LXR qemu/hw/remote/iommu.c

   1/**
   2 * IOMMU for remote device
   3 *
   4 * Copyright © 2022 Oracle and/or its affiliates.
   5 *
   6 * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7 * See the COPYING file in the top-level directory.
   8 *
   9 */
  10
  11#include "qemu/osdep.h"
  12
  13#include "hw/remote/iommu.h"
  14#include "hw/pci/pci_bus.h"
  15#include "hw/pci/pci.h"
  16#include "exec/memory.h"
  17#include "exec/address-spaces.h"
  18#include "trace.h"
  19
  20/**
  21 * IOMMU for TYPE_REMOTE_MACHINE - manages DMA address space isolation
  22 *     for remote machine. It is used by TYPE_VFIO_USER_SERVER.
  23 *
  24 * - Each TYPE_VFIO_USER_SERVER instance handles one PCIDevice on a PCIBus.
  25 *   There is one RemoteIommu per PCIBus, so the RemoteIommu tracks multiple
  26 *   PCIDevices by maintaining a ->elem_by_devfn mapping.
  27 *
  28 * - memory_region_init_iommu() is not used because vfio-user MemoryRegions
  29 *   will be added to the elem->mr container instead. This is more natural
  30 *   than implementing the IOMMUMemoryRegionClass APIs since vfio-user
  31 *   provides something that is close to a full-fledged MemoryRegion and
  32 *   not like an IOMMU mapping.
  33 *
  34 * - When a device is hot unplugged, the elem->mr reference is dropped so
  35 *   all vfio-user MemoryRegions associated with this vfio-user server are
  36 *   destroyed.
  37 */
  38
  39static AddressSpace *remote_iommu_find_add_as(PCIBus *pci_bus,
  40                                              void *opaque, int devfn)
  41{
  42    RemoteIommu *iommu = opaque;
  43    RemoteIommuElem *elem = NULL;
  44
  45    qemu_mutex_lock(&iommu->lock);
  46
  47    elem = g_hash_table_lookup(iommu->elem_by_devfn, INT2VOIDP(devfn));
  48
  49    if (!elem) {
  50        elem = g_malloc0(sizeof(RemoteIommuElem));
  51        g_hash_table_insert(iommu->elem_by_devfn, INT2VOIDP(devfn), elem);
  52    }
  53
  54    if (!elem->mr) {
  55        elem->mr = MEMORY_REGION(object_new(TYPE_MEMORY_REGION));
  56        memory_region_set_size(elem->mr, UINT64_MAX);
  57        address_space_init(&elem->as, elem->mr, NULL);
  58    }
  59
  60    qemu_mutex_unlock(&iommu->lock);
  61
  62    return &elem->as;
  63}
  64
  65void remote_iommu_unplug_dev(PCIDevice *pci_dev)
  66{
  67    AddressSpace *as = pci_device_iommu_address_space(pci_dev);
  68    RemoteIommuElem *elem = NULL;
  69
  70    if (as == &address_space_memory) {
  71        return;
  72    }
  73
  74    elem = container_of(as, RemoteIommuElem, as);
  75
  76    address_space_destroy(&elem->as);
  77
  78    object_unref(elem->mr);
  79
  80    elem->mr = NULL;
  81}
  82
  83static void remote_iommu_init(Object *obj)
  84{
  85    RemoteIommu *iommu = REMOTE_IOMMU(obj);
  86
  87    iommu->elem_by_devfn = g_hash_table_new_full(NULL, NULL, NULL, g_free);
  88
  89    qemu_mutex_init(&iommu->lock);
  90}
  91
  92static void remote_iommu_finalize(Object *obj)
  93{
  94    RemoteIommu *iommu = REMOTE_IOMMU(obj);
  95
  96    qemu_mutex_destroy(&iommu->lock);
  97
  98    g_hash_table_destroy(iommu->elem_by_devfn);
  99
 100    iommu->elem_by_devfn = NULL;
 101}
 102
 103void remote_iommu_setup(PCIBus *pci_bus)
 104{
 105    RemoteIommu *iommu = NULL;
 106
 107    g_assert(pci_bus);
 108
 109    iommu = REMOTE_IOMMU(object_new(TYPE_REMOTE_IOMMU));
 110
 111    pci_setup_iommu(pci_bus, remote_iommu_find_add_as, iommu);
 112
 113    object_property_add_child(OBJECT(pci_bus), "remote-iommu", OBJECT(iommu));
 114
 115    object_unref(OBJECT(iommu));
 116}
 117
 118static const TypeInfo remote_iommu_info = {
 119    .name = TYPE_REMOTE_IOMMU,
 120    .parent = TYPE_OBJECT,
 121    .instance_size = sizeof(RemoteIommu),
 122    .instance_init = remote_iommu_init,
 123    .instance_finalize = remote_iommu_finalize,
 124};
 125
 126static void remote_iommu_register_types(void)
 127{
 128    type_register_static(&remote_iommu_info);
 129}
 130
 131type_init(remote_iommu_register_types)
 132