1/* SPDX-License-Identifier: GPL-2.0-only */
 2/*
 3 * Copyright © 2015 Intel Corporation.
 4 *
 5 * Authors: David Woodhouse <David.Woodhouse@intel.com>
 6 */
 7
 8#ifndef __INTEL_SVM_H__
 9#define __INTEL_SVM_H__
10
 
 
 
 
 
 
 
11/* Values for rxwp in fault_cb callback */
12#define SVM_REQ_READ	(1<<3)
13#define SVM_REQ_WRITE	(1<<2)
14#define SVM_REQ_EXEC	(1<<1)
15#define SVM_REQ_PRIV	(1<<0)
16
 
 
 
 
 
 
 
 
 
 
 
17/*
18 * The SVM_FLAG_SUPERVISOR_MODE flag requests a PASID which can be used only
19 * for access to kernel addresses. No IOTLB flushes are automatically done
20 * for kernel mappings; it is valid only for access to the kernel's static
21 * 1:1 mapping of physical memory — not to vmalloc or even module mappings.
22 * A future API addition may permit the use of such ranges, by means of an
23 * explicit IOTLB flush call (akin to the DMA API's unmap method).
24 *
25 * It is unlikely that we will ever hook into flush_tlb_kernel_range() to
26 * do such IOTLB flushes automatically.
27 */
28#define SVM_FLAG_SUPERVISOR_MODE	BIT(0)
29/*
30 * The SVM_FLAG_GUEST_MODE flag is used when a PASID bind is for guest
31 * processes. Compared to the host bind, the primary differences are:
32 * 1. mm life cycle management
33 * 2. fault reporting
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
34 */
35#define SVM_FLAG_GUEST_MODE		BIT(1)
36/*
37 * The SVM_FLAG_GUEST_PASID flag is used when a guest has its own PASID space,
38 * which requires guest and host PASID translation at both directions.
 
 
 
 
 
 
 
 
 
 
 
 
 
39 */
40#define SVM_FLAG_GUEST_PASID		BIT(2)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
41
42#endif /* __INTEL_SVM_H__ */

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * Copyright © 2015 Intel Corporation.
  4 *
  5 * Authors: David Woodhouse <David.Woodhouse@intel.com>
  6 */
  7
  8#ifndef __INTEL_SVM_H__
  9#define __INTEL_SVM_H__
 10
 11struct device;
 12
 13struct svm_dev_ops {
 14	void (*fault_cb)(struct device *dev, int pasid, u64 address,
 15			 void *private, int rwxp, int response);
 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
 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 */
 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)
 47
 48#ifdef CONFIG_INTEL_IOMMU_SVM
 49
 50/**
 51 * intel_svm_bind_mm() - Bind the current process to a PASID
 52 * @dev:	Device to be granted access
 53 * @pasid:	Address for allocated PASID
 54 * @flags:	Flags. Later for requesting supervisor mode, etc.
 55 * @ops:	Callbacks to device driver
 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 */
 77extern int intel_svm_bind_mm(struct device *dev, int *pasid, int flags,
 78			     struct svm_dev_ops *ops);
 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 */
 95extern int intel_svm_unbind_mm(struct device *dev, int pasid);
 96
 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 */
110extern int intel_svm_is_pasid_valid(struct device *dev, int pasid);
111
112#else /* CONFIG_INTEL_IOMMU_SVM */
113
114static inline int intel_svm_bind_mm(struct device *dev, int *pasid,
115				    int flags, struct svm_dev_ops *ops)
116{
117	return -ENOSYS;
118}
119
120static inline int intel_svm_unbind_mm(struct device *dev, int pasid)
121{
122	BUG();
123}
124
125static int intel_svm_is_pasid_valid(struct device *dev, int pasid)
126{
127	return -EINVAL;
128}
129#endif /* CONFIG_INTEL_IOMMU_SVM */
130
131#define intel_svm_available(dev) (!intel_svm_bind_mm((dev), NULL, 0, NULL))
132
133#endif /* __INTEL_SVM_H__ */