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 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;
189
190 if (!dev_is_pci(dev))
191 return ERR_PTR(-ENODEV);
192
193 zdev = to_zpci_dev(dev);
194
195 return &zdev->iommu_dev;
196 }
197
s390_iommu_release_device(struct device * dev)198 static void s390_iommu_release_device(struct device *dev)
199 {
200 struct zpci_dev *zdev = to_zpci_dev(dev);
201 struct iommu_domain *domain;
202
203 /*
204 * This is a workaround for a scenario where the IOMMU API common code
205 * "forgets" to call the detach_dev callback: After binding a device
206 * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
207 * the attach_dev), removing the device via
208 * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
209 * only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
210 * notifier.
211 *
212 * So let's call detach_dev from here if it hasn't been called before.
213 */
214 if (zdev && zdev->s390_domain) {
215 domain = iommu_get_domain_for_dev(dev);
216 if (domain)
217 s390_iommu_detach_device(domain, dev);
218 }
219 }
220
s390_iommu_update_trans(struct s390_domain * s390_domain,phys_addr_t pa,dma_addr_t dma_addr,size_t size,int flags)221 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
222 phys_addr_t pa, dma_addr_t dma_addr,
223 size_t size, int flags)
224 {
225 struct s390_domain_device *domain_device;
226 phys_addr_t page_addr = pa & PAGE_MASK;
227 dma_addr_t start_dma_addr = dma_addr;
228 unsigned long irq_flags, nr_pages, i;
229 unsigned long *entry;
230 int rc = 0;
231
232 if (dma_addr < s390_domain->domain.geometry.aperture_start ||
233 dma_addr + size > s390_domain->domain.geometry.aperture_end)
234 return -EINVAL;
235
236 nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
237 if (!nr_pages)
238 return 0;
239
240 spin_lock_irqsave(&s390_domain->dma_table_lock, irq_flags);
241 for (i = 0; i < nr_pages; i++) {
242 entry = dma_walk_cpu_trans(s390_domain->dma_table, dma_addr);
243 if (!entry) {
244 rc = -ENOMEM;
245 goto undo_cpu_trans;
246 }
247 dma_update_cpu_trans(entry, page_addr, flags);
248 page_addr += PAGE_SIZE;
249 dma_addr += PAGE_SIZE;
250 }
251
252 spin_lock(&s390_domain->list_lock);
253 list_for_each_entry(domain_device, &s390_domain->devices, list) {
254 rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
255 start_dma_addr, nr_pages * PAGE_SIZE);
256 if (rc)
257 break;
258 }
259 spin_unlock(&s390_domain->list_lock);
260
261 undo_cpu_trans:
262 if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
263 flags = ZPCI_PTE_INVALID;
264 while (i-- > 0) {
265 page_addr -= PAGE_SIZE;
266 dma_addr -= PAGE_SIZE;
267 entry = dma_walk_cpu_trans(s390_domain->dma_table,
268 dma_addr);
269 if (!entry)
270 break;
271 dma_update_cpu_trans(entry, page_addr, flags);
272 }
273 }
274 spin_unlock_irqrestore(&s390_domain->dma_table_lock, irq_flags);
275
276 return rc;
277 }
278
s390_iommu_map(struct iommu_domain * domain,unsigned long iova,phys_addr_t paddr,size_t size,int prot,gfp_t gfp)279 static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
280 phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
281 {
282 struct s390_domain *s390_domain = to_s390_domain(domain);
283 int flags = ZPCI_PTE_VALID, rc = 0;
284
285 if (!(prot & IOMMU_READ))
286 return -EINVAL;
287
288 if (!(prot & IOMMU_WRITE))
289 flags |= ZPCI_TABLE_PROTECTED;
290
291 rc = s390_iommu_update_trans(s390_domain, paddr, iova,
292 size, flags);
293
294 return rc;
295 }
296
s390_iommu_iova_to_phys(struct iommu_domain * domain,dma_addr_t iova)297 static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
298 dma_addr_t iova)
299 {
300 struct s390_domain *s390_domain = to_s390_domain(domain);
301 unsigned long *sto, *pto, *rto, flags;
302 unsigned int rtx, sx, px;
303 phys_addr_t phys = 0;
304
305 if (iova < domain->geometry.aperture_start ||
306 iova > domain->geometry.aperture_end)
307 return 0;
308
309 rtx = calc_rtx(iova);
310 sx = calc_sx(iova);
311 px = calc_px(iova);
312 rto = s390_domain->dma_table;
313
314 spin_lock_irqsave(&s390_domain->dma_table_lock, flags);
315 if (rto && reg_entry_isvalid(rto[rtx])) {
316 sto = get_rt_sto(rto[rtx]);
317 if (sto && reg_entry_isvalid(sto[sx])) {
318 pto = get_st_pto(sto[sx]);
319 if (pto && pt_entry_isvalid(pto[px]))
320 phys = pto[px] & ZPCI_PTE_ADDR_MASK;
321 }
322 }
323 spin_unlock_irqrestore(&s390_domain->dma_table_lock, flags);
324
325 return phys;
326 }
327
s390_iommu_unmap(struct iommu_domain * domain,unsigned long iova,size_t size,struct iommu_iotlb_gather * gather)328 static size_t s390_iommu_unmap(struct iommu_domain *domain,
329 unsigned long iova, size_t size,
330 struct iommu_iotlb_gather *gather)
331 {
332 struct s390_domain *s390_domain = to_s390_domain(domain);
333 int flags = ZPCI_PTE_INVALID;
334 phys_addr_t paddr;
335 int rc;
336
337 paddr = s390_iommu_iova_to_phys(domain, iova);
338 if (!paddr)
339 return 0;
340
341 rc = s390_iommu_update_trans(s390_domain, paddr, iova,
342 size, flags);
343 if (rc)
344 return 0;
345
346 return size;
347 }
348
zpci_init_iommu(struct zpci_dev * zdev)349 int zpci_init_iommu(struct zpci_dev *zdev)
350 {
351 int rc = 0;
352
353 rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
354 "s390-iommu.%08x", zdev->fid);
355 if (rc)
356 goto out_err;
357
358 rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL);
359 if (rc)
360 goto out_sysfs;
361
362 return 0;
363
364 out_sysfs:
365 iommu_device_sysfs_remove(&zdev->iommu_dev);
366
367 out_err:
368 return rc;
369 }
370
zpci_destroy_iommu(struct zpci_dev * zdev)371 void zpci_destroy_iommu(struct zpci_dev *zdev)
372 {
373 iommu_device_unregister(&zdev->iommu_dev);
374 iommu_device_sysfs_remove(&zdev->iommu_dev);
375 }
376
377 static const struct iommu_ops s390_iommu_ops = {
378 .capable = s390_iommu_capable,
379 .domain_alloc = s390_domain_alloc,
380 .probe_device = s390_iommu_probe_device,
381 .release_device = s390_iommu_release_device,
382 .device_group = generic_device_group,
383 .pgsize_bitmap = S390_IOMMU_PGSIZES,
384 .default_domain_ops = &(const struct iommu_domain_ops) {
385 .attach_dev = s390_iommu_attach_device,
386 .detach_dev = s390_iommu_detach_device,
387 .map = s390_iommu_map,
388 .unmap = s390_iommu_unmap,
389 .iova_to_phys = s390_iommu_iova_to_phys,
390 .free = s390_domain_free,
391 }
392 };
393
