xref: /openbmc/qemu/hw/virtio/vhost-iova-tree.c (revision 05caa062)
1 /*
2  * vhost software live migration iova tree
3  *
4  * SPDX-FileCopyrightText: Red Hat, Inc. 2021
5  * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
6  *
7  * SPDX-License-Identifier: GPL-2.0-or-later
8  */
9 
10 #include "qemu/osdep.h"
11 #include "qemu/iova-tree.h"
12 #include "vhost-iova-tree.h"
13 
14 #define iova_min_addr qemu_real_host_page_size()
15 
16 /**
17  * VhostIOVATree, able to:
18  * - Translate iova address
19  * - Reverse translate iova address (from translated to iova)
20  * - Allocate IOVA regions for translated range (linear operation)
21  */
22 struct VhostIOVATree {
23     /* First addressable iova address in the device */
24     uint64_t iova_first;
25 
26     /* Last addressable iova address in the device */
27     uint64_t iova_last;
28 
29     /* IOVA address to qemu memory maps. */
30     IOVATree *iova_taddr_map;
31 };
32 
33 /**
34  * Create a new IOVA tree
35  *
36  * Returns the new IOVA tree
37  */
38 VhostIOVATree *vhost_iova_tree_new(hwaddr iova_first, hwaddr iova_last)
39 {
40     VhostIOVATree *tree = g_new(VhostIOVATree, 1);
41 
42     /* Some devices do not like 0 addresses */
43     tree->iova_first = MAX(iova_first, iova_min_addr);
44     tree->iova_last = iova_last;
45 
46     tree->iova_taddr_map = iova_tree_new();
47     return tree;
48 }
49 
50 /**
51  * Delete an iova tree
52  */
53 void vhost_iova_tree_delete(VhostIOVATree *iova_tree)
54 {
55     iova_tree_destroy(iova_tree->iova_taddr_map);
56     g_free(iova_tree);
57 }
58 
59 /**
60  * Find the IOVA address stored from a memory address
61  *
62  * @tree: The iova tree
63  * @map: The map with the memory address
64  *
65  * Return the stored mapping, or NULL if not found.
66  */
67 const DMAMap *vhost_iova_tree_find_iova(const VhostIOVATree *tree,
68                                         const DMAMap *map)
69 {
70     return iova_tree_find_iova(tree->iova_taddr_map, map);
71 }
72 
73 /**
74  * Allocate a new mapping
75  *
76  * @tree: The iova tree
77  * @map: The iova map
78  *
79  * Returns:
80  * - IOVA_OK if the map fits in the container
81  * - IOVA_ERR_INVALID if the map does not make sense (like size overflow)
82  * - IOVA_ERR_NOMEM if tree cannot allocate more space.
83  *
84  * It returns assignated iova in map->iova if return value is VHOST_DMA_MAP_OK.
85  */
86 int vhost_iova_tree_map_alloc(VhostIOVATree *tree, DMAMap *map)
87 {
88     /* Some vhost devices do not like addr 0. Skip first page */
89     hwaddr iova_first = tree->iova_first ?: qemu_real_host_page_size();
90 
91     if (map->translated_addr + map->size < map->translated_addr ||
92         map->perm == IOMMU_NONE) {
93         return IOVA_ERR_INVALID;
94     }
95 
96     /* Allocate a node in IOVA address */
97     return iova_tree_alloc_map(tree->iova_taddr_map, map, iova_first,
98                                tree->iova_last);
99 }
100 
101 /**
102  * Remove existing mappings from iova tree
103  *
104  * @iova_tree: The vhost iova tree
105  * @map: The map to remove
106  */
107 void vhost_iova_tree_remove(VhostIOVATree *iova_tree, DMAMap map)
108 {
109     iova_tree_remove(iova_tree->iova_taddr_map, map);
110 }
111