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- // SPDX-License-Identifier: GPL-2.0-only
- /* Copyright (C) 2020 Red Hat, Inc.
- * Author: Jason Wang <[email protected]>
- *
- * 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 <[email protected]>"
- #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);
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