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 #ifndef IB_UMEM_ODP_H
34 #define IB_UMEM_ODP_H
35
36 #include <rdma/ib_umem.h>
37 #include <rdma/ib_verbs.h>
38 #include <linux/interval_tree.h>
39
40 struct ib_umem_odp {
41 struct ib_umem umem;
42 struct ib_ucontext_per_mm *per_mm;
43
44 /*
45 * An array of the pages included in the on-demand paging umem.
46 * Indices of pages that are currently not mapped into the device will
47 * contain NULL.
48 */
49 struct page **page_list;
50 /*
51 * An array of the same size as page_list, with DMA addresses mapped
52 * for pages the pages in page_list. The lower two bits designate
53 * access permissions. See ODP_READ_ALLOWED_BIT and
54 * ODP_WRITE_ALLOWED_BIT.
55 */
56 dma_addr_t *dma_list;
57 /*
58 * The umem_mutex protects the page_list and dma_list fields of an ODP
59 * umem, allowing only a single thread to map/unmap pages. The mutex
60 * also protects access to the mmu notifier counters.
61 */
62 struct mutex umem_mutex;
63 void *private; /* for the HW driver to use. */
64
65 int notifiers_seq;
66 int notifiers_count;
67 int npages;
68
69 /* Tree tracking */
70 struct interval_tree_node interval_tree;
71
72 /*
73 * An implicit odp umem cannot be DMA mapped, has 0 length, and serves
74 * only as an anchor for the driver to hold onto the per_mm. FIXME:
75 * This should be removed and drivers should work with the per_mm
76 * directly.
77 */
78 bool is_implicit_odp;
79
80 struct completion notifier_completion;
81 int dying;
82 unsigned int page_shift;
83 struct work_struct work;
84 };
85
86 static inline struct ib_umem_odp *to_ib_umem_odp(struct ib_umem *umem)
87 {
88 return container_of(umem, struct ib_umem_odp, umem);
89 }
90
91 /* Returns the first page of an ODP umem. */
92 static inline unsigned long ib_umem_start(struct ib_umem_odp *umem_odp)
93 {
94 return umem_odp->interval_tree.start;
95 }
96
97 /* Returns the address of the page after the last one of an ODP umem. */
98 static inline unsigned long ib_umem_end(struct ib_umem_odp *umem_odp)
99 {
100 return umem_odp->interval_tree.last + 1;
101 }
102
103 static inline size_t ib_umem_odp_num_pages(struct ib_umem_odp *umem_odp)
104 {
105 return (ib_umem_end(umem_odp) - ib_umem_start(umem_odp)) >>
106 umem_odp->page_shift;
107 }
108
109 /*
110 * The lower 2 bits of the DMA address signal the R/W permissions for
111 * the entry. To upgrade the permissions, provide the appropriate
112 * bitmask to the map_dma_pages function.
113 *
114 * Be aware that upgrading a mapped address might result in change of
115 * the DMA address for the page.
116 */
117 #define ODP_READ_ALLOWED_BIT (1<<0ULL)
118 #define ODP_WRITE_ALLOWED_BIT (1<<1ULL)
119
120 #define ODP_DMA_ADDR_MASK (~(ODP_READ_ALLOWED_BIT | ODP_WRITE_ALLOWED_BIT))
121
122 #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
123
124 struct ib_ucontext_per_mm {
125 struct mmu_notifier mn;
126 struct pid *tgid;
127
128 struct rb_root_cached umem_tree;
129 /* Protects umem_tree */
130 struct rw_semaphore umem_rwsem;
131 };
132
133 struct ib_umem_odp *ib_umem_odp_get(struct ib_udata *udata, unsigned long addr,
134 size_t size, int access);
135 struct ib_umem_odp *ib_umem_odp_alloc_implicit(struct ib_udata *udata,
136 int access);
137 struct ib_umem_odp *ib_umem_odp_alloc_child(struct ib_umem_odp *root_umem,
138 unsigned long addr, size_t size);
139 void ib_umem_odp_release(struct ib_umem_odp *umem_odp);
140
141 int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 start_offset,
142 u64 bcnt, u64 access_mask,
143 unsigned long current_seq);
144
145 void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 start_offset,
146 u64 bound);
147
148 typedef int (*umem_call_back)(struct ib_umem_odp *item, u64 start, u64 end,
149 void *cookie);
150 /*
151 * Call the callback on each ib_umem in the range. Returns the logical or of
152 * the return values of the functions called.
153 */
154 int rbt_ib_umem_for_each_in_range(struct rb_root_cached *root,
155 u64 start, u64 end,
156 umem_call_back cb,
157 bool blockable, void *cookie);
158
159 /*
160 * Find first region intersecting with address range.
161 * Return NULL if not found
162 */
163 static inline struct ib_umem_odp *
164 rbt_ib_umem_lookup(struct rb_root_cached *root, u64 addr, u64 length)
165 {
166 struct interval_tree_node *node;
167
168 node = interval_tree_iter_first(root, addr, addr + length - 1);
169 if (!node)
170 return NULL;
171 return container_of(node, struct ib_umem_odp, interval_tree);
172
173 }
174
175 static inline int ib_umem_mmu_notifier_retry(struct ib_umem_odp *umem_odp,
176 unsigned long mmu_seq)
177 {
178 /*
179 * This code is strongly based on the KVM code from
180 * mmu_notifier_retry. Should be called with
181 * the relevant locks taken (umem_odp->umem_mutex
182 * and the ucontext umem_mutex semaphore locked for read).
183 */
184
185 if (unlikely(umem_odp->notifiers_count))
186 return 1;
187 if (umem_odp->notifiers_seq != mmu_seq)
188 return 1;
189 return 0;
190 }
191
192 #else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
193
194 static inline struct ib_umem_odp *ib_umem_odp_get(struct ib_udata *udata,
195 unsigned long addr,
196 size_t size, int access)
197 {
198 return ERR_PTR(-EINVAL);
199 }
200
201 static inline void ib_umem_odp_release(struct ib_umem_odp *umem_odp) {}
202
203 #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
204
205 #endif /* IB_UMEM_ODP_H */