diff options
Diffstat (limited to 'drivers/vhost/iotlb.c')
| -rw-r--r-- | drivers/vhost/iotlb.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/drivers/vhost/iotlb.c b/drivers/vhost/iotlb.c new file mode 100644 index 000000000..ea61330a3 --- /dev/null +++ b/drivers/vhost/iotlb.c @@ -0,0 +1,217 @@ +// 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); |