From eecf5eedbdc0fc04f39abcf3afeedfbf21b25ca4 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Fri, 18 May 2018 15:25:16 +0800 Subject: util: implement simple iova tree Introduce a simplest iova tree implementation based on GTree. CC: QEMU Stable Signed-off-by: Peter Xu Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- MAINTAINERS | 6 +++ include/qemu/iova-tree.h | 134 +++++++++++++++++++++++++++++++++++++++++++++++ util/Makefile.objs | 1 + util/iova-tree.c | 114 ++++++++++++++++++++++++++++++++++++++++ 4 files changed, 255 insertions(+) create mode 100644 include/qemu/iova-tree.h create mode 100644 util/iova-tree.c diff --git a/MAINTAINERS b/MAINTAINERS index e187b1f18f..f07fcee72e 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1783,6 +1783,12 @@ F: include/sysemu/replay.h F: docs/replay.txt F: stubs/replay.c +IOVA Tree +M: Peter Xu +S: Maintained +F: include/qemu/iova-tree.h +F: util/iova-tree.c + Usermode Emulation ------------------ Overall diff --git a/include/qemu/iova-tree.h b/include/qemu/iova-tree.h new file mode 100644 index 0000000000..b061932097 --- /dev/null +++ b/include/qemu/iova-tree.h @@ -0,0 +1,134 @@ +/* + * An very simplified iova tree implementation based on GTree. + * + * Copyright 2018 Red Hat, Inc. + * + * Authors: + * Peter Xu + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + */ +#ifndef IOVA_TREE_H +#define IOVA_TREE_H + +/* + * Currently the iova tree will only allow to keep ranges + * information, and no extra user data is allowed for each element. A + * benefit is that we can merge adjacent ranges internally within the + * tree. It can save a lot of memory when the ranges are splitted but + * mostly continuous. + * + * Note that current implementation does not provide any thread + * protections. Callers of the iova tree should be responsible + * for the thread safety issue. + */ + +#include "qemu/osdep.h" +#include "exec/memory.h" +#include "exec/hwaddr.h" + +#define IOVA_OK (0) +#define IOVA_ERR_INVALID (-1) /* Invalid parameters */ +#define IOVA_ERR_OVERLAP (-2) /* IOVA range overlapped */ + +typedef struct IOVATree IOVATree; +typedef struct DMAMap { + hwaddr iova; + hwaddr translated_addr; + hwaddr size; /* Inclusive */ + IOMMUAccessFlags perm; +} QEMU_PACKED DMAMap; +typedef gboolean (*iova_tree_iterator)(DMAMap *map); + +/** + * iova_tree_new: + * + * Create a new iova tree. + * + * Returns: the tree pointer when succeeded, or NULL if error. + */ +IOVATree *iova_tree_new(void); + +/** + * iova_tree_insert: + * + * @tree: the iova tree to insert + * @map: the mapping to insert + * + * Insert an iova range to the tree. If there is overlapped + * ranges, IOVA_ERR_OVERLAP will be returned. + * + * Return: 0 if succeeded, or <0 if error. + */ +int iova_tree_insert(IOVATree *tree, DMAMap *map); + +/** + * iova_tree_remove: + * + * @tree: the iova tree to remove range from + * @map: the map range to remove + * + * Remove mappings from the tree that are covered by the map range + * provided. The range does not need to be exactly what has inserted, + * all the mappings that are included in the provided range will be + * removed from the tree. Here map->translated_addr is meaningless. + * + * Return: 0 if succeeded, or <0 if error. + */ +int iova_tree_remove(IOVATree *tree, DMAMap *map); + +/** + * iova_tree_find: + * + * @tree: the iova tree to search from + * @map: the mapping to search + * + * Search for a mapping in the iova tree that overlaps with the + * mapping range specified. Only the first found mapping will be + * returned. + * + * Return: DMAMap pointer if found, or NULL if not found. Note that + * the returned DMAMap pointer is maintained internally. User should + * only read the content but never modify or free the content. Also, + * user is responsible to make sure the pointer is valid (say, no + * concurrent deletion in progress). + */ +DMAMap *iova_tree_find(IOVATree *tree, DMAMap *map); + +/** + * iova_tree_find_address: + * + * @tree: the iova tree to search from + * @iova: the iova address to find + * + * Similar to iova_tree_find(), but it tries to find mapping with + * range iova=iova & size=0. + * + * Return: same as iova_tree_find(). + */ +DMAMap *iova_tree_find_address(IOVATree *tree, hwaddr iova); + +/** + * iova_tree_foreach: + * + * @tree: the iova tree to iterate on + * @iterator: the interator for the mappings, return true to stop + * + * Iterate over the iova tree. + * + * Return: 1 if found any overlap, 0 if not, <0 if error. + */ +void iova_tree_foreach(IOVATree *tree, iova_tree_iterator iterator); + +/** + * iova_tree_destroy: + * + * @tree: the iova tree to destroy + * + * Destroy an existing iova tree. + * + * Return: None. + */ +void iova_tree_destroy(IOVATree *tree); + +#endif diff --git a/util/Makefile.objs b/util/Makefile.objs index 728c3541db..e1c3fed4dc 100644 --- a/util/Makefile.objs +++ b/util/Makefile.objs @@ -47,4 +47,5 @@ util-obj-y += qht.o util-obj-y += range.o util-obj-y += stats64.o util-obj-y += systemd.o +util-obj-y += iova-tree.o util-obj-$(CONFIG_LINUX) += vfio-helpers.o diff --git a/util/iova-tree.c b/util/iova-tree.c new file mode 100644 index 0000000000..2d9cebfc89 --- /dev/null +++ b/util/iova-tree.c @@ -0,0 +1,114 @@ +/* + * IOVA tree implementation based on GTree. + * + * Copyright 2018 Red Hat, Inc. + * + * Authors: + * Peter Xu + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + */ + +#include +#include "qemu/iova-tree.h" + +struct IOVATree { + GTree *tree; +}; + +static int iova_tree_compare(gconstpointer a, gconstpointer b, gpointer data) +{ + const DMAMap *m1 = a, *m2 = b; + + if (m1->iova > m2->iova + m2->size) { + return 1; + } + + if (m1->iova + m1->size < m2->iova) { + return -1; + } + + /* Overlapped */ + return 0; +} + +IOVATree *iova_tree_new(void) +{ + IOVATree *iova_tree = g_new0(IOVATree, 1); + + /* We don't have values actually, no need to free */ + iova_tree->tree = g_tree_new_full(iova_tree_compare, NULL, g_free, NULL); + + return iova_tree; +} + +DMAMap *iova_tree_find(IOVATree *tree, DMAMap *map) +{ + return g_tree_lookup(tree->tree, map); +} + +DMAMap *iova_tree_find_address(IOVATree *tree, hwaddr iova) +{ + DMAMap map = { .iova = iova, .size = 0 }; + + return iova_tree_find(tree, &map); +} + +static inline void iova_tree_insert_internal(GTree *gtree, DMAMap *range) +{ + /* Key and value are sharing the same range data */ + g_tree_insert(gtree, range, range); +} + +int iova_tree_insert(IOVATree *tree, DMAMap *map) +{ + DMAMap *new; + + if (map->iova + map->size < map->iova || map->perm == IOMMU_NONE) { + return IOVA_ERR_INVALID; + } + + /* We don't allow to insert range that overlaps with existings */ + if (iova_tree_find(tree, map)) { + return IOVA_ERR_OVERLAP; + } + + new = g_new0(DMAMap, 1); + memcpy(new, map, sizeof(*new)); + iova_tree_insert_internal(tree->tree, new); + + return IOVA_OK; +} + +static gboolean iova_tree_traverse(gpointer key, gpointer value, + gpointer data) +{ + iova_tree_iterator iterator = data; + DMAMap *map = key; + + g_assert(key == value); + + return iterator(map); +} + +void iova_tree_foreach(IOVATree *tree, iova_tree_iterator iterator) +{ + g_tree_foreach(tree->tree, iova_tree_traverse, iterator); +} + +int iova_tree_remove(IOVATree *tree, DMAMap *map) +{ + DMAMap *overlap; + + while ((overlap = iova_tree_find(tree, map))) { + g_tree_remove(tree->tree, overlap); + } + + return IOVA_OK; +} + +void iova_tree_destroy(IOVATree *tree) +{ + g_tree_destroy(tree->tree); + g_free(tree); +} -- cgit v1.2.3