t phys = 0;
355
356 if (iova < domain->geometry.aperture_start ||
357 iova > domain->geometry.aperture_end)
358 return 0;
359
360 rtx = calc_rtx(iova);
361 sx = calc_sx(iova);
362 px = calc_px(iova);
363 rto = s390_domain->dma_table;
364
365 rte = READ_ONCE(rto[rtx]);
366 if (reg_entry_isvalid(rte)) {
367 sto = get_rt_sto(rte);
368 ste = READ_ONCE(sto[sx]);
369 if (reg_entry_isvalid(ste)) {
370 pto = get_st_pto(ste);
371 pte = READ_ONCE(pto[px]);
372 if (pt_entry_isvalid(pte))
373 phys = pte & ZPCI_PTE_ADDR_MASK;
374 }
375 }
376
377 return phys;
378}
379
380static size_t s390_iommu_unmap_pages(struct iommu_domain *domain,
381 unsigned long iova,
382 size_t pgsize, size_t pgcount,
383 struct iommu_iotlb_gather *gather)
384{
385 struct s390_domain *s390_domain = to_s390_domain(dom: domain);
386 size_t size = pgcount << __ffs(pgsize);
387 int rc;
388
389 if (WARN_ON(iova < s390_domain->domain.geometry.aperture_start ||
390 (iova + size - 1) > s390_domain->domain.geometry.aperture_end))
391 return 0;
392
393 rc = s390_iommu_invalidate_trans(s390_domain, dma_addr: iova, nr_pages: pgcount);
394 if (rc)
395 return 0;
396
397 iommu_iotlb_gather_add_range(gather, iova, size);
398
399 return size;
400}
401
402int zpci_init_iommu(struct zpci_dev *zdev)
403{
404 int rc = 0;
405
406 rc = iommu_device_sysfs_add(iommu: &zdev->iommu_dev, NULL, NULL,
407 fmt: "s390-iommu.%08x", zdev->fid);
408 if (rc)
409 goto out_err;
410
411 rc = iommu_device_register(iommu: &zdev->iommu_dev, ops: &s390_iommu_ops, NULL);
412 if (rc)
413 goto out_sysfs;
414
415 return 0;
416
417out_sysfs:
418 iommu_device_sysfs_remove(iommu: &zdev->iommu_dev);
419
420out_err:
421 return rc;
422}
423
424void zpci_destroy_iommu(struct zpci_dev *zdev)
425{
426 iommu_device_unregister(iommu: &zdev->iommu_dev);
427 iommu_device_sysfs_remove(iommu: &zdev->iommu_dev);
428}
429
430static const struct iommu_ops s390_iommu_ops = {
431 .capable = s390_iommu_capable,
432 .domain_alloc = s390_domain_alloc,
433 .probe_device = s390_iommu_probe_device,
434 .release_device = s390_iommu_release_device,
435 .device_group = generic_device_group,
436 .set_platform_dma_ops = s390_iommu_set_platform_dma,
437 .pgsize_bitmap = SZ_4K,
438 .get_resv_regions = s390_iommu_get_resv_regions,
439 .default_domain_ops = &(const struct iommu_domain_ops) {
440 .attach_dev = s390_iommu_attach_device,
441 .map_pages = s390_iommu_map_pages,
442 .unmap_pages = s390_iommu_unmap_pages,
443 .flush_iotlb_all = s390_iommu_flush_iotlb_all,
444 .iotlb_sync = s390_iommu_iotlb_sync,
445 .iotlb_sync_map = s390_iommu_iotlb_sync_map,
446 .iova_to_phys = s390_iommu_iova_to_phys,
447 .free = s390_domain_free,
448 }
449};
450

source code of linux/drivers/iommu/s390-iommu.c