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2025cf9e | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2f26e0a9 DW |
2 | /* |
3 | * Copyright © 2015 Intel Corporation. | |
4 | * | |
5 | * Authors: David Woodhouse <David.Woodhouse@intel.com> | |
2f26e0a9 DW |
6 | */ |
7 | ||
8 | #ifndef __INTEL_SVM_H__ | |
9 | #define __INTEL_SVM_H__ | |
10 | ||
2f26e0a9 DW |
11 | struct device; |
12 | ||
0204a496 DW |
13 | struct svm_dev_ops { |
14 | void (*fault_cb)(struct device *dev, int pasid, u64 address, | |
5b438f4b | 15 | void *private, int rwxp, int response); |
0204a496 DW |
16 | }; |
17 | ||
18 | /* Values for rxwp in fault_cb callback */ | |
19 | #define SVM_REQ_READ (1<<3) | |
20 | #define SVM_REQ_WRITE (1<<2) | |
21 | #define SVM_REQ_EXEC (1<<1) | |
22 | #define SVM_REQ_PRIV (1<<0) | |
23 | ||
569e4f77 DW |
24 | |
25 | /* | |
26 | * The SVM_FLAG_PRIVATE_PASID flag requests a PASID which is *not* the "main" | |
27 | * PASID for the current process. Even if a PASID already exists, a new one | |
28 | * will be allocated. And the PASID allocated with SVM_FLAG_PRIVATE_PASID | |
29 | * will not be given to subsequent callers. This facility allows a driver to | |
30 | * disambiguate between multiple device contexts which access the same MM, | |
31 | * if there is no other way to do so. It should be used sparingly, if at all. | |
32 | */ | |
5cec7537 DW |
33 | #define SVM_FLAG_PRIVATE_PASID (1<<0) |
34 | ||
35 | /* | |
36 | * The SVM_FLAG_SUPERVISOR_MODE flag requests a PASID which can be used only | |
37 | * for access to kernel addresses. No IOTLB flushes are automatically done | |
38 | * for kernel mappings; it is valid only for access to the kernel's static | |
39 | * 1:1 mapping of physical memory — not to vmalloc or even module mappings. | |
40 | * A future API addition may permit the use of such ranges, by means of an | |
41 | * explicit IOTLB flush call (akin to the DMA API's unmap method). | |
42 | * | |
43 | * It is unlikely that we will ever hook into flush_tlb_kernel_range() to | |
44 | * do such IOTLB flushes automatically. | |
45 | */ | |
46 | #define SVM_FLAG_SUPERVISOR_MODE (1<<1) | |
569e4f77 | 47 | |
da4689c0 DW |
48 | #ifdef CONFIG_INTEL_IOMMU_SVM |
49 | ||
2f26e0a9 DW |
50 | /** |
51 | * intel_svm_bind_mm() - Bind the current process to a PASID | |
f34e1176 | 52 | * @dev: Device to be granted access |
2f26e0a9 | 53 | * @pasid: Address for allocated PASID |
0204a496 DW |
54 | * @flags: Flags. Later for requesting supervisor mode, etc. |
55 | * @ops: Callbacks to device driver | |
2f26e0a9 DW |
56 | * |
57 | * This function attempts to enable PASID support for the given device. | |
58 | * If the @pasid argument is non-%NULL, a PASID is allocated for access | |
59 | * to the MM of the current process. | |
60 | * | |
61 | * By using a %NULL value for the @pasid argument, this function can | |
62 | * be used to simply validate that PASID support is available for the | |
63 | * given device — i.e. that it is behind an IOMMU which has the | |
64 | * requisite support, and is enabled. | |
65 | * | |
66 | * Page faults are handled transparently by the IOMMU code, and there | |
67 | * should be no need for the device driver to be involved. If a page | |
68 | * fault cannot be handled (i.e. is an invalid address rather than | |
69 | * just needs paging in), then the page request will be completed by | |
70 | * the core IOMMU code with appropriate status, and the device itself | |
71 | * can then report the resulting fault to its driver via whatever | |
72 | * mechanism is appropriate. | |
73 | * | |
74 | * Multiple calls from the same process may result in the same PASID | |
75 | * being re-used. A reference count is kept. | |
76 | */ | |
0204a496 DW |
77 | extern int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, |
78 | struct svm_dev_ops *ops); | |
2f26e0a9 DW |
79 | |
80 | /** | |
81 | * intel_svm_unbind_mm() - Unbind a specified PASID | |
82 | * @dev: Device for which PASID was allocated | |
83 | * @pasid: PASID value to be unbound | |
84 | * | |
85 | * This function allows a PASID to be retired when the device no | |
86 | * longer requires access to the address space of a given process. | |
87 | * | |
88 | * If the use count for the PASID in question reaches zero, the | |
89 | * PASID is revoked and may no longer be used by hardware. | |
90 | * | |
91 | * Device drivers are required to ensure that no access (including | |
92 | * page requests) is currently outstanding for the PASID in question, | |
93 | * before calling this function. | |
94 | */ | |
95 | extern int intel_svm_unbind_mm(struct device *dev, int pasid); | |
96 | ||
15060aba CT |
97 | /** |
98 | * intel_svm_is_pasid_valid() - check if pasid is valid | |
99 | * @dev: Device for which PASID was allocated | |
100 | * @pasid: PASID value to be checked | |
101 | * | |
102 | * This function checks if the specified pasid is still valid. A | |
103 | * valid pasid means the backing mm is still having a valid user. | |
104 | * For kernel callers init_mm is always valid. for other mm, if mm->mm_users | |
105 | * is non-zero, it is valid. | |
106 | * | |
107 | * returns -EINVAL if invalid pasid, 0 if pasid ref count is invalid | |
108 | * 1 if pasid is valid. | |
109 | */ | |
110 | extern int intel_svm_is_pasid_valid(struct device *dev, int pasid); | |
111 | ||
2f26e0a9 DW |
112 | #else /* CONFIG_INTEL_IOMMU_SVM */ |
113 | ||
0204a496 DW |
114 | static inline int intel_svm_bind_mm(struct device *dev, int *pasid, |
115 | int flags, struct svm_dev_ops *ops) | |
2f26e0a9 DW |
116 | { |
117 | return -ENOSYS; | |
118 | } | |
119 | ||
120 | static inline int intel_svm_unbind_mm(struct device *dev, int pasid) | |
121 | { | |
122 | BUG(); | |
123 | } | |
15060aba CT |
124 | |
125 | static int intel_svm_is_pasid_valid(struct device *dev, int pasid) | |
126 | { | |
127 | return -EINVAL; | |
128 | } | |
2f26e0a9 DW |
129 | #endif /* CONFIG_INTEL_IOMMU_SVM */ |
130 | ||
0204a496 | 131 | #define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL, 0, NULL)) |
2f26e0a9 DW |
132 | |
133 | #endif /* __INTEL_SVM_H__ */ |