xref: /openbmc/linux/drivers/infiniband/hw/mlx5/odp.c (revision 6cc23ed2)
1 /*
2  * Copyright (c) 2013-2015, Mellanox Technologies. All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *      - Redistributions of source code must retain the above
15  *        copyright notice, this list of conditions and the following
16  *        disclaimer.
17  *
18  *      - Redistributions in binary form must reproduce the above
19  *        copyright notice, this list of conditions and the following
20  *        disclaimer in the documentation and/or other materials
21  *        provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  */
32 
33 #include <rdma/ib_umem.h>
34 #include <rdma/ib_umem_odp.h>
35 #include <linux/kernel.h>
36 
37 #include "mlx5_ib.h"
38 #include "cmd.h"
39 
40 #include <linux/mlx5/eq.h>
41 
42 /* Contains the details of a pagefault. */
43 struct mlx5_pagefault {
44 	u32			bytes_committed;
45 	u32			token;
46 	u8			event_subtype;
47 	u8			type;
48 	union {
49 		/* Initiator or send message responder pagefault details. */
50 		struct {
51 			/* Received packet size, only valid for responders. */
52 			u32	packet_size;
53 			/*
54 			 * Number of resource holding WQE, depends on type.
55 			 */
56 			u32	wq_num;
57 			/*
58 			 * WQE index. Refers to either the send queue or
59 			 * receive queue, according to event_subtype.
60 			 */
61 			u16	wqe_index;
62 		} wqe;
63 		/* RDMA responder pagefault details */
64 		struct {
65 			u32	r_key;
66 			/*
67 			 * Received packet size, minimal size page fault
68 			 * resolution required for forward progress.
69 			 */
70 			u32	packet_size;
71 			u32	rdma_op_len;
72 			u64	rdma_va;
73 		} rdma;
74 	};
75 
76 	struct mlx5_ib_pf_eq	*eq;
77 	struct work_struct	work;
78 };
79 
80 #define MAX_PREFETCH_LEN (4*1024*1024U)
81 
82 /* Timeout in ms to wait for an active mmu notifier to complete when handling
83  * a pagefault. */
84 #define MMU_NOTIFIER_TIMEOUT 1000
85 
86 #define MLX5_IMR_MTT_BITS (30 - PAGE_SHIFT)
87 #define MLX5_IMR_MTT_SHIFT (MLX5_IMR_MTT_BITS + PAGE_SHIFT)
88 #define MLX5_IMR_MTT_ENTRIES BIT_ULL(MLX5_IMR_MTT_BITS)
89 #define MLX5_IMR_MTT_SIZE BIT_ULL(MLX5_IMR_MTT_SHIFT)
90 #define MLX5_IMR_MTT_MASK (~(MLX5_IMR_MTT_SIZE - 1))
91 
92 #define MLX5_KSM_PAGE_SHIFT MLX5_IMR_MTT_SHIFT
93 
94 static u64 mlx5_imr_ksm_entries;
95 
96 static int check_parent(struct ib_umem_odp *odp,
97 			       struct mlx5_ib_mr *parent)
98 {
99 	struct mlx5_ib_mr *mr = odp->private;
100 
101 	return mr && mr->parent == parent && !odp->dying;
102 }
103 
104 static struct ib_ucontext_per_mm *mr_to_per_mm(struct mlx5_ib_mr *mr)
105 {
106 	if (WARN_ON(!mr || !is_odp_mr(mr)))
107 		return NULL;
108 
109 	return to_ib_umem_odp(mr->umem)->per_mm;
110 }
111 
112 static struct ib_umem_odp *odp_next(struct ib_umem_odp *odp)
113 {
114 	struct mlx5_ib_mr *mr = odp->private, *parent = mr->parent;
115 	struct ib_ucontext_per_mm *per_mm = odp->per_mm;
116 	struct rb_node *rb;
117 
118 	down_read(&per_mm->umem_rwsem);
119 	while (1) {
120 		rb = rb_next(&odp->interval_tree.rb);
121 		if (!rb)
122 			goto not_found;
123 		odp = rb_entry(rb, struct ib_umem_odp, interval_tree.rb);
124 		if (check_parent(odp, parent))
125 			goto end;
126 	}
127 not_found:
128 	odp = NULL;
129 end:
130 	up_read(&per_mm->umem_rwsem);
131 	return odp;
132 }
133 
134 static struct ib_umem_odp *odp_lookup(u64 start, u64 length,
135 				      struct mlx5_ib_mr *parent)
136 {
137 	struct ib_ucontext_per_mm *per_mm = mr_to_per_mm(parent);
138 	struct ib_umem_odp *odp;
139 	struct rb_node *rb;
140 
141 	down_read(&per_mm->umem_rwsem);
142 	odp = rbt_ib_umem_lookup(&per_mm->umem_tree, start, length);
143 	if (!odp)
144 		goto end;
145 
146 	while (1) {
147 		if (check_parent(odp, parent))
148 			goto end;
149 		rb = rb_next(&odp->interval_tree.rb);
150 		if (!rb)
151 			goto not_found;
152 		odp = rb_entry(rb, struct ib_umem_odp, interval_tree.rb);
153 		if (ib_umem_start(odp) > start + length)
154 			goto not_found;
155 	}
156 not_found:
157 	odp = NULL;
158 end:
159 	up_read(&per_mm->umem_rwsem);
160 	return odp;
161 }
162 
163 void mlx5_odp_populate_klm(struct mlx5_klm *pklm, size_t offset,
164 			   size_t nentries, struct mlx5_ib_mr *mr, int flags)
165 {
166 	struct ib_pd *pd = mr->ibmr.pd;
167 	struct mlx5_ib_dev *dev = to_mdev(pd->device);
168 	struct ib_umem_odp *odp;
169 	unsigned long va;
170 	int i;
171 
172 	if (flags & MLX5_IB_UPD_XLT_ZAP) {
173 		for (i = 0; i < nentries; i++, pklm++) {
174 			pklm->bcount = cpu_to_be32(MLX5_IMR_MTT_SIZE);
175 			pklm->key = cpu_to_be32(dev->null_mkey);
176 			pklm->va = 0;
177 		}
178 		return;
179 	}
180 
181 	odp = odp_lookup(offset * MLX5_IMR_MTT_SIZE,
182 			 nentries * MLX5_IMR_MTT_SIZE, mr);
183 
184 	for (i = 0; i < nentries; i++, pklm++) {
185 		pklm->bcount = cpu_to_be32(MLX5_IMR_MTT_SIZE);
186 		va = (offset + i) * MLX5_IMR_MTT_SIZE;
187 		if (odp && ib_umem_start(odp) == va) {
188 			struct mlx5_ib_mr *mtt = odp->private;
189 
190 			pklm->key = cpu_to_be32(mtt->ibmr.lkey);
191 			odp = odp_next(odp);
192 		} else {
193 			pklm->key = cpu_to_be32(dev->null_mkey);
194 		}
195 		mlx5_ib_dbg(dev, "[%d] va %lx key %x\n",
196 			    i, va, be32_to_cpu(pklm->key));
197 	}
198 }
199 
200 static void mr_leaf_free_action(struct work_struct *work)
201 {
202 	struct ib_umem_odp *odp = container_of(work, struct ib_umem_odp, work);
203 	int idx = ib_umem_start(odp) >> MLX5_IMR_MTT_SHIFT;
204 	struct mlx5_ib_mr *mr = odp->private, *imr = mr->parent;
205 
206 	mr->parent = NULL;
207 	synchronize_srcu(&mr->dev->mr_srcu);
208 
209 	ib_umem_odp_release(odp);
210 	if (imr->live)
211 		mlx5_ib_update_xlt(imr, idx, 1, 0,
212 				   MLX5_IB_UPD_XLT_INDIRECT |
213 				   MLX5_IB_UPD_XLT_ATOMIC);
214 	mlx5_mr_cache_free(mr->dev, mr);
215 
216 	if (atomic_dec_and_test(&imr->num_leaf_free))
217 		wake_up(&imr->q_leaf_free);
218 }
219 
220 void mlx5_ib_invalidate_range(struct ib_umem_odp *umem_odp, unsigned long start,
221 			      unsigned long end)
222 {
223 	struct mlx5_ib_mr *mr;
224 	const u64 umr_block_mask = (MLX5_UMR_MTT_ALIGNMENT /
225 				    sizeof(struct mlx5_mtt)) - 1;
226 	u64 idx = 0, blk_start_idx = 0;
227 	int in_block = 0;
228 	u64 addr;
229 
230 	if (!umem_odp) {
231 		pr_err("invalidation called on NULL umem or non-ODP umem\n");
232 		return;
233 	}
234 
235 	mr = umem_odp->private;
236 
237 	if (!mr || !mr->ibmr.pd)
238 		return;
239 
240 	start = max_t(u64, ib_umem_start(umem_odp), start);
241 	end = min_t(u64, ib_umem_end(umem_odp), end);
242 
243 	/*
244 	 * Iteration one - zap the HW's MTTs. The notifiers_count ensures that
245 	 * while we are doing the invalidation, no page fault will attempt to
246 	 * overwrite the same MTTs.  Concurent invalidations might race us,
247 	 * but they will write 0s as well, so no difference in the end result.
248 	 */
249 	mutex_lock(&umem_odp->umem_mutex);
250 	for (addr = start; addr < end; addr += BIT(umem_odp->page_shift)) {
251 		idx = (addr - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
252 		/*
253 		 * Strive to write the MTTs in chunks, but avoid overwriting
254 		 * non-existing MTTs. The huristic here can be improved to
255 		 * estimate the cost of another UMR vs. the cost of bigger
256 		 * UMR.
257 		 */
258 		if (umem_odp->dma_list[idx] &
259 		    (ODP_READ_ALLOWED_BIT | ODP_WRITE_ALLOWED_BIT)) {
260 			if (!in_block) {
261 				blk_start_idx = idx;
262 				in_block = 1;
263 			}
264 		} else {
265 			u64 umr_offset = idx & umr_block_mask;
266 
267 			if (in_block && umr_offset == 0) {
268 				mlx5_ib_update_xlt(mr, blk_start_idx,
269 						   idx - blk_start_idx, 0,
270 						   MLX5_IB_UPD_XLT_ZAP |
271 						   MLX5_IB_UPD_XLT_ATOMIC);
272 				in_block = 0;
273 			}
274 		}
275 	}
276 	if (in_block)
277 		mlx5_ib_update_xlt(mr, blk_start_idx,
278 				   idx - blk_start_idx + 1, 0,
279 				   MLX5_IB_UPD_XLT_ZAP |
280 				   MLX5_IB_UPD_XLT_ATOMIC);
281 	mutex_unlock(&umem_odp->umem_mutex);
282 	/*
283 	 * We are now sure that the device will not access the
284 	 * memory. We can safely unmap it, and mark it as dirty if
285 	 * needed.
286 	 */
287 
288 	ib_umem_odp_unmap_dma_pages(umem_odp, start, end);
289 
290 	if (unlikely(!umem_odp->npages && mr->parent &&
291 		     !umem_odp->dying)) {
292 		WRITE_ONCE(umem_odp->dying, 1);
293 		atomic_inc(&mr->parent->num_leaf_free);
294 		schedule_work(&umem_odp->work);
295 	}
296 }
297 
298 void mlx5_ib_internal_fill_odp_caps(struct mlx5_ib_dev *dev)
299 {
300 	struct ib_odp_caps *caps = &dev->odp_caps;
301 
302 	memset(caps, 0, sizeof(*caps));
303 
304 	if (!MLX5_CAP_GEN(dev->mdev, pg) ||
305 	    !mlx5_ib_can_use_umr(dev, true))
306 		return;
307 
308 	caps->general_caps = IB_ODP_SUPPORT;
309 
310 	if (MLX5_CAP_GEN(dev->mdev, umr_extended_translation_offset))
311 		dev->odp_max_size = U64_MAX;
312 	else
313 		dev->odp_max_size = BIT_ULL(MLX5_MAX_UMR_SHIFT + PAGE_SHIFT);
314 
315 	if (MLX5_CAP_ODP(dev->mdev, ud_odp_caps.send))
316 		caps->per_transport_caps.ud_odp_caps |= IB_ODP_SUPPORT_SEND;
317 
318 	if (MLX5_CAP_ODP(dev->mdev, ud_odp_caps.srq_receive))
319 		caps->per_transport_caps.ud_odp_caps |= IB_ODP_SUPPORT_SRQ_RECV;
320 
321 	if (MLX5_CAP_ODP(dev->mdev, rc_odp_caps.send))
322 		caps->per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_SEND;
323 
324 	if (MLX5_CAP_ODP(dev->mdev, rc_odp_caps.receive))
325 		caps->per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_RECV;
326 
327 	if (MLX5_CAP_ODP(dev->mdev, rc_odp_caps.write))
328 		caps->per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_WRITE;
329 
330 	if (MLX5_CAP_ODP(dev->mdev, rc_odp_caps.read))
331 		caps->per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_READ;
332 
333 	if (MLX5_CAP_ODP(dev->mdev, rc_odp_caps.atomic))
334 		caps->per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_ATOMIC;
335 
336 	if (MLX5_CAP_ODP(dev->mdev, rc_odp_caps.srq_receive))
337 		caps->per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_SRQ_RECV;
338 
339 	if (MLX5_CAP_ODP(dev->mdev, xrc_odp_caps.send))
340 		caps->per_transport_caps.xrc_odp_caps |= IB_ODP_SUPPORT_SEND;
341 
342 	if (MLX5_CAP_ODP(dev->mdev, xrc_odp_caps.receive))
343 		caps->per_transport_caps.xrc_odp_caps |= IB_ODP_SUPPORT_RECV;
344 
345 	if (MLX5_CAP_ODP(dev->mdev, xrc_odp_caps.write))
346 		caps->per_transport_caps.xrc_odp_caps |= IB_ODP_SUPPORT_WRITE;
347 
348 	if (MLX5_CAP_ODP(dev->mdev, xrc_odp_caps.read))
349 		caps->per_transport_caps.xrc_odp_caps |= IB_ODP_SUPPORT_READ;
350 
351 	if (MLX5_CAP_ODP(dev->mdev, xrc_odp_caps.atomic))
352 		caps->per_transport_caps.xrc_odp_caps |= IB_ODP_SUPPORT_ATOMIC;
353 
354 	if (MLX5_CAP_ODP(dev->mdev, xrc_odp_caps.srq_receive))
355 		caps->per_transport_caps.xrc_odp_caps |= IB_ODP_SUPPORT_SRQ_RECV;
356 
357 	if (MLX5_CAP_GEN(dev->mdev, fixed_buffer_size) &&
358 	    MLX5_CAP_GEN(dev->mdev, null_mkey) &&
359 	    MLX5_CAP_GEN(dev->mdev, umr_extended_translation_offset) &&
360 	    !MLX5_CAP_GEN(dev->mdev, umr_indirect_mkey_disabled))
361 		caps->general_caps |= IB_ODP_SUPPORT_IMPLICIT;
362 
363 	return;
364 }
365 
366 static void mlx5_ib_page_fault_resume(struct mlx5_ib_dev *dev,
367 				      struct mlx5_pagefault *pfault,
368 				      int error)
369 {
370 	int wq_num = pfault->event_subtype == MLX5_PFAULT_SUBTYPE_WQE ?
371 		     pfault->wqe.wq_num : pfault->token;
372 	u32 out[MLX5_ST_SZ_DW(page_fault_resume_out)] = { };
373 	u32 in[MLX5_ST_SZ_DW(page_fault_resume_in)]   = { };
374 	int err;
375 
376 	MLX5_SET(page_fault_resume_in, in, opcode, MLX5_CMD_OP_PAGE_FAULT_RESUME);
377 	MLX5_SET(page_fault_resume_in, in, page_fault_type, pfault->type);
378 	MLX5_SET(page_fault_resume_in, in, token, pfault->token);
379 	MLX5_SET(page_fault_resume_in, in, wq_number, wq_num);
380 	MLX5_SET(page_fault_resume_in, in, error, !!error);
381 
382 	err = mlx5_cmd_exec(dev->mdev, in, sizeof(in), out, sizeof(out));
383 	if (err)
384 		mlx5_ib_err(dev, "Failed to resolve the page fault on WQ 0x%x err %d\n",
385 			    wq_num, err);
386 }
387 
388 static struct mlx5_ib_mr *implicit_mr_alloc(struct ib_pd *pd,
389 					    struct ib_umem_odp *umem_odp,
390 					    bool ksm, int access_flags)
391 {
392 	struct mlx5_ib_dev *dev = to_mdev(pd->device);
393 	struct mlx5_ib_mr *mr;
394 	int err;
395 
396 	mr = mlx5_mr_cache_alloc(dev, ksm ? MLX5_IMR_KSM_CACHE_ENTRY :
397 					    MLX5_IMR_MTT_CACHE_ENTRY);
398 
399 	if (IS_ERR(mr))
400 		return mr;
401 
402 	mr->ibmr.pd = pd;
403 
404 	mr->dev = dev;
405 	mr->access_flags = access_flags;
406 	mr->mmkey.iova = 0;
407 	mr->umem = &umem_odp->umem;
408 
409 	if (ksm) {
410 		err = mlx5_ib_update_xlt(mr, 0,
411 					 mlx5_imr_ksm_entries,
412 					 MLX5_KSM_PAGE_SHIFT,
413 					 MLX5_IB_UPD_XLT_INDIRECT |
414 					 MLX5_IB_UPD_XLT_ZAP |
415 					 MLX5_IB_UPD_XLT_ENABLE);
416 
417 	} else {
418 		err = mlx5_ib_update_xlt(mr, 0,
419 					 MLX5_IMR_MTT_ENTRIES,
420 					 PAGE_SHIFT,
421 					 MLX5_IB_UPD_XLT_ZAP |
422 					 MLX5_IB_UPD_XLT_ENABLE |
423 					 MLX5_IB_UPD_XLT_ATOMIC);
424 	}
425 
426 	if (err)
427 		goto fail;
428 
429 	mr->ibmr.lkey = mr->mmkey.key;
430 	mr->ibmr.rkey = mr->mmkey.key;
431 
432 	mr->live = 1;
433 
434 	mlx5_ib_dbg(dev, "key %x dev %p mr %p\n",
435 		    mr->mmkey.key, dev->mdev, mr);
436 
437 	return mr;
438 
439 fail:
440 	mlx5_ib_err(dev, "Failed to register MKEY %d\n", err);
441 	mlx5_mr_cache_free(dev, mr);
442 
443 	return ERR_PTR(err);
444 }
445 
446 static struct ib_umem_odp *implicit_mr_get_data(struct mlx5_ib_mr *mr,
447 						u64 io_virt, size_t bcnt)
448 {
449 	struct mlx5_ib_dev *dev = to_mdev(mr->ibmr.pd->device);
450 	struct ib_umem_odp *odp, *result = NULL;
451 	struct ib_umem_odp *odp_mr = to_ib_umem_odp(mr->umem);
452 	u64 addr = io_virt & MLX5_IMR_MTT_MASK;
453 	int nentries = 0, start_idx = 0, ret;
454 	struct mlx5_ib_mr *mtt;
455 
456 	mutex_lock(&odp_mr->umem_mutex);
457 	odp = odp_lookup(addr, 1, mr);
458 
459 	mlx5_ib_dbg(dev, "io_virt:%llx bcnt:%zx addr:%llx odp:%p\n",
460 		    io_virt, bcnt, addr, odp);
461 
462 next_mr:
463 	if (likely(odp)) {
464 		if (nentries)
465 			nentries++;
466 	} else {
467 		odp = ib_umem_odp_alloc_child(odp_mr, addr, MLX5_IMR_MTT_SIZE);
468 		if (IS_ERR(odp)) {
469 			mutex_unlock(&odp_mr->umem_mutex);
470 			return ERR_CAST(odp);
471 		}
472 
473 		mtt = implicit_mr_alloc(mr->ibmr.pd, odp, 0,
474 					mr->access_flags);
475 		if (IS_ERR(mtt)) {
476 			mutex_unlock(&odp_mr->umem_mutex);
477 			ib_umem_odp_release(odp);
478 			return ERR_CAST(mtt);
479 		}
480 
481 		odp->private = mtt;
482 		mtt->umem = &odp->umem;
483 		mtt->mmkey.iova = addr;
484 		mtt->parent = mr;
485 		INIT_WORK(&odp->work, mr_leaf_free_action);
486 
487 		if (!nentries)
488 			start_idx = addr >> MLX5_IMR_MTT_SHIFT;
489 		nentries++;
490 	}
491 
492 	/* Return first odp if region not covered by single one */
493 	if (likely(!result))
494 		result = odp;
495 
496 	addr += MLX5_IMR_MTT_SIZE;
497 	if (unlikely(addr < io_virt + bcnt)) {
498 		odp = odp_next(odp);
499 		if (odp && ib_umem_start(odp) != addr)
500 			odp = NULL;
501 		goto next_mr;
502 	}
503 
504 	if (unlikely(nentries)) {
505 		ret = mlx5_ib_update_xlt(mr, start_idx, nentries, 0,
506 					 MLX5_IB_UPD_XLT_INDIRECT |
507 					 MLX5_IB_UPD_XLT_ATOMIC);
508 		if (ret) {
509 			mlx5_ib_err(dev, "Failed to update PAS\n");
510 			result = ERR_PTR(ret);
511 		}
512 	}
513 
514 	mutex_unlock(&odp_mr->umem_mutex);
515 	return result;
516 }
517 
518 struct mlx5_ib_mr *mlx5_ib_alloc_implicit_mr(struct mlx5_ib_pd *pd,
519 					     struct ib_udata *udata,
520 					     int access_flags)
521 {
522 	struct mlx5_ib_mr *imr;
523 	struct ib_umem_odp *umem_odp;
524 
525 	umem_odp = ib_umem_odp_alloc_implicit(udata, access_flags);
526 	if (IS_ERR(umem_odp))
527 		return ERR_CAST(umem_odp);
528 
529 	imr = implicit_mr_alloc(&pd->ibpd, umem_odp, 1, access_flags);
530 	if (IS_ERR(imr)) {
531 		ib_umem_odp_release(umem_odp);
532 		return ERR_CAST(imr);
533 	}
534 
535 	imr->umem = &umem_odp->umem;
536 	init_waitqueue_head(&imr->q_leaf_free);
537 	atomic_set(&imr->num_leaf_free, 0);
538 	atomic_set(&imr->num_pending_prefetch, 0);
539 
540 	return imr;
541 }
542 
543 void mlx5_ib_free_implicit_mr(struct mlx5_ib_mr *imr)
544 {
545 	struct ib_ucontext_per_mm *per_mm = mr_to_per_mm(imr);
546 	struct rb_node *node;
547 
548 	down_read(&per_mm->umem_rwsem);
549 	for (node = rb_first_cached(&per_mm->umem_tree); node;
550 	     node = rb_next(node)) {
551 		struct ib_umem_odp *umem_odp =
552 			rb_entry(node, struct ib_umem_odp, interval_tree.rb);
553 		struct mlx5_ib_mr *mr = umem_odp->private;
554 
555 		if (mr->parent != imr)
556 			continue;
557 
558 		ib_umem_odp_unmap_dma_pages(umem_odp, ib_umem_start(umem_odp),
559 					    ib_umem_end(umem_odp));
560 
561 		if (umem_odp->dying)
562 			continue;
563 
564 		WRITE_ONCE(umem_odp->dying, 1);
565 		atomic_inc(&imr->num_leaf_free);
566 		schedule_work(&umem_odp->work);
567 	}
568 	up_read(&per_mm->umem_rwsem);
569 
570 	wait_event(imr->q_leaf_free, !atomic_read(&imr->num_leaf_free));
571 }
572 
573 #define MLX5_PF_FLAGS_PREFETCH  BIT(0)
574 #define MLX5_PF_FLAGS_DOWNGRADE BIT(1)
575 static int pagefault_mr(struct mlx5_ib_dev *dev, struct mlx5_ib_mr *mr,
576 			u64 io_virt, size_t bcnt, u32 *bytes_mapped,
577 			u32 flags)
578 {
579 	int npages = 0, current_seq, page_shift, ret, np;
580 	struct ib_umem_odp *odp_mr = to_ib_umem_odp(mr->umem);
581 	bool downgrade = flags & MLX5_PF_FLAGS_DOWNGRADE;
582 	bool prefetch = flags & MLX5_PF_FLAGS_PREFETCH;
583 	u64 access_mask;
584 	u64 start_idx, page_mask;
585 	struct ib_umem_odp *odp;
586 	size_t size;
587 
588 	if (odp_mr->is_implicit_odp) {
589 		odp = implicit_mr_get_data(mr, io_virt, bcnt);
590 
591 		if (IS_ERR(odp))
592 			return PTR_ERR(odp);
593 		mr = odp->private;
594 	} else {
595 		odp = odp_mr;
596 	}
597 
598 next_mr:
599 	size = min_t(size_t, bcnt, ib_umem_end(odp) - io_virt);
600 
601 	page_shift = odp->page_shift;
602 	page_mask = ~(BIT(page_shift) - 1);
603 	start_idx = (io_virt - (mr->mmkey.iova & page_mask)) >> page_shift;
604 	access_mask = ODP_READ_ALLOWED_BIT;
605 
606 	if (prefetch && !downgrade && !odp->umem.writable) {
607 		/* prefetch with write-access must
608 		 * be supported by the MR
609 		 */
610 		ret = -EINVAL;
611 		goto out;
612 	}
613 
614 	if (odp->umem.writable && !downgrade)
615 		access_mask |= ODP_WRITE_ALLOWED_BIT;
616 
617 	current_seq = READ_ONCE(odp->notifiers_seq);
618 	/*
619 	 * Ensure the sequence number is valid for some time before we call
620 	 * gup.
621 	 */
622 	smp_rmb();
623 
624 	ret = ib_umem_odp_map_dma_pages(odp, io_virt, size, access_mask,
625 					current_seq);
626 
627 	if (ret < 0)
628 		goto out;
629 
630 	np = ret;
631 
632 	mutex_lock(&odp->umem_mutex);
633 	if (!ib_umem_mmu_notifier_retry(odp, current_seq)) {
634 		/*
635 		 * No need to check whether the MTTs really belong to
636 		 * this MR, since ib_umem_odp_map_dma_pages already
637 		 * checks this.
638 		 */
639 		ret = mlx5_ib_update_xlt(mr, start_idx, np,
640 					 page_shift, MLX5_IB_UPD_XLT_ATOMIC);
641 	} else {
642 		ret = -EAGAIN;
643 	}
644 	mutex_unlock(&odp->umem_mutex);
645 
646 	if (ret < 0) {
647 		if (ret != -EAGAIN)
648 			mlx5_ib_err(dev, "Failed to update mkey page tables\n");
649 		goto out;
650 	}
651 
652 	if (bytes_mapped) {
653 		u32 new_mappings = (np << page_shift) -
654 			(io_virt - round_down(io_virt, 1 << page_shift));
655 		*bytes_mapped += min_t(u32, new_mappings, size);
656 	}
657 
658 	npages += np << (page_shift - PAGE_SHIFT);
659 	bcnt -= size;
660 
661 	if (unlikely(bcnt)) {
662 		struct ib_umem_odp *next;
663 
664 		io_virt += size;
665 		next = odp_next(odp);
666 		if (unlikely(!next || ib_umem_start(next) != io_virt)) {
667 			mlx5_ib_dbg(dev, "next implicit leaf removed at 0x%llx. got %p\n",
668 				    io_virt, next);
669 			return -EAGAIN;
670 		}
671 		odp = next;
672 		mr = odp->private;
673 		goto next_mr;
674 	}
675 
676 	return npages;
677 
678 out:
679 	if (ret == -EAGAIN) {
680 		unsigned long timeout = msecs_to_jiffies(MMU_NOTIFIER_TIMEOUT);
681 
682 		if (!wait_for_completion_timeout(&odp->notifier_completion,
683 						 timeout)) {
684 			mlx5_ib_warn(
685 				dev,
686 				"timeout waiting for mmu notifier. seq %d against %d. notifiers_count=%d\n",
687 				current_seq, odp->notifiers_seq,
688 				odp->notifiers_count);
689 		}
690 	}
691 
692 	return ret;
693 }
694 
695 struct pf_frame {
696 	struct pf_frame *next;
697 	u32 key;
698 	u64 io_virt;
699 	size_t bcnt;
700 	int depth;
701 };
702 
703 static bool mkey_is_eq(struct mlx5_core_mkey *mmkey, u32 key)
704 {
705 	if (!mmkey)
706 		return false;
707 	if (mmkey->type == MLX5_MKEY_MW)
708 		return mlx5_base_mkey(mmkey->key) == mlx5_base_mkey(key);
709 	return mmkey->key == key;
710 }
711 
712 static int get_indirect_num_descs(struct mlx5_core_mkey *mmkey)
713 {
714 	struct mlx5_ib_mw *mw;
715 	struct mlx5_ib_devx_mr *devx_mr;
716 
717 	if (mmkey->type == MLX5_MKEY_MW) {
718 		mw = container_of(mmkey, struct mlx5_ib_mw, mmkey);
719 		return mw->ndescs;
720 	}
721 
722 	devx_mr = container_of(mmkey, struct mlx5_ib_devx_mr,
723 			       mmkey);
724 	return devx_mr->ndescs;
725 }
726 
727 /*
728  * Handle a single data segment in a page-fault WQE or RDMA region.
729  *
730  * Returns number of OS pages retrieved on success. The caller may continue to
731  * the next data segment.
732  * Can return the following error codes:
733  * -EAGAIN to designate a temporary error. The caller will abort handling the
734  *  page fault and resolve it.
735  * -EFAULT when there's an error mapping the requested pages. The caller will
736  *  abort the page fault handling.
737  */
738 static int pagefault_single_data_segment(struct mlx5_ib_dev *dev,
739 					 struct ib_pd *pd, u32 key,
740 					 u64 io_virt, size_t bcnt,
741 					 u32 *bytes_committed,
742 					 u32 *bytes_mapped, u32 flags)
743 {
744 	int npages = 0, srcu_key, ret, i, outlen, cur_outlen = 0, depth = 0;
745 	bool prefetch = flags & MLX5_PF_FLAGS_PREFETCH;
746 	struct pf_frame *head = NULL, *frame;
747 	struct mlx5_core_mkey *mmkey;
748 	struct mlx5_ib_mr *mr;
749 	struct mlx5_klm *pklm;
750 	u32 *out = NULL;
751 	size_t offset;
752 	int ndescs;
753 
754 	srcu_key = srcu_read_lock(&dev->mr_srcu);
755 
756 	io_virt += *bytes_committed;
757 	bcnt -= *bytes_committed;
758 
759 next_mr:
760 	mmkey = xa_load(&dev->mdev->priv.mkey_table, mlx5_base_mkey(key));
761 	if (!mkey_is_eq(mmkey, key)) {
762 		mlx5_ib_dbg(dev, "failed to find mkey %x\n", key);
763 		ret = -EFAULT;
764 		goto srcu_unlock;
765 	}
766 
767 	if (prefetch && mmkey->type != MLX5_MKEY_MR) {
768 		mlx5_ib_dbg(dev, "prefetch is allowed only for MR\n");
769 		ret = -EINVAL;
770 		goto srcu_unlock;
771 	}
772 
773 	switch (mmkey->type) {
774 	case MLX5_MKEY_MR:
775 		mr = container_of(mmkey, struct mlx5_ib_mr, mmkey);
776 		if (!mr->live || !mr->ibmr.pd) {
777 			mlx5_ib_dbg(dev, "got dead MR\n");
778 			ret = -EFAULT;
779 			goto srcu_unlock;
780 		}
781 
782 		if (prefetch) {
783 			if (!is_odp_mr(mr) ||
784 			    mr->ibmr.pd != pd) {
785 				mlx5_ib_dbg(dev, "Invalid prefetch request: %s\n",
786 					    is_odp_mr(mr) ?  "MR is not ODP" :
787 					    "PD is not of the MR");
788 				ret = -EINVAL;
789 				goto srcu_unlock;
790 			}
791 		}
792 
793 		if (!is_odp_mr(mr)) {
794 			mlx5_ib_dbg(dev, "skipping non ODP MR (lkey=0x%06x) in page fault handler.\n",
795 				    key);
796 			if (bytes_mapped)
797 				*bytes_mapped += bcnt;
798 			ret = 0;
799 			goto srcu_unlock;
800 		}
801 
802 		ret = pagefault_mr(dev, mr, io_virt, bcnt, bytes_mapped, flags);
803 		if (ret < 0)
804 			goto srcu_unlock;
805 
806 		npages += ret;
807 		ret = 0;
808 		break;
809 
810 	case MLX5_MKEY_MW:
811 	case MLX5_MKEY_INDIRECT_DEVX:
812 		ndescs = get_indirect_num_descs(mmkey);
813 
814 		if (depth >= MLX5_CAP_GEN(dev->mdev, max_indirection)) {
815 			mlx5_ib_dbg(dev, "indirection level exceeded\n");
816 			ret = -EFAULT;
817 			goto srcu_unlock;
818 		}
819 
820 		outlen = MLX5_ST_SZ_BYTES(query_mkey_out) +
821 			sizeof(*pklm) * (ndescs - 2);
822 
823 		if (outlen > cur_outlen) {
824 			kfree(out);
825 			out = kzalloc(outlen, GFP_KERNEL);
826 			if (!out) {
827 				ret = -ENOMEM;
828 				goto srcu_unlock;
829 			}
830 			cur_outlen = outlen;
831 		}
832 
833 		pklm = (struct mlx5_klm *)MLX5_ADDR_OF(query_mkey_out, out,
834 						       bsf0_klm0_pas_mtt0_1);
835 
836 		ret = mlx5_core_query_mkey(dev->mdev, mmkey, out, outlen);
837 		if (ret)
838 			goto srcu_unlock;
839 
840 		offset = io_virt - MLX5_GET64(query_mkey_out, out,
841 					      memory_key_mkey_entry.start_addr);
842 
843 		for (i = 0; bcnt && i < ndescs; i++, pklm++) {
844 			if (offset >= be32_to_cpu(pklm->bcount)) {
845 				offset -= be32_to_cpu(pklm->bcount);
846 				continue;
847 			}
848 
849 			frame = kzalloc(sizeof(*frame), GFP_KERNEL);
850 			if (!frame) {
851 				ret = -ENOMEM;
852 				goto srcu_unlock;
853 			}
854 
855 			frame->key = be32_to_cpu(pklm->key);
856 			frame->io_virt = be64_to_cpu(pklm->va) + offset;
857 			frame->bcnt = min_t(size_t, bcnt,
858 					    be32_to_cpu(pklm->bcount) - offset);
859 			frame->depth = depth + 1;
860 			frame->next = head;
861 			head = frame;
862 
863 			bcnt -= frame->bcnt;
864 			offset = 0;
865 		}
866 		break;
867 
868 	default:
869 		mlx5_ib_dbg(dev, "wrong mkey type %d\n", mmkey->type);
870 		ret = -EFAULT;
871 		goto srcu_unlock;
872 	}
873 
874 	if (head) {
875 		frame = head;
876 		head = frame->next;
877 
878 		key = frame->key;
879 		io_virt = frame->io_virt;
880 		bcnt = frame->bcnt;
881 		depth = frame->depth;
882 		kfree(frame);
883 
884 		goto next_mr;
885 	}
886 
887 srcu_unlock:
888 	while (head) {
889 		frame = head;
890 		head = frame->next;
891 		kfree(frame);
892 	}
893 	kfree(out);
894 
895 	srcu_read_unlock(&dev->mr_srcu, srcu_key);
896 	*bytes_committed = 0;
897 	return ret ? ret : npages;
898 }
899 
900 /**
901  * Parse a series of data segments for page fault handling.
902  *
903  * @pfault contains page fault information.
904  * @wqe points at the first data segment in the WQE.
905  * @wqe_end points after the end of the WQE.
906  * @bytes_mapped receives the number of bytes that the function was able to
907  *               map. This allows the caller to decide intelligently whether
908  *               enough memory was mapped to resolve the page fault
909  *               successfully (e.g. enough for the next MTU, or the entire
910  *               WQE).
911  * @total_wqe_bytes receives the total data size of this WQE in bytes (minus
912  *                  the committed bytes).
913  *
914  * Returns the number of pages loaded if positive, zero for an empty WQE, or a
915  * negative error code.
916  */
917 static int pagefault_data_segments(struct mlx5_ib_dev *dev,
918 				   struct mlx5_pagefault *pfault,
919 				   void *wqe,
920 				   void *wqe_end, u32 *bytes_mapped,
921 				   u32 *total_wqe_bytes, bool receive_queue)
922 {
923 	int ret = 0, npages = 0;
924 	u64 io_virt;
925 	u32 key;
926 	u32 byte_count;
927 	size_t bcnt;
928 	int inline_segment;
929 
930 	if (bytes_mapped)
931 		*bytes_mapped = 0;
932 	if (total_wqe_bytes)
933 		*total_wqe_bytes = 0;
934 
935 	while (wqe < wqe_end) {
936 		struct mlx5_wqe_data_seg *dseg = wqe;
937 
938 		io_virt = be64_to_cpu(dseg->addr);
939 		key = be32_to_cpu(dseg->lkey);
940 		byte_count = be32_to_cpu(dseg->byte_count);
941 		inline_segment = !!(byte_count &  MLX5_INLINE_SEG);
942 		bcnt	       = byte_count & ~MLX5_INLINE_SEG;
943 
944 		if (inline_segment) {
945 			bcnt = bcnt & MLX5_WQE_INLINE_SEG_BYTE_COUNT_MASK;
946 			wqe += ALIGN(sizeof(struct mlx5_wqe_inline_seg) + bcnt,
947 				     16);
948 		} else {
949 			wqe += sizeof(*dseg);
950 		}
951 
952 		/* receive WQE end of sg list. */
953 		if (receive_queue && bcnt == 0 && key == MLX5_INVALID_LKEY &&
954 		    io_virt == 0)
955 			break;
956 
957 		if (!inline_segment && total_wqe_bytes) {
958 			*total_wqe_bytes += bcnt - min_t(size_t, bcnt,
959 					pfault->bytes_committed);
960 		}
961 
962 		/* A zero length data segment designates a length of 2GB. */
963 		if (bcnt == 0)
964 			bcnt = 1U << 31;
965 
966 		if (inline_segment || bcnt <= pfault->bytes_committed) {
967 			pfault->bytes_committed -=
968 				min_t(size_t, bcnt,
969 				      pfault->bytes_committed);
970 			continue;
971 		}
972 
973 		ret = pagefault_single_data_segment(dev, NULL, key,
974 						    io_virt, bcnt,
975 						    &pfault->bytes_committed,
976 						    bytes_mapped, 0);
977 		if (ret < 0)
978 			break;
979 		npages += ret;
980 	}
981 
982 	return ret < 0 ? ret : npages;
983 }
984 
985 /*
986  * Parse initiator WQE. Advances the wqe pointer to point at the
987  * scatter-gather list, and set wqe_end to the end of the WQE.
988  */
989 static int mlx5_ib_mr_initiator_pfault_handler(
990 	struct mlx5_ib_dev *dev, struct mlx5_pagefault *pfault,
991 	struct mlx5_ib_qp *qp, void **wqe, void **wqe_end, int wqe_length)
992 {
993 	struct mlx5_wqe_ctrl_seg *ctrl = *wqe;
994 	u16 wqe_index = pfault->wqe.wqe_index;
995 	struct mlx5_base_av *av;
996 	unsigned ds, opcode;
997 	u32 qpn = qp->trans_qp.base.mqp.qpn;
998 
999 	ds = be32_to_cpu(ctrl->qpn_ds) & MLX5_WQE_CTRL_DS_MASK;
1000 	if (ds * MLX5_WQE_DS_UNITS > wqe_length) {
1001 		mlx5_ib_err(dev, "Unable to read the complete WQE. ds = 0x%x, ret = 0x%x\n",
1002 			    ds, wqe_length);
1003 		return -EFAULT;
1004 	}
1005 
1006 	if (ds == 0) {
1007 		mlx5_ib_err(dev, "Got WQE with zero DS. wqe_index=%x, qpn=%x\n",
1008 			    wqe_index, qpn);
1009 		return -EFAULT;
1010 	}
1011 
1012 	*wqe_end = *wqe + ds * MLX5_WQE_DS_UNITS;
1013 	*wqe += sizeof(*ctrl);
1014 
1015 	opcode = be32_to_cpu(ctrl->opmod_idx_opcode) &
1016 		 MLX5_WQE_CTRL_OPCODE_MASK;
1017 
1018 	if (qp->ibqp.qp_type == IB_QPT_XRC_INI)
1019 		*wqe += sizeof(struct mlx5_wqe_xrc_seg);
1020 
1021 	if (qp->ibqp.qp_type == IB_QPT_UD ||
1022 	    qp->qp_sub_type == MLX5_IB_QPT_DCI) {
1023 		av = *wqe;
1024 		if (av->dqp_dct & cpu_to_be32(MLX5_EXTENDED_UD_AV))
1025 			*wqe += sizeof(struct mlx5_av);
1026 		else
1027 			*wqe += sizeof(struct mlx5_base_av);
1028 	}
1029 
1030 	switch (opcode) {
1031 	case MLX5_OPCODE_RDMA_WRITE:
1032 	case MLX5_OPCODE_RDMA_WRITE_IMM:
1033 	case MLX5_OPCODE_RDMA_READ:
1034 		*wqe += sizeof(struct mlx5_wqe_raddr_seg);
1035 		break;
1036 	case MLX5_OPCODE_ATOMIC_CS:
1037 	case MLX5_OPCODE_ATOMIC_FA:
1038 		*wqe += sizeof(struct mlx5_wqe_raddr_seg);
1039 		*wqe += sizeof(struct mlx5_wqe_atomic_seg);
1040 		break;
1041 	}
1042 
1043 	return 0;
1044 }
1045 
1046 /*
1047  * Parse responder WQE and set wqe_end to the end of the WQE.
1048  */
1049 static int mlx5_ib_mr_responder_pfault_handler_srq(struct mlx5_ib_dev *dev,
1050 						   struct mlx5_ib_srq *srq,
1051 						   void **wqe, void **wqe_end,
1052 						   int wqe_length)
1053 {
1054 	int wqe_size = 1 << srq->msrq.wqe_shift;
1055 
1056 	if (wqe_size > wqe_length) {
1057 		mlx5_ib_err(dev, "Couldn't read all of the receive WQE's content\n");
1058 		return -EFAULT;
1059 	}
1060 
1061 	*wqe_end = *wqe + wqe_size;
1062 	*wqe += sizeof(struct mlx5_wqe_srq_next_seg);
1063 
1064 	return 0;
1065 }
1066 
1067 static int mlx5_ib_mr_responder_pfault_handler_rq(struct mlx5_ib_dev *dev,
1068 						  struct mlx5_ib_qp *qp,
1069 						  void *wqe, void **wqe_end,
1070 						  int wqe_length)
1071 {
1072 	struct mlx5_ib_wq *wq = &qp->rq;
1073 	int wqe_size = 1 << wq->wqe_shift;
1074 
1075 	if (qp->wq_sig) {
1076 		mlx5_ib_err(dev, "ODP fault with WQE signatures is not supported\n");
1077 		return -EFAULT;
1078 	}
1079 
1080 	if (wqe_size > wqe_length) {
1081 		mlx5_ib_err(dev, "Couldn't read all of the receive WQE's content\n");
1082 		return -EFAULT;
1083 	}
1084 
1085 	*wqe_end = wqe + wqe_size;
1086 
1087 	return 0;
1088 }
1089 
1090 static inline struct mlx5_core_rsc_common *odp_get_rsc(struct mlx5_ib_dev *dev,
1091 						       u32 wq_num, int pf_type)
1092 {
1093 	struct mlx5_core_rsc_common *common = NULL;
1094 	struct mlx5_core_srq *srq;
1095 
1096 	switch (pf_type) {
1097 	case MLX5_WQE_PF_TYPE_RMP:
1098 		srq = mlx5_cmd_get_srq(dev, wq_num);
1099 		if (srq)
1100 			common = &srq->common;
1101 		break;
1102 	case MLX5_WQE_PF_TYPE_REQ_SEND_OR_WRITE:
1103 	case MLX5_WQE_PF_TYPE_RESP:
1104 	case MLX5_WQE_PF_TYPE_REQ_READ_OR_ATOMIC:
1105 		common = mlx5_core_res_hold(dev->mdev, wq_num, MLX5_RES_QP);
1106 		break;
1107 	default:
1108 		break;
1109 	}
1110 
1111 	return common;
1112 }
1113 
1114 static inline struct mlx5_ib_qp *res_to_qp(struct mlx5_core_rsc_common *res)
1115 {
1116 	struct mlx5_core_qp *mqp = (struct mlx5_core_qp *)res;
1117 
1118 	return to_mibqp(mqp);
1119 }
1120 
1121 static inline struct mlx5_ib_srq *res_to_srq(struct mlx5_core_rsc_common *res)
1122 {
1123 	struct mlx5_core_srq *msrq =
1124 		container_of(res, struct mlx5_core_srq, common);
1125 
1126 	return to_mibsrq(msrq);
1127 }
1128 
1129 static void mlx5_ib_mr_wqe_pfault_handler(struct mlx5_ib_dev *dev,
1130 					  struct mlx5_pagefault *pfault)
1131 {
1132 	bool sq = pfault->type & MLX5_PFAULT_REQUESTOR;
1133 	u16 wqe_index = pfault->wqe.wqe_index;
1134 	void *wqe, *wqe_start = NULL, *wqe_end = NULL;
1135 	u32 bytes_mapped, total_wqe_bytes;
1136 	struct mlx5_core_rsc_common *res;
1137 	int resume_with_error = 1;
1138 	struct mlx5_ib_qp *qp;
1139 	size_t bytes_copied;
1140 	int ret = 0;
1141 
1142 	res = odp_get_rsc(dev, pfault->wqe.wq_num, pfault->type);
1143 	if (!res) {
1144 		mlx5_ib_dbg(dev, "wqe page fault for missing resource %d\n", pfault->wqe.wq_num);
1145 		return;
1146 	}
1147 
1148 	if (res->res != MLX5_RES_QP && res->res != MLX5_RES_SRQ &&
1149 	    res->res != MLX5_RES_XSRQ) {
1150 		mlx5_ib_err(dev, "wqe page fault for unsupported type %d\n",
1151 			    pfault->type);
1152 		goto resolve_page_fault;
1153 	}
1154 
1155 	wqe_start = (void *)__get_free_page(GFP_KERNEL);
1156 	if (!wqe_start) {
1157 		mlx5_ib_err(dev, "Error allocating memory for IO page fault handling.\n");
1158 		goto resolve_page_fault;
1159 	}
1160 
1161 	wqe = wqe_start;
1162 	qp = (res->res == MLX5_RES_QP) ? res_to_qp(res) : NULL;
1163 	if (qp && sq) {
1164 		ret = mlx5_ib_read_user_wqe_sq(qp, wqe_index, wqe, PAGE_SIZE,
1165 					       &bytes_copied);
1166 		if (ret)
1167 			goto read_user;
1168 		ret = mlx5_ib_mr_initiator_pfault_handler(
1169 			dev, pfault, qp, &wqe, &wqe_end, bytes_copied);
1170 	} else if (qp && !sq) {
1171 		ret = mlx5_ib_read_user_wqe_rq(qp, wqe_index, wqe, PAGE_SIZE,
1172 					       &bytes_copied);
1173 		if (ret)
1174 			goto read_user;
1175 		ret = mlx5_ib_mr_responder_pfault_handler_rq(
1176 			dev, qp, wqe, &wqe_end, bytes_copied);
1177 	} else if (!qp) {
1178 		struct mlx5_ib_srq *srq = res_to_srq(res);
1179 
1180 		ret = mlx5_ib_read_user_wqe_srq(srq, wqe_index, wqe, PAGE_SIZE,
1181 						&bytes_copied);
1182 		if (ret)
1183 			goto read_user;
1184 		ret = mlx5_ib_mr_responder_pfault_handler_srq(
1185 			dev, srq, &wqe, &wqe_end, bytes_copied);
1186 	}
1187 
1188 	if (ret < 0 || wqe >= wqe_end)
1189 		goto resolve_page_fault;
1190 
1191 	ret = pagefault_data_segments(dev, pfault, wqe, wqe_end, &bytes_mapped,
1192 				      &total_wqe_bytes, !sq);
1193 	if (ret == -EAGAIN)
1194 		goto out;
1195 
1196 	if (ret < 0 || total_wqe_bytes > bytes_mapped)
1197 		goto resolve_page_fault;
1198 
1199 out:
1200 	ret = 0;
1201 	resume_with_error = 0;
1202 
1203 read_user:
1204 	if (ret)
1205 		mlx5_ib_err(
1206 			dev,
1207 			"Failed reading a WQE following page fault, error %d, wqe_index %x, qpn %x\n",
1208 			ret, wqe_index, pfault->token);
1209 
1210 resolve_page_fault:
1211 	mlx5_ib_page_fault_resume(dev, pfault, resume_with_error);
1212 	mlx5_ib_dbg(dev, "PAGE FAULT completed. QP 0x%x resume_with_error=%d, type: 0x%x\n",
1213 		    pfault->wqe.wq_num, resume_with_error,
1214 		    pfault->type);
1215 	mlx5_core_res_put(res);
1216 	free_page((unsigned long)wqe_start);
1217 }
1218 
1219 static int pages_in_range(u64 address, u32 length)
1220 {
1221 	return (ALIGN(address + length, PAGE_SIZE) -
1222 		(address & PAGE_MASK)) >> PAGE_SHIFT;
1223 }
1224 
1225 static void mlx5_ib_mr_rdma_pfault_handler(struct mlx5_ib_dev *dev,
1226 					   struct mlx5_pagefault *pfault)
1227 {
1228 	u64 address;
1229 	u32 length;
1230 	u32 prefetch_len = pfault->bytes_committed;
1231 	int prefetch_activated = 0;
1232 	u32 rkey = pfault->rdma.r_key;
1233 	int ret;
1234 
1235 	/* The RDMA responder handler handles the page fault in two parts.
1236 	 * First it brings the necessary pages for the current packet
1237 	 * (and uses the pfault context), and then (after resuming the QP)
1238 	 * prefetches more pages. The second operation cannot use the pfault
1239 	 * context and therefore uses the dummy_pfault context allocated on
1240 	 * the stack */
1241 	pfault->rdma.rdma_va += pfault->bytes_committed;
1242 	pfault->rdma.rdma_op_len -= min(pfault->bytes_committed,
1243 					 pfault->rdma.rdma_op_len);
1244 	pfault->bytes_committed = 0;
1245 
1246 	address = pfault->rdma.rdma_va;
1247 	length  = pfault->rdma.rdma_op_len;
1248 
1249 	/* For some operations, the hardware cannot tell the exact message
1250 	 * length, and in those cases it reports zero. Use prefetch
1251 	 * logic. */
1252 	if (length == 0) {
1253 		prefetch_activated = 1;
1254 		length = pfault->rdma.packet_size;
1255 		prefetch_len = min(MAX_PREFETCH_LEN, prefetch_len);
1256 	}
1257 
1258 	ret = pagefault_single_data_segment(dev, NULL, rkey, address, length,
1259 					    &pfault->bytes_committed, NULL,
1260 					    0);
1261 	if (ret == -EAGAIN) {
1262 		/* We're racing with an invalidation, don't prefetch */
1263 		prefetch_activated = 0;
1264 	} else if (ret < 0 || pages_in_range(address, length) > ret) {
1265 		mlx5_ib_page_fault_resume(dev, pfault, 1);
1266 		if (ret != -ENOENT)
1267 			mlx5_ib_dbg(dev, "PAGE FAULT error %d. QP 0x%x, type: 0x%x\n",
1268 				    ret, pfault->token, pfault->type);
1269 		return;
1270 	}
1271 
1272 	mlx5_ib_page_fault_resume(dev, pfault, 0);
1273 	mlx5_ib_dbg(dev, "PAGE FAULT completed. QP 0x%x, type: 0x%x, prefetch_activated: %d\n",
1274 		    pfault->token, pfault->type,
1275 		    prefetch_activated);
1276 
1277 	/* At this point, there might be a new pagefault already arriving in
1278 	 * the eq, switch to the dummy pagefault for the rest of the
1279 	 * processing. We're still OK with the objects being alive as the
1280 	 * work-queue is being fenced. */
1281 
1282 	if (prefetch_activated) {
1283 		u32 bytes_committed = 0;
1284 
1285 		ret = pagefault_single_data_segment(dev, NULL, rkey, address,
1286 						    prefetch_len,
1287 						    &bytes_committed, NULL,
1288 						    0);
1289 		if (ret < 0 && ret != -EAGAIN) {
1290 			mlx5_ib_dbg(dev, "Prefetch failed. ret: %d, QP 0x%x, address: 0x%.16llx, length = 0x%.16x\n",
1291 				    ret, pfault->token, address, prefetch_len);
1292 		}
1293 	}
1294 }
1295 
1296 static void mlx5_ib_pfault(struct mlx5_ib_dev *dev, struct mlx5_pagefault *pfault)
1297 {
1298 	u8 event_subtype = pfault->event_subtype;
1299 
1300 	switch (event_subtype) {
1301 	case MLX5_PFAULT_SUBTYPE_WQE:
1302 		mlx5_ib_mr_wqe_pfault_handler(dev, pfault);
1303 		break;
1304 	case MLX5_PFAULT_SUBTYPE_RDMA:
1305 		mlx5_ib_mr_rdma_pfault_handler(dev, pfault);
1306 		break;
1307 	default:
1308 		mlx5_ib_err(dev, "Invalid page fault event subtype: 0x%x\n",
1309 			    event_subtype);
1310 		mlx5_ib_page_fault_resume(dev, pfault, 1);
1311 	}
1312 }
1313 
1314 static void mlx5_ib_eqe_pf_action(struct work_struct *work)
1315 {
1316 	struct mlx5_pagefault *pfault = container_of(work,
1317 						     struct mlx5_pagefault,
1318 						     work);
1319 	struct mlx5_ib_pf_eq *eq = pfault->eq;
1320 
1321 	mlx5_ib_pfault(eq->dev, pfault);
1322 	mempool_free(pfault, eq->pool);
1323 }
1324 
1325 static void mlx5_ib_eq_pf_process(struct mlx5_ib_pf_eq *eq)
1326 {
1327 	struct mlx5_eqe_page_fault *pf_eqe;
1328 	struct mlx5_pagefault *pfault;
1329 	struct mlx5_eqe *eqe;
1330 	int cc = 0;
1331 
1332 	while ((eqe = mlx5_eq_get_eqe(eq->core, cc))) {
1333 		pfault = mempool_alloc(eq->pool, GFP_ATOMIC);
1334 		if (!pfault) {
1335 			schedule_work(&eq->work);
1336 			break;
1337 		}
1338 
1339 		pf_eqe = &eqe->data.page_fault;
1340 		pfault->event_subtype = eqe->sub_type;
1341 		pfault->bytes_committed = be32_to_cpu(pf_eqe->bytes_committed);
1342 
1343 		mlx5_ib_dbg(eq->dev,
1344 			    "PAGE_FAULT: subtype: 0x%02x, bytes_committed: 0x%06x\n",
1345 			    eqe->sub_type, pfault->bytes_committed);
1346 
1347 		switch (eqe->sub_type) {
1348 		case MLX5_PFAULT_SUBTYPE_RDMA:
1349 			/* RDMA based event */
1350 			pfault->type =
1351 				be32_to_cpu(pf_eqe->rdma.pftype_token) >> 24;
1352 			pfault->token =
1353 				be32_to_cpu(pf_eqe->rdma.pftype_token) &
1354 				MLX5_24BIT_MASK;
1355 			pfault->rdma.r_key =
1356 				be32_to_cpu(pf_eqe->rdma.r_key);
1357 			pfault->rdma.packet_size =
1358 				be16_to_cpu(pf_eqe->rdma.packet_length);
1359 			pfault->rdma.rdma_op_len =
1360 				be32_to_cpu(pf_eqe->rdma.rdma_op_len);
1361 			pfault->rdma.rdma_va =
1362 				be64_to_cpu(pf_eqe->rdma.rdma_va);
1363 			mlx5_ib_dbg(eq->dev,
1364 				    "PAGE_FAULT: type:0x%x, token: 0x%06x, r_key: 0x%08x\n",
1365 				    pfault->type, pfault->token,
1366 				    pfault->rdma.r_key);
1367 			mlx5_ib_dbg(eq->dev,
1368 				    "PAGE_FAULT: rdma_op_len: 0x%08x, rdma_va: 0x%016llx\n",
1369 				    pfault->rdma.rdma_op_len,
1370 				    pfault->rdma.rdma_va);
1371 			break;
1372 
1373 		case MLX5_PFAULT_SUBTYPE_WQE:
1374 			/* WQE based event */
1375 			pfault->type =
1376 				(be32_to_cpu(pf_eqe->wqe.pftype_wq) >> 24) & 0x7;
1377 			pfault->token =
1378 				be32_to_cpu(pf_eqe->wqe.token);
1379 			pfault->wqe.wq_num =
1380 				be32_to_cpu(pf_eqe->wqe.pftype_wq) &
1381 				MLX5_24BIT_MASK;
1382 			pfault->wqe.wqe_index =
1383 				be16_to_cpu(pf_eqe->wqe.wqe_index);
1384 			pfault->wqe.packet_size =
1385 				be16_to_cpu(pf_eqe->wqe.packet_length);
1386 			mlx5_ib_dbg(eq->dev,
1387 				    "PAGE_FAULT: type:0x%x, token: 0x%06x, wq_num: 0x%06x, wqe_index: 0x%04x\n",
1388 				    pfault->type, pfault->token,
1389 				    pfault->wqe.wq_num,
1390 				    pfault->wqe.wqe_index);
1391 			break;
1392 
1393 		default:
1394 			mlx5_ib_warn(eq->dev,
1395 				     "Unsupported page fault event sub-type: 0x%02hhx\n",
1396 				     eqe->sub_type);
1397 			/* Unsupported page faults should still be
1398 			 * resolved by the page fault handler
1399 			 */
1400 		}
1401 
1402 		pfault->eq = eq;
1403 		INIT_WORK(&pfault->work, mlx5_ib_eqe_pf_action);
1404 		queue_work(eq->wq, &pfault->work);
1405 
1406 		cc = mlx5_eq_update_cc(eq->core, ++cc);
1407 	}
1408 
1409 	mlx5_eq_update_ci(eq->core, cc, 1);
1410 }
1411 
1412 static int mlx5_ib_eq_pf_int(struct notifier_block *nb, unsigned long type,
1413 			     void *data)
1414 {
1415 	struct mlx5_ib_pf_eq *eq =
1416 		container_of(nb, struct mlx5_ib_pf_eq, irq_nb);
1417 	unsigned long flags;
1418 
1419 	if (spin_trylock_irqsave(&eq->lock, flags)) {
1420 		mlx5_ib_eq_pf_process(eq);
1421 		spin_unlock_irqrestore(&eq->lock, flags);
1422 	} else {
1423 		schedule_work(&eq->work);
1424 	}
1425 
1426 	return IRQ_HANDLED;
1427 }
1428 
1429 /* mempool_refill() was proposed but unfortunately wasn't accepted
1430  * http://lkml.iu.edu/hypermail/linux/kernel/1512.1/05073.html
1431  * Cheap workaround.
1432  */
1433 static void mempool_refill(mempool_t *pool)
1434 {
1435 	while (pool->curr_nr < pool->min_nr)
1436 		mempool_free(mempool_alloc(pool, GFP_KERNEL), pool);
1437 }
1438 
1439 static void mlx5_ib_eq_pf_action(struct work_struct *work)
1440 {
1441 	struct mlx5_ib_pf_eq *eq =
1442 		container_of(work, struct mlx5_ib_pf_eq, work);
1443 
1444 	mempool_refill(eq->pool);
1445 
1446 	spin_lock_irq(&eq->lock);
1447 	mlx5_ib_eq_pf_process(eq);
1448 	spin_unlock_irq(&eq->lock);
1449 }
1450 
1451 enum {
1452 	MLX5_IB_NUM_PF_EQE	= 0x1000,
1453 	MLX5_IB_NUM_PF_DRAIN	= 64,
1454 };
1455 
1456 static int
1457 mlx5_ib_create_pf_eq(struct mlx5_ib_dev *dev, struct mlx5_ib_pf_eq *eq)
1458 {
1459 	struct mlx5_eq_param param = {};
1460 	int err;
1461 
1462 	INIT_WORK(&eq->work, mlx5_ib_eq_pf_action);
1463 	spin_lock_init(&eq->lock);
1464 	eq->dev = dev;
1465 
1466 	eq->pool = mempool_create_kmalloc_pool(MLX5_IB_NUM_PF_DRAIN,
1467 					       sizeof(struct mlx5_pagefault));
1468 	if (!eq->pool)
1469 		return -ENOMEM;
1470 
1471 	eq->wq = alloc_workqueue("mlx5_ib_page_fault",
1472 				 WQ_HIGHPRI | WQ_UNBOUND | WQ_MEM_RECLAIM,
1473 				 MLX5_NUM_CMD_EQE);
1474 	if (!eq->wq) {
1475 		err = -ENOMEM;
1476 		goto err_mempool;
1477 	}
1478 
1479 	eq->irq_nb.notifier_call = mlx5_ib_eq_pf_int;
1480 	param = (struct mlx5_eq_param) {
1481 		.irq_index = 0,
1482 		.nent = MLX5_IB_NUM_PF_EQE,
1483 	};
1484 	param.mask[0] = 1ull << MLX5_EVENT_TYPE_PAGE_FAULT;
1485 	eq->core = mlx5_eq_create_generic(dev->mdev, &param);
1486 	if (IS_ERR(eq->core)) {
1487 		err = PTR_ERR(eq->core);
1488 		goto err_wq;
1489 	}
1490 	err = mlx5_eq_enable(dev->mdev, eq->core, &eq->irq_nb);
1491 	if (err) {
1492 		mlx5_ib_err(dev, "failed to enable odp EQ %d\n", err);
1493 		goto err_eq;
1494 	}
1495 
1496 	return 0;
1497 err_eq:
1498 	mlx5_eq_destroy_generic(dev->mdev, eq->core);
1499 err_wq:
1500 	destroy_workqueue(eq->wq);
1501 err_mempool:
1502 	mempool_destroy(eq->pool);
1503 	return err;
1504 }
1505 
1506 static int
1507 mlx5_ib_destroy_pf_eq(struct mlx5_ib_dev *dev, struct mlx5_ib_pf_eq *eq)
1508 {
1509 	int err;
1510 
1511 	mlx5_eq_disable(dev->mdev, eq->core, &eq->irq_nb);
1512 	err = mlx5_eq_destroy_generic(dev->mdev, eq->core);
1513 	cancel_work_sync(&eq->work);
1514 	destroy_workqueue(eq->wq);
1515 	mempool_destroy(eq->pool);
1516 
1517 	return err;
1518 }
1519 
1520 void mlx5_odp_init_mr_cache_entry(struct mlx5_cache_ent *ent)
1521 {
1522 	if (!(ent->dev->odp_caps.general_caps & IB_ODP_SUPPORT_IMPLICIT))
1523 		return;
1524 
1525 	switch (ent->order - 2) {
1526 	case MLX5_IMR_MTT_CACHE_ENTRY:
1527 		ent->page = PAGE_SHIFT;
1528 		ent->xlt = MLX5_IMR_MTT_ENTRIES *
1529 			   sizeof(struct mlx5_mtt) /
1530 			   MLX5_IB_UMR_OCTOWORD;
1531 		ent->access_mode = MLX5_MKC_ACCESS_MODE_MTT;
1532 		ent->limit = 0;
1533 		break;
1534 
1535 	case MLX5_IMR_KSM_CACHE_ENTRY:
1536 		ent->page = MLX5_KSM_PAGE_SHIFT;
1537 		ent->xlt = mlx5_imr_ksm_entries *
1538 			   sizeof(struct mlx5_klm) /
1539 			   MLX5_IB_UMR_OCTOWORD;
1540 		ent->access_mode = MLX5_MKC_ACCESS_MODE_KSM;
1541 		ent->limit = 0;
1542 		break;
1543 	}
1544 }
1545 
1546 static const struct ib_device_ops mlx5_ib_dev_odp_ops = {
1547 	.advise_mr = mlx5_ib_advise_mr,
1548 	.invalidate_range = mlx5_ib_invalidate_range,
1549 };
1550 
1551 int mlx5_ib_odp_init_one(struct mlx5_ib_dev *dev)
1552 {
1553 	int ret = 0;
1554 
1555 	if (!(dev->odp_caps.general_caps & IB_ODP_SUPPORT))
1556 		return ret;
1557 
1558 	ib_set_device_ops(&dev->ib_dev, &mlx5_ib_dev_odp_ops);
1559 
1560 	if (dev->odp_caps.general_caps & IB_ODP_SUPPORT_IMPLICIT) {
1561 		ret = mlx5_cmd_null_mkey(dev->mdev, &dev->null_mkey);
1562 		if (ret) {
1563 			mlx5_ib_err(dev, "Error getting null_mkey %d\n", ret);
1564 			return ret;
1565 		}
1566 	}
1567 
1568 	ret = mlx5_ib_create_pf_eq(dev, &dev->odp_pf_eq);
1569 
1570 	return ret;
1571 }
1572 
1573 void mlx5_ib_odp_cleanup_one(struct mlx5_ib_dev *dev)
1574 {
1575 	if (!(dev->odp_caps.general_caps & IB_ODP_SUPPORT))
1576 		return;
1577 
1578 	mlx5_ib_destroy_pf_eq(dev, &dev->odp_pf_eq);
1579 }
1580 
1581 int mlx5_ib_odp_init(void)
1582 {
1583 	mlx5_imr_ksm_entries = BIT_ULL(get_order(TASK_SIZE) -
1584 				       MLX5_IMR_MTT_BITS);
1585 
1586 	return 0;
1587 }
1588 
1589 struct prefetch_mr_work {
1590 	struct work_struct work;
1591 	struct ib_pd *pd;
1592 	u32 pf_flags;
1593 	u32 num_sge;
1594 	struct ib_sge sg_list[0];
1595 };
1596 
1597 static void num_pending_prefetch_dec(struct mlx5_ib_dev *dev,
1598 				     struct ib_sge *sg_list, u32 num_sge,
1599 				     u32 from)
1600 {
1601 	u32 i;
1602 	int srcu_key;
1603 
1604 	srcu_key = srcu_read_lock(&dev->mr_srcu);
1605 
1606 	for (i = from; i < num_sge; ++i) {
1607 		struct mlx5_core_mkey *mmkey;
1608 		struct mlx5_ib_mr *mr;
1609 
1610 		mmkey = xa_load(&dev->mdev->priv.mkey_table,
1611 				mlx5_base_mkey(sg_list[i].lkey));
1612 		mr = container_of(mmkey, struct mlx5_ib_mr, mmkey);
1613 		atomic_dec(&mr->num_pending_prefetch);
1614 	}
1615 
1616 	srcu_read_unlock(&dev->mr_srcu, srcu_key);
1617 }
1618 
1619 static bool num_pending_prefetch_inc(struct ib_pd *pd,
1620 				     struct ib_sge *sg_list, u32 num_sge)
1621 {
1622 	struct mlx5_ib_dev *dev = to_mdev(pd->device);
1623 	bool ret = true;
1624 	u32 i;
1625 
1626 	for (i = 0; i < num_sge; ++i) {
1627 		struct mlx5_core_mkey *mmkey;
1628 		struct mlx5_ib_mr *mr;
1629 
1630 		mmkey = xa_load(&dev->mdev->priv.mkey_table,
1631 				mlx5_base_mkey(sg_list[i].lkey));
1632 		if (!mmkey || mmkey->key != sg_list[i].lkey) {
1633 			ret = false;
1634 			break;
1635 		}
1636 
1637 		if (mmkey->type != MLX5_MKEY_MR) {
1638 			ret = false;
1639 			break;
1640 		}
1641 
1642 		mr = container_of(mmkey, struct mlx5_ib_mr, mmkey);
1643 
1644 		if (mr->ibmr.pd != pd) {
1645 			ret = false;
1646 			break;
1647 		}
1648 
1649 		if (!mr->live) {
1650 			ret = false;
1651 			break;
1652 		}
1653 
1654 		atomic_inc(&mr->num_pending_prefetch);
1655 	}
1656 
1657 	if (!ret)
1658 		num_pending_prefetch_dec(dev, sg_list, i, 0);
1659 
1660 	return ret;
1661 }
1662 
1663 static int mlx5_ib_prefetch_sg_list(struct ib_pd *pd, u32 pf_flags,
1664 				    struct ib_sge *sg_list, u32 num_sge)
1665 {
1666 	u32 i;
1667 	int ret = 0;
1668 	struct mlx5_ib_dev *dev = to_mdev(pd->device);
1669 
1670 	for (i = 0; i < num_sge; ++i) {
1671 		struct ib_sge *sg = &sg_list[i];
1672 		int bytes_committed = 0;
1673 
1674 		ret = pagefault_single_data_segment(dev, pd, sg->lkey, sg->addr,
1675 						    sg->length,
1676 						    &bytes_committed, NULL,
1677 						    pf_flags);
1678 		if (ret < 0)
1679 			break;
1680 	}
1681 
1682 	return ret < 0 ? ret : 0;
1683 }
1684 
1685 static void mlx5_ib_prefetch_mr_work(struct work_struct *work)
1686 {
1687 	struct prefetch_mr_work *w =
1688 		container_of(work, struct prefetch_mr_work, work);
1689 
1690 	if (ib_device_try_get(w->pd->device)) {
1691 		mlx5_ib_prefetch_sg_list(w->pd, w->pf_flags, w->sg_list,
1692 					 w->num_sge);
1693 		ib_device_put(w->pd->device);
1694 	}
1695 
1696 	num_pending_prefetch_dec(to_mdev(w->pd->device), w->sg_list,
1697 				 w->num_sge, 0);
1698 	kvfree(w);
1699 }
1700 
1701 int mlx5_ib_advise_mr_prefetch(struct ib_pd *pd,
1702 			       enum ib_uverbs_advise_mr_advice advice,
1703 			       u32 flags, struct ib_sge *sg_list, u32 num_sge)
1704 {
1705 	struct mlx5_ib_dev *dev = to_mdev(pd->device);
1706 	u32 pf_flags = MLX5_PF_FLAGS_PREFETCH;
1707 	struct prefetch_mr_work *work;
1708 	bool valid_req;
1709 	int srcu_key;
1710 
1711 	if (advice == IB_UVERBS_ADVISE_MR_ADVICE_PREFETCH)
1712 		pf_flags |= MLX5_PF_FLAGS_DOWNGRADE;
1713 
1714 	if (flags & IB_UVERBS_ADVISE_MR_FLAG_FLUSH)
1715 		return mlx5_ib_prefetch_sg_list(pd, pf_flags, sg_list,
1716 						num_sge);
1717 
1718 	work = kvzalloc(struct_size(work, sg_list, num_sge), GFP_KERNEL);
1719 	if (!work)
1720 		return -ENOMEM;
1721 
1722 	memcpy(work->sg_list, sg_list, num_sge * sizeof(struct ib_sge));
1723 
1724 	/* It is guaranteed that the pd when work is executed is the pd when
1725 	 * work was queued since pd can't be destroyed while it holds MRs and
1726 	 * destroying a MR leads to flushing the workquque
1727 	 */
1728 	work->pd = pd;
1729 	work->pf_flags = pf_flags;
1730 	work->num_sge = num_sge;
1731 
1732 	INIT_WORK(&work->work, mlx5_ib_prefetch_mr_work);
1733 
1734 	srcu_key = srcu_read_lock(&dev->mr_srcu);
1735 
1736 	valid_req = num_pending_prefetch_inc(pd, sg_list, num_sge);
1737 	if (valid_req)
1738 		queue_work(system_unbound_wq, &work->work);
1739 	else
1740 		kvfree(work);
1741 
1742 	srcu_read_unlock(&dev->mr_srcu, srcu_key);
1743 
1744 	return valid_req ? 0 : -EINVAL;
1745 }
1746