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  1/*
  2 * Copyright 2018 Red Hat Inc.
  3 *
  4 * Permission is hereby granted, free of charge, to any person obtaining a
  5 * copy of this software and associated documentation files (the "Software"),
  6 * to deal in the Software without restriction, including without limitation
  7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  8 * and/or sell copies of the Software, and to permit persons to whom the
  9 * Software is furnished to do so, subject to the following conditions:
 10 *
 11 * The above copyright notice and this permission notice shall be included in
 12 * all copies or substantial portions of the Software.
 13 *
 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 20 * OTHER DEALINGS IN THE SOFTWARE.
 21 */
 22#include "nouveau_svm.h"
 23#include "nouveau_drv.h"
 24#include "nouveau_chan.h"
 25#include "nouveau_dmem.h"
 26
 27#include <nvif/notify.h>
 28#include <nvif/object.h>
 29#include <nvif/vmm.h>
 30
 31#include <nvif/class.h>
 32#include <nvif/clb069.h>
 33#include <nvif/ifc00d.h>
 34
 35#include <linux/sched/mm.h>
 36#include <linux/sort.h>
 37#include <linux/hmm.h>
 38
 39struct nouveau_svm {
 40	struct nouveau_drm *drm;
 41	struct mutex mutex;
 42	struct list_head inst;
 43
 44	struct nouveau_svm_fault_buffer {
 45		int id;
 46		struct nvif_object object;
 47		u32 entries;
 48		u32 getaddr;
 49		u32 putaddr;
 50		u32 get;
 51		u32 put;
 52		struct nvif_notify notify;
 53
 54		struct nouveau_svm_fault {
 55			u64 inst;
 56			u64 addr;
 57			u64 time;
 58			u32 engine;
 59			u8  gpc;
 60			u8  hub;
 61			u8  access;
 62			u8  client;
 63			u8  fault;
 64			struct nouveau_svmm *svmm;
 65		} **fault;
 66		int fault_nr;
 67	} buffer[1];
 68};
 69
 70#define SVM_DBG(s,f,a...) NV_DEBUG((s)->drm, "svm: "f"\n", ##a)
 71#define SVM_ERR(s,f,a...) NV_WARN((s)->drm, "svm: "f"\n", ##a)
 72
 73struct nouveau_ivmm {
 74	struct nouveau_svmm *svmm;
 75	u64 inst;
 76	struct list_head head;
 77};
 78
 79static struct nouveau_ivmm *
 80nouveau_ivmm_find(struct nouveau_svm *svm, u64 inst)
 81{
 82	struct nouveau_ivmm *ivmm;
 83	list_for_each_entry(ivmm, &svm->inst, head) {
 84		if (ivmm->inst == inst)
 85			return ivmm;
 86	}
 87	return NULL;
 88}
 89
 90struct nouveau_svmm {
 91	struct nouveau_vmm *vmm;
 92	struct {
 93		unsigned long start;
 94		unsigned long limit;
 95	} unmanaged;
 96
 97	struct mutex mutex;
 98
 99	struct mm_struct *mm;
100	struct hmm_mirror mirror;
101};
102
103#define SVMM_DBG(s,f,a...)                                                     \
104	NV_DEBUG((s)->vmm->cli->drm, "svm-%p: "f"\n", (s), ##a)
105#define SVMM_ERR(s,f,a...)                                                     \
106	NV_WARN((s)->vmm->cli->drm, "svm-%p: "f"\n", (s), ##a)
107
108int
109nouveau_svmm_bind(struct drm_device *dev, void *data,
110		  struct drm_file *file_priv)
111{
112	struct nouveau_cli *cli = nouveau_cli(file_priv);
113	struct drm_nouveau_svm_bind *args = data;
114	unsigned target, cmd, priority;
115	unsigned long addr, end, size;
116	struct mm_struct *mm;
117
118	args->va_start &= PAGE_MASK;
119	args->va_end &= PAGE_MASK;
120
121	/* Sanity check arguments */
122	if (args->reserved0 || args->reserved1)
123		return -EINVAL;
124	if (args->header & (~NOUVEAU_SVM_BIND_VALID_MASK))
125		return -EINVAL;
126	if (args->va_start >= args->va_end)
127		return -EINVAL;
128	if (!args->npages)
129		return -EINVAL;
130
131	cmd = args->header >> NOUVEAU_SVM_BIND_COMMAND_SHIFT;
132	cmd &= NOUVEAU_SVM_BIND_COMMAND_MASK;
133	switch (cmd) {
134	case NOUVEAU_SVM_BIND_COMMAND__MIGRATE:
135		break;
136	default:
137		return -EINVAL;
138	}
139
140	priority = args->header >> NOUVEAU_SVM_BIND_PRIORITY_SHIFT;
141	priority &= NOUVEAU_SVM_BIND_PRIORITY_MASK;
142
143	/* FIXME support CPU target ie all target value < GPU_VRAM */
144	target = args->header >> NOUVEAU_SVM_BIND_TARGET_SHIFT;
145	target &= NOUVEAU_SVM_BIND_TARGET_MASK;
146	switch (target) {
147	case NOUVEAU_SVM_BIND_TARGET__GPU_VRAM:
148		break;
149	default:
150		return -EINVAL;
151	}
152
153	/*
154	 * FIXME: For now refuse non 0 stride, we need to change the migrate
155	 * kernel function to handle stride to avoid to create a mess within
156	 * each device driver.
157	 */
158	if (args->stride)
159		return -EINVAL;
160
161	size = ((unsigned long)args->npages) << PAGE_SHIFT;
162	if ((args->va_start + size) <= args->va_start)
163		return -EINVAL;
164	if ((args->va_start + size) > args->va_end)
165		return -EINVAL;
166
167	/*
168	 * Ok we are ask to do something sane, for now we only support migrate
169	 * commands but we will add things like memory policy (what to do on
170	 * page fault) and maybe some other commands.
171	 */
172
173	mm = get_task_mm(current);
174	down_read(&mm->mmap_sem);
175
176	for (addr = args->va_start, end = args->va_start + size; addr < end;) {
177		struct vm_area_struct *vma;
178		unsigned long next;
179
180		vma = find_vma_intersection(mm, addr, end);
181		if (!vma)
182			break;
183
184		next = min(vma->vm_end, end);
185		/* This is a best effort so we ignore errors */
186		nouveau_dmem_migrate_vma(cli->drm, vma, addr, next);
187		addr = next;
188	}
189
190	/*
191	 * FIXME Return the number of page we have migrated, again we need to
192	 * update the migrate API to return that information so that we can
193	 * report it to user space.
194	 */
195	args->result = 0;
196
197	up_read(&mm->mmap_sem);
198	mmput(mm);
199
200	return 0;
201}
202
203/* Unlink channel instance from SVMM. */
204void
205nouveau_svmm_part(struct nouveau_svmm *svmm, u64 inst)
206{
207	struct nouveau_ivmm *ivmm;
208	if (svmm) {
209		mutex_lock(&svmm->vmm->cli->drm->svm->mutex);
210		ivmm = nouveau_ivmm_find(svmm->vmm->cli->drm->svm, inst);
211		if (ivmm) {
212			list_del(&ivmm->head);
213			kfree(ivmm);
214		}
215		mutex_unlock(&svmm->vmm->cli->drm->svm->mutex);
216	}
217}
218
219/* Link channel instance to SVMM. */
220int
221nouveau_svmm_join(struct nouveau_svmm *svmm, u64 inst)
222{
223	struct nouveau_ivmm *ivmm;
224	if (svmm) {
225		if (!(ivmm = kmalloc(sizeof(*ivmm), GFP_KERNEL)))
226			return -ENOMEM;
227		ivmm->svmm = svmm;
228		ivmm->inst = inst;
229
230		mutex_lock(&svmm->vmm->cli->drm->svm->mutex);
231		list_add(&ivmm->head, &svmm->vmm->cli->drm->svm->inst);
232		mutex_unlock(&svmm->vmm->cli->drm->svm->mutex);
233	}
234	return 0;
235}
236
237/* Invalidate SVMM address-range on GPU. */
238static void
239nouveau_svmm_invalidate(struct nouveau_svmm *svmm, u64 start, u64 limit)
240{
241	if (limit > start) {
242		bool super = svmm->vmm->vmm.object.client->super;
243		svmm->vmm->vmm.object.client->super = true;
244		nvif_object_mthd(&svmm->vmm->vmm.object, NVIF_VMM_V0_PFNCLR,
245				 &(struct nvif_vmm_pfnclr_v0) {
246					.addr = start,
247					.size = limit - start,
248				 }, sizeof(struct nvif_vmm_pfnclr_v0));
249		svmm->vmm->vmm.object.client->super = super;
250	}
251}
252
253static int
254nouveau_svmm_sync_cpu_device_pagetables(struct hmm_mirror *mirror,
255					const struct mmu_notifier_range *update)
256{
257	struct nouveau_svmm *svmm = container_of(mirror, typeof(*svmm), mirror);
258	unsigned long start = update->start;
259	unsigned long limit = update->end;
260
261	if (!mmu_notifier_range_blockable(update))
262		return -EAGAIN;
263
264	SVMM_DBG(svmm, "invalidate %016lx-%016lx", start, limit);
265
266	mutex_lock(&svmm->mutex);
267	if (limit > svmm->unmanaged.start && start < svmm->unmanaged.limit) {
268		if (start < svmm->unmanaged.start) {
269			nouveau_svmm_invalidate(svmm, start,
270						svmm->unmanaged.limit);
271		}
272		start = svmm->unmanaged.limit;
273	}
274
275	nouveau_svmm_invalidate(svmm, start, limit);
276	mutex_unlock(&svmm->mutex);
277	return 0;
278}
279
280static void
281nouveau_svmm_release(struct hmm_mirror *mirror)
282{
283}
284
285static const struct hmm_mirror_ops
286nouveau_svmm = {
287	.sync_cpu_device_pagetables = nouveau_svmm_sync_cpu_device_pagetables,
288	.release = nouveau_svmm_release,
289};
290
291void
292nouveau_svmm_fini(struct nouveau_svmm **psvmm)
293{
294	struct nouveau_svmm *svmm = *psvmm;
295	if (svmm) {
296		hmm_mirror_unregister(&svmm->mirror);
297		kfree(*psvmm);
298		*psvmm = NULL;
299	}
300}
301
302int
303nouveau_svmm_init(struct drm_device *dev, void *data,
304		  struct drm_file *file_priv)
305{
306	struct nouveau_cli *cli = nouveau_cli(file_priv);
307	struct nouveau_svmm *svmm;
308	struct drm_nouveau_svm_init *args = data;
309	int ret;
310
311	/* Allocate tracking for SVM-enabled VMM. */
312	if (!(svmm = kzalloc(sizeof(*svmm), GFP_KERNEL)))
313		return -ENOMEM;
314	svmm->vmm = &cli->svm;
315	svmm->unmanaged.start = args->unmanaged_addr;
316	svmm->unmanaged.limit = args->unmanaged_addr + args->unmanaged_size;
317	mutex_init(&svmm->mutex);
318
319	/* Check that SVM isn't already enabled for the client. */
320	mutex_lock(&cli->mutex);
321	if (cli->svm.cli) {
322		ret = -EBUSY;
323		goto done;
324	}
325
326	/* Allocate a new GPU VMM that can support SVM (managed by the
327	 * client, with replayable faults enabled).
328	 *
329	 * All future channel/memory allocations will make use of this
330	 * VMM instead of the standard one.
331	 */
332	ret = nvif_vmm_init(&cli->mmu, cli->vmm.vmm.object.oclass, true,
333			    args->unmanaged_addr, args->unmanaged_size,
334			    &(struct gp100_vmm_v0) {
335				.fault_replay = true,
336			    }, sizeof(struct gp100_vmm_v0), &cli->svm.vmm);
337	if (ret)
338		goto done;
339
340	/* Enable HMM mirroring of CPU address-space to VMM. */
341	svmm->mm = get_task_mm(current);
342	down_write(&svmm->mm->mmap_sem);
343	svmm->mirror.ops = &nouveau_svmm;
344	ret = hmm_mirror_register(&svmm->mirror, svmm->mm);
345	if (ret == 0) {
346		cli->svm.svmm = svmm;
347		cli->svm.cli = cli;
348	}
349	up_write(&svmm->mm->mmap_sem);
350	mmput(svmm->mm);
351
352done:
353	if (ret)
354		nouveau_svmm_fini(&svmm);
355	mutex_unlock(&cli->mutex);
356	return ret;
357}
358
359static const u64
360nouveau_svm_pfn_flags[HMM_PFN_FLAG_MAX] = {
361	[HMM_PFN_VALID         ] = NVIF_VMM_PFNMAP_V0_V,
362	[HMM_PFN_WRITE         ] = NVIF_VMM_PFNMAP_V0_W,
363	[HMM_PFN_DEVICE_PRIVATE] = NVIF_VMM_PFNMAP_V0_VRAM,
364};
365
366static const u64
367nouveau_svm_pfn_values[HMM_PFN_VALUE_MAX] = {
368	[HMM_PFN_ERROR  ] = ~NVIF_VMM_PFNMAP_V0_V,
369	[HMM_PFN_NONE   ] =  NVIF_VMM_PFNMAP_V0_NONE,
370	[HMM_PFN_SPECIAL] = ~NVIF_VMM_PFNMAP_V0_V,
371};
372
373/* Issue fault replay for GPU to retry accesses that faulted previously. */
374static void
375nouveau_svm_fault_replay(struct nouveau_svm *svm)
376{
377	SVM_DBG(svm, "replay");
378	WARN_ON(nvif_object_mthd(&svm->drm->client.vmm.vmm.object,
379				 GP100_VMM_VN_FAULT_REPLAY,
380				 &(struct gp100_vmm_fault_replay_vn) {},
381				 sizeof(struct gp100_vmm_fault_replay_vn)));
382}
383
384/* Cancel a replayable fault that could not be handled.
385 *
386 * Cancelling the fault will trigger recovery to reset the engine
387 * and kill the offending channel (ie. GPU SIGSEGV).
388 */
389static void
390nouveau_svm_fault_cancel(struct nouveau_svm *svm,
391			 u64 inst, u8 hub, u8 gpc, u8 client)
392{
393	SVM_DBG(svm, "cancel %016llx %d %02x %02x", inst, hub, gpc, client);
394	WARN_ON(nvif_object_mthd(&svm->drm->client.vmm.vmm.object,
395				 GP100_VMM_VN_FAULT_CANCEL,
396				 &(struct gp100_vmm_fault_cancel_v0) {
397					.hub = hub,
398					.gpc = gpc,
399					.client = client,
400					.inst = inst,
401				 }, sizeof(struct gp100_vmm_fault_cancel_v0)));
402}
403
404static void
405nouveau_svm_fault_cancel_fault(struct nouveau_svm *svm,
406			       struct nouveau_svm_fault *fault)
407{
408	nouveau_svm_fault_cancel(svm, fault->inst,
409				      fault->hub,
410				      fault->gpc,
411				      fault->client);
412}
413
414static int
415nouveau_svm_fault_cmp(const void *a, const void *b)
416{
417	const struct nouveau_svm_fault *fa = *(struct nouveau_svm_fault **)a;
418	const struct nouveau_svm_fault *fb = *(struct nouveau_svm_fault **)b;
419	int ret;
420	if ((ret = (s64)fa->inst - fb->inst))
421		return ret;
422	if ((ret = (s64)fa->addr - fb->addr))
423		return ret;
424	/*XXX: atomic? */
425	return (fa->access == 0 || fa->access == 3) -
426	       (fb->access == 0 || fb->access == 3);
427}
428
429static void
430nouveau_svm_fault_cache(struct nouveau_svm *svm,
431			struct nouveau_svm_fault_buffer *buffer, u32 offset)
432{
433	struct nvif_object *memory = &buffer->object;
434	const u32 instlo = nvif_rd32(memory, offset + 0x00);
435	const u32 insthi = nvif_rd32(memory, offset + 0x04);
436	const u32 addrlo = nvif_rd32(memory, offset + 0x08);
437	const u32 addrhi = nvif_rd32(memory, offset + 0x0c);
438	const u32 timelo = nvif_rd32(memory, offset + 0x10);
439	const u32 timehi = nvif_rd32(memory, offset + 0x14);
440	const u32 engine = nvif_rd32(memory, offset + 0x18);
441	const u32   info = nvif_rd32(memory, offset + 0x1c);
442	const u64   inst = (u64)insthi << 32 | instlo;
443	const u8     gpc = (info & 0x1f000000) >> 24;
444	const u8     hub = (info & 0x00100000) >> 20;
445	const u8  client = (info & 0x00007f00) >> 8;
446	struct nouveau_svm_fault *fault;
447
448	//XXX: i think we're supposed to spin waiting */
449	if (WARN_ON(!(info & 0x80000000)))
450		return;
451
452	nvif_mask(memory, offset + 0x1c, 0x80000000, 0x00000000);
453
454	if (!buffer->fault[buffer->fault_nr]) {
455		fault = kmalloc(sizeof(*fault), GFP_KERNEL);
456		if (WARN_ON(!fault)) {
457			nouveau_svm_fault_cancel(svm, inst, hub, gpc, client);
458			return;
459		}
460		buffer->fault[buffer->fault_nr] = fault;
461	}
462
463	fault = buffer->fault[buffer->fault_nr++];
464	fault->inst   = inst;
465	fault->addr   = (u64)addrhi << 32 | addrlo;
466	fault->time   = (u64)timehi << 32 | timelo;
467	fault->engine = engine;
468	fault->gpc    = gpc;
469	fault->hub    = hub;
470	fault->access = (info & 0x000f0000) >> 16;
471	fault->client = client;
472	fault->fault  = (info & 0x0000001f);
473
474	SVM_DBG(svm, "fault %016llx %016llx %02x",
475		fault->inst, fault->addr, fault->access);
476}
477
478static inline bool
479nouveau_range_done(struct hmm_range *range)
480{
481	bool ret = hmm_range_valid(range);
482
483	hmm_range_unregister(range);
484	return ret;
485}
486
487static int
488nouveau_range_fault(struct nouveau_svmm *svmm, struct hmm_range *range)
489{
490	long ret;
491
492	range->default_flags = 0;
493	range->pfn_flags_mask = -1UL;
494
495	ret = hmm_range_register(range, &svmm->mirror);
496	if (ret) {
497		up_read(&svmm->mm->mmap_sem);
498		return (int)ret;
499	}
500
501	if (!hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT)) {
502		up_read(&svmm->mm->mmap_sem);
503		return -EBUSY;
504	}
505
506	ret = hmm_range_fault(range, 0);
507	if (ret <= 0) {
508		if (ret == 0)
509			ret = -EBUSY;
510		up_read(&svmm->mm->mmap_sem);
511		hmm_range_unregister(range);
512		return ret;
513	}
514	return 0;
515}
516
517static int
518nouveau_svm_fault(struct nvif_notify *notify)
519{
520	struct nouveau_svm_fault_buffer *buffer =
521		container_of(notify, typeof(*buffer), notify);
522	struct nouveau_svm *svm =
523		container_of(buffer, typeof(*svm), buffer[buffer->id]);
524	struct nvif_object *device = &svm->drm->client.device.object;
525	struct nouveau_svmm *svmm;
526	struct {
527		struct {
528			struct nvif_ioctl_v0 i;
529			struct nvif_ioctl_mthd_v0 m;
530			struct nvif_vmm_pfnmap_v0 p;
531		} i;
532		u64 phys[16];
533	} args;
534	struct hmm_range range;
535	struct vm_area_struct *vma;
536	u64 inst, start, limit;
537	int fi, fn, pi, fill;
538	int replay = 0, ret;
539
540	/* Parse available fault buffer entries into a cache, and update
541	 * the GET pointer so HW can reuse the entries.
542	 */
543	SVM_DBG(svm, "fault handler");
544	if (buffer->get == buffer->put) {
545		buffer->put = nvif_rd32(device, buffer->putaddr);
546		buffer->get = nvif_rd32(device, buffer->getaddr);
547		if (buffer->get == buffer->put)
548			return NVIF_NOTIFY_KEEP;
549	}
550	buffer->fault_nr = 0;
551
552	SVM_DBG(svm, "get %08x put %08x", buffer->get, buffer->put);
553	while (buffer->get != buffer->put) {
554		nouveau_svm_fault_cache(svm, buffer, buffer->get * 0x20);
555		if (++buffer->get == buffer->entries)
556			buffer->get = 0;
557	}
558	nvif_wr32(device, buffer->getaddr, buffer->get);
559	SVM_DBG(svm, "%d fault(s) pending", buffer->fault_nr);
560
561	/* Sort parsed faults by instance pointer to prevent unnecessary
562	 * instance to SVMM translations, followed by address and access
563	 * type to reduce the amount of work when handling the faults.
564	 */
565	sort(buffer->fault, buffer->fault_nr, sizeof(*buffer->fault),
566	     nouveau_svm_fault_cmp, NULL);
567
568	/* Lookup SVMM structure for each unique instance pointer. */
569	mutex_lock(&svm->mutex);
570	for (fi = 0, svmm = NULL; fi < buffer->fault_nr; fi++) {
571		if (!svmm || buffer->fault[fi]->inst != inst) {
572			struct nouveau_ivmm *ivmm =
573				nouveau_ivmm_find(svm, buffer->fault[fi]->inst);
574			svmm = ivmm ? ivmm->svmm : NULL;
575			inst = buffer->fault[fi]->inst;
576			SVM_DBG(svm, "inst %016llx -> svm-%p", inst, svmm);
577		}
578		buffer->fault[fi]->svmm = svmm;
579	}
580	mutex_unlock(&svm->mutex);
581
582	/* Process list of faults. */
583	args.i.i.version = 0;
584	args.i.i.type = NVIF_IOCTL_V0_MTHD;
585	args.i.m.version = 0;
586	args.i.m.method = NVIF_VMM_V0_PFNMAP;
587	args.i.p.version = 0;
588
589	for (fi = 0; fn = fi + 1, fi < buffer->fault_nr; fi = fn) {
590		/* Cancel any faults from non-SVM channels. */
591		if (!(svmm = buffer->fault[fi]->svmm)) {
592			nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
593			continue;
594		}
595		SVMM_DBG(svmm, "addr %016llx", buffer->fault[fi]->addr);
596
597		/* We try and group handling of faults within a small
598		 * window into a single update.
599		 */
600		start = buffer->fault[fi]->addr;
601		limit = start + (ARRAY_SIZE(args.phys) << PAGE_SHIFT);
602		if (start < svmm->unmanaged.limit)
603			limit = min_t(u64, limit, svmm->unmanaged.start);
604		else
605		if (limit > svmm->unmanaged.start)
606			start = max_t(u64, start, svmm->unmanaged.limit);
607		SVMM_DBG(svmm, "wndw %016llx-%016llx", start, limit);
608
609		/* Intersect fault window with the CPU VMA, cancelling
610		 * the fault if the address is invalid.
611		 */
612		down_read(&svmm->mm->mmap_sem);
613		vma = find_vma_intersection(svmm->mm, start, limit);
614		if (!vma) {
615			SVMM_ERR(svmm, "wndw %016llx-%016llx", start, limit);
616			up_read(&svmm->mm->mmap_sem);
617			nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
618			continue;
619		}
620		start = max_t(u64, start, vma->vm_start);
621		limit = min_t(u64, limit, vma->vm_end);
622		SVMM_DBG(svmm, "wndw %016llx-%016llx", start, limit);
623
624		if (buffer->fault[fi]->addr != start) {
625			SVMM_ERR(svmm, "addr %016llx", buffer->fault[fi]->addr);
626			up_read(&svmm->mm->mmap_sem);
627			nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
628			continue;
629		}
630
631		/* Prepare the GPU-side update of all pages within the
632		 * fault window, determining required pages and access
633		 * permissions based on pending faults.
634		 */
635		args.i.p.page = PAGE_SHIFT;
636		args.i.p.addr = start;
637		for (fn = fi, pi = 0;;) {
638			/* Determine required permissions based on GPU fault
639			 * access flags.
640			 *XXX: atomic?
641			 */
642			if (buffer->fault[fn]->access != 0 /* READ. */ &&
643			    buffer->fault[fn]->access != 3 /* PREFETCH. */) {
644				args.phys[pi++] = NVIF_VMM_PFNMAP_V0_V |
645						  NVIF_VMM_PFNMAP_V0_W;
646			} else {
647				args.phys[pi++] = NVIF_VMM_PFNMAP_V0_V;
648			}
649			args.i.p.size = pi << PAGE_SHIFT;
650
651			/* It's okay to skip over duplicate addresses from the
652			 * same SVMM as faults are ordered by access type such
653			 * that only the first one needs to be handled.
654			 *
655			 * ie. WRITE faults appear first, thus any handling of
656			 * pending READ faults will already be satisfied.
657			 */
658			while (++fn < buffer->fault_nr &&
659			       buffer->fault[fn]->svmm == svmm &&
660			       buffer->fault[fn    ]->addr ==
661			       buffer->fault[fn - 1]->addr);
662
663			/* If the next fault is outside the window, or all GPU
664			 * faults have been dealt with, we're done here.
665			 */
666			if (fn >= buffer->fault_nr ||
667			    buffer->fault[fn]->svmm != svmm ||
668			    buffer->fault[fn]->addr >= limit)
669				break;
670
671			/* Fill in the gap between this fault and the next. */
672			fill = (buffer->fault[fn    ]->addr -
673				buffer->fault[fn - 1]->addr) >> PAGE_SHIFT;
674			while (--fill)
675				args.phys[pi++] = NVIF_VMM_PFNMAP_V0_NONE;
676		}
677
678		SVMM_DBG(svmm, "wndw %016llx-%016llx covering %d fault(s)",
679			 args.i.p.addr,
680			 args.i.p.addr + args.i.p.size, fn - fi);
681
682		/* Have HMM fault pages within the fault window to the GPU. */
683		range.start = args.i.p.addr;
684		range.end = args.i.p.addr + args.i.p.size;
685		range.pfns = args.phys;
686		range.flags = nouveau_svm_pfn_flags;
687		range.values = nouveau_svm_pfn_values;
688		range.pfn_shift = NVIF_VMM_PFNMAP_V0_ADDR_SHIFT;
689again:
690		ret = nouveau_range_fault(svmm, &range);
691		if (ret == 0) {
692			mutex_lock(&svmm->mutex);
693			if (!nouveau_range_done(&range)) {
694				mutex_unlock(&svmm->mutex);
695				goto again;
696			}
697
698			nouveau_dmem_convert_pfn(svm->drm, &range);
699
700			svmm->vmm->vmm.object.client->super = true;
701			ret = nvif_object_ioctl(&svmm->vmm->vmm.object,
702						&args, sizeof(args.i) +
703						pi * sizeof(args.phys[0]),
704						NULL);
705			svmm->vmm->vmm.object.client->super = false;
706			mutex_unlock(&svmm->mutex);
707			up_read(&svmm->mm->mmap_sem);
708		}
709
710		/* Cancel any faults in the window whose pages didn't manage
711		 * to keep their valid bit, or stay writeable when required.
712		 *
713		 * If handling failed completely, cancel all faults.
714		 */
715		while (fi < fn) {
716			struct nouveau_svm_fault *fault = buffer->fault[fi++];
717			pi = (fault->addr - range.start) >> PAGE_SHIFT;
718			if (ret ||
719			     !(range.pfns[pi] & NVIF_VMM_PFNMAP_V0_V) ||
720			    (!(range.pfns[pi] & NVIF_VMM_PFNMAP_V0_W) &&
721			     fault->access != 0 && fault->access != 3)) {
722				nouveau_svm_fault_cancel_fault(svm, fault);
723				continue;
724			}
725			replay++;
726		}
727	}
728
729	/* Issue fault replay to the GPU. */
730	if (replay)
731		nouveau_svm_fault_replay(svm);
732	return NVIF_NOTIFY_KEEP;
733}
734
735static void
736nouveau_svm_fault_buffer_fini(struct nouveau_svm *svm, int id)
737{
738	struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
739	nvif_notify_put(&buffer->notify);
740}
741
742static int
743nouveau_svm_fault_buffer_init(struct nouveau_svm *svm, int id)
744{
745	struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
746	struct nvif_object *device = &svm->drm->client.device.object;
747	buffer->get = nvif_rd32(device, buffer->getaddr);
748	buffer->put = nvif_rd32(device, buffer->putaddr);
749	SVM_DBG(svm, "get %08x put %08x (init)", buffer->get, buffer->put);
750	return nvif_notify_get(&buffer->notify);
751}
752
753static void
754nouveau_svm_fault_buffer_dtor(struct nouveau_svm *svm, int id)
755{
756	struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
757	int i;
758
759	if (buffer->fault) {
760		for (i = 0; buffer->fault[i] && i < buffer->entries; i++)
761			kfree(buffer->fault[i]);
762		kvfree(buffer->fault);
763	}
764
765	nouveau_svm_fault_buffer_fini(svm, id);
766
767	nvif_notify_fini(&buffer->notify);
768	nvif_object_fini(&buffer->object);
769}
770
771static int
772nouveau_svm_fault_buffer_ctor(struct nouveau_svm *svm, s32 oclass, int id)
773{
774	struct nouveau_svm_fault_buffer *buffer = &svm->buffer[id];
775	struct nouveau_drm *drm = svm->drm;
776	struct nvif_object *device = &drm->client.device.object;
777	struct nvif_clb069_v0 args = {};
778	int ret;
779
780	buffer->id = id;
781
782	ret = nvif_object_init(device, 0, oclass, &args, sizeof(args),
783			       &buffer->object);
784	if (ret < 0) {
785		SVM_ERR(svm, "Fault buffer allocation failed: %d", ret);
786		return ret;
787	}
788
789	nvif_object_map(&buffer->object, NULL, 0);
790	buffer->entries = args.entries;
791	buffer->getaddr = args.get;
792	buffer->putaddr = args.put;
793
794	ret = nvif_notify_init(&buffer->object, nouveau_svm_fault, true,
795			       NVB069_V0_NTFY_FAULT, NULL, 0, 0,
796			       &buffer->notify);
797	if (ret)
798		return ret;
799
800	buffer->fault = kvzalloc(sizeof(*buffer->fault) * buffer->entries, GFP_KERNEL);
801	if (!buffer->fault)
802		return -ENOMEM;
803
804	return nouveau_svm_fault_buffer_init(svm, id);
805}
806
807void
808nouveau_svm_resume(struct nouveau_drm *drm)
809{
810	struct nouveau_svm *svm = drm->svm;
811	if (svm)
812		nouveau_svm_fault_buffer_init(svm, 0);
813}
814
815void
816nouveau_svm_suspend(struct nouveau_drm *drm)
817{
818	struct nouveau_svm *svm = drm->svm;
819	if (svm)
820		nouveau_svm_fault_buffer_fini(svm, 0);
821}
822
823void
824nouveau_svm_fini(struct nouveau_drm *drm)
825{
826	struct nouveau_svm *svm = drm->svm;
827	if (svm) {
828		nouveau_svm_fault_buffer_dtor(svm, 0);
829		kfree(drm->svm);
830		drm->svm = NULL;
831	}
832}
833
834void
835nouveau_svm_init(struct nouveau_drm *drm)
836{
837	static const struct nvif_mclass buffers[] = {
838		{   VOLTA_FAULT_BUFFER_A, 0 },
839		{ MAXWELL_FAULT_BUFFER_A, 0 },
840		{}
841	};
842	struct nouveau_svm *svm;
843	int ret;
844
845	/* Disable on Volta and newer until channel recovery is fixed,
846	 * otherwise clients will have a trivial way to trash the GPU
847	 * for everyone.
848	 */
849	if (drm->client.device.info.family > NV_DEVICE_INFO_V0_PASCAL)
850		return;
851
852	if (!(drm->svm = svm = kzalloc(sizeof(*drm->svm), GFP_KERNEL)))
853		return;
854
855	drm->svm->drm = drm;
856	mutex_init(&drm->svm->mutex);
857	INIT_LIST_HEAD(&drm->svm->inst);
858
859	ret = nvif_mclass(&drm->client.device.object, buffers);
860	if (ret < 0) {
861		SVM_DBG(svm, "No supported fault buffer class");
862		nouveau_svm_fini(drm);
863		return;
864	}
865
866	ret = nouveau_svm_fault_buffer_ctor(svm, buffers[ret].oclass, 0);
867	if (ret) {
868		nouveau_svm_fini(drm);
869		return;
870	}
871
872	SVM_DBG(svm, "Initialised");
873}