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
  39 static 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_new0(RemoteIommuElem, 1);
  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
  65 void 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
  83 static 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
  92 static 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
 103 static const PCIIOMMUOps remote_iommu_ops = {
 104     .get_address_space = remote_iommu_find_add_as,
 105 };
 106
 107 void remote_iommu_setup(PCIBus *pci_bus)
 108 {
 109     RemoteIommu *iommu = NULL;
 110
 111     g_assert(pci_bus);
 112
 113     iommu = REMOTE_IOMMU(object_new(TYPE_REMOTE_IOMMU));
 114
 115     pci_setup_iommu(pci_bus, &remote_iommu_ops, iommu);
 116
 117     object_property_add_child(OBJECT(pci_bus), "remote-iommu", OBJECT(iommu));
 118
 119     object_unref(OBJECT(iommu));
 120 }
 121
 122 static const TypeInfo remote_iommu_info = {
 123     .name = TYPE_REMOTE_IOMMU,
 124     .parent = TYPE_OBJECT,
 125     .instance_size = sizeof(RemoteIommu),
 126     .instance_init = remote_iommu_init,
 127     .instance_finalize = remote_iommu_finalize,
 128 };
 129
 130 static void remote_iommu_register_types(void)
 131 {
 132     type_register_static(&remote_iommu_info);
 133 }
 134
 135 type_init(remote_iommu_register_types)