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1 | /* |
2 | * Copyright © 2015 Intel Corporation. | |
3 | * | |
4 | * Authors: David Woodhouse <David.Woodhouse@intel.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms and conditions of the GNU General Public License, | |
8 | * version 2, as published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope it will be useful, but WITHOUT | |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
13 | * more details. | |
14 | */ | |
15 | ||
16 | #ifndef __INTEL_SVM_H__ | |
17 | #define __INTEL_SVM_H__ | |
18 | ||
19 | #ifdef CONFIG_INTEL_IOMMU_SVM | |
20 | ||
21 | struct device; | |
22 | ||
0204a496 DW |
23 | struct svm_dev_ops { |
24 | void (*fault_cb)(struct device *dev, int pasid, u64 address, | |
25 | u32 private, int rwxp, int response); | |
26 | }; | |
27 | ||
28 | /* Values for rxwp in fault_cb callback */ | |
29 | #define SVM_REQ_READ (1<<3) | |
30 | #define SVM_REQ_WRITE (1<<2) | |
31 | #define SVM_REQ_EXEC (1<<1) | |
32 | #define SVM_REQ_PRIV (1<<0) | |
33 | ||
569e4f77 DW |
34 | |
35 | /* | |
36 | * The SVM_FLAG_PRIVATE_PASID flag requests a PASID which is *not* the "main" | |
37 | * PASID for the current process. Even if a PASID already exists, a new one | |
38 | * will be allocated. And the PASID allocated with SVM_FLAG_PRIVATE_PASID | |
39 | * will not be given to subsequent callers. This facility allows a driver to | |
40 | * disambiguate between multiple device contexts which access the same MM, | |
41 | * if there is no other way to do so. It should be used sparingly, if at all. | |
42 | */ | |
43 | #define SVM_FLAG_PRIVATE_PASID (1<<0) | |
44 | ||
2f26e0a9 DW |
45 | /** |
46 | * intel_svm_bind_mm() - Bind the current process to a PASID | |
47 | * @dev: Device to be granted acccess | |
48 | * @pasid: Address for allocated PASID | |
0204a496 DW |
49 | * @flags: Flags. Later for requesting supervisor mode, etc. |
50 | * @ops: Callbacks to device driver | |
2f26e0a9 DW |
51 | * |
52 | * This function attempts to enable PASID support for the given device. | |
53 | * If the @pasid argument is non-%NULL, a PASID is allocated for access | |
54 | * to the MM of the current process. | |
55 | * | |
56 | * By using a %NULL value for the @pasid argument, this function can | |
57 | * be used to simply validate that PASID support is available for the | |
58 | * given device — i.e. that it is behind an IOMMU which has the | |
59 | * requisite support, and is enabled. | |
60 | * | |
61 | * Page faults are handled transparently by the IOMMU code, and there | |
62 | * should be no need for the device driver to be involved. If a page | |
63 | * fault cannot be handled (i.e. is an invalid address rather than | |
64 | * just needs paging in), then the page request will be completed by | |
65 | * the core IOMMU code with appropriate status, and the device itself | |
66 | * can then report the resulting fault to its driver via whatever | |
67 | * mechanism is appropriate. | |
68 | * | |
69 | * Multiple calls from the same process may result in the same PASID | |
70 | * being re-used. A reference count is kept. | |
71 | */ | |
0204a496 DW |
72 | extern int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, |
73 | struct svm_dev_ops *ops); | |
2f26e0a9 DW |
74 | |
75 | /** | |
76 | * intel_svm_unbind_mm() - Unbind a specified PASID | |
77 | * @dev: Device for which PASID was allocated | |
78 | * @pasid: PASID value to be unbound | |
79 | * | |
80 | * This function allows a PASID to be retired when the device no | |
81 | * longer requires access to the address space of a given process. | |
82 | * | |
83 | * If the use count for the PASID in question reaches zero, the | |
84 | * PASID is revoked and may no longer be used by hardware. | |
85 | * | |
86 | * Device drivers are required to ensure that no access (including | |
87 | * page requests) is currently outstanding for the PASID in question, | |
88 | * before calling this function. | |
89 | */ | |
90 | extern int intel_svm_unbind_mm(struct device *dev, int pasid); | |
91 | ||
92 | #else /* CONFIG_INTEL_IOMMU_SVM */ | |
93 | ||
0204a496 DW |
94 | static inline int intel_svm_bind_mm(struct device *dev, int *pasid, |
95 | int flags, struct svm_dev_ops *ops) | |
2f26e0a9 DW |
96 | { |
97 | return -ENOSYS; | |
98 | } | |
99 | ||
100 | static inline int intel_svm_unbind_mm(struct device *dev, int pasid) | |
101 | { | |
102 | BUG(); | |
103 | } | |
104 | #endif /* CONFIG_INTEL_IOMMU_SVM */ | |
105 | ||
0204a496 | 106 | #define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL, 0, NULL)) |
2f26e0a9 DW |
107 | |
108 | #endif /* __INTEL_SVM_H__ */ |