xref: /openbmc/linux/drivers/iommu/intel/svm.c (revision b61701881f2ff809e9cd229f129bdc4e09ca688e)
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/rculist.h>
13 #include <linux/pci.h>
14 #include <linux/pci-ats.h>
15 #include <linux/dmar.h>
16 #include <linux/interrupt.h>
17 #include <linux/mm_types.h>
18 #include <linux/xarray.h>
19 #include <asm/page.h>
20 #include <asm/fpu/api.h>
21 
22 #include "iommu.h"
23 #include "pasid.h"
24 #include "perf.h"
25 #include "../iommu-sva.h"
26 #include "trace.h"
27 
28 static irqreturn_t prq_event_thread(int irq, void *d);
29 static void intel_svm_drain_prq(struct device *dev, u32 pasid);
30 #define to_intel_svm_dev(handle) container_of(handle, struct intel_svm_dev, sva)
31 
32 static DEFINE_XARRAY_ALLOC(pasid_private_array);
33 static int pasid_private_add(ioasid_t pasid, void *priv)
34 {
35 	return xa_alloc(&pasid_private_array, &pasid, priv,
36 			XA_LIMIT(pasid, pasid), GFP_ATOMIC);
37 }
38 
39 static void pasid_private_remove(ioasid_t pasid)
40 {
41 	xa_erase(&pasid_private_array, pasid);
42 }
43 
44 static void *pasid_private_find(ioasid_t pasid)
45 {
46 	return xa_load(&pasid_private_array, pasid);
47 }
48 
49 static struct intel_svm_dev *
50 svm_lookup_device_by_dev(struct intel_svm *svm, struct device *dev)
51 {
52 	struct intel_svm_dev *sdev = NULL, *t;
53 
54 	rcu_read_lock();
55 	list_for_each_entry_rcu(t, &svm->devs, list) {
56 		if (t->dev == dev) {
57 			sdev = t;
58 			break;
59 		}
60 	}
61 	rcu_read_unlock();
62 
63 	return sdev;
64 }
65 
66 int intel_svm_enable_prq(struct intel_iommu *iommu)
67 {
68 	struct iopf_queue *iopfq;
69 	struct page *pages;
70 	int irq, ret;
71 
72 	pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, PRQ_ORDER);
73 	if (!pages) {
74 		pr_warn("IOMMU: %s: Failed to allocate page request queue\n",
75 			iommu->name);
76 		return -ENOMEM;
77 	}
78 	iommu->prq = page_address(pages);
79 
80 	irq = dmar_alloc_hwirq(IOMMU_IRQ_ID_OFFSET_PRQ + iommu->seq_id, iommu->node, iommu);
81 	if (irq <= 0) {
82 		pr_err("IOMMU: %s: Failed to create IRQ vector for page request queue\n",
83 		       iommu->name);
84 		ret = -EINVAL;
85 		goto free_prq;
86 	}
87 	iommu->pr_irq = irq;
88 
89 	snprintf(iommu->iopfq_name, sizeof(iommu->iopfq_name),
90 		 "dmar%d-iopfq", iommu->seq_id);
91 	iopfq = iopf_queue_alloc(iommu->iopfq_name);
92 	if (!iopfq) {
93 		pr_err("IOMMU: %s: Failed to allocate iopf queue\n", iommu->name);
94 		ret = -ENOMEM;
95 		goto free_hwirq;
96 	}
97 	iommu->iopf_queue = iopfq;
98 
99 	snprintf(iommu->prq_name, sizeof(iommu->prq_name), "dmar%d-prq", iommu->seq_id);
100 
101 	ret = request_threaded_irq(irq, NULL, prq_event_thread, IRQF_ONESHOT,
102 				   iommu->prq_name, iommu);
103 	if (ret) {
104 		pr_err("IOMMU: %s: Failed to request IRQ for page request queue\n",
105 		       iommu->name);
106 		goto free_iopfq;
107 	}
108 	dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL);
109 	dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL);
110 	dmar_writeq(iommu->reg + DMAR_PQA_REG, virt_to_phys(iommu->prq) | PRQ_ORDER);
111 
112 	init_completion(&iommu->prq_complete);
113 
114 	return 0;
115 
116 free_iopfq:
117 	iopf_queue_free(iommu->iopf_queue);
118 	iommu->iopf_queue = NULL;
119 free_hwirq:
120 	dmar_free_hwirq(irq);
121 	iommu->pr_irq = 0;
122 free_prq:
123 	free_pages((unsigned long)iommu->prq, PRQ_ORDER);
124 	iommu->prq = NULL;
125 
126 	return ret;
127 }
128 
129 int intel_svm_finish_prq(struct intel_iommu *iommu)
130 {
131 	dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL);
132 	dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL);
133 	dmar_writeq(iommu->reg + DMAR_PQA_REG, 0ULL);
134 
135 	if (iommu->pr_irq) {
136 		free_irq(iommu->pr_irq, iommu);
137 		dmar_free_hwirq(iommu->pr_irq);
138 		iommu->pr_irq = 0;
139 	}
140 
141 	if (iommu->iopf_queue) {
142 		iopf_queue_free(iommu->iopf_queue);
143 		iommu->iopf_queue = NULL;
144 	}
145 
146 	free_pages((unsigned long)iommu->prq, PRQ_ORDER);
147 	iommu->prq = NULL;
148 
149 	return 0;
150 }
151 
152 void intel_svm_check(struct intel_iommu *iommu)
153 {
154 	if (!pasid_supported(iommu))
155 		return;
156 
157 	if (cpu_feature_enabled(X86_FEATURE_GBPAGES) &&
158 	    !cap_fl1gp_support(iommu->cap)) {
159 		pr_err("%s SVM disabled, incompatible 1GB page capability\n",
160 		       iommu->name);
161 		return;
162 	}
163 
164 	if (cpu_feature_enabled(X86_FEATURE_LA57) &&
165 	    !cap_fl5lp_support(iommu->cap)) {
166 		pr_err("%s SVM disabled, incompatible paging mode\n",
167 		       iommu->name);
168 		return;
169 	}
170 
171 	iommu->flags |= VTD_FLAG_SVM_CAPABLE;
172 }
173 
174 static void __flush_svm_range_dev(struct intel_svm *svm,
175 				  struct intel_svm_dev *sdev,
176 				  unsigned long address,
177 				  unsigned long pages, int ih)
178 {
179 	struct device_domain_info *info = dev_iommu_priv_get(sdev->dev);
180 
181 	if (WARN_ON(!pages))
182 		return;
183 
184 	qi_flush_piotlb(sdev->iommu, sdev->did, svm->pasid, address, pages, ih);
185 	if (info->ats_enabled) {
186 		qi_flush_dev_iotlb_pasid(sdev->iommu, sdev->sid, info->pfsid,
187 					 svm->pasid, sdev->qdep, address,
188 					 order_base_2(pages));
189 		quirk_extra_dev_tlb_flush(info, address, order_base_2(pages),
190 					  svm->pasid, sdev->qdep);
191 	}
192 }
193 
194 static void intel_flush_svm_range_dev(struct intel_svm *svm,
195 				      struct intel_svm_dev *sdev,
196 				      unsigned long address,
197 				      unsigned long pages, int ih)
198 {
199 	unsigned long shift = ilog2(__roundup_pow_of_two(pages));
200 	unsigned long align = (1ULL << (VTD_PAGE_SHIFT + shift));
201 	unsigned long start = ALIGN_DOWN(address, align);
202 	unsigned long end = ALIGN(address + (pages << VTD_PAGE_SHIFT), align);
203 
204 	while (start < end) {
205 		__flush_svm_range_dev(svm, sdev, start, align >> VTD_PAGE_SHIFT, ih);
206 		start += align;
207 	}
208 }
209 
210 static void intel_flush_svm_range(struct intel_svm *svm, unsigned long address,
211 				unsigned long pages, int ih)
212 {
213 	struct intel_svm_dev *sdev;
214 
215 	rcu_read_lock();
216 	list_for_each_entry_rcu(sdev, &svm->devs, list)
217 		intel_flush_svm_range_dev(svm, sdev, address, pages, ih);
218 	rcu_read_unlock();
219 }
220 
221 /* Pages have been freed at this point */
222 static void intel_invalidate_range(struct mmu_notifier *mn,
223 				   struct mm_struct *mm,
224 				   unsigned long start, unsigned long end)
225 {
226 	struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
227 
228 	intel_flush_svm_range(svm, start,
229 			      (end - start + PAGE_SIZE - 1) >> VTD_PAGE_SHIFT, 0);
230 }
231 
232 static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
233 {
234 	struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
235 	struct intel_svm_dev *sdev;
236 
237 	/* This might end up being called from exit_mmap(), *before* the page
238 	 * tables are cleared. And __mmu_notifier_release() will delete us from
239 	 * the list of notifiers so that our invalidate_range() callback doesn't
240 	 * get called when the page tables are cleared. So we need to protect
241 	 * against hardware accessing those page tables.
242 	 *
243 	 * We do it by clearing the entry in the PASID table and then flushing
244 	 * the IOTLB and the PASID table caches. This might upset hardware;
245 	 * perhaps we'll want to point the PASID to a dummy PGD (like the zero
246 	 * page) so that we end up taking a fault that the hardware really
247 	 * *has* to handle gracefully without affecting other processes.
248 	 */
249 	rcu_read_lock();
250 	list_for_each_entry_rcu(sdev, &svm->devs, list)
251 		intel_pasid_tear_down_entry(sdev->iommu, sdev->dev,
252 					    svm->pasid, true);
253 	rcu_read_unlock();
254 
255 }
256 
257 static const struct mmu_notifier_ops intel_mmuops = {
258 	.release = intel_mm_release,
259 	.invalidate_range = intel_invalidate_range,
260 };
261 
262 static int pasid_to_svm_sdev(struct device *dev, unsigned int pasid,
263 			     struct intel_svm **rsvm,
264 			     struct intel_svm_dev **rsdev)
265 {
266 	struct intel_svm_dev *sdev = NULL;
267 	struct intel_svm *svm;
268 
269 	if (pasid == IOMMU_PASID_INVALID || pasid >= PASID_MAX)
270 		return -EINVAL;
271 
272 	svm = pasid_private_find(pasid);
273 	if (IS_ERR(svm))
274 		return PTR_ERR(svm);
275 
276 	if (!svm)
277 		goto out;
278 
279 	/*
280 	 * If we found svm for the PASID, there must be at least one device
281 	 * bond.
282 	 */
283 	if (WARN_ON(list_empty(&svm->devs)))
284 		return -EINVAL;
285 	sdev = svm_lookup_device_by_dev(svm, dev);
286 
287 out:
288 	*rsvm = svm;
289 	*rsdev = sdev;
290 
291 	return 0;
292 }
293 
294 static int intel_svm_bind_mm(struct intel_iommu *iommu, struct device *dev,
295 			     struct mm_struct *mm)
296 {
297 	struct device_domain_info *info = dev_iommu_priv_get(dev);
298 	struct intel_svm_dev *sdev;
299 	struct intel_svm *svm;
300 	unsigned long sflags;
301 	int ret = 0;
302 
303 	svm = pasid_private_find(mm->pasid);
304 	if (!svm) {
305 		svm = kzalloc(sizeof(*svm), GFP_KERNEL);
306 		if (!svm)
307 			return -ENOMEM;
308 
309 		svm->pasid = mm->pasid;
310 		svm->mm = mm;
311 		INIT_LIST_HEAD_RCU(&svm->devs);
312 
313 		svm->notifier.ops = &intel_mmuops;
314 		ret = mmu_notifier_register(&svm->notifier, mm);
315 		if (ret) {
316 			kfree(svm);
317 			return ret;
318 		}
319 
320 		ret = pasid_private_add(svm->pasid, svm);
321 		if (ret) {
322 			mmu_notifier_unregister(&svm->notifier, mm);
323 			kfree(svm);
324 			return ret;
325 		}
326 	}
327 
328 	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
329 	if (!sdev) {
330 		ret = -ENOMEM;
331 		goto free_svm;
332 	}
333 
334 	sdev->dev = dev;
335 	sdev->iommu = iommu;
336 	sdev->did = FLPT_DEFAULT_DID;
337 	sdev->sid = PCI_DEVID(info->bus, info->devfn);
338 	init_rcu_head(&sdev->rcu);
339 	if (info->ats_enabled) {
340 		sdev->qdep = info->ats_qdep;
341 		if (sdev->qdep >= QI_DEV_EIOTLB_MAX_INVS)
342 			sdev->qdep = 0;
343 	}
344 
345 	/* Setup the pasid table: */
346 	sflags = cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0;
347 	ret = intel_pasid_setup_first_level(iommu, dev, mm->pgd, mm->pasid,
348 					    FLPT_DEFAULT_DID, sflags);
349 	if (ret)
350 		goto free_sdev;
351 
352 	list_add_rcu(&sdev->list, &svm->devs);
353 
354 	return 0;
355 
356 free_sdev:
357 	kfree(sdev);
358 free_svm:
359 	if (list_empty(&svm->devs)) {
360 		mmu_notifier_unregister(&svm->notifier, mm);
361 		pasid_private_remove(mm->pasid);
362 		kfree(svm);
363 	}
364 
365 	return ret;
366 }
367 
368 void intel_svm_remove_dev_pasid(struct device *dev, u32 pasid)
369 {
370 	struct intel_svm_dev *sdev;
371 	struct intel_iommu *iommu;
372 	struct intel_svm *svm;
373 	struct mm_struct *mm;
374 
375 	iommu = device_to_iommu(dev, NULL, NULL);
376 	if (!iommu)
377 		return;
378 
379 	if (pasid_to_svm_sdev(dev, pasid, &svm, &sdev))
380 		return;
381 	mm = svm->mm;
382 
383 	if (sdev) {
384 		list_del_rcu(&sdev->list);
385 		/*
386 		 * Flush the PASID cache and IOTLB for this device.
387 		 * Note that we do depend on the hardware *not* using
388 		 * the PASID any more. Just as we depend on other
389 		 * devices never using PASIDs that they have no right
390 		 * to use. We have a *shared* PASID table, because it's
391 		 * large and has to be physically contiguous. So it's
392 		 * hard to be as defensive as we might like.
393 		 */
394 		intel_pasid_tear_down_entry(iommu, dev, svm->pasid, false);
395 		intel_svm_drain_prq(dev, svm->pasid);
396 		kfree_rcu(sdev, rcu);
397 
398 		if (list_empty(&svm->devs)) {
399 			if (svm->notifier.ops)
400 				mmu_notifier_unregister(&svm->notifier, mm);
401 			pasid_private_remove(svm->pasid);
402 			/*
403 			 * We mandate that no page faults may be outstanding
404 			 * for the PASID when intel_svm_unbind_mm() is called.
405 			 * If that is not obeyed, subtle errors will happen.
406 			 * Let's make them less subtle...
407 			 */
408 			memset(svm, 0x6b, sizeof(*svm));
409 			kfree(svm);
410 		}
411 	}
412 }
413 
414 /* Page request queue descriptor */
415 struct page_req_dsc {
416 	union {
417 		struct {
418 			u64 type:8;
419 			u64 pasid_present:1;
420 			u64 priv_data_present:1;
421 			u64 rsvd:6;
422 			u64 rid:16;
423 			u64 pasid:20;
424 			u64 exe_req:1;
425 			u64 pm_req:1;
426 			u64 rsvd2:10;
427 		};
428 		u64 qw_0;
429 	};
430 	union {
431 		struct {
432 			u64 rd_req:1;
433 			u64 wr_req:1;
434 			u64 lpig:1;
435 			u64 prg_index:9;
436 			u64 addr:52;
437 		};
438 		u64 qw_1;
439 	};
440 	u64 priv_data[2];
441 };
442 
443 static bool is_canonical_address(u64 addr)
444 {
445 	int shift = 64 - (__VIRTUAL_MASK_SHIFT + 1);
446 	long saddr = (long) addr;
447 
448 	return (((saddr << shift) >> shift) == saddr);
449 }
450 
451 /**
452  * intel_svm_drain_prq - Drain page requests and responses for a pasid
453  * @dev: target device
454  * @pasid: pasid for draining
455  *
456  * Drain all pending page requests and responses related to @pasid in both
457  * software and hardware. This is supposed to be called after the device
458  * driver has stopped DMA, the pasid entry has been cleared, and both IOTLB
459  * and DevTLB have been invalidated.
460  *
461  * It waits until all pending page requests for @pasid in the page fault
462  * queue are completed by the prq handling thread. Then follow the steps
463  * described in VT-d spec CH7.10 to drain all page requests and page
464  * responses pending in the hardware.
465  */
466 static void intel_svm_drain_prq(struct device *dev, u32 pasid)
467 {
468 	struct device_domain_info *info;
469 	struct dmar_domain *domain;
470 	struct intel_iommu *iommu;
471 	struct qi_desc desc[3];
472 	struct pci_dev *pdev;
473 	int head, tail;
474 	u16 sid, did;
475 	int qdep;
476 
477 	info = dev_iommu_priv_get(dev);
478 	if (WARN_ON(!info || !dev_is_pci(dev)))
479 		return;
480 
481 	if (!info->pri_enabled)
482 		return;
483 
484 	iommu = info->iommu;
485 	domain = info->domain;
486 	pdev = to_pci_dev(dev);
487 	sid = PCI_DEVID(info->bus, info->devfn);
488 	did = domain_id_iommu(domain, iommu);
489 	qdep = pci_ats_queue_depth(pdev);
490 
491 	/*
492 	 * Check and wait until all pending page requests in the queue are
493 	 * handled by the prq handling thread.
494 	 */
495 prq_retry:
496 	reinit_completion(&iommu->prq_complete);
497 	tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
498 	head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
499 	while (head != tail) {
500 		struct page_req_dsc *req;
501 
502 		req = &iommu->prq[head / sizeof(*req)];
503 		if (!req->pasid_present || req->pasid != pasid) {
504 			head = (head + sizeof(*req)) & PRQ_RING_MASK;
505 			continue;
506 		}
507 
508 		wait_for_completion(&iommu->prq_complete);
509 		goto prq_retry;
510 	}
511 
512 	iopf_queue_flush_dev(dev);
513 
514 	/*
515 	 * Perform steps described in VT-d spec CH7.10 to drain page
516 	 * requests and responses in hardware.
517 	 */
518 	memset(desc, 0, sizeof(desc));
519 	desc[0].qw0 = QI_IWD_STATUS_DATA(QI_DONE) |
520 			QI_IWD_FENCE |
521 			QI_IWD_TYPE;
522 	desc[1].qw0 = QI_EIOTLB_PASID(pasid) |
523 			QI_EIOTLB_DID(did) |
524 			QI_EIOTLB_GRAN(QI_GRAN_NONG_PASID) |
525 			QI_EIOTLB_TYPE;
526 	desc[2].qw0 = QI_DEV_EIOTLB_PASID(pasid) |
527 			QI_DEV_EIOTLB_SID(sid) |
528 			QI_DEV_EIOTLB_QDEP(qdep) |
529 			QI_DEIOTLB_TYPE |
530 			QI_DEV_IOTLB_PFSID(info->pfsid);
531 qi_retry:
532 	reinit_completion(&iommu->prq_complete);
533 	qi_submit_sync(iommu, desc, 3, QI_OPT_WAIT_DRAIN);
534 	if (readl(iommu->reg + DMAR_PRS_REG) & DMA_PRS_PRO) {
535 		wait_for_completion(&iommu->prq_complete);
536 		goto qi_retry;
537 	}
538 }
539 
540 static int prq_to_iommu_prot(struct page_req_dsc *req)
541 {
542 	int prot = 0;
543 
544 	if (req->rd_req)
545 		prot |= IOMMU_FAULT_PERM_READ;
546 	if (req->wr_req)
547 		prot |= IOMMU_FAULT_PERM_WRITE;
548 	if (req->exe_req)
549 		prot |= IOMMU_FAULT_PERM_EXEC;
550 	if (req->pm_req)
551 		prot |= IOMMU_FAULT_PERM_PRIV;
552 
553 	return prot;
554 }
555 
556 static int intel_svm_prq_report(struct intel_iommu *iommu, struct device *dev,
557 				struct page_req_dsc *desc)
558 {
559 	struct iommu_fault_event event;
560 
561 	if (!dev || !dev_is_pci(dev))
562 		return -ENODEV;
563 
564 	/* Fill in event data for device specific processing */
565 	memset(&event, 0, sizeof(struct iommu_fault_event));
566 	event.fault.type = IOMMU_FAULT_PAGE_REQ;
567 	event.fault.prm.addr = (u64)desc->addr << VTD_PAGE_SHIFT;
568 	event.fault.prm.pasid = desc->pasid;
569 	event.fault.prm.grpid = desc->prg_index;
570 	event.fault.prm.perm = prq_to_iommu_prot(desc);
571 
572 	if (desc->lpig)
573 		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
574 	if (desc->pasid_present) {
575 		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
576 		event.fault.prm.flags |= IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID;
577 	}
578 	if (desc->priv_data_present) {
579 		/*
580 		 * Set last page in group bit if private data is present,
581 		 * page response is required as it does for LPIG.
582 		 * iommu_report_device_fault() doesn't understand this vendor
583 		 * specific requirement thus we set last_page as a workaround.
584 		 */
585 		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
586 		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
587 		event.fault.prm.private_data[0] = desc->priv_data[0];
588 		event.fault.prm.private_data[1] = desc->priv_data[1];
589 	} else if (dmar_latency_enabled(iommu, DMAR_LATENCY_PRQ)) {
590 		/*
591 		 * If the private data fields are not used by hardware, use it
592 		 * to monitor the prq handle latency.
593 		 */
594 		event.fault.prm.private_data[0] = ktime_to_ns(ktime_get());
595 	}
596 
597 	return iommu_report_device_fault(dev, &event);
598 }
599 
600 static void handle_bad_prq_event(struct intel_iommu *iommu,
601 				 struct page_req_dsc *req, int result)
602 {
603 	struct qi_desc desc;
604 
605 	pr_err("%s: Invalid page request: %08llx %08llx\n",
606 	       iommu->name, ((unsigned long long *)req)[0],
607 	       ((unsigned long long *)req)[1]);
608 
609 	/*
610 	 * Per VT-d spec. v3.0 ch7.7, system software must
611 	 * respond with page group response if private data
612 	 * is present (PDP) or last page in group (LPIG) bit
613 	 * is set. This is an additional VT-d feature beyond
614 	 * PCI ATS spec.
615 	 */
616 	if (!req->lpig && !req->priv_data_present)
617 		return;
618 
619 	desc.qw0 = QI_PGRP_PASID(req->pasid) |
620 			QI_PGRP_DID(req->rid) |
621 			QI_PGRP_PASID_P(req->pasid_present) |
622 			QI_PGRP_PDP(req->priv_data_present) |
623 			QI_PGRP_RESP_CODE(result) |
624 			QI_PGRP_RESP_TYPE;
625 	desc.qw1 = QI_PGRP_IDX(req->prg_index) |
626 			QI_PGRP_LPIG(req->lpig);
627 
628 	if (req->priv_data_present) {
629 		desc.qw2 = req->priv_data[0];
630 		desc.qw3 = req->priv_data[1];
631 	} else {
632 		desc.qw2 = 0;
633 		desc.qw3 = 0;
634 	}
635 
636 	qi_submit_sync(iommu, &desc, 1, 0);
637 }
638 
639 static irqreturn_t prq_event_thread(int irq, void *d)
640 {
641 	struct intel_iommu *iommu = d;
642 	struct page_req_dsc *req;
643 	int head, tail, handled;
644 	struct pci_dev *pdev;
645 	u64 address;
646 
647 	/*
648 	 * Clear PPR bit before reading head/tail registers, to ensure that
649 	 * we get a new interrupt if needed.
650 	 */
651 	writel(DMA_PRS_PPR, iommu->reg + DMAR_PRS_REG);
652 
653 	tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
654 	head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
655 	handled = (head != tail);
656 	while (head != tail) {
657 		req = &iommu->prq[head / sizeof(*req)];
658 		address = (u64)req->addr << VTD_PAGE_SHIFT;
659 
660 		if (unlikely(!req->pasid_present)) {
661 			pr_err("IOMMU: %s: Page request without PASID\n",
662 			       iommu->name);
663 bad_req:
664 			handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
665 			goto prq_advance;
666 		}
667 
668 		if (unlikely(!is_canonical_address(address))) {
669 			pr_err("IOMMU: %s: Address is not canonical\n",
670 			       iommu->name);
671 			goto bad_req;
672 		}
673 
674 		if (unlikely(req->pm_req && (req->rd_req | req->wr_req))) {
675 			pr_err("IOMMU: %s: Page request in Privilege Mode\n",
676 			       iommu->name);
677 			goto bad_req;
678 		}
679 
680 		if (unlikely(req->exe_req && req->rd_req)) {
681 			pr_err("IOMMU: %s: Execution request not supported\n",
682 			       iommu->name);
683 			goto bad_req;
684 		}
685 
686 		/* Drop Stop Marker message. No need for a response. */
687 		if (unlikely(req->lpig && !req->rd_req && !req->wr_req))
688 			goto prq_advance;
689 
690 		pdev = pci_get_domain_bus_and_slot(iommu->segment,
691 						   PCI_BUS_NUM(req->rid),
692 						   req->rid & 0xff);
693 		/*
694 		 * If prq is to be handled outside iommu driver via receiver of
695 		 * the fault notifiers, we skip the page response here.
696 		 */
697 		if (!pdev)
698 			goto bad_req;
699 
700 		if (intel_svm_prq_report(iommu, &pdev->dev, req))
701 			handle_bad_prq_event(iommu, req, QI_RESP_INVALID);
702 		else
703 			trace_prq_report(iommu, &pdev->dev, req->qw_0, req->qw_1,
704 					 req->priv_data[0], req->priv_data[1],
705 					 iommu->prq_seq_number++);
706 		pci_dev_put(pdev);
707 prq_advance:
708 		head = (head + sizeof(*req)) & PRQ_RING_MASK;
709 	}
710 
711 	dmar_writeq(iommu->reg + DMAR_PQH_REG, tail);
712 
713 	/*
714 	 * Clear the page request overflow bit and wake up all threads that
715 	 * are waiting for the completion of this handling.
716 	 */
717 	if (readl(iommu->reg + DMAR_PRS_REG) & DMA_PRS_PRO) {
718 		pr_info_ratelimited("IOMMU: %s: PRQ overflow detected\n",
719 				    iommu->name);
720 		head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
721 		tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
722 		if (head == tail) {
723 			iopf_queue_discard_partial(iommu->iopf_queue);
724 			writel(DMA_PRS_PRO, iommu->reg + DMAR_PRS_REG);
725 			pr_info_ratelimited("IOMMU: %s: PRQ overflow cleared",
726 					    iommu->name);
727 		}
728 	}
729 
730 	if (!completion_done(&iommu->prq_complete))
731 		complete(&iommu->prq_complete);
732 
733 	return IRQ_RETVAL(handled);
734 }
735 
736 int intel_svm_page_response(struct device *dev,
737 			    struct iommu_fault_event *evt,
738 			    struct iommu_page_response *msg)
739 {
740 	struct iommu_fault_page_request *prm;
741 	struct intel_iommu *iommu;
742 	bool private_present;
743 	bool pasid_present;
744 	bool last_page;
745 	u8 bus, devfn;
746 	int ret = 0;
747 	u16 sid;
748 
749 	if (!dev || !dev_is_pci(dev))
750 		return -ENODEV;
751 
752 	iommu = device_to_iommu(dev, &bus, &devfn);
753 	if (!iommu)
754 		return -ENODEV;
755 
756 	if (!msg || !evt)
757 		return -EINVAL;
758 
759 	prm = &evt->fault.prm;
760 	sid = PCI_DEVID(bus, devfn);
761 	pasid_present = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
762 	private_present = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
763 	last_page = prm->flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
764 
765 	if (!pasid_present) {
766 		ret = -EINVAL;
767 		goto out;
768 	}
769 
770 	if (prm->pasid == 0 || prm->pasid >= PASID_MAX) {
771 		ret = -EINVAL;
772 		goto out;
773 	}
774 
775 	/*
776 	 * Per VT-d spec. v3.0 ch7.7, system software must respond
777 	 * with page group response if private data is present (PDP)
778 	 * or last page in group (LPIG) bit is set. This is an
779 	 * additional VT-d requirement beyond PCI ATS spec.
780 	 */
781 	if (last_page || private_present) {
782 		struct qi_desc desc;
783 
784 		desc.qw0 = QI_PGRP_PASID(prm->pasid) | QI_PGRP_DID(sid) |
785 				QI_PGRP_PASID_P(pasid_present) |
786 				QI_PGRP_PDP(private_present) |
787 				QI_PGRP_RESP_CODE(msg->code) |
788 				QI_PGRP_RESP_TYPE;
789 		desc.qw1 = QI_PGRP_IDX(prm->grpid) | QI_PGRP_LPIG(last_page);
790 		desc.qw2 = 0;
791 		desc.qw3 = 0;
792 
793 		if (private_present) {
794 			desc.qw2 = prm->private_data[0];
795 			desc.qw3 = prm->private_data[1];
796 		} else if (prm->private_data[0]) {
797 			dmar_latency_update(iommu, DMAR_LATENCY_PRQ,
798 				ktime_to_ns(ktime_get()) - prm->private_data[0]);
799 		}
800 
801 		qi_submit_sync(iommu, &desc, 1, 0);
802 	}
803 out:
804 	return ret;
805 }
806 
807 static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
808 				   struct device *dev, ioasid_t pasid)
809 {
810 	struct device_domain_info *info = dev_iommu_priv_get(dev);
811 	struct intel_iommu *iommu = info->iommu;
812 	struct mm_struct *mm = domain->mm;
813 
814 	return intel_svm_bind_mm(iommu, dev, mm);
815 }
816 
817 static void intel_svm_domain_free(struct iommu_domain *domain)
818 {
819 	kfree(to_dmar_domain(domain));
820 }
821 
822 static const struct iommu_domain_ops intel_svm_domain_ops = {
823 	.set_dev_pasid		= intel_svm_set_dev_pasid,
824 	.free			= intel_svm_domain_free
825 };
826 
827 struct iommu_domain *intel_svm_domain_alloc(void)
828 {
829 	struct dmar_domain *domain;
830 
831 	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
832 	if (!domain)
833 		return NULL;
834 	domain->domain.ops = &intel_svm_domain_ops;
835 
836 	return &domain->domain;
837 }
838