qemu

FORK: QEMU emulator
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iommu.c (3473B)

      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 void 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 
    118 static 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 
    126 static void remote_iommu_register_types(void)
    127 {
    128     type_register_static(&remote_iommu_info);
    129 }
    130 
    131 type_init(remote_iommu_register_types)