a89b34be5e
As qemu guidelines: Unless a pointer is used to modify the pointed-to storage, give it the "const" attribute. In the particular case of iova_tree_find it allows to enforce what is requested by its comment, since the compiler would shout in case of modifying or freeing the const-qualified returned pointer. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20211013182713.888753-2-eperezma@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
134 lines
3.5 KiB
C
134 lines
3.5 KiB
C
/*
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* An very simplified iova tree implementation based on GTree.
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*
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* Copyright 2018 Red Hat, Inc.
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*
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* Authors:
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* Peter Xu <peterx@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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*/
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#ifndef IOVA_TREE_H
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#define IOVA_TREE_H
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/*
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* Currently the iova tree will only allow to keep ranges
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* information, and no extra user data is allowed for each element. A
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* benefit is that we can merge adjacent ranges internally within the
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* tree. It can save a lot of memory when the ranges are splitted but
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* mostly continuous.
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*
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* Note that current implementation does not provide any thread
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* protections. Callers of the iova tree should be responsible
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* for the thread safety issue.
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*/
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#include "exec/memory.h"
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#include "exec/hwaddr.h"
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#define IOVA_OK (0)
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#define IOVA_ERR_INVALID (-1) /* Invalid parameters */
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#define IOVA_ERR_OVERLAP (-2) /* IOVA range overlapped */
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typedef struct IOVATree IOVATree;
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typedef struct DMAMap {
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hwaddr iova;
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hwaddr translated_addr;
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hwaddr size; /* Inclusive */
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IOMMUAccessFlags perm;
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} QEMU_PACKED DMAMap;
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typedef gboolean (*iova_tree_iterator)(DMAMap *map);
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/**
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* iova_tree_new:
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*
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* Create a new iova tree.
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*
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* Returns: the tree pointer when succeeded, or NULL if error.
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*/
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IOVATree *iova_tree_new(void);
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/**
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* iova_tree_insert:
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*
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* @tree: the iova tree to insert
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* @map: the mapping to insert
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*
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* Insert an iova range to the tree. If there is overlapped
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* ranges, IOVA_ERR_OVERLAP will be returned.
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*
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* Return: 0 if succeeded, or <0 if error.
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*/
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int iova_tree_insert(IOVATree *tree, const DMAMap *map);
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/**
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* iova_tree_remove:
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*
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* @tree: the iova tree to remove range from
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* @map: the map range to remove
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*
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* Remove mappings from the tree that are covered by the map range
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* provided. The range does not need to be exactly what has inserted,
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* all the mappings that are included in the provided range will be
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* removed from the tree. Here map->translated_addr is meaningless.
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*
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* Return: 0 if succeeded, or <0 if error.
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*/
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int iova_tree_remove(IOVATree *tree, const DMAMap *map);
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/**
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* iova_tree_find:
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*
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* @tree: the iova tree to search from
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* @map: the mapping to search
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*
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* Search for a mapping in the iova tree that overlaps with the
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* mapping range specified. Only the first found mapping will be
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* returned.
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*
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* Return: DMAMap pointer if found, or NULL if not found. Note that
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* the returned DMAMap pointer is maintained internally. User should
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* only read the content but never modify or free the content. Also,
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* user is responsible to make sure the pointer is valid (say, no
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* concurrent deletion in progress).
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*/
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const DMAMap *iova_tree_find(const IOVATree *tree, const DMAMap *map);
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/**
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* iova_tree_find_address:
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*
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* @tree: the iova tree to search from
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* @iova: the iova address to find
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*
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* Similar to iova_tree_find(), but it tries to find mapping with
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* range iova=iova & size=0.
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*
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* Return: same as iova_tree_find().
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*/
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const DMAMap *iova_tree_find_address(const IOVATree *tree, hwaddr iova);
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/**
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* iova_tree_foreach:
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*
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* @tree: the iova tree to iterate on
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* @iterator: the interator for the mappings, return true to stop
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*
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* Iterate over the iova tree.
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*
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* Return: 1 if found any overlap, 0 if not, <0 if error.
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*/
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void iova_tree_foreach(IOVATree *tree, iova_tree_iterator iterator);
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/**
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* iova_tree_destroy:
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*
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* @tree: the iova tree to destroy
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*
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* Destroy an existing iova tree.
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*
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* Return: None.
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*/
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void iova_tree_destroy(IOVATree *tree);
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#endif
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