1// SPDX-License-Identifier: GPL-2.0-only
  2/* Copyright (C) 2020 Red Hat, Inc.
  3 * Author: Jason Wang <jasowang@redhat.com>
  4 *
  5 * IOTLB implementation for vhost.
  6 */
  7#include <linux/slab.h>
  8#include <linux/vhost_iotlb.h>
  9#include <linux/module.h>
 10
 11#define MOD_VERSION  "0.1"
 12#define MOD_DESC     "VHOST IOTLB"
 13#define MOD_AUTHOR   "Jason Wang <jasowang@redhat.com>"
 14#define MOD_LICENSE  "GPL v2"
 15
 16#define START(map) ((map)->start)
 17#define LAST(map) ((map)->last)
 18
 19INTERVAL_TREE_DEFINE(struct vhost_iotlb_map,
 20		     rb, __u64, __subtree_last,
 21		     START, LAST, static inline, vhost_iotlb_itree);
 22
 23/**
 24 * vhost_iotlb_map_free - remove a map node and free it
 25 * @iotlb: the IOTLB
 26 * @map: the map that want to be remove and freed
 27 */
 28void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
 29			  struct vhost_iotlb_map *map)
 30{
 31	vhost_iotlb_itree_remove(map, &iotlb->root);
 32	list_del(&map->link);
 33	kfree(map);
 34	iotlb->nmaps--;
 35}
 36EXPORT_SYMBOL_GPL(vhost_iotlb_map_free);
 37
 38/**
 39 * vhost_iotlb_add_range - add a new range to vhost IOTLB
 40 * @iotlb: the IOTLB
 41 * @start: start of the IOVA range
 42 * @last: last of IOVA range
 43 * @addr: the address that is mapped to @start
 44 * @perm: access permission of this range
 45 *
 46 * Returns an error last is smaller than start or memory allocation
 47 * fails
 48 */
 49int vhost_iotlb_add_range(struct vhost_iotlb *iotlb,
 50			  u64 start, u64 last,
 51			  u64 addr, unsigned int perm)
 52{
 53	struct vhost_iotlb_map *map;
 54
 55	if (last < start)
 56		return -EFAULT;
 57
 58	if (iotlb->limit &&
 59	    iotlb->nmaps == iotlb->limit &&
 60	    iotlb->flags & VHOST_IOTLB_FLAG_RETIRE) {
 61		map = list_first_entry(&iotlb->list, typeof(*map), link);
 62		vhost_iotlb_map_free(iotlb, map);
 63	}
 64
 65	map = kmalloc(sizeof(*map), GFP_ATOMIC);
 66	if (!map)
 67		return -ENOMEM;
 68
 69	map->start = start;
 70	map->size = last - start + 1;
 71	map->last = last;
 72	map->addr = addr;
 73	map->perm = perm;
 74
 75	iotlb->nmaps++;
 76	vhost_iotlb_itree_insert(map, &iotlb->root);
 77
 78	INIT_LIST_HEAD(&map->link);
 79	list_add_tail(&map->link, &iotlb->list);
 80
 81	return 0;
 82}
 83EXPORT_SYMBOL_GPL(vhost_iotlb_add_range);
 84
 85/**
 86 * vring_iotlb_del_range - delete overlapped ranges from vhost IOTLB
 87 * @iotlb: the IOTLB
 88 * @start: start of the IOVA range
 89 * @last: last of IOVA range
 90 */
 91void vhost_iotlb_del_range(struct vhost_iotlb *iotlb, u64 start, u64 last)
 92{
 93	struct vhost_iotlb_map *map;
 94
 95	while ((map = vhost_iotlb_itree_iter_first(&iotlb->root,
 96						   start, last)))
 97		vhost_iotlb_map_free(iotlb, map);
 98}
 99EXPORT_SYMBOL_GPL(vhost_iotlb_del_range);
100
101/**
102 * vhost_iotlb_alloc - add a new vhost IOTLB
103 * @limit: maximum number of IOTLB entries
104 * @flags: VHOST_IOTLB_FLAG_XXX
105 *
106 * Returns an error is memory allocation fails
107 */
108struct vhost_iotlb *vhost_iotlb_alloc(unsigned int limit, unsigned int flags)
109{
110	struct vhost_iotlb *iotlb = kzalloc(sizeof(*iotlb), GFP_KERNEL);
111
112	if (!iotlb)
113		return NULL;
114
115	iotlb->root = RB_ROOT_CACHED;
116	iotlb->limit = limit;
117	iotlb->nmaps = 0;
118	iotlb->flags = flags;
119	INIT_LIST_HEAD(&iotlb->list);
120
121	return iotlb;
122}
123EXPORT_SYMBOL_GPL(vhost_iotlb_alloc);
124
125/**
126 * vhost_iotlb_reset - reset vhost IOTLB (free all IOTLB entries)
127 * @iotlb: the IOTLB to be reset
128 */
129void vhost_iotlb_reset(struct vhost_iotlb *iotlb)
130{
131	vhost_iotlb_del_range(iotlb, 0ULL, 0ULL - 1);
132}
133EXPORT_SYMBOL_GPL(vhost_iotlb_reset);
134
135/**
136 * vhost_iotlb_free - reset and free vhost IOTLB
137 * @iotlb: the IOTLB to be freed
138 */
139void vhost_iotlb_free(struct vhost_iotlb *iotlb)
140{
141	if (iotlb) {
142		vhost_iotlb_reset(iotlb);
143		kfree(iotlb);
144	}
145}
146EXPORT_SYMBOL_GPL(vhost_iotlb_free);
147
148/**
149 * vhost_iotlb_itree_first - return the first overlapped range
150 * @iotlb: the IOTLB
151 * @start: start of IOVA range
152 * @last: last byte in IOVA range
153 */
154struct vhost_iotlb_map *
155vhost_iotlb_itree_first(struct vhost_iotlb *iotlb, u64 start, u64 last)
156{
157	return vhost_iotlb_itree_iter_first(&iotlb->root, start, last);
158}
159EXPORT_SYMBOL_GPL(vhost_iotlb_itree_first);
160
161/**
162 * vhost_iotlb_itree_next - return the next overlapped range
163 * @map: the starting map node
164 * @start: start of IOVA range
165 * @last: last byte IOVA range
166 */
167struct vhost_iotlb_map *
168vhost_iotlb_itree_next(struct vhost_iotlb_map *map, u64 start, u64 last)
169{
170	return vhost_iotlb_itree_iter_next(map, start, last);
171}
172EXPORT_SYMBOL_GPL(vhost_iotlb_itree_next);
173
174MODULE_VERSION(MOD_VERSION);
175MODULE_DESCRIPTION(MOD_DESC);
176MODULE_AUTHOR(MOD_AUTHOR);
177MODULE_LICENSE(MOD_LICENSE);