1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2021-2022, NVIDIA CORPORATION & AFFILIATES
4 */
5 #include <linux/iommu.h>
6 #include <uapi/linux/iommufd.h>
7
8 #include "iommufd_private.h"
9
iommufd_hw_pagetable_destroy(struct iommufd_object * obj)10 void iommufd_hw_pagetable_destroy(struct iommufd_object *obj)
11 {
12 struct iommufd_hw_pagetable *hwpt =
13 container_of(obj, struct iommufd_hw_pagetable, obj);
14
15 if (!list_empty(&hwpt->hwpt_item)) {
16 mutex_lock(&hwpt->ioas->mutex);
17 list_del(&hwpt->hwpt_item);
18 mutex_unlock(&hwpt->ioas->mutex);
19
20 iopt_table_remove_domain(&hwpt->ioas->iopt, hwpt->domain);
21 }
22
23 if (hwpt->domain)
24 iommu_domain_free(hwpt->domain);
25
26 refcount_dec(&hwpt->ioas->obj.users);
27 }
28
iommufd_hw_pagetable_abort(struct iommufd_object * obj)29 void iommufd_hw_pagetable_abort(struct iommufd_object *obj)
30 {
31 struct iommufd_hw_pagetable *hwpt =
32 container_of(obj, struct iommufd_hw_pagetable, obj);
33
34 /* The ioas->mutex must be held until finalize is called. */
35 lockdep_assert_held(&hwpt->ioas->mutex);
36
37 if (!list_empty(&hwpt->hwpt_item)) {
38 list_del_init(&hwpt->hwpt_item);
39 iopt_table_remove_domain(&hwpt->ioas->iopt, hwpt->domain);
40 }
41 iommufd_hw_pagetable_destroy(obj);
42 }
43
iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable * hwpt)44 int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
45 {
46 if (hwpt->enforce_cache_coherency)
47 return 0;
48
49 if (hwpt->domain->ops->enforce_cache_coherency)
50 hwpt->enforce_cache_coherency =
51 hwpt->domain->ops->enforce_cache_coherency(
52 hwpt->domain);
53 if (!hwpt->enforce_cache_coherency)
54 return -EINVAL;
55 return 0;
56 }
57
58 /**
59 * iommufd_hw_pagetable_alloc() - Get an iommu_domain for a device
60 * @ictx: iommufd context
61 * @ioas: IOAS to associate the domain with
62 * @idev: Device to get an iommu_domain for
63 * @immediate_attach: True if idev should be attached to the hwpt
64 *
65 * Allocate a new iommu_domain and return it as a hw_pagetable. The HWPT
66 * will be linked to the given ioas and upon return the underlying iommu_domain
67 * is fully popoulated.
68 *
69 * The caller must hold the ioas->mutex until after
70 * iommufd_object_abort_and_destroy() or iommufd_object_finalize() is called on
71 * the returned hwpt.
72 */
73 struct iommufd_hw_pagetable *
iommufd_hw_pagetable_alloc(struct iommufd_ctx * ictx,struct iommufd_ioas * ioas,struct iommufd_device * idev,bool immediate_attach)74 iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
75 struct iommufd_device *idev, bool immediate_attach)
76 {
77 struct iommufd_hw_pagetable *hwpt;
78 int rc;
79
80 lockdep_assert_held(&ioas->mutex);
81
82 hwpt = iommufd_object_alloc(ictx, hwpt, IOMMUFD_OBJ_HW_PAGETABLE);
83 if (IS_ERR(hwpt))
84 return hwpt;
85
86 INIT_LIST_HEAD(&hwpt->hwpt_item);
87 /* Pairs with iommufd_hw_pagetable_destroy() */
88 refcount_inc(&ioas->obj.users);
89 hwpt->ioas = ioas;
90
91 hwpt->domain = iommu_domain_alloc(idev->dev->bus);
92 if (!hwpt->domain) {
93 rc = -ENOMEM;
94 goto out_abort;
95 }
96
97 /*
98 * Set the coherency mode before we do iopt_table_add_domain() as some
99 * iommus have a per-PTE bit that controls it and need to decide before
100 * doing any maps. It is an iommu driver bug to report
101 * IOMMU_CAP_ENFORCE_CACHE_COHERENCY but fail enforce_cache_coherency on
102 * a new domain.
103 */
104 if (idev->enforce_cache_coherency) {
105 rc = iommufd_hw_pagetable_enforce_cc(hwpt);
106 if (WARN_ON(rc))
107 goto out_abort;
108 }
109
110 /*
111 * immediate_attach exists only to accommodate iommu drivers that cannot
112 * directly allocate a domain. These drivers do not finish creating the
113 * domain until attach is completed. Thus we must have this call
114 * sequence. Once those drivers are fixed this should be removed.
115 */
116 if (immediate_attach) {
117 rc = iommufd_hw_pagetable_attach(hwpt, idev);
118 if (rc)
119 goto out_abort;
120 }
121
122 rc = iopt_table_add_domain(&hwpt->ioas->iopt, hwpt->domain);
123 if (rc)
124 goto out_detach;
125 list_add_tail(&hwpt->hwpt_item, &hwpt->ioas->hwpt_list);
126 return hwpt;
127
128 out_detach:
129 if (immediate_attach)
130 iommufd_hw_pagetable_detach(idev);
131 out_abort:
132 iommufd_object_abort_and_destroy(ictx, &hwpt->obj);
133 return ERR_PTR(rc);
134 }
135
iommufd_hwpt_alloc(struct iommufd_ucmd * ucmd)136 int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
137 {
138 struct iommu_hwpt_alloc *cmd = ucmd->cmd;
139 struct iommufd_hw_pagetable *hwpt;
140 struct iommufd_device *idev;
141 struct iommufd_ioas *ioas;
142 int rc;
143
144 if (cmd->flags || cmd->__reserved)
145 return -EOPNOTSUPP;
146
147 idev = iommufd_get_device(ucmd, cmd->dev_id);
148 if (IS_ERR(idev))
149 return PTR_ERR(idev);
150
151 ioas = iommufd_get_ioas(ucmd->ictx, cmd->pt_id);
152 if (IS_ERR(ioas)) {
153 rc = PTR_ERR(ioas);
154 goto out_put_idev;
155 }
156
157 mutex_lock(&ioas->mutex);
158 hwpt = iommufd_hw_pagetable_alloc(ucmd->ictx, ioas, idev, false);
159 if (IS_ERR(hwpt)) {
160 rc = PTR_ERR(hwpt);
161 goto out_unlock;
162 }
163
164 cmd->out_hwpt_id = hwpt->obj.id;
165 rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
166 if (rc)
167 goto out_hwpt;
168 iommufd_object_finalize(ucmd->ictx, &hwpt->obj);
169 goto out_unlock;
170
171 out_hwpt:
172 iommufd_object_abort_and_destroy(ucmd->ictx, &hwpt->obj);
173 out_unlock:
174 mutex_unlock(&ioas->mutex);
175 iommufd_put_object(&ioas->obj);
176 out_put_idev:
177 iommufd_put_object(&idev->obj);
178 return rc;
179 }
180
