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2 * Copyright © 2015 Intel Corporation.
4 * Authors: David Woodhouse <David.Woodhouse@intel.com>
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.
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
16 #ifndef __INTEL_SVM_H__
17 #define __INTEL_SVM_H__
22 void (*fault_cb
)(struct device
*dev
, int pasid
, u64 address
,
23 u32
private, int rwxp
, int response
);
26 /* Values for rxwp in fault_cb callback */
27 #define SVM_REQ_READ (1<<3)
28 #define SVM_REQ_WRITE (1<<2)
29 #define SVM_REQ_EXEC (1<<1)
30 #define SVM_REQ_PRIV (1<<0)
34 * The SVM_FLAG_PRIVATE_PASID flag requests a PASID which is *not* the "main"
35 * PASID for the current process. Even if a PASID already exists, a new one
36 * will be allocated. And the PASID allocated with SVM_FLAG_PRIVATE_PASID
37 * will not be given to subsequent callers. This facility allows a driver to
38 * disambiguate between multiple device contexts which access the same MM,
39 * if there is no other way to do so. It should be used sparingly, if at all.
41 #define SVM_FLAG_PRIVATE_PASID (1<<0)
44 * The SVM_FLAG_SUPERVISOR_MODE flag requests a PASID which can be used only
45 * for access to kernel addresses. No IOTLB flushes are automatically done
46 * for kernel mappings; it is valid only for access to the kernel's static
47 * 1:1 mapping of physical memory — not to vmalloc or even module mappings.
48 * A future API addition may permit the use of such ranges, by means of an
49 * explicit IOTLB flush call (akin to the DMA API's unmap method).
51 * It is unlikely that we will ever hook into flush_tlb_kernel_range() to
52 * do such IOTLB flushes automatically.
54 #define SVM_FLAG_SUPERVISOR_MODE (1<<1)
56 #ifdef CONFIG_INTEL_IOMMU_SVM
59 * intel_svm_bind_mm() - Bind the current process to a PASID
60 * @dev: Device to be granted acccess
61 * @pasid: Address for allocated PASID
62 * @flags: Flags. Later for requesting supervisor mode, etc.
63 * @ops: Callbacks to device driver
65 * This function attempts to enable PASID support for the given device.
66 * If the @pasid argument is non-%NULL, a PASID is allocated for access
67 * to the MM of the current process.
69 * By using a %NULL value for the @pasid argument, this function can
70 * be used to simply validate that PASID support is available for the
71 * given device — i.e. that it is behind an IOMMU which has the
72 * requisite support, and is enabled.
74 * Page faults are handled transparently by the IOMMU code, and there
75 * should be no need for the device driver to be involved. If a page
76 * fault cannot be handled (i.e. is an invalid address rather than
77 * just needs paging in), then the page request will be completed by
78 * the core IOMMU code with appropriate status, and the device itself
79 * can then report the resulting fault to its driver via whatever
80 * mechanism is appropriate.
82 * Multiple calls from the same process may result in the same PASID
83 * being re-used. A reference count is kept.
85 extern int intel_svm_bind_mm(struct device
*dev
, int *pasid
, int flags
,
86 struct svm_dev_ops
*ops
);
89 * intel_svm_unbind_mm() - Unbind a specified PASID
90 * @dev: Device for which PASID was allocated
91 * @pasid: PASID value to be unbound
93 * This function allows a PASID to be retired when the device no
94 * longer requires access to the address space of a given process.
96 * If the use count for the PASID in question reaches zero, the
97 * PASID is revoked and may no longer be used by hardware.
99 * Device drivers are required to ensure that no access (including
100 * page requests) is currently outstanding for the PASID in question,
101 * before calling this function.
103 extern int intel_svm_unbind_mm(struct device
*dev
, int pasid
);
106 * intel_svm_is_pasid_valid() - check if pasid is valid
107 * @dev: Device for which PASID was allocated
108 * @pasid: PASID value to be checked
110 * This function checks if the specified pasid is still valid. A
111 * valid pasid means the backing mm is still having a valid user.
112 * For kernel callers init_mm is always valid. for other mm, if mm->mm_users
113 * is non-zero, it is valid.
115 * returns -EINVAL if invalid pasid, 0 if pasid ref count is invalid
116 * 1 if pasid is valid.
118 extern int intel_svm_is_pasid_valid(struct device
*dev
, int pasid
);
120 #else /* CONFIG_INTEL_IOMMU_SVM */
122 static inline int intel_svm_bind_mm(struct device
*dev
, int *pasid
,
123 int flags
, struct svm_dev_ops
*ops
)
128 static inline int intel_svm_unbind_mm(struct device
*dev
, int pasid
)
133 static int intel_svm_is_pasid_valid(struct device
*dev
, int pasid
)
137 #endif /* CONFIG_INTEL_IOMMU_SVM */
139 #define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL, 0, NULL))
141 #endif /* __INTEL_SVM_H__ */