backends/iommufd.c

   1 /*
   2  * iommufd container backend
   3  *
   4  * Copyright (C) 2023 Intel Corporation.
   5  * Copyright Red Hat, Inc. 2023
   6  *
   7  * Authors: Yi Liu <yi.l.liu@intel.com>
   8  *          Eric Auger <eric.auger@redhat.com>
   9  *
  10  * SPDX-License-Identifier: GPL-2.0-or-later
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "sysemu/iommufd.h"
  15 #include "qapi/error.h"
  16 #include "qemu/module.h"
  17 #include "qom/object_interfaces.h"
  18 #include "qemu/error-report.h"
  19 #include "monitor/monitor.h"
  20 #include "trace.h"
  21 #include <sys/ioctl.h>
  22 #include <linux/iommufd.h>
  23
  24 static void iommufd_backend_init(Object *obj)
  25 {
  26     IOMMUFDBackend *be = IOMMUFD_BACKEND(obj);
  27
  28     be->fd = -1;
  29     be->users = 0;
  30     be->owned = true;
  31 }
  32
  33 static void iommufd_backend_finalize(Object *obj)
  34 {
  35     IOMMUFDBackend *be = IOMMUFD_BACKEND(obj);
  36
  37     if (be->owned) {
  38         close(be->fd);
  39         be->fd = -1;
  40     }
  41 }
  42
  43 static void iommufd_backend_set_fd(Object *obj, const char *str, Error **errp)
  44 {
  45     ERRP_GUARD();
  46     IOMMUFDBackend *be = IOMMUFD_BACKEND(obj);
  47     int fd = -1;
  48
  49     fd = monitor_fd_param(monitor_cur(), str, errp);
  50     if (fd == -1) {
  51         error_prepend(errp, "Could not parse remote object fd %s:", str);
  52         return;
  53     }
  54     be->fd = fd;
  55     be->owned = false;
  56     trace_iommu_backend_set_fd(be->fd);
  57 }
  58
  59 static bool iommufd_backend_can_be_deleted(UserCreatable *uc)
  60 {
  61     IOMMUFDBackend *be = IOMMUFD_BACKEND(uc);
  62
  63     return !be->users;
  64 }
  65
  66 static void iommufd_backend_class_init(ObjectClass *oc, void *data)
  67 {
  68     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
  69
  70     ucc->can_be_deleted = iommufd_backend_can_be_deleted;
  71
  72     object_class_property_add_str(oc, "fd", NULL, iommufd_backend_set_fd);
  73 }
  74
  75 int iommufd_backend_connect(IOMMUFDBackend *be, Error **errp)
  76 {
  77     int fd, ret = 0;
  78
  79     if (be->owned && !be->users) {
  80         fd = qemu_open_old("/dev/iommu", O_RDWR);
  81         if (fd < 0) {
  82             error_setg_errno(errp, errno, "/dev/iommu opening failed");
  83             ret = fd;
  84             goto out;
  85         }
  86         be->fd = fd;
  87     }
  88     be->users++;
  89 out:
  90     trace_iommufd_backend_connect(be->fd, be->owned,
  91                                   be->users, ret);
  92     return ret;
  93 }
  94
  95 void iommufd_backend_disconnect(IOMMUFDBackend *be)
  96 {
  97     if (!be->users) {
  98         goto out;
  99     }
 100     be->users--;
 101     if (!be->users && be->owned) {
 102         close(be->fd);
 103         be->fd = -1;
 104     }
 105 out:
 106     trace_iommufd_backend_disconnect(be->fd, be->users);
 107 }
 108
 109 int iommufd_backend_alloc_ioas(IOMMUFDBackend *be, uint32_t *ioas_id,
 110                                Error **errp)
 111 {
 112     int ret, fd = be->fd;
 113     struct iommu_ioas_alloc alloc_data  = {
 114         .size = sizeof(alloc_data),
 115         .flags = 0,
 116     };
 117
 118     ret = ioctl(fd, IOMMU_IOAS_ALLOC, &alloc_data);
 119     if (ret) {
 120         error_setg_errno(errp, errno, "Failed to allocate ioas");
 121         return ret;
 122     }
 123
 124     *ioas_id = alloc_data.out_ioas_id;
 125     trace_iommufd_backend_alloc_ioas(fd, *ioas_id, ret);
 126
 127     return ret;
 128 }
 129
 130 void iommufd_backend_free_id(IOMMUFDBackend *be, uint32_t id)
 131 {
 132     int ret, fd = be->fd;
 133     struct iommu_destroy des = {
 134         .size = sizeof(des),
 135         .id = id,
 136     };
 137
 138     ret = ioctl(fd, IOMMU_DESTROY, &des);
 139     trace_iommufd_backend_free_id(fd, id, ret);
 140     if (ret) {
 141         error_report("Failed to free id: %u %m", id);
 142     }
 143 }
 144
 145 int iommufd_backend_map_dma(IOMMUFDBackend *be, uint32_t ioas_id, hwaddr iova,
 146                             ram_addr_t size, void *vaddr, bool readonly)
 147 {
 148     int ret, fd = be->fd;
 149     struct iommu_ioas_map map = {
 150         .size = sizeof(map),
 151         .flags = IOMMU_IOAS_MAP_READABLE |
 152                  IOMMU_IOAS_MAP_FIXED_IOVA,
 153         .ioas_id = ioas_id,
 154         .__reserved = 0,
 155         .user_va = (uintptr_t)vaddr,
 156         .iova = iova,
 157         .length = size,
 158     };
 159
 160     if (!readonly) {
 161         map.flags |= IOMMU_IOAS_MAP_WRITEABLE;
 162     }
 163
 164     ret = ioctl(fd, IOMMU_IOAS_MAP, &map);
 165     trace_iommufd_backend_map_dma(fd, ioas_id, iova, size,
 166                                   vaddr, readonly, ret);
 167     if (ret) {
 168         ret = -errno;
 169
 170         /* TODO: Not support mapping hardware PCI BAR region for now. */
 171         if (errno == EFAULT) {
 172             warn_report("IOMMU_IOAS_MAP failed: %m, PCI BAR?");
 173         } else {
 174             error_report("IOMMU_IOAS_MAP failed: %m");
 175         }
 176     }
 177     return ret;
 178 }
 179
 180 int iommufd_backend_unmap_dma(IOMMUFDBackend *be, uint32_t ioas_id,
 181                               hwaddr iova, ram_addr_t size)
 182 {
 183     int ret, fd = be->fd;
 184     struct iommu_ioas_unmap unmap = {
 185         .size = sizeof(unmap),
 186         .ioas_id = ioas_id,
 187         .iova = iova,
 188         .length = size,
 189     };
 190
 191     ret = ioctl(fd, IOMMU_IOAS_UNMAP, &unmap);
 192     /*
 193      * IOMMUFD takes mapping as some kind of object, unmapping
 194      * nonexistent mapping is treated as deleting a nonexistent
 195      * object and return ENOENT. This is different from legacy
 196      * backend which allows it. vIOMMU may trigger a lot of
 197      * redundant unmapping, to avoid flush the log, treat them
 198      * as succeess for IOMMUFD just like legacy backend.
 199      */
 200     if (ret && errno == ENOENT) {
 201         trace_iommufd_backend_unmap_dma_non_exist(fd, ioas_id, iova, size, ret);
 202         ret = 0;
 203     } else {
 204         trace_iommufd_backend_unmap_dma(fd, ioas_id, iova, size, ret);
 205     }
 206
 207     if (ret) {
 208         ret = -errno;
 209         error_report("IOMMU_IOAS_UNMAP failed: %m");
 210     }
 211     return ret;
 212 }
 213
 214 static const TypeInfo iommufd_backend_info = {
 215     .name = TYPE_IOMMUFD_BACKEND,
 216     .parent = TYPE_OBJECT,
 217     .instance_size = sizeof(IOMMUFDBackend),
 218     .instance_init = iommufd_backend_init,
 219     .instance_finalize = iommufd_backend_finalize,
 220     .class_size = sizeof(IOMMUFDBackendClass),
 221     .class_init = iommufd_backend_class_init,
 222     .interfaces = (InterfaceInfo[]) {
 223         { TYPE_USER_CREATABLE },
 224         { }
 225     }
 226 };
 227
 228 static void register_types(void)
 229 {
 230     type_register_static(&iommufd_backend_info);
 231 }
 232
 233 type_init(register_types);