xref: /openbmc/linux/include/rdma/ib_umem_odp.h (revision 842ed298)
1 /* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
2 /*
3  * Copyright (c) 2014 Mellanox Technologies. All rights reserved.
4  */
5 
6 #ifndef IB_UMEM_ODP_H
7 #define IB_UMEM_ODP_H
8 
9 #include <rdma/ib_umem.h>
10 #include <rdma/ib_verbs.h>
11 
12 struct ib_umem_odp {
13 	struct ib_umem umem;
14 	struct mmu_interval_notifier notifier;
15 	struct pid *tgid;
16 
17 	/* An array of the pfns included in the on-demand paging umem. */
18 	unsigned long *pfn_list;
19 
20 	/*
21 	 * An array with DMA addresses mapped for pfns in pfn_list.
22 	 * The lower two bits designate access permissions.
23 	 * See ODP_READ_ALLOWED_BIT and ODP_WRITE_ALLOWED_BIT.
24 	 */
25 	dma_addr_t		*dma_list;
26 	/*
27 	 * The umem_mutex protects the page_list and dma_list fields of an ODP
28 	 * umem, allowing only a single thread to map/unmap pages. The mutex
29 	 * also protects access to the mmu notifier counters.
30 	 */
31 	struct mutex		umem_mutex;
32 	void			*private; /* for the HW driver to use. */
33 
34 	int npages;
35 
36 	/*
37 	 * An implicit odp umem cannot be DMA mapped, has 0 length, and serves
38 	 * only as an anchor for the driver to hold onto the per_mm. FIXME:
39 	 * This should be removed and drivers should work with the per_mm
40 	 * directly.
41 	 */
42 	bool is_implicit_odp;
43 
44 	unsigned int		page_shift;
45 };
46 
47 static inline struct ib_umem_odp *to_ib_umem_odp(struct ib_umem *umem)
48 {
49 	return container_of(umem, struct ib_umem_odp, umem);
50 }
51 
52 /* Returns the first page of an ODP umem. */
53 static inline unsigned long ib_umem_start(struct ib_umem_odp *umem_odp)
54 {
55 	return umem_odp->notifier.interval_tree.start;
56 }
57 
58 /* Returns the address of the page after the last one of an ODP umem. */
59 static inline unsigned long ib_umem_end(struct ib_umem_odp *umem_odp)
60 {
61 	return umem_odp->notifier.interval_tree.last + 1;
62 }
63 
64 static inline size_t ib_umem_odp_num_pages(struct ib_umem_odp *umem_odp)
65 {
66 	return (ib_umem_end(umem_odp) - ib_umem_start(umem_odp)) >>
67 	       umem_odp->page_shift;
68 }
69 
70 /*
71  * The lower 2 bits of the DMA address signal the R/W permissions for
72  * the entry. To upgrade the permissions, provide the appropriate
73  * bitmask to the map_dma_pages function.
74  *
75  * Be aware that upgrading a mapped address might result in change of
76  * the DMA address for the page.
77  */
78 #define ODP_READ_ALLOWED_BIT  (1<<0ULL)
79 #define ODP_WRITE_ALLOWED_BIT (1<<1ULL)
80 
81 #define ODP_DMA_ADDR_MASK (~(ODP_READ_ALLOWED_BIT | ODP_WRITE_ALLOWED_BIT))
82 
83 #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
84 
85 struct ib_umem_odp *
86 ib_umem_odp_get(struct ib_device *device, unsigned long addr, size_t size,
87 		int access, const struct mmu_interval_notifier_ops *ops);
88 struct ib_umem_odp *ib_umem_odp_alloc_implicit(struct ib_device *device,
89 					       int access);
90 struct ib_umem_odp *
91 ib_umem_odp_alloc_child(struct ib_umem_odp *root_umem, unsigned long addr,
92 			size_t size,
93 			const struct mmu_interval_notifier_ops *ops);
94 void ib_umem_odp_release(struct ib_umem_odp *umem_odp);
95 
96 int ib_umem_odp_map_dma_and_lock(struct ib_umem_odp *umem_odp, u64 start_offset,
97 				 u64 bcnt, u64 access_mask, bool fault);
98 
99 void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 start_offset,
100 				 u64 bound);
101 
102 #else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
103 
104 static inline struct ib_umem_odp *
105 ib_umem_odp_get(struct ib_device *device, unsigned long addr, size_t size,
106 		int access, const struct mmu_interval_notifier_ops *ops)
107 {
108 	return ERR_PTR(-EINVAL);
109 }
110 
111 static inline void ib_umem_odp_release(struct ib_umem_odp *umem_odp) {}
112 
113 #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
114 
115 #endif /* IB_UMEM_ODP_H */
116