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(struct device * dev,enum iommu_cap cap)42 static bool s390_iommu_capable(struct device *dev, 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 WARN_ON(!list_empty(&s390_domain->devices));
83 dma_cleanup_tables(s390_domain->dma_table);
84 kfree(s390_domain);
85 }
86
__s390_iommu_detach_device(struct zpci_dev * zdev)87 static void __s390_iommu_detach_device(struct zpci_dev *zdev)
88 {
89 struct s390_domain *s390_domain = zdev->s390_domain;
90 struct s390_domain_device *domain_device, *tmp;
91 unsigned long flags;
92
93 if (!s390_domain)
94 return;
95
96 spin_lock_irqsave(&s390_domain->list_lock, flags);
97 list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
98 list) {
99 if (domain_device->zdev == zdev) {
100 list_del(&domain_device->list);
101 kfree(domain_device);
102 break;
103 }
104 }
105 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
106
107 zpci_unregister_ioat(zdev, 0);
108 zdev->s390_domain = NULL;
109 zdev->dma_table = NULL;
110 }
111
s390_iommu_attach_device(struct iommu_domain * domain,struct device * dev)112 static int s390_iommu_attach_device(struct iommu_domain *domain,
113 struct device *dev)
114 {
115 struct s390_domain *s390_domain = to_s390_domain(domain);
116 struct zpci_dev *zdev = to_zpci_dev(dev);
117 struct s390_domain_device *domain_device;
118 unsigned long flags;
119 int cc, rc = 0;
120
121 if (!zdev)
122 return -ENODEV;
123
124 domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
125 if (!domain_device)
126 return -ENOMEM;
127
128 if (zdev->s390_domain)
129 __s390_iommu_detach_device(zdev);
130 else if (zdev->dma_table)
131 zpci_dma_exit_device(zdev);
132
133 cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
134 virt_to_phys(s390_domain->dma_table));
135 if (cc) {
136 rc = -EIO;
137 goto out_free;
138 }
139 zdev->dma_table = s390_domain->dma_table;
140
141 spin_lock_irqsave(&s390_domain->list_lock, flags);
142 /* First device defines the DMA range limits */
143 if (list_empty(&s390_domain->devices)) {
144 domain->geometry.aperture_start = zdev->start_dma;
145 domain->geometry.aperture_end = zdev->end_dma;
146 domain->geometry.force_aperture = true;
147 /* Allow only devices with identical DMA range limits */
148 } else if (domain->geometry.aperture_start != zdev->start_dma ||
149 domain->geometry.aperture_end != zdev->end_dma) {
150 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
151 rc = -EINVAL;
152 goto out_unregister;
153 }
154 domain_device->zdev = zdev;
155 zdev->s390_domain = s390_domain;
156 list_add(&domain_device->list, &s390_domain->devices);
157 spin_unlock_irqrestore(&s390_domain->list_lock, flags);
158
159 return 0;
160
161 out_unregister:
162 zpci_unregister_ioat(zdev, 0);
163 zdev->dma_table = NULL;
164 out_free:
165 kfree(domain_device);
166
167 return rc;
168 }
169
s390_iommu_detach_device(struct iommu_domain * domain,struct device * dev)170 static void s390_iommu_detach_device(struct iommu_domain *domain,
171 struct device *dev)
172 {
173 struct zpci_dev *zdev = to_zpci_dev(dev);
174
175 WARN_ON(zdev->s390_domain != to_s390_domain(domain));
176
177 __s390_iommu_detach_device(zdev);
178 zpci_dma_init_device(zdev);
179 }
180
s390_iommu_probe_device(struct device * dev)181 static struct iommu_device *s390_iommu_probe_device(struct device *dev)
182 {
183 struct zpci_dev *zdev;
184
185 if (!dev_is_pci(dev))
186 return ERR_PTR(-ENODEV);
187
188 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
197 /*
198 * release_device is expected to detach any domain currently attached
199 * to the device, but keep it attached to other devices in the group.
200 */
201 if (zdev)
202 __s390_iommu_detach_device(zdev);
203 }
204
s390_iommu_update_trans(struct s390_domain * s390_domain,phys_addr_t pa,dma_addr_t dma_addr,size_t size,int flags)205 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
206 phys_addr_t pa, dma_addr_t dma_addr,
207 size_t size, int flags)
208 {
209 struct s390_domain_device *domain_device;
210 phys_addr_t page_addr = pa & PAGE_MASK;
211 dma_addr_t start_dma_addr = dma_addr;
212 unsigned long irq_flags, nr_pages, i;
213 unsigned long *entry;
214 int rc = 0;
215
216 if (dma_addr < s390_domain->domain.geometry.aperture_start ||
217 dma_addr + size > s390_domain->domain.geometry.aperture_end)
218 return -EINVAL;
219
220 nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
221 if (!nr_pages)
222 return 0;
223
224 spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
225 for (i = 0; i < nr_pages; i++) {
226 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
227 if (!entry) {
228 rc = -ENOMEM;
229 goto undo_cpu_trans;
230 }
231 dma_update_cpu_trans(entry, page_addr, flags);
232 page_addr += PAGE_SIZE;
233 dma_addr += PAGE_SIZE;
234 }
235
236 spin_lock(&s390_domain->list_lock);
237 list_for_each_entry(domain_device, &s390_domain->devices, list) {
238 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
239 start_dma_addr, nr_pages * PAGE_SIZE);
240 if (rc)
241 break;
242 }
243 spin_unlock(&s390_domain->list_lock);
244
245 undo_cpu_trans:
246 if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
247 flags = ZPCI_PTE_INVALID;
248 while (i-- > 0) {
249 page_addr -= PAGE_SIZE;
250 dma_addr -= PAGE_SIZE;
251 entry = dma_walk_cpu_trans(s390_domain->dma_table,
252 dma_addr);
253 if (!entry)
254 break;
255 dma_update_cpu_trans(entry, page_addr, flags);
256 }
257 }
258 spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
259
260 return rc;
261 }
262
s390_iommu_map(struct iommu_domain * domain,unsigned long iova,phys_addr_t paddr,size_t size,int prot,gfp_t gfp)263 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
264 phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
265 {
266 struct s390_domain *s390_domain = to_s390_domain(domain);
267 int flags = ZPCI_PTE_VALID, rc = 0;
268
269 if (!(prot & IOMMU_READ))
270 return -EINVAL;
271
272 if (!(prot & IOMMU_WRITE))
273 flags |= ZPCI_TABLE_PROTECTED;
274
275 rc = s390_iommu_update_trans(s390_domain, paddr, iova,
276 size, flags);
277
278 return rc;
279 }
280
s390_iommu_iova_to_phys(struct iommu_domain * domain,dma_addr_t iova)281 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
282 dma_addr_t iova)
283 {
284 struct s390_domain *s390_domain = to_s390_domain(domain);
285 unsigned long *sto, *pto, *rto, flags;
286 unsigned int rtx, sx, px;
287 phys_addr_t phys = 0;
288
289 if (iova < domain->geometry.aperture_start ||
290 iova > domain->geometry.aperture_end)
291 return 0;
292
293 rtx = calc_rtx(iova);
294 sx = calc_sx(iova);
295 px = calc_px(iova);
296 rto = s390_domain->dma_table;
297
298 spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
299 if (rto && reg_entry_isvalid(rto[rtx])) {
300 sto = get_rt_sto(rto[rtx]);
301 if (sto && reg_entry_isvalid(sto[sx])) {
302 pto = get_st_pto(sto[sx]);
303 if (pto && pt_entry_isvalid(pto[px]))
304 phys = pto[px] & ZPCI_PTE_ADDR_MASK;
305 }
306 }
307 spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
308
309 return phys;
310 }
311
s390_iommu_unmap(struct iommu_domain * domain,unsigned long iova,size_t size,struct iommu_iotlb_gather * gather)312 static size_t s390_iommu_unmap(struct iommu_domain *domain,
313 unsigned long iova, size_t size,
314 struct iommu_iotlb_gather *gather)
315 {
316 struct s390_domain *s390_domain = to_s390_domain(domain);
317 int flags = ZPCI_PTE_INVALID;
318 phys_addr_t paddr;
319 int rc;
320
321 paddr = s390_iommu_iova_to_phys(domain, iova);
322 if (!paddr)
323 return 0;
324
325 rc = s390_iommu_update_trans(s390_domain, paddr, iova,
326 size, flags);
327 if (rc)
328 return 0;
329
330 return size;
331 }
332
zpci_init_iommu(struct zpci_dev * zdev)333 int zpci_init_iommu(struct zpci_dev *zdev)
334 {
335 int rc = 0;
336
337 rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
338 "s390-iommu.%08x", zdev->fid);
339 if (rc)
340 goto out_err;
341
342 rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL);
343 if (rc)
344 goto out_sysfs;
345
346 return 0;
347
348 out_sysfs:
349 iommu_device_sysfs_remove(&zdev->iommu_dev);
350
351 out_err:
352 return rc;
353 }
354
zpci_destroy_iommu(struct zpci_dev * zdev)355 void zpci_destroy_iommu(struct zpci_dev *zdev)
356 {
357 iommu_device_unregister(&zdev->iommu_dev);
358 iommu_device_sysfs_remove(&zdev->iommu_dev);
359 }
360
361 static const struct iommu_ops s390_iommu_ops = {
362 .capable = s390_iommu_capable,
363 .domain_alloc = s390_domain_alloc,
364 .probe_device = s390_iommu_probe_device,
365 .release_device = s390_iommu_release_device,
366 .device_group = generic_device_group,
367 .pgsize_bitmap = S390_IOMMU_PGSIZES,
368 .default_domain_ops = &(const struct iommu_domain_ops) {
369 .attach_dev = s390_iommu_attach_device,
370 .detach_dev = s390_iommu_detach_device,
371 .map = s390_iommu_map,
372 .unmap = s390_iommu_unmap,
373 .iova_to_phys = s390_iommu_iova_to_phys,
374 .free = s390_domain_free,
375 }
376 };
377