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 
17 static const struct iommu_ops s390_iommu_ops;
18 
19 struct 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 
to_s390_domain(struct iommu_domain * dom)27 static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
28 {
29 	return container_of(dom, struct s390_domain, domain);
30 }
31 
s390_iommu_capable(struct device * dev,enum iommu_cap cap)32 static 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 
s390_domain_alloc(unsigned domain_type)42 static 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(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(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(&s390_domain->devices);
64 
65 	return &s390_domain->domain;
66 }
67 
s390_iommu_rcu_free_domain(struct rcu_head * head)68 static 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(s390_domain);
74 }
75 
s390_domain_free(struct iommu_domain * domain)76 static void s390_domain_free(struct iommu_domain *domain)
77 {
78 	struct s390_domain *s390_domain = to_s390_domain(domain);
79 
80 	rcu_read_lock();
81 	WARN_ON(!list_empty(&s390_domain->devices));
82 	rcu_read_unlock();
83 
84 	call_rcu(&s390_domain->rcu, s390_iommu_rcu_free_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 	unsigned long flags;
91 
92 	if (!s390_domain)
93 		return;
94 
95 	spin_lock_irqsave(&s390_domain->list_lock, flags);
96 	list_del_rcu(&zdev->iommu_list);
97 	spin_unlock_irqrestore(&s390_domain->list_lock, flags);
98 
99 	zpci_unregister_ioat(zdev, 0);
100 	zdev->s390_domain = NULL;
101 	zdev->dma_table = NULL;
102 }
103 
s390_iommu_attach_device(struct iommu_domain * domain,struct device * dev)104 static int s390_iommu_attach_device(struct iommu_domain *domain,
105 				    struct device *dev)
106 {
107 	struct s390_domain *s390_domain = to_s390_domain(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(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(&zdev->iommu_list, &s390_domain->devices);
140 	spin_unlock_irqrestore(&s390_domain->list_lock, flags);
141 
142 	return 0;
143 }
144 
s390_iommu_set_platform_dma(struct device * dev)145 static 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 
s390_iommu_get_resv_regions(struct device * dev,struct list_head * list)153 static 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(0, zdev->start_dma, 0,
161 						 IOMMU_RESV_RESERVED, GFP_KERNEL);
162 		if (!region)
163 			return;
164 		list_add_tail(&region->list, list);
165 	}
166 
167 	if (zdev->end_dma < ZPCI_TABLE_SIZE_RT - 1) {
168 		region = iommu_alloc_resv_region(zdev->end_dma + 1,
169 						 ZPCI_TABLE_SIZE_RT - zdev->end_dma - 1,
170 						 0, IOMMU_RESV_RESERVED, GFP_KERNEL);
171 		if (!region)
172 			return;
173 		list_add_tail(&region->list, list);
174 	}
175 }
176 
s390_iommu_probe_device(struct device * dev)177 static 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(-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(-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 
s390_iommu_release_device(struct device * dev)196 static 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 
s390_iommu_flush_iotlb_all(struct iommu_domain * domain)208 static void s390_iommu_flush_iotlb_all(struct iommu_domain *domain)
209 {
210 	struct s390_domain *s390_domain = to_s390_domain(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 
s390_iommu_iotlb_sync(struct iommu_domain * domain,struct iommu_iotlb_gather * gather)221 static 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(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 
s390_iommu_iotlb_sync_map(struct iommu_domain * domain,unsigned long iova,size_t size)240 static 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(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 
s390_iommu_validate_trans(struct s390_domain * s390_domain,phys_addr_t pa,dma_addr_t dma_addr,unsigned long nr_pages,int flags,gfp_t gfp)256 static 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 
280 undo_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 
s390_iommu_invalidate_trans(struct s390_domain * s390_domain,dma_addr_t dma_addr,unsigned long nr_pages)293 static 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 
s390_iommu_map_pages(struct iommu_domain * domain,unsigned long iova,phys_addr_t paddr,size_t pgsize,size_t pgcount,int prot,gfp_t gfp,size_t * mapped)314 static 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(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, paddr, iova,
340 				       pgcount, flags, gfp);
341 	if (!rc)
342 		*mapped = size;
343 
344 	return rc;
345 }
346 
s390_iommu_iova_to_phys(struct iommu_domain * domain,dma_addr_t iova)347 static 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(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 
s390_iommu_unmap_pages(struct iommu_domain * domain,unsigned long iova,size_t pgsize,size_t pgcount,struct iommu_iotlb_gather * gather)380 static 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(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, iova, pgcount);
394 	if (rc)
395 		return 0;
396 
397 	iommu_iotlb_gather_add_range(gather, iova, size);
398 
399 	return size;
400 }
401 
zpci_init_iommu(struct zpci_dev * zdev)402 int zpci_init_iommu(struct zpci_dev *zdev)
403 {
404 	int rc = 0;
405 
406 	rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
407 				    "s390-iommu.%08x", zdev->fid);
408 	if (rc)
409 		goto out_err;
410 
411 	rc = iommu_device_register(&zdev->iommu_dev, &s390_iommu_ops, NULL);
412 	if (rc)
413 		goto out_sysfs;
414 
415 	return 0;
416 
417 out_sysfs:
418 	iommu_device_sysfs_remove(&zdev->iommu_dev);
419 
420 out_err:
421 	return rc;
422 }
423 
zpci_destroy_iommu(struct zpci_dev * zdev)424 void zpci_destroy_iommu(struct zpci_dev *zdev)
425 {
426 	iommu_device_unregister(&zdev->iommu_dev);
427 	iommu_device_sysfs_remove(&zdev->iommu_dev);
428 }
429 
430 static 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