summaryrefslogtreecommitdiff
path: root/drivers/vhost/iotlb.c
blob: ea61330a34310226134411a20881cecfcbd374e5 (plain)
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
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (C) 2020 Red Hat, Inc.
 * Author: Jason Wang <jasowang@redhat.com>
 *
 * IOTLB implementation for vhost.
 */
#include <linux/slab.h>
#include <linux/vhost_iotlb.h>
#include <linux/module.h>

#define MOD_VERSION  "0.1"
#define MOD_DESC     "VHOST IOTLB"
#define MOD_AUTHOR   "Jason Wang <jasowang@redhat.com>"
#define MOD_LICENSE  "GPL v2"

#define START(map) ((map)->start)
#define LAST(map) ((map)->last)

INTERVAL_TREE_DEFINE(struct vhost_iotlb_map,
		     rb, __u64, __subtree_last,
		     START, LAST, static inline, vhost_iotlb_itree);

/**
 * vhost_iotlb_map_free - remove a map node and free it
 * @iotlb: the IOTLB
 * @map: the map that want to be remove and freed
 */
void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
			  struct vhost_iotlb_map *map)
{
	vhost_iotlb_itree_remove(map, &iotlb->root);
	list_del(&map->link);
	kfree(map);
	iotlb->nmaps--;
}
EXPORT_SYMBOL_GPL(vhost_iotlb_map_free);

/**
 * vhost_iotlb_add_range_ctx - add a new range to vhost IOTLB
 * @iotlb: the IOTLB
 * @start: start of the IOVA range
 * @last: last of IOVA range
 * @addr: the address that is mapped to @start
 * @perm: access permission of this range
 * @opaque: the opaque pointer for the new mapping
 *
 * Returns an error last is smaller than start or memory allocation
 * fails
 */
int vhost_iotlb_add_range_ctx(struct vhost_iotlb *iotlb,
			      u64 start, u64 last,
			      u64 addr, unsigned int perm,
			      void *opaque)
{
	struct vhost_iotlb_map *map;

	if (last < start)
		return -EFAULT;

	/* If the range being mapped is [0, ULONG_MAX], split it into two entries
	 * otherwise its size would overflow u64.
	 */
	if (start == 0 && last == ULONG_MAX) {
		u64 mid = last / 2;
		int err = vhost_iotlb_add_range_ctx(iotlb, start, mid, addr,
				perm, opaque);

		if (err)
			return err;

		addr += mid + 1;
		start = mid + 1;
	}

	if (iotlb->limit &&
	    iotlb->nmaps == iotlb->limit &&
	    iotlb->flags & VHOST_IOTLB_FLAG_RETIRE) {
		map = list_first_entry(&iotlb->list, typeof(*map), link);
		vhost_iotlb_map_free(iotlb, map);
	}

	map = kmalloc(sizeof(*map), GFP_ATOMIC);
	if (!map)
		return -ENOMEM;

	map->start = start;
	map->size = last - start + 1;
	map->last = last;
	map->addr = addr;
	map->perm = perm;
	map->opaque = opaque;

	iotlb->nmaps++;
	vhost_iotlb_itree_insert(map, &iotlb->root);

	INIT_LIST_HEAD(&map->link);
	list_add_tail(&map->link, &iotlb->list);

	return 0;
}
EXPORT_SYMBOL_GPL(vhost_iotlb_add_range_ctx);

int vhost_iotlb_add_range(struct vhost_iotlb *iotlb,
			  u64 start, u64 last,
			  u64 addr, unsigned int perm)
{
	return vhost_iotlb_add_range_ctx(iotlb, start, last,
					 addr, perm, NULL);
}
EXPORT_SYMBOL_GPL(vhost_iotlb_add_range);

/**
 * vhost_iotlb_del_range - delete overlapped ranges from vhost IOTLB
 * @iotlb: the IOTLB
 * @start: start of the IOVA range
 * @last: last of IOVA range
 */
void vhost_iotlb_del_range(struct vhost_iotlb *iotlb, u64 start, u64 last)
{
	struct vhost_iotlb_map *map;

	while ((map = vhost_iotlb_itree_iter_first(&iotlb->root,
						   start, last)))
		vhost_iotlb_map_free(iotlb, map);
}
EXPORT_SYMBOL_GPL(vhost_iotlb_del_range);

/**
 * vhost_iotlb_init - initialize a vhost IOTLB
 * @iotlb: the IOTLB that needs to be initialized
 * @limit: maximum number of IOTLB entries
 * @flags: VHOST_IOTLB_FLAG_XXX
 */
void vhost_iotlb_init(struct vhost_iotlb *iotlb, unsigned int limit,
		      unsigned int flags)
{
	iotlb->root = RB_ROOT_CACHED;
	iotlb->limit = limit;
	iotlb->nmaps = 0;
	iotlb->flags = flags;
	INIT_LIST_HEAD(&iotlb->list);
}
EXPORT_SYMBOL_GPL(vhost_iotlb_init);

/**
 * vhost_iotlb_alloc - add a new vhost IOTLB
 * @limit: maximum number of IOTLB entries
 * @flags: VHOST_IOTLB_FLAG_XXX
 *
 * Returns an error is memory allocation fails
 */
struct vhost_iotlb *vhost_iotlb_alloc(unsigned int limit, unsigned int flags)
{
	struct vhost_iotlb *iotlb = kzalloc(sizeof(*iotlb), GFP_KERNEL);

	if (!iotlb)
		return NULL;

	vhost_iotlb_init(iotlb, limit, flags);

	return iotlb;
}
EXPORT_SYMBOL_GPL(vhost_iotlb_alloc);

/**
 * vhost_iotlb_reset - reset vhost IOTLB (free all IOTLB entries)
 * @iotlb: the IOTLB to be reset
 */
void vhost_iotlb_reset(struct vhost_iotlb *iotlb)
{
	vhost_iotlb_del_range(iotlb, 0ULL, 0ULL - 1);
}
EXPORT_SYMBOL_GPL(vhost_iotlb_reset);

/**
 * vhost_iotlb_free - reset and free vhost IOTLB
 * @iotlb: the IOTLB to be freed
 */
void vhost_iotlb_free(struct vhost_iotlb *iotlb)
{
	if (iotlb) {
		vhost_iotlb_reset(iotlb);
		kfree(iotlb);
	}
}
EXPORT_SYMBOL_GPL(vhost_iotlb_free);

/**
 * vhost_iotlb_itree_first - return the first overlapped range
 * @iotlb: the IOTLB
 * @start: start of IOVA range
 * @last: last byte in IOVA range
 */
struct vhost_iotlb_map *
vhost_iotlb_itree_first(struct vhost_iotlb *iotlb, u64 start, u64 last)
{
	return vhost_iotlb_itree_iter_first(&iotlb->root, start, last);
}
EXPORT_SYMBOL_GPL(vhost_iotlb_itree_first);

/**
 * vhost_iotlb_itree_next - return the next overlapped range
 * @map: the starting map node
 * @start: start of IOVA range
 * @last: last byte IOVA range
 */
struct vhost_iotlb_map *
vhost_iotlb_itree_next(struct vhost_iotlb_map *map, u64 start, u64 last)
{
	return vhost_iotlb_itree_iter_next(map, start, last);
}
EXPORT_SYMBOL_GPL(vhost_iotlb_itree_next);

MODULE_VERSION(MOD_VERSION);
MODULE_DESCRIPTION(MOD_DESC);
MODULE_AUTHOR(MOD_AUTHOR);
MODULE_LICENSE(MOD_LICENSE);