1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
// SPDX-License-Identifier: GPL-2.0
/*
* Helpers for IOMMU drivers implementing SVA
*/
#include <linux/mmu_context.h>
#include <linux/mutex.h>
#include <linux/sched/mm.h>
#include <linux/iommu.h>
#include "iommu-sva.h"
static DEFINE_MUTEX(iommu_sva_lock);
static DEFINE_IDA(iommu_global_pasid_ida);
/* Allocate a PASID for the mm within range (inclusive) */
static int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max)
{
int ret = 0;
if (min == IOMMU_PASID_INVALID ||
max == IOMMU_PASID_INVALID ||
min == 0 || max < min)
return -EINVAL;
if (!arch_pgtable_dma_compat(mm))
return -EBUSY;
mutex_lock(&iommu_sva_lock);
/* Is a PASID already associated with this mm? */
if (mm_valid_pasid(mm)) {
if (mm->pasid < min || mm->pasid > max)
ret = -EOVERFLOW;
goto out;
}
ret = ida_alloc_range(&iommu_global_pasid_ida, min, max, GFP_KERNEL);
if (ret < min)
goto out;
mm->pasid = ret;
ret = 0;
out:
mutex_unlock(&iommu_sva_lock);
return ret;
}
/**
* iommu_sva_bind_device() - Bind a process address space to a device
* @dev: the device
* @mm: the mm to bind, caller must hold a reference to mm_users
*
* Create a bond between device and address space, allowing the device to
* access the mm using the PASID returned by iommu_sva_get_pasid(). If a
* bond already exists between @device and @mm, an additional internal
* reference is taken. Caller must call iommu_sva_unbind_device()
* to release each reference.
*
* iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) must be called first, to
* initialize the required SVA features.
*
* On error, returns an ERR_PTR value.
*/
struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
{
struct iommu_domain *domain;
struct iommu_sva *handle;
ioasid_t max_pasids;
int ret;
max_pasids = dev->iommu->max_pasids;
if (!max_pasids)
return ERR_PTR(-EOPNOTSUPP);
/* Allocate mm->pasid if necessary. */
ret = iommu_sva_alloc_pasid(mm, 1, max_pasids - 1);
if (ret)
return ERR_PTR(ret);
handle = kzalloc(sizeof(*handle), GFP_KERNEL);
if (!handle)
return ERR_PTR(-ENOMEM);
mutex_lock(&iommu_sva_lock);
/* Search for an existing domain. */
domain = iommu_get_domain_for_dev_pasid(dev, mm->pasid,
IOMMU_DOMAIN_SVA);
if (IS_ERR(domain)) {
ret = PTR_ERR(domain);
goto out_unlock;
}
if (domain) {
domain->users++;
goto out;
}
/* Allocate a new domain and set it on device pasid. */
domain = iommu_sva_domain_alloc(dev, mm);
if (!domain) {
ret = -ENOMEM;
goto out_unlock;
}
ret = iommu_attach_device_pasid(domain, dev, mm->pasid);
if (ret)
goto out_free_domain;
domain->users = 1;
out:
mutex_unlock(&iommu_sva_lock);
handle->dev = dev;
handle->domain = domain;
return handle;
out_free_domain:
iommu_domain_free(domain);
out_unlock:
mutex_unlock(&iommu_sva_lock);
kfree(handle);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(iommu_sva_bind_device);
/**
* iommu_sva_unbind_device() - Remove a bond created with iommu_sva_bind_device
* @handle: the handle returned by iommu_sva_bind_device()
*
* Put reference to a bond between device and address space. The device should
* not be issuing any more transaction for this PASID. All outstanding page
* requests for this PASID must have been flushed to the IOMMU.
*/
void iommu_sva_unbind_device(struct iommu_sva *handle)
{
struct iommu_domain *domain = handle->domain;
ioasid_t pasid = domain->mm->pasid;
struct device *dev = handle->dev;
mutex_lock(&iommu_sva_lock);
if (--domain->users == 0) {
iommu_detach_device_pasid(domain, dev, pasid);
iommu_domain_free(domain);
}
mutex_unlock(&iommu_sva_lock);
kfree(handle);
}
EXPORT_SYMBOL_GPL(iommu_sva_unbind_device);
u32 iommu_sva_get_pasid(struct iommu_sva *handle)
{
struct iommu_domain *domain = handle->domain;
return domain->mm->pasid;
}
EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
/*
* I/O page fault handler for SVA
*/
enum iommu_page_response_code
iommu_sva_handle_iopf(struct iommu_fault *fault, void *data)
{
vm_fault_t ret;
struct vm_area_struct *vma;
struct mm_struct *mm = data;
unsigned int access_flags = 0;
unsigned int fault_flags = FAULT_FLAG_REMOTE;
struct iommu_fault_page_request *prm = &fault->prm;
enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID;
if (!(prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID))
return status;
if (!mmget_not_zero(mm))
return status;
mmap_read_lock(mm);
vma = find_extend_vma(mm, prm->addr);
if (!vma)
/* Unmapped area */
goto out_put_mm;
if (prm->perm & IOMMU_FAULT_PERM_READ)
access_flags |= VM_READ;
if (prm->perm & IOMMU_FAULT_PERM_WRITE) {
access_flags |= VM_WRITE;
fault_flags |= FAULT_FLAG_WRITE;
}
if (prm->perm & IOMMU_FAULT_PERM_EXEC) {
access_flags |= VM_EXEC;
fault_flags |= FAULT_FLAG_INSTRUCTION;
}
if (!(prm->perm & IOMMU_FAULT_PERM_PRIV))
fault_flags |= FAULT_FLAG_USER;
if (access_flags & ~vma->vm_flags)
/* Access fault */
goto out_put_mm;
ret = handle_mm_fault(vma, prm->addr, fault_flags, NULL);
status = ret & VM_FAULT_ERROR ? IOMMU_PAGE_RESP_INVALID :
IOMMU_PAGE_RESP_SUCCESS;
out_put_mm:
mmap_read_unlock(mm);
mmput(mm);
return status;
}
void mm_pasid_drop(struct mm_struct *mm)
{
if (likely(!mm_valid_pasid(mm)))
return;
ida_free(&iommu_global_pasid_ida, mm->pasid);
}
|
