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c942fddf | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
133ff0ea JG |
2 | /* |
3 | * Copyright 2013 Red Hat Inc. | |
4 | * | |
f813f219 | 5 | * Authors: Jérôme Glisse <jglisse@redhat.com> |
133ff0ea | 6 | * |
ee65728e | 7 | * See Documentation/mm/hmm.rst for reasons and overview of what HMM is. |
133ff0ea JG |
8 | */ |
9 | #ifndef LINUX_HMM_H | |
10 | #define LINUX_HMM_H | |
11 | ||
730ff521 | 12 | #include <linux/mm.h> |
133ff0ea | 13 | |
730ff521 | 14 | struct mmu_interval_notifier; |
4ef589dc | 15 | |
133ff0ea | 16 | /* |
2733ea14 JG |
17 | * On output: |
18 | * 0 - The page is faultable and a future call with | |
19 | * HMM_PFN_REQ_FAULT could succeed. | |
20 | * HMM_PFN_VALID - the pfn field points to a valid PFN. This PFN is at | |
21 | * least readable. If dev_private_owner is !NULL then this could | |
22 | * point at a DEVICE_PRIVATE page. | |
23 | * HMM_PFN_WRITE - if the page memory can be written to (requires HMM_PFN_VALID) | |
24 | * HMM_PFN_ERROR - accessing the pfn is impossible and the device should | |
25 | * fail. ie poisoned memory, special pages, no vma, etc | |
8cad4713 LR |
26 | * HMM_PFN_P2PDMA - P2P page |
27 | * HMM_PFN_P2PDMA_BUS - Bus mapped P2P transfer | |
285e8718 LR |
28 | * HMM_PFN_DMA_MAPPED - Flag preserved on input-to-output transformation |
29 | * to mark that page is already DMA mapped | |
f88a1e90 | 30 | * |
2733ea14 JG |
31 | * On input: |
32 | * 0 - Return the current state of the page, do not fault it. | |
33 | * HMM_PFN_REQ_FAULT - The output must have HMM_PFN_VALID or hmm_range_fault() | |
34 | * will fail | |
35 | * HMM_PFN_REQ_WRITE - The output must have HMM_PFN_WRITE or hmm_range_fault() | |
36 | * will fail. Must be combined with HMM_PFN_REQ_FAULT. | |
f88a1e90 | 37 | */ |
2733ea14 | 38 | enum hmm_pfn_flags { |
3b50a6e5 | 39 | /* Output fields and flags */ |
2733ea14 JG |
40 | HMM_PFN_VALID = 1UL << (BITS_PER_LONG - 1), |
41 | HMM_PFN_WRITE = 1UL << (BITS_PER_LONG - 2), | |
42 | HMM_PFN_ERROR = 1UL << (BITS_PER_LONG - 3), | |
285e8718 LR |
43 | /* |
44 | * Sticky flags, carried from input to output, | |
45 | * don't forget to update HMM_PFN_INOUT_FLAGS | |
46 | */ | |
47 | HMM_PFN_DMA_MAPPED = 1UL << (BITS_PER_LONG - 4), | |
8cad4713 LR |
48 | HMM_PFN_P2PDMA = 1UL << (BITS_PER_LONG - 5), |
49 | HMM_PFN_P2PDMA_BUS = 1UL << (BITS_PER_LONG - 6), | |
285e8718 | 50 | |
8cad4713 | 51 | HMM_PFN_ORDER_SHIFT = (BITS_PER_LONG - 11), |
2733ea14 JG |
52 | |
53 | /* Input flags */ | |
54 | HMM_PFN_REQ_FAULT = HMM_PFN_VALID, | |
55 | HMM_PFN_REQ_WRITE = HMM_PFN_WRITE, | |
56 | ||
285e8718 | 57 | HMM_PFN_FLAGS = ~((1UL << HMM_PFN_ORDER_SHIFT) - 1), |
f88a1e90 JG |
58 | }; |
59 | ||
60 | /* | |
2733ea14 | 61 | * hmm_pfn_to_page() - return struct page pointed to by a device entry |
f88a1e90 | 62 | * |
2733ea14 JG |
63 | * This must be called under the caller 'user_lock' after a successful |
64 | * mmu_interval_read_begin(). The caller must have tested for HMM_PFN_VALID | |
65 | * already. | |
133ff0ea | 66 | */ |
2733ea14 JG |
67 | static inline struct page *hmm_pfn_to_page(unsigned long hmm_pfn) |
68 | { | |
69 | return pfn_to_page(hmm_pfn & ~HMM_PFN_FLAGS); | |
70 | } | |
f88a1e90 | 71 | |
285e8718 LR |
72 | /* |
73 | * hmm_pfn_to_phys() - return physical address pointed to by a device entry | |
74 | */ | |
75 | static inline phys_addr_t hmm_pfn_to_phys(unsigned long hmm_pfn) | |
76 | { | |
77 | return __pfn_to_phys(hmm_pfn & ~HMM_PFN_FLAGS); | |
78 | } | |
79 | ||
3b50a6e5 RC |
80 | /* |
81 | * hmm_pfn_to_map_order() - return the CPU mapping size order | |
82 | * | |
83 | * This is optionally useful to optimize processing of the pfn result | |
84 | * array. It indicates that the page starts at the order aligned VA and is | |
85 | * 1<<order bytes long. Every pfn within an high order page will have the | |
86 | * same pfn flags, both access protections and the map_order. The caller must | |
87 | * be careful with edge cases as the start and end VA of the given page may | |
88 | * extend past the range used with hmm_range_fault(). | |
89 | * | |
90 | * This must be called under the caller 'user_lock' after a successful | |
91 | * mmu_interval_read_begin(). The caller must have tested for HMM_PFN_VALID | |
92 | * already. | |
93 | */ | |
94 | static inline unsigned int hmm_pfn_to_map_order(unsigned long hmm_pfn) | |
95 | { | |
96 | return (hmm_pfn >> HMM_PFN_ORDER_SHIFT) & 0x1F; | |
97 | } | |
98 | ||
f88a1e90 JG |
99 | /* |
100 | * struct hmm_range - track invalidation lock on virtual address range | |
101 | * | |
a22dd506 JG |
102 | * @notifier: a mmu_interval_notifier that includes the start/end |
103 | * @notifier_seq: result of mmu_interval_read_begin() | |
f88a1e90 JG |
104 | * @start: range virtual start address (inclusive) |
105 | * @end: range virtual end address (exclusive) | |
2733ea14 | 106 | * @hmm_pfns: array of pfns (big enough for the range) |
023a019a JG |
107 | * @default_flags: default flags for the range (write, read, ... see hmm doc) |
108 | * @pfn_flags_mask: allows to mask pfn flags so that only default_flags matter | |
08ddddda | 109 | * @dev_private_owner: owner of device private pages |
f88a1e90 JG |
110 | */ |
111 | struct hmm_range { | |
04ec32fb JG |
112 | struct mmu_interval_notifier *notifier; |
113 | unsigned long notifier_seq; | |
f88a1e90 JG |
114 | unsigned long start; |
115 | unsigned long end; | |
2733ea14 JG |
116 | unsigned long *hmm_pfns; |
117 | unsigned long default_flags; | |
118 | unsigned long pfn_flags_mask; | |
08ddddda | 119 | void *dev_private_owner; |
f88a1e90 | 120 | }; |
133ff0ea | 121 | |
da4c3c73 | 122 | /* |
ee65728e | 123 | * Please see Documentation/mm/hmm.rst for how to use the range API. |
da4c3c73 | 124 | */ |
be957c88 | 125 | int hmm_range_fault(struct hmm_range *range); |
74eee180 JG |
126 | |
127 | /* | |
a3e0d41c | 128 | * HMM_RANGE_DEFAULT_TIMEOUT - default timeout (ms) when waiting for a range |
74eee180 | 129 | * |
a3e0d41c | 130 | * When waiting for mmu notifiers we need some kind of time out otherwise we |
06c88398 | 131 | * could potentially wait for ever, 1000ms ie 1s sounds like a long time to |
a3e0d41c | 132 | * wait already. |
74eee180 | 133 | */ |
a3e0d41c JG |
134 | #define HMM_RANGE_DEFAULT_TIMEOUT 1000 |
135 | ||
133ff0ea | 136 | #endif /* LINUX_HMM_H */ |