hw/virtio/vhost-iova-tree.c

   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 }