xref: /openbmc/linux/drivers/infiniband/core/umem_odp.c (revision 4f2c0a4acffbec01079c28f839422e64ddeff004)
1  /*
2   * Copyright (c) 2014 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 <linux/types.h>
34  #include <linux/sched.h>
35  #include <linux/sched/mm.h>
36  #include <linux/sched/task.h>
37  #include <linux/pid.h>
38  #include <linux/slab.h>
39  #include <linux/export.h>
40  #include <linux/vmalloc.h>
41  #include <linux/hugetlb.h>
42  #include <linux/interval_tree.h>
43  #include <linux/hmm.h>
44  #include <linux/pagemap.h>
45  
46  #include <rdma/ib_umem_odp.h>
47  
48  #include "uverbs.h"
49  
ib_init_umem_odp(struct ib_umem_odp * umem_odp,const struct mmu_interval_notifier_ops * ops)50  static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
51  				   const struct mmu_interval_notifier_ops *ops)
52  {
53  	int ret;
54  
55  	umem_odp->umem.is_odp = 1;
56  	mutex_init(&umem_odp->umem_mutex);
57  
58  	if (!umem_odp->is_implicit_odp) {
59  		size_t page_size = 1UL << umem_odp->page_shift;
60  		unsigned long start;
61  		unsigned long end;
62  		size_t ndmas, npfns;
63  
64  		start = ALIGN_DOWN(umem_odp->umem.address, page_size);
65  		if (check_add_overflow(umem_odp->umem.address,
66  				       (unsigned long)umem_odp->umem.length,
67  				       &end))
68  			return -EOVERFLOW;
69  		end = ALIGN(end, page_size);
70  		if (unlikely(end < page_size))
71  			return -EOVERFLOW;
72  
73  		ndmas = (end - start) >> umem_odp->page_shift;
74  		if (!ndmas)
75  			return -EINVAL;
76  
77  		npfns = (end - start) >> PAGE_SHIFT;
78  		umem_odp->pfn_list = kvcalloc(
79  			npfns, sizeof(*umem_odp->pfn_list), GFP_KERNEL);
80  		if (!umem_odp->pfn_list)
81  			return -ENOMEM;
82  
83  		umem_odp->dma_list = kvcalloc(
84  			ndmas, sizeof(*umem_odp->dma_list), GFP_KERNEL);
85  		if (!umem_odp->dma_list) {
86  			ret = -ENOMEM;
87  			goto out_pfn_list;
88  		}
89  
90  		ret = mmu_interval_notifier_insert(&umem_odp->notifier,
91  						   umem_odp->umem.owning_mm,
92  						   start, end - start, ops);
93  		if (ret)
94  			goto out_dma_list;
95  	}
96  
97  	return 0;
98  
99  out_dma_list:
100  	kvfree(umem_odp->dma_list);
101  out_pfn_list:
102  	kvfree(umem_odp->pfn_list);
103  	return ret;
104  }
105  
106  /**
107   * ib_umem_odp_alloc_implicit - Allocate a parent implicit ODP umem
108   *
109   * Implicit ODP umems do not have a VA range and do not have any page lists.
110   * They exist only to hold the per_mm reference to help the driver create
111   * children umems.
112   *
113   * @device: IB device to create UMEM
114   * @access: ib_reg_mr access flags
115   */
ib_umem_odp_alloc_implicit(struct ib_device * device,int access)116  struct ib_umem_odp *ib_umem_odp_alloc_implicit(struct ib_device *device,
117  					       int access)
118  {
119  	struct ib_umem *umem;
120  	struct ib_umem_odp *umem_odp;
121  	int ret;
122  
123  	if (access & IB_ACCESS_HUGETLB)
124  		return ERR_PTR(-EINVAL);
125  
126  	umem_odp = kzalloc(sizeof(*umem_odp), GFP_KERNEL);
127  	if (!umem_odp)
128  		return ERR_PTR(-ENOMEM);
129  	umem = &umem_odp->umem;
130  	umem->ibdev = device;
131  	umem->writable = ib_access_writable(access);
132  	umem->owning_mm = current->mm;
133  	umem_odp->is_implicit_odp = 1;
134  	umem_odp->page_shift = PAGE_SHIFT;
135  
136  	umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID);
137  	ret = ib_init_umem_odp(umem_odp, NULL);
138  	if (ret) {
139  		put_pid(umem_odp->tgid);
140  		kfree(umem_odp);
141  		return ERR_PTR(ret);
142  	}
143  	return umem_odp;
144  }
145  EXPORT_SYMBOL(ib_umem_odp_alloc_implicit);
146  
147  /**
148   * ib_umem_odp_alloc_child - Allocate a child ODP umem under an implicit
149   *                           parent ODP umem
150   *
151   * @root: The parent umem enclosing the child. This must be allocated using
152   *        ib_alloc_implicit_odp_umem()
153   * @addr: The starting userspace VA
154   * @size: The length of the userspace VA
155   * @ops: MMU interval ops, currently only @invalidate
156   */
157  struct ib_umem_odp *
ib_umem_odp_alloc_child(struct ib_umem_odp * root,unsigned long addr,size_t size,const struct mmu_interval_notifier_ops * ops)158  ib_umem_odp_alloc_child(struct ib_umem_odp *root, unsigned long addr,
159  			size_t size,
160  			const struct mmu_interval_notifier_ops *ops)
161  {
162  	/*
163  	 * Caller must ensure that root cannot be freed during the call to
164  	 * ib_alloc_odp_umem.
165  	 */
166  	struct ib_umem_odp *odp_data;
167  	struct ib_umem *umem;
168  	int ret;
169  
170  	if (WARN_ON(!root->is_implicit_odp))
171  		return ERR_PTR(-EINVAL);
172  
173  	odp_data = kzalloc(sizeof(*odp_data), GFP_KERNEL);
174  	if (!odp_data)
175  		return ERR_PTR(-ENOMEM);
176  	umem = &odp_data->umem;
177  	umem->ibdev = root->umem.ibdev;
178  	umem->length     = size;
179  	umem->address    = addr;
180  	umem->writable   = root->umem.writable;
181  	umem->owning_mm  = root->umem.owning_mm;
182  	odp_data->page_shift = PAGE_SHIFT;
183  	odp_data->notifier.ops = ops;
184  
185  	/*
186  	 * A mmget must be held when registering a notifier, the owming_mm only
187  	 * has a mm_grab at this point.
188  	 */
189  	if (!mmget_not_zero(umem->owning_mm)) {
190  		ret = -EFAULT;
191  		goto out_free;
192  	}
193  
194  	odp_data->tgid = get_pid(root->tgid);
195  	ret = ib_init_umem_odp(odp_data, ops);
196  	if (ret)
197  		goto out_tgid;
198  	mmput(umem->owning_mm);
199  	return odp_data;
200  
201  out_tgid:
202  	put_pid(odp_data->tgid);
203  	mmput(umem->owning_mm);
204  out_free:
205  	kfree(odp_data);
206  	return ERR_PTR(ret);
207  }
208  EXPORT_SYMBOL(ib_umem_odp_alloc_child);
209  
210  /**
211   * ib_umem_odp_get - Create a umem_odp for a userspace va
212   *
213   * @device: IB device struct to get UMEM
214   * @addr: userspace virtual address to start at
215   * @size: length of region to pin
216   * @access: IB_ACCESS_xxx flags for memory being pinned
217   * @ops: MMU interval ops, currently only @invalidate
218   *
219   * The driver should use when the access flags indicate ODP memory. It avoids
220   * pinning, instead, stores the mm for future page fault handling in
221   * conjunction with MMU notifiers.
222   */
ib_umem_odp_get(struct ib_device * device,unsigned long addr,size_t size,int access,const struct mmu_interval_notifier_ops * ops)223  struct ib_umem_odp *ib_umem_odp_get(struct ib_device *device,
224  				    unsigned long addr, size_t size, int access,
225  				    const struct mmu_interval_notifier_ops *ops)
226  {
227  	struct ib_umem_odp *umem_odp;
228  	int ret;
229  
230  	if (WARN_ON_ONCE(!(access & IB_ACCESS_ON_DEMAND)))
231  		return ERR_PTR(-EINVAL);
232  
233  	umem_odp = kzalloc(sizeof(struct ib_umem_odp), GFP_KERNEL);
234  	if (!umem_odp)
235  		return ERR_PTR(-ENOMEM);
236  
237  	umem_odp->umem.ibdev = device;
238  	umem_odp->umem.length = size;
239  	umem_odp->umem.address = addr;
240  	umem_odp->umem.writable = ib_access_writable(access);
241  	umem_odp->umem.owning_mm = current->mm;
242  	umem_odp->notifier.ops = ops;
243  
244  	umem_odp->page_shift = PAGE_SHIFT;
245  #ifdef CONFIG_HUGETLB_PAGE
246  	if (access & IB_ACCESS_HUGETLB)
247  		umem_odp->page_shift = HPAGE_SHIFT;
248  #endif
249  
250  	umem_odp->tgid = get_task_pid(current->group_leader, PIDTYPE_PID);
251  	ret = ib_init_umem_odp(umem_odp, ops);
252  	if (ret)
253  		goto err_put_pid;
254  	return umem_odp;
255  
256  err_put_pid:
257  	put_pid(umem_odp->tgid);
258  	kfree(umem_odp);
259  	return ERR_PTR(ret);
260  }
261  EXPORT_SYMBOL(ib_umem_odp_get);
262  
ib_umem_odp_release(struct ib_umem_odp * umem_odp)263  void ib_umem_odp_release(struct ib_umem_odp *umem_odp)
264  {
265  	/*
266  	 * Ensure that no more pages are mapped in the umem.
267  	 *
268  	 * It is the driver's responsibility to ensure, before calling us,
269  	 * that the hardware will not attempt to access the MR any more.
270  	 */
271  	if (!umem_odp->is_implicit_odp) {
272  		mutex_lock(&umem_odp->umem_mutex);
273  		ib_umem_odp_unmap_dma_pages(umem_odp, ib_umem_start(umem_odp),
274  					    ib_umem_end(umem_odp));
275  		mutex_unlock(&umem_odp->umem_mutex);
276  		mmu_interval_notifier_remove(&umem_odp->notifier);
277  		kvfree(umem_odp->dma_list);
278  		kvfree(umem_odp->pfn_list);
279  	}
280  	put_pid(umem_odp->tgid);
281  	kfree(umem_odp);
282  }
283  EXPORT_SYMBOL(ib_umem_odp_release);
284  
285  /*
286   * Map for DMA and insert a single page into the on-demand paging page tables.
287   *
288   * @umem: the umem to insert the page to.
289   * @dma_index: index in the umem to add the dma to.
290   * @page: the page struct to map and add.
291   * @access_mask: access permissions needed for this page.
292   *
293   * The function returns -EFAULT if the DMA mapping operation fails.
294   *
295   */
ib_umem_odp_map_dma_single_page(struct ib_umem_odp * umem_odp,unsigned int dma_index,struct page * page,u64 access_mask)296  static int ib_umem_odp_map_dma_single_page(
297  		struct ib_umem_odp *umem_odp,
298  		unsigned int dma_index,
299  		struct page *page,
300  		u64 access_mask)
301  {
302  	struct ib_device *dev = umem_odp->umem.ibdev;
303  	dma_addr_t *dma_addr = &umem_odp->dma_list[dma_index];
304  
305  	if (*dma_addr) {
306  		/*
307  		 * If the page is already dma mapped it means it went through
308  		 * a non-invalidating trasition, like read-only to writable.
309  		 * Resync the flags.
310  		 */
311  		*dma_addr = (*dma_addr & ODP_DMA_ADDR_MASK) | access_mask;
312  		return 0;
313  	}
314  
315  	*dma_addr = ib_dma_map_page(dev, page, 0, 1 << umem_odp->page_shift,
316  				    DMA_BIDIRECTIONAL);
317  	if (ib_dma_mapping_error(dev, *dma_addr)) {
318  		*dma_addr = 0;
319  		return -EFAULT;
320  	}
321  	umem_odp->npages++;
322  	*dma_addr |= access_mask;
323  	return 0;
324  }
325  
326  /**
327   * ib_umem_odp_map_dma_and_lock - DMA map userspace memory in an ODP MR and lock it.
328   *
329   * Maps the range passed in the argument to DMA addresses.
330   * The DMA addresses of the mapped pages is updated in umem_odp->dma_list.
331   * Upon success the ODP MR will be locked to let caller complete its device
332   * page table update.
333   *
334   * Returns the number of pages mapped in success, negative error code
335   * for failure.
336   * @umem_odp: the umem to map and pin
337   * @user_virt: the address from which we need to map.
338   * @bcnt: the minimal number of bytes to pin and map. The mapping might be
339   *        bigger due to alignment, and may also be smaller in case of an error
340   *        pinning or mapping a page. The actual pages mapped is returned in
341   *        the return value.
342   * @access_mask: bit mask of the requested access permissions for the given
343   *               range.
344   * @fault: is faulting required for the given range
345   */
ib_umem_odp_map_dma_and_lock(struct ib_umem_odp * umem_odp,u64 user_virt,u64 bcnt,u64 access_mask,bool fault)346  int ib_umem_odp_map_dma_and_lock(struct ib_umem_odp *umem_odp, u64 user_virt,
347  				 u64 bcnt, u64 access_mask, bool fault)
348  			__acquires(&umem_odp->umem_mutex)
349  {
350  	struct task_struct *owning_process  = NULL;
351  	struct mm_struct *owning_mm = umem_odp->umem.owning_mm;
352  	int pfn_index, dma_index, ret = 0, start_idx;
353  	unsigned int page_shift, hmm_order, pfn_start_idx;
354  	unsigned long num_pfns, current_seq;
355  	struct hmm_range range = {};
356  	unsigned long timeout;
357  
358  	if (access_mask == 0)
359  		return -EINVAL;
360  
361  	if (user_virt < ib_umem_start(umem_odp) ||
362  	    user_virt + bcnt > ib_umem_end(umem_odp))
363  		return -EFAULT;
364  
365  	page_shift = umem_odp->page_shift;
366  
367  	/*
368  	 * owning_process is allowed to be NULL, this means somehow the mm is
369  	 * existing beyond the lifetime of the originating process.. Presumably
370  	 * mmget_not_zero will fail in this case.
371  	 */
372  	owning_process = get_pid_task(umem_odp->tgid, PIDTYPE_PID);
373  	if (!owning_process || !mmget_not_zero(owning_mm)) {
374  		ret = -EINVAL;
375  		goto out_put_task;
376  	}
377  
378  	range.notifier = &umem_odp->notifier;
379  	range.start = ALIGN_DOWN(user_virt, 1UL << page_shift);
380  	range.end = ALIGN(user_virt + bcnt, 1UL << page_shift);
381  	pfn_start_idx = (range.start - ib_umem_start(umem_odp)) >> PAGE_SHIFT;
382  	num_pfns = (range.end - range.start) >> PAGE_SHIFT;
383  	if (fault) {
384  		range.default_flags = HMM_PFN_REQ_FAULT;
385  
386  		if (access_mask & ODP_WRITE_ALLOWED_BIT)
387  			range.default_flags |= HMM_PFN_REQ_WRITE;
388  	}
389  
390  	range.hmm_pfns = &(umem_odp->pfn_list[pfn_start_idx]);
391  	timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
392  
393  retry:
394  	current_seq = range.notifier_seq =
395  		mmu_interval_read_begin(&umem_odp->notifier);
396  
397  	mmap_read_lock(owning_mm);
398  	ret = hmm_range_fault(&range);
399  	mmap_read_unlock(owning_mm);
400  	if (unlikely(ret)) {
401  		if (ret == -EBUSY && !time_after(jiffies, timeout))
402  			goto retry;
403  		goto out_put_mm;
404  	}
405  
406  	start_idx = (range.start - ib_umem_start(umem_odp)) >> page_shift;
407  	dma_index = start_idx;
408  
409  	mutex_lock(&umem_odp->umem_mutex);
410  	if (mmu_interval_read_retry(&umem_odp->notifier, current_seq)) {
411  		mutex_unlock(&umem_odp->umem_mutex);
412  		goto retry;
413  	}
414  
415  	for (pfn_index = 0; pfn_index < num_pfns;
416  		pfn_index += 1 << (page_shift - PAGE_SHIFT), dma_index++) {
417  
418  		if (fault) {
419  			/*
420  			 * Since we asked for hmm_range_fault() to populate
421  			 * pages it shouldn't return an error entry on success.
422  			 */
423  			WARN_ON(range.hmm_pfns[pfn_index] & HMM_PFN_ERROR);
424  			WARN_ON(!(range.hmm_pfns[pfn_index] & HMM_PFN_VALID));
425  		} else {
426  			if (!(range.hmm_pfns[pfn_index] & HMM_PFN_VALID)) {
427  				WARN_ON(umem_odp->dma_list[dma_index]);
428  				continue;
429  			}
430  			access_mask = ODP_READ_ALLOWED_BIT;
431  			if (range.hmm_pfns[pfn_index] & HMM_PFN_WRITE)
432  				access_mask |= ODP_WRITE_ALLOWED_BIT;
433  		}
434  
435  		hmm_order = hmm_pfn_to_map_order(range.hmm_pfns[pfn_index]);
436  		/* If a hugepage was detected and ODP wasn't set for, the umem
437  		 * page_shift will be used, the opposite case is an error.
438  		 */
439  		if (hmm_order + PAGE_SHIFT < page_shift) {
440  			ret = -EINVAL;
441  			ibdev_dbg(umem_odp->umem.ibdev,
442  				  "%s: un-expected hmm_order %u, page_shift %u\n",
443  				  __func__, hmm_order, page_shift);
444  			break;
445  		}
446  
447  		ret = ib_umem_odp_map_dma_single_page(
448  				umem_odp, dma_index, hmm_pfn_to_page(range.hmm_pfns[pfn_index]),
449  				access_mask);
450  		if (ret < 0) {
451  			ibdev_dbg(umem_odp->umem.ibdev,
452  				  "ib_umem_odp_map_dma_single_page failed with error %d\n", ret);
453  			break;
454  		}
455  	}
456  	/* upon success lock should stay on hold for the callee */
457  	if (!ret)
458  		ret = dma_index - start_idx;
459  	else
460  		mutex_unlock(&umem_odp->umem_mutex);
461  
462  out_put_mm:
463  	mmput_async(owning_mm);
464  out_put_task:
465  	if (owning_process)
466  		put_task_struct(owning_process);
467  	return ret;
468  }
469  EXPORT_SYMBOL(ib_umem_odp_map_dma_and_lock);
470  
ib_umem_odp_unmap_dma_pages(struct ib_umem_odp * umem_odp,u64 virt,u64 bound)471  void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt,
472  				 u64 bound)
473  {
474  	dma_addr_t dma_addr;
475  	dma_addr_t dma;
476  	int idx;
477  	u64 addr;
478  	struct ib_device *dev = umem_odp->umem.ibdev;
479  
480  	lockdep_assert_held(&umem_odp->umem_mutex);
481  
482  	virt = max_t(u64, virt, ib_umem_start(umem_odp));
483  	bound = min_t(u64, bound, ib_umem_end(umem_odp));
484  	for (addr = virt; addr < bound; addr += BIT(umem_odp->page_shift)) {
485  		idx = (addr - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
486  		dma = umem_odp->dma_list[idx];
487  
488  		/* The access flags guaranteed a valid DMA address in case was NULL */
489  		if (dma) {
490  			unsigned long pfn_idx = (addr - ib_umem_start(umem_odp)) >> PAGE_SHIFT;
491  			struct page *page = hmm_pfn_to_page(umem_odp->pfn_list[pfn_idx]);
492  
493  			dma_addr = dma & ODP_DMA_ADDR_MASK;
494  			ib_dma_unmap_page(dev, dma_addr,
495  					  BIT(umem_odp->page_shift),
496  					  DMA_BIDIRECTIONAL);
497  			if (dma & ODP_WRITE_ALLOWED_BIT) {
498  				struct page *head_page = compound_head(page);
499  				/*
500  				 * set_page_dirty prefers being called with
501  				 * the page lock. However, MMU notifiers are
502  				 * called sometimes with and sometimes without
503  				 * the lock. We rely on the umem_mutex instead
504  				 * to prevent other mmu notifiers from
505  				 * continuing and allowing the page mapping to
506  				 * be removed.
507  				 */
508  				set_page_dirty(head_page);
509  			}
510  			umem_odp->dma_list[idx] = 0;
511  			umem_odp->npages--;
512  		}
513  	}
514  }
515  EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages);
516