xref: /openbmc/linux/drivers/iommu/intel/svm.c (revision 612cf4d2)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright © 2015 Intel Corporation.
4  *
5  * Authors: David Woodhouse <dwmw2@infradead.org>
6  */
7 
8 #include <linux/mmu_notifier.h>
9 #include <linux/sched.h>
10 #include <linux/sched/mm.h>
11 #include <linux/slab.h>
12 #include <linux/intel-svm.h>
13 #include <linux/rculist.h>
14 #include <linux/pci.h>
15 #include <linux/pci-ats.h>
16 #include <linux/dmar.h>
17 #include <linux/interrupt.h>
18 #include <linux/mm_types.h>
19 #include <linux/xarray.h>
20 #include <linux/ioasid.h>
21 #include <asm/page.h>
22 #include <asm/fpu/api.h>
23 
24 #include "iommu.h"
25 #include "pasid.h"
26 #include "perf.h"
27 #include "../iommu-sva.h"
28 #include "trace.h"
29 
30 static irqreturn_t prq_event_thread(int irq, void *d);
31 static void intel_svm_drain_prq(struct device *dev, u32 pasid);
32 #define to_intel_svm_dev(handle) container_of(handle, struct intel_svm_dev, sva)
33 
34 static DEFINE_XARRAY_ALLOC(pasid_private_array);
35 static int pasid_private_add(ioasid_t pasid, void *priv)
36 {
37 	return xa_alloc(&pasid_private_array, &pasid, priv,
38 			XA_LIMIT(pasid, pasid), GFP_ATOMIC);
39 }
40 
41 static void pasid_private_remove(ioasid_t pasid)
42 {
43 	xa_erase(&pasid_private_array, pasid);
44 }
45 
46 static void *pasid_private_find(ioasid_t pasid)
47 {
48 	return xa_load(&pasid_private_array, pasid);
49 }
50 
51 static struct intel_svm_dev *
52 svm_lookup_device_by_dev(struct intel_svm *svm, struct device *dev)
53 {
54 	struct intel_svm_dev *sdev = NULL, *t;
55 
56 	rcu_read_lock();
57 	list_for_each_entry_rcu(t, &svm->devs, list) {
58 		if (t->dev == dev) {
59 			sdev = t;
60 			break;
61 		}
62 	}
63 	rcu_read_unlock();
64 
65 	return sdev;
66 }
67 
68 int intel_svm_enable_prq(struct intel_iommu *iommu)
69 {
70 	struct iopf_queue *iopfq;
71 	struct page *pages;
72 	int irq, ret;
73 
74 	pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, PRQ_ORDER);
75 	if (!pages) {
76 		pr_warn("IOMMU: %s: Failed to allocate page request queue\n",
77 			iommu->name);
78 		return -ENOMEM;
79 	}
80 	iommu->prq = page_address(pages);
81 
82 	irq = dmar_alloc_hwirq(DMAR_UNITS_SUPPORTED + iommu->seq_id, iommu->node, iommu);
83 	if (irq <= 0) {
84 		pr_err("IOMMU: %s: Failed to create IRQ vector for page request queue\n",
85 		       iommu->name);
86 		ret = -EINVAL;
87 		goto free_prq;
88 	}
89 	iommu->pr_irq = irq;
90 
91 	snprintf(iommu->iopfq_name, sizeof(iommu->iopfq_name),
92 		 "dmar%d-iopfq", iommu->seq_id);
93 	iopfq = iopf_queue_alloc(iommu->iopfq_name);
94 	if (!iopfq) {
95 		pr_err("IOMMU: %s: Failed to allocate iopf queue\n", iommu->name);
96 		ret = -ENOMEM;
97 		goto free_hwirq;
98 	}
99 	iommu->iopf_queue = iopfq;
100 
101 	snprintf(iommu->prq_name, sizeof(iommu->prq_name), "dmar%d-prq", iommu->seq_id);
102 
103 	ret = request_threaded_irq(irq, NULL, prq_event_thread, IRQF_ONESHOT,
104 				   iommu->prq_name, iommu);
105 	if (ret) {
106 		pr_err("IOMMU: %s: Failed to request IRQ for page request queue\n",
107 		       iommu->name);
108 		goto free_iopfq;
109 	}
110 	dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL);
111 	dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL);
112 	dmar_writeq(iommu->reg + DMAR_PQA_REG, virt_to_phys(iommu->prq) | PRQ_ORDER);
113 
114 	init_completion(&iommu->prq_complete);
115 
116 	return 0;
117 
118 free_iopfq:
119 	iopf_queue_free(iommu->iopf_queue);
120 	iommu->iopf_queue = NULL;
121 free_hwirq:
122 	dmar_free_hwirq(irq);
123 	iommu->pr_irq = 0;
124 free_prq:
125 	free_pages((unsigned long)iommu->prq, PRQ_ORDER);
126 	iommu->prq = NULL;
127 
128 	return ret;
129 }
130 
131 int intel_svm_finish_prq(struct intel_iommu *iommu)
132 {
133 	dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL);
134 	dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL);
135 	dmar_writeq(iommu->reg + DMAR_PQA_REG, 0ULL);
136 
137 	if (iommu->pr_irq) {
138 		free_irq(iommu->pr_irq, iommu);
139 		dmar_free_hwirq(iommu->pr_irq);
140 		iommu->pr_irq = 0;
141 	}
142 
143 	if (iommu->iopf_queue) {
144 		iopf_queue_free(iommu->iopf_queue);
145 		iommu->iopf_queue = NULL;
146 	}
147 
148 	free_pages((unsigned long)iommu->prq, PRQ_ORDER);
149 	iommu->prq = NULL;
150 
151 	return 0;
152 }
153 
154 void intel_svm_check(struct intel_iommu *iommu)
155 {
156 	if (!pasid_supported(iommu))
157 		return;
158 
159 	if (cpu_feature_enabled(X86_FEATURE_GBPAGES) &&
160 	    !cap_fl1gp_support(iommu->cap)) {
161 		pr_err("%s SVM disabled, incompatible 1GB page capability\n",
162 		       iommu->name);
163 		return;
164 	}
165 
166 	if (cpu_feature_enabled(X86_FEATURE_LA57) &&
167 	    !cap_fl5lp_support(iommu->cap)) {
168 		pr_err("%s SVM disabled, incompatible paging mode\n",
169 		       iommu->name);
170 		return;
171 	}
172 
173 	iommu->flags |= VTD_FLAG_SVM_CAPABLE;
174 }
175 
176 static void __flush_svm_range_dev(struct intel_svm *svm,
177 				  struct intel_svm_dev *sdev,
178 				  unsigned long address,
179 				  unsigned long pages, int ih)
180 {
181 	struct device_domain_info *info = dev_iommu_priv_get(sdev->dev);
182 
183 	if (WARN_ON(!pages))
184 		return;
185 
186 	qi_flush_piotlb(sdev->iommu, sdev->did, svm->pasid, address, pages, ih);
187 	if (info->ats_enabled) {
188 		qi_flush_dev_iotlb_pasid(sdev->iommu, sdev->sid, info->pfsid,
189 					 svm->pasid, sdev->qdep, address,
190 					 order_base_2(pages));
191 		quirk_extra_dev_tlb_flush(info, address, order_base_2(pages),
192 					  svm->pasid, sdev->qdep);
193 	}
194 }
195 
196 static void intel_flush_svm_range_dev(struct intel_svm *svm,
197 				      struct intel_svm_dev *sdev,
198 				      unsigned long address,
199 				      unsigned long pages, int ih)
200 {
201 	unsigned long shift = ilog2(__roundup_pow_of_two(pages));
202 	unsigned long align = (1ULL << (VTD_PAGE_SHIFT + shift));
203 	unsigned long start = ALIGN_DOWN(address, align);
204 	unsigned long end = ALIGN(address + (pages << VTD_PAGE_SHIFT), align);
205 
206 	while (start < end) {
207 		__flush_svm_range_dev(svm, sdev, start, align >> VTD_PAGE_SHIFT, ih);
208 		start += align;
209 	}
210 }
211 
212 static void intel_flush_svm_range(struct intel_svm *svm, unsigned long address,
213 				unsigned long pages, int ih)
214 {
215 	struct intel_svm_dev *sdev;
216 
217 	rcu_read_lock();
218 	list_for_each_entry_rcu(sdev, &svm->devs, list)
219 		intel_flush_svm_range_dev(svm, sdev, address, pages, ih);
220 	rcu_read_unlock();
221 }
222 
223 /* Pages have been freed at this point */
224 static void intel_invalidate_range(struct mmu_notifier *mn,
225 				   struct mm_struct *mm,
226 				   unsigned long start, unsigned long end)
227 {
228 	struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
229 
230 	intel_flush_svm_range(svm, start,
231 			      (end - start + PAGE_SIZE - 1) >> VTD_PAGE_SHIFT, 0);
232 }
233 
234 static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
235 {
236 	struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
237 	struct intel_svm_dev *sdev;
238 
239 	/* This might end up being called from exit_mmap(), *before* the page
240 	 * tables are cleared. And __mmu_notifier_release() will delete us from
241 	 * the list of notifiers so that our invalidate_range() callback doesn't
242 	 * get called when the page tables are cleared. So we need to protect
243 	 * against hardware accessing those page tables.
244 	 *
245 	 * We do it by clearing the entry in the PASID table and then flushing
246 	 * the IOTLB and the PASID table caches. This might upset hardware;
247 	 * perhaps we'll want to point the PASID to a dummy PGD (like the zero
248 	 * page) so that we end up taking a fault that the hardware really
249 	 * *has* to handle gracefully without affecting other processes.
250 	 */
251 	rcu_read_lock();
252 	list_for_each_entry_rcu(sdev, &svm->devs, list)
253 		intel_pasid_tear_down_entry(sdev->iommu, sdev->dev,
254 					    svm->pasid, true);
255 	rcu_read_unlock();
256 
257 }
258 
259 static const struct mmu_notifier_ops intel_mmuops = {
260 	.release = intel_mm_release,
261 	.invalidate_range = intel_invalidate_range,
262 };
263 
264 static DEFINE_MUTEX(pasid_mutex);
265 
266 static int pasid_to_svm_sdev(struct device *dev, unsigned int pasid,
267 			     struct intel_svm **rsvm,
268 			     struct intel_svm_dev **rsdev)
269 {
270 	struct intel_svm_dev *sdev = NULL;
271 	struct intel_svm *svm;
272 
273 	/* The caller should hold the pasid_mutex lock */
274 	if (WARN_ON(!mutex_is_locked(&pasid_mutex)))
275 		return -EINVAL;
276 
277 	if (pasid == INVALID_IOASID || pasid >= PASID_MAX)
278 		return -EINVAL;
279 
280 	svm = pasid_private_find(pasid);
281 	if (IS_ERR(svm))
282 		return PTR_ERR(svm);
283 
284 	if (!svm)
285 		goto out;
286 
287 	/*
288 	 * If we found svm for the PASID, there must be at least one device
289 	 * bond.
290 	 */
291 	if (WARN_ON(list_empty(&svm->devs)))
292 		return -EINVAL;
293 	sdev = svm_lookup_device_by_dev(svm, dev);
294 
295 out:
296 	*rsvm = svm;
297 	*rsdev = sdev;
298 
299 	return 0;
300 }
301 
302 static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu,
303 					   struct device *dev,
304 					   struct mm_struct *mm)
305 {
306 	struct device_domain_info *info = dev_iommu_priv_get(dev);
307 	struct intel_svm_dev *sdev;
308 	struct intel_svm *svm;
309 	unsigned long sflags;
310 	int ret = 0;
311 
312 	svm = pasid_private_find(mm->pasid);
313 	if (!svm) {
314 		svm = kzalloc(sizeof(*svm), GFP_KERNEL);
315 		if (!svm)
316 			return ERR_PTR(-ENOMEM);
317 
318 		svm->pasid = mm->pasid;
319 		svm->mm = mm;
320 		INIT_LIST_HEAD_RCU(&svm->devs);
321 
322 		svm->notifier.ops = &intel_mmuops;
323 		ret = mmu_notifier_register(&svm->notifier, mm);
324 		if (ret) {
325 			kfree(svm);
326 			return ERR_PTR(ret);
327 		}
328 
329 		ret = pasid_private_add(svm->pasid, svm);
330 		if (ret) {
331 			mmu_notifier_unregister(&svm->notifier, mm);
332 			kfree(svm);
333 			return ERR_PTR(ret);
334 		}
335 	}
336 
337 	/* Find the matching device in svm list */
338 	sdev = svm_lookup_device_by_dev(svm, dev);
339 	if (sdev) {
340 		sdev->users++;
341 		goto success;
342 	}
343 
344 	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
345 	if (!sdev) {
346 		ret = -ENOMEM;
347 		goto free_svm;
348 	}
349 
350 	sdev->dev = dev;
351 	sdev->iommu = iommu;
352 	sdev->did = FLPT_DEFAULT_DID;
353 	sdev->sid = PCI_DEVID(info->bus, info->devfn);
354 	sdev->users = 1;
355 	sdev->pasid = svm->pasid;
356 	sdev->sva.dev = dev;
357 	init_rcu_head(&sdev->rcu);
358 	if (info->ats_enabled) {
359 		sdev->dev_iotlb = 1;
360 		sdev->qdep = info->ats_qdep;
361 		if (sdev->qdep >= QI_DEV_EIOTLB_MAX_INVS)
362 			sdev->qdep = 0;
363 	}
364 
365 	/* Setup the pasid table: */
366 	sflags = cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0;
367 	ret = intel_pasid_setup_first_level(iommu, dev, mm->pgd, mm->pasid,
368 					    FLPT_DEFAULT_DID, sflags);
369 	if (ret)
370 		goto free_sdev;
371 
372 	list_add_rcu(&sdev->list, &svm->devs);
373 success:
374 	return &sdev->sva;
375 
376 free_sdev:
377 	kfree(sdev);
378 free_svm:
379 	if (list_empty(&svm->devs)) {
380 		mmu_notifier_unregister(&svm->notifier, mm);
381 		pasid_private_remove(mm->pasid);
382 		kfree(svm);
383 	}
384 
385 	return ERR_PTR(ret);
386 }
387 
388 /* Caller must hold pasid_mutex */
389 static int intel_svm_unbind_mm(struct device *dev, u32 pasid)
390 {
391 	struct intel_svm_dev *sdev;
392 	struct intel_iommu *iommu;
393 	struct intel_svm *svm;
394 	struct mm_struct *mm;
395 	int ret = -EINVAL;
396 
397 	iommu = device_to_iommu(dev, NULL, NULL);
398 	if (!iommu)
399 		goto out;
400 
401 	ret = pasid_to_svm_sdev(dev, pasid, &svm, &sdev);
402 	if (ret)
403 		goto out;
404 	mm = svm->mm;
405 
406 	if (sdev) {
407 		sdev->users--;
408 		if (!sdev->users) {
409 			list_del_rcu(&sdev->list);
410 			/* Flush the PASID cache and IOTLB for this device.
411 			 * Note that we do depend on the hardware *not* using
412 			 * the PASID any more. Just as we depend on other
413 			 * devices never using PASIDs that they have no right
414 			 * to use. We have a *shared* PASID table, because it's
415 			 * large and has to be physically contiguous. So it's
416 			 * hard to be as defensive as we might like. */
417 			intel_pasid_tear_down_entry(iommu, dev,
418 						    svm->pasid, false);
419 			intel_svm_drain_prq(dev, svm->pasid);
420 			kfree_rcu(sdev, rcu);
421 
422 			if (list_empty(&svm->devs)) {
423 				if (svm->notifier.ops)
424 					mmu_notifier_unregister(&svm->notifier, mm);
425 				pasid_private_remove(svm->pasid);
426 				/* We mandate that no page faults may be outstanding
427 				 * for the PASID when intel_svm_unbind_mm() is called.
428 				 * If that is not obeyed, subtle errors will happen.
429 				 * Let's make them less subtle... */
430 				memset(svm, 0x6b, sizeof(*svm));
431 				kfree(svm);
432 			}
433 		}
434 	}
435 out:
436 	return ret;
437 }
438 
439 /* Page request queue descriptor */
440 struct page_req_dsc {
441 	union {
442 		struct {
443 			u64 type:8;
444 			u64 pasid_present:1;
445 			u64 priv_data_present:1;
446 			u64 rsvd:6;
447 			u64 rid:16;
448 			u64 pasid:20;
449 			u64 exe_req:1;
450 			u64 pm_req:1;
451 			u64 rsvd2:10;
452 		};
453 		u64 qw_0;
454 	};
455 	union {
456 		struct {
457 			u64 rd_req:1;
458 			u64 wr_req:1;
459 			u64 lpig:1;
460 			u64 prg_index:9;
461 			u64 addr:52;
462 		};
463 		u64 qw_1;
464 	};
465 	u64 priv_data[2];
466 };
467 
468 static bool is_canonical_address(u64 addr)
469 {
470 	int shift = 64 - (__VIRTUAL_MASK_SHIFT + 1);
471 	long saddr = (long) addr;
472 
473 	return (((saddr << shift) >> shift) == saddr);
474 }
475 
476 /**
477  * intel_svm_drain_prq - Drain page requests and responses for a pasid
478  * @dev: target device
479  * @pasid: pasid for draining
480  *
481  * Drain all pending page requests and responses related to @pasid in both
482  * software and hardware. This is supposed to be called after the device
483  * driver has stopped DMA, the pasid entry has been cleared, and both IOTLB
484  * and DevTLB have been invalidated.
485  *
486  * It waits until all pending page requests for @pasid in the page fault
487  * queue are completed by the prq handling thread. Then follow the steps
488  * described in VT-d spec CH7.10 to drain all page requests and page
489  * responses pending in the hardware.
490  */
491 static void intel_svm_drain_prq(struct device *dev, u32 pasid)
492 {
493 	struct device_domain_info *info;
494 	struct dmar_domain *domain;
495 	struct intel_iommu *iommu;
496 	struct qi_desc desc[3];
497 	struct pci_dev *pdev;
498 	int head, tail;
499 	u16 sid, did;
500 	int qdep;
501 
502 	info = dev_iommu_priv_get(dev);
503 	if (WARN_ON(!info || !dev_is_pci(dev)))
504 		return;
505 
506 	if (!info->pri_enabled)
507 		return;
508 
509 	iommu = info->iommu;
510 	domain = info->domain;
511 	pdev = to_pci_dev(dev);
512 	sid = PCI_DEVID(info->bus, info->devfn);
513 	did = domain_id_iommu(domain, iommu);
514 	qdep = pci_ats_queue_depth(pdev);
515 
516 	/*
517 	 * Check and wait until all pending page requests in the queue are
518 	 * handled by the prq handling thread.
519 	 */
520 prq_retry:
521 	reinit_completion(&iommu->prq_complete);
522 	tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
523 	head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
524 	while (head != tail) {
525 		struct page_req_dsc *req;
526 
527 		req = &iommu->prq[head / sizeof(*req)];
528 		if (!req->pasid_present || req->pasid != pasid) {
529 			head = (head + sizeof(*req)) & PRQ_RING_MASK;
530 			continue;
531 		}
532 
533 		wait_for_completion(&iommu->prq_complete);
534 		goto prq_retry;
535 	}
536 
537 	/*
538 	 * A work in IO page fault workqueue may try to lock pasid_mutex now.
539 	 * Holding pasid_mutex while waiting in iopf_queue_flush_dev() for
540 	 * all works in the workqueue to finish may cause deadlock.
541 	 *
542 	 * It's unnecessary to hold pasid_mutex in iopf_queue_flush_dev().
543 	 * Unlock it to allow the works to be handled while waiting for
544 	 * them to finish.
545 	 */
546 	lockdep_assert_held(&pasid_mutex);
547 	mutex_unlock(&pasid_mutex);
548 	iopf_queue_flush_dev(dev);
549 	mutex_lock(&pasid_mutex);
550 
551 	/*
552 	 * Perform steps described in VT-d spec CH7.10 to drain page
553 	 * requests and responses in hardware.
554 	 */
555 	memset(desc, 0, sizeof(desc));
556 	desc[0].qw0 = QI_IWD_STATUS_DATA(QI_DONE) |
557 			QI_IWD_FENCE |
558 			QI_IWD_TYPE;
559 	desc[1].qw0 = QI_EIOTLB_PASID(pasid) |
560 			QI_EIOTLB_DID(did) |
561 			QI_EIOTLB_GRAN(QI_GRAN_NONG_PASID) |
562 			QI_EIOTLB_TYPE;
563 	desc[2].qw0 = QI_DEV_EIOTLB_PASID(pasid) |
564 			QI_DEV_EIOTLB_SID(sid) |
565 			QI_DEV_EIOTLB_QDEP(qdep) |
566 			QI_DEIOTLB_TYPE |
567 			QI_DEV_IOTLB_PFSID(info->pfsid);
568 qi_retry:
569 	reinit_completion(&iommu->prq_complete);
570 	qi_submit_sync(iommu, desc, 3, QI_OPT_WAIT_DRAIN);
571 	if (readl(iommu->reg + DMAR_PRS_REG) & DMA_PRS_PRO) {
572 		wait_for_completion(&iommu->prq_complete);
573 		goto qi_retry;
574 	}
575 }
576 
577 static int prq_to_iommu_prot(struct page_req_dsc *req)
578 {
579 	int prot = 0;
580 
581 	if (req->rd_req)
582 		prot |= IOMMU_FAULT_PERM_READ;
583 	if (req->wr_req)
584 		prot |= IOMMU_FAULT_PERM_WRITE;
585 	if (req->exe_req)
586 		prot |= IOMMU_FAULT_PERM_EXEC;
587 	if (req->pm_req)
588 		prot |= IOMMU_FAULT_PERM_PRIV;
589 
590 	return prot;
591 }
592 
593 static int intel_svm_prq_report(struct intel_iommu *iommu, struct device *dev,
594 				struct page_req_dsc *desc)
595 {
596 	struct iommu_fault_event event;
597 
598 	if (!dev || !dev_is_pci(dev))
599 		return -ENODEV;
600 
601 	/* Fill in event data for device specific processing */
602 	memset(&event, 0, sizeof(struct iommu_fault_event));
603 	event.fault.type = IOMMU_FAULT_PAGE_REQ;
604 	event.fault.prm.addr = (u64)desc->addr << VTD_PAGE_SHIFT;
605 	event.fault.prm.pasid = desc->pasid;
606 	event.fault.prm.grpid = desc->prg_index;
607 	event.fault.prm.perm = prq_to_iommu_prot(desc);
608 
609 	if (desc->lpig)
610 		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
611 	if (desc->pasid_present) {
612 		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
613 		event.fault.prm.flags |= IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID;
614 	}
615 	if (desc->priv_data_present) {
616 		/*
617 		 * Set last page in group bit if private data is present,
618 		 * page response is required as it does for LPIG.
619 		 * iommu_report_device_fault() doesn't understand this vendor
620 		 * specific requirement thus we set last_page as a workaround.
621 		 */
622 		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
623 		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
624 		event.fault.prm.private_data[0] = desc->priv_data[0];
625 		event.fault.prm.private_data[1] = desc->priv_data[1];
626 	} else if (dmar_latency_enabled(iommu, DMAR_LATENCY_PRQ)) {
627 		/*
628 		 * If the private data fields are not used by hardware, use it
629 		 * to monitor the prq handle latency.
630 		 */
631 		event.fault.prm.private_data[0] = ktime_to_ns(ktime_get());
632 	}
633 
634 	return iommu_report_device_fault(dev, &event);
635 }
636 
637 static void handle_bad_prq_event(struct intel_iommu *iommu,
638 				 struct page_req_dsc *req, int result)
639 {
640 	struct qi_desc desc;
641 
642 	pr_err("%s: Invalid page request: %08llx %08llx\n",
643 	       iommu->name, ((unsigned long long *)req)[0],
644 	       ((unsigned long long *)req)[1]);
645 
646 	/*
647 	 * Per VT-d spec. v3.0 ch7.7, system software must
648 	 * respond with page group response if private data
649 	 * is present (PDP) or last page in group (LPIG) bit
650 	 * is set. This is an additional VT-d feature beyond
651 	 * PCI ATS spec.
652 	 */
653 	if (!req->lpig && !req->priv_data_present)
654 		return;
655 
656 	desc.qw0 = QI_PGRP_PASID(req->pasid) |
657 			QI_PGRP_DID(req->rid) |
658 			QI_PGRP_PASID_P(req->pasid_present) |
659 			QI_PGRP_PDP(req->priv_data_present) |
660 			QI_PGRP_RESP_CODE(result) |
661 			QI_PGRP_RESP_TYPE;
662 	desc.qw1 = QI_PGRP_IDX(req->prg_index) |
663 			QI_PGRP_LPIG(req->lpig);
664 
665 	if (req->priv_data_present) {
666 		desc.qw2 = req->priv_data[0];
667 		desc.qw3 = req->priv_data[1];
668 	} else {
669 		desc.qw2 = 0;
670 		desc.qw3 = 0;
671 	}
672 
673 	qi_submit_sync(iommu, &desc, 1, 0);
674 }
675 
676 static irqreturn_t prq_event_thread(int irq, void *d)
677 {
678 	struct intel_iommu *iommu = d;
679 	struct page_req_dsc *req;
680 	int head, tail, handled;
681 	struct pci_dev *pdev;
682 	u64 address;
683 
684 	/*
685 	 * Clear PPR bit before reading head/tail registers, to ensure that
686 	 * we get a new interrupt if needed.
687 	 */
688 	writel(DMA_PRS_PPR, iommu->reg + DMAR_PRS_REG);
689 
690 	tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
691 	head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
692 	handled = (head != tail);
693 	while (head != tail) {
694 		req = &iommu->prq[head / sizeof(*req)];
695 		address = (u64)req->addr << VTD_PAGE_SHIFT;
696 
697 		if (unlikely(!req->pasid_present)) {
698 			pr_err("IOMMU: %s: Page request without PASID\n",
699 			       iommu->name);
700 bad_req:
701 			handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
702 			goto prq_advance;
703 		}
704 
705 		if (unlikely(!is_canonical_address(address))) {
706 			pr_err("IOMMU: %s: Address is not canonical\n",
707 			       iommu->name);
708 			goto bad_req;
709 		}
710 
711 		if (unlikely(req->pm_req && (req->rd_req | req->wr_req))) {
712 			pr_err("IOMMU: %s: Page request in Privilege Mode\n",
713 			       iommu->name);
714 			goto bad_req;
715 		}
716 
717 		if (unlikely(req->exe_req && req->rd_req)) {
718 			pr_err("IOMMU: %s: Execution request not supported\n",
719 			       iommu->name);
720 			goto bad_req;
721 		}
722 
723 		/* Drop Stop Marker message. No need for a response. */
724 		if (unlikely(req->lpig && !req->rd_req && !req->wr_req))
725 			goto prq_advance;
726 
727 		pdev = pci_get_domain_bus_and_slot(iommu->segment,
728 						   PCI_BUS_NUM(req->rid),
729 						   req->rid & 0xff);
730 		/*
731 		 * If prq is to be handled outside iommu driver via receiver of
732 		 * the fault notifiers, we skip the page response here.
733 		 */
734 		if (!pdev)
735 			goto bad_req;
736 
737 		if (intel_svm_prq_report(iommu, &pdev->dev, req))
738 			handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
739 		else
740 			trace_prq_report(iommu, &pdev->dev, req->qw_0, req->qw_1,
741 					 req->priv_data[0], req->priv_data[1],
742 					 iommu->prq_seq_number++);
743 		pci_dev_put(pdev);
744 prq_advance:
745 		head = (head + sizeof(*req)) & PRQ_RING_MASK;
746 	}
747 
748 	dmar_writeq(iommu->reg + DMAR_PQH_REG, tail);
749 
750 	/*
751 	 * Clear the page request overflow bit and wake up all threads that
752 	 * are waiting for the completion of this handling.
753 	 */
754 	if (readl(iommu->reg + DMAR_PRS_REG) & DMA_PRS_PRO) {
755 		pr_info_ratelimited("IOMMU: %s: PRQ overflow detected\n",
756 				    iommu->name);
757 		head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
758 		tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
759 		if (head == tail) {
760 			iopf_queue_discard_partial(iommu->iopf_queue);
761 			writel(DMA_PRS_PRO, iommu->reg + DMAR_PRS_REG);
762 			pr_info_ratelimited("IOMMU: %s: PRQ overflow cleared",
763 					    iommu->name);
764 		}
765 	}
766 
767 	if (!completion_done(&iommu->prq_complete))
768 		complete(&iommu->prq_complete);
769 
770 	return IRQ_RETVAL(handled);
771 }
772 
773 int intel_svm_page_response(struct device *dev,
774 			    struct iommu_fault_event *evt,
775 			    struct iommu_page_response *msg)
776 {
777 	struct iommu_fault_page_request *prm;
778 	struct intel_iommu *iommu;
779 	bool private_present;
780 	bool pasid_present;
781 	bool last_page;
782 	u8 bus, devfn;
783 	int ret = 0;
784 	u16 sid;
785 
786 	if (!dev || !dev_is_pci(dev))
787 		return -ENODEV;
788 
789 	iommu = device_to_iommu(dev, &bus, &devfn);
790 	if (!iommu)
791 		return -ENODEV;
792 
793 	if (!msg || !evt)
794 		return -EINVAL;
795 
796 	prm = &evt->fault.prm;
797 	sid = PCI_DEVID(bus, devfn);
798 	pasid_present = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
799 	private_present = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
800 	last_page = prm->flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
801 
802 	if (!pasid_present) {
803 		ret = -EINVAL;
804 		goto out;
805 	}
806 
807 	if (prm->pasid == 0 || prm->pasid >= PASID_MAX) {
808 		ret = -EINVAL;
809 		goto out;
810 	}
811 
812 	/*
813 	 * Per VT-d spec. v3.0 ch7.7, system software must respond
814 	 * with page group response if private data is present (PDP)
815 	 * or last page in group (LPIG) bit is set. This is an
816 	 * additional VT-d requirement beyond PCI ATS spec.
817 	 */
818 	if (last_page || private_present) {
819 		struct qi_desc desc;
820 
821 		desc.qw0 = QI_PGRP_PASID(prm->pasid) | QI_PGRP_DID(sid) |
822 				QI_PGRP_PASID_P(pasid_present) |
823 				QI_PGRP_PDP(private_present) |
824 				QI_PGRP_RESP_CODE(msg->code) |
825 				QI_PGRP_RESP_TYPE;
826 		desc.qw1 = QI_PGRP_IDX(prm->grpid) | QI_PGRP_LPIG(last_page);
827 		desc.qw2 = 0;
828 		desc.qw3 = 0;
829 
830 		if (private_present) {
831 			desc.qw2 = prm->private_data[0];
832 			desc.qw3 = prm->private_data[1];
833 		} else if (prm->private_data[0]) {
834 			dmar_latency_update(iommu, DMAR_LATENCY_PRQ,
835 				ktime_to_ns(ktime_get()) - prm->private_data[0]);
836 		}
837 
838 		qi_submit_sync(iommu, &desc, 1, 0);
839 	}
840 out:
841 	return ret;
842 }
843 
844 void intel_svm_remove_dev_pasid(struct device *dev, ioasid_t pasid)
845 {
846 	mutex_lock(&pasid_mutex);
847 	intel_svm_unbind_mm(dev, pasid);
848 	mutex_unlock(&pasid_mutex);
849 }
850 
851 static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
852 				   struct device *dev, ioasid_t pasid)
853 {
854 	struct device_domain_info *info = dev_iommu_priv_get(dev);
855 	struct intel_iommu *iommu = info->iommu;
856 	struct mm_struct *mm = domain->mm;
857 	struct iommu_sva *sva;
858 	int ret = 0;
859 
860 	mutex_lock(&pasid_mutex);
861 	sva = intel_svm_bind_mm(iommu, dev, mm);
862 	if (IS_ERR(sva))
863 		ret = PTR_ERR(sva);
864 	mutex_unlock(&pasid_mutex);
865 
866 	return ret;
867 }
868 
869 static void intel_svm_domain_free(struct iommu_domain *domain)
870 {
871 	kfree(to_dmar_domain(domain));
872 }
873 
874 static const struct iommu_domain_ops intel_svm_domain_ops = {
875 	.set_dev_pasid		= intel_svm_set_dev_pasid,
876 	.free			= intel_svm_domain_free
877 };
878 
879 struct iommu_domain *intel_svm_domain_alloc(void)
880 {
881 	struct dmar_domain *domain;
882 
883 	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
884 	if (!domain)
885 		return NULL;
886 	domain->domain.ops = &intel_svm_domain_ops;
887 
888 	return &domain->domain;
889 }
890