backends/hostmem.c

   1 /*
   2  * QEMU Host Memory Backend
   3  *
   4  * Copyright (C) 2013-2014 Red Hat Inc
   5  *
   6  * Authors:
   7  *   Igor Mammedov <imammedo@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12 #include "sysemu/hostmem.h"
  13 #include "sysemu/sysemu.h"
  14 #include "qapi/visitor.h"
  15 #include "qapi/qmp/qerror.h"
  16 #include "qemu/config-file.h"
  17 #include "qom/object_interfaces.h"
  18
  19 static void
  20 host_memory_backend_get_size(Object *obj, Visitor *v, void *opaque,
  21                              const char *name, Error **errp)
  22 {
  23     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  24     uint64_t value = backend->size;
  25
  26     visit_type_size(v, &value, name, errp);
  27 }
  28
  29 static void
  30 host_memory_backend_set_size(Object *obj, Visitor *v, void *opaque,
  31                              const char *name, Error **errp)
  32 {
  33     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  34     Error *local_err = NULL;
  35     uint64_t value;
  36
  37     if (memory_region_size(&backend->mr)) {
  38         error_setg(&local_err, "cannot change property value");
  39         goto out;
  40     }
  41
  42     visit_type_size(v, &value, name, &local_err);
  43     if (local_err) {
  44         goto out;
  45     }
  46     if (!value) {
  47         error_setg(&local_err, "Property '%s.%s' doesn't take value '%"
  48                    PRIu64 "'", object_get_typename(obj), name, value);
  49         goto out;
  50     }
  51     backend->size = value;
  52 out:
  53     error_propagate(errp, local_err);
  54 }
  55
  56 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
  57 {
  58     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  59
  60     return backend->merge;
  61 }
  62
  63 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
  64 {
  65     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  66
  67     if (!memory_region_size(&backend->mr)) {
  68         backend->merge = value;
  69         return;
  70     }
  71
  72     if (value != backend->merge) {
  73         void *ptr = memory_region_get_ram_ptr(&backend->mr);
  74         uint64_t sz = memory_region_size(&backend->mr);
  75
  76         qemu_madvise(ptr, sz,
  77                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
  78         backend->merge = value;
  79     }
  80 }
  81
  82 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
  83 {
  84     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  85
  86     return backend->dump;
  87 }
  88
  89 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
  90 {
  91     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  92
  93     if (!memory_region_size(&backend->mr)) {
  94         backend->dump = value;
  95         return;
  96     }
  97
  98     if (value != backend->dump) {
  99         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 100         uint64_t sz = memory_region_size(&backend->mr);
 101
 102         qemu_madvise(ptr, sz,
 103                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
 104         backend->dump = value;
 105     }
 106 }
 107
 108 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
 109 {
 110     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 111
 112     return backend->prealloc || backend->force_prealloc;
 113 }
 114
 115 static void host_memory_backend_set_prealloc(Object *obj, bool value,
 116                                              Error **errp)
 117 {
 118     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 119
 120     if (backend->force_prealloc) {
 121         if (value) {
 122             error_setg(errp,
 123                        "remove -mem-prealloc to use the prealloc property");
 124             return;
 125         }
 126     }
 127
 128     if (!memory_region_size(&backend->mr)) {
 129         backend->prealloc = value;
 130         return;
 131     }
 132
 133     if (value && !backend->prealloc) {
 134         int fd = memory_region_get_fd(&backend->mr);
 135         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 136         uint64_t sz = memory_region_size(&backend->mr);
 137
 138         os_mem_prealloc(fd, ptr, sz);
 139         backend->prealloc = true;
 140     }
 141 }
 142
 143 static void host_memory_backend_init(Object *obj)
 144 {
 145     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 146
 147     backend->merge = qemu_opt_get_bool(qemu_get_machine_opts(),
 148                                        "mem-merge", true);
 149     backend->dump = qemu_opt_get_bool(qemu_get_machine_opts(),
 150                                       "dump-guest-core", true);
 151     backend->prealloc = mem_prealloc;
 152
 153     object_property_add_bool(obj, "merge",
 154                         host_memory_backend_get_merge,
 155                         host_memory_backend_set_merge, NULL);
 156     object_property_add_bool(obj, "dump",
 157                         host_memory_backend_get_dump,
 158                         host_memory_backend_set_dump, NULL);
 159     object_property_add_bool(obj, "prealloc",
 160                         host_memory_backend_get_prealloc,
 161                         host_memory_backend_set_prealloc, NULL);
 162     object_property_add(obj, "size", "int",
 163                         host_memory_backend_get_size,
 164                         host_memory_backend_set_size, NULL, NULL, NULL);
 165 }
 166
 167 static void host_memory_backend_finalize(Object *obj)
 168 {
 169     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 170
 171     if (memory_region_size(&backend->mr)) {
 172         memory_region_destroy(&backend->mr);
 173     }
 174 }
 175
 176 MemoryRegion *
 177 host_memory_backend_get_memory(HostMemoryBackend *backend, Error **errp)
 178 {
 179     return memory_region_size(&backend->mr) ? &backend->mr : NULL;
 180 }
 181
 182 static void
 183 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
 184 {
 185     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
 186     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
 187     Error *local_err = NULL;
 188     void *ptr;
 189     uint64_t sz;
 190
 191     if (bc->alloc) {
 192         bc->alloc(backend, &local_err);
 193         if (local_err) {
 194             error_propagate(errp, local_err);
 195             return;
 196         }
 197
 198         ptr = memory_region_get_ram_ptr(&backend->mr);
 199         sz = memory_region_size(&backend->mr);
 200
 201         if (backend->merge) {
 202             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
 203         }
 204         if (!backend->dump) {
 205             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
 206         }
 207         if (backend->prealloc) {
 208             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz);
 209         }
 210     }
 211 }
 212
 213 static void
 214 host_memory_backend_class_init(ObjectClass *oc, void *data)
 215 {
 216     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 217
 218     ucc->complete = host_memory_backend_memory_complete;
 219 }
 220
 221 static const TypeInfo host_memory_backend_info = {
 222     .name = TYPE_MEMORY_BACKEND,
 223     .parent = TYPE_OBJECT,
 224     .abstract = true,
 225     .class_size = sizeof(HostMemoryBackendClass),
 226     .class_init = host_memory_backend_class_init,
 227     .instance_size = sizeof(HostMemoryBackend),
 228     .instance_init = host_memory_backend_init,
 229     .instance_finalize = host_memory_backend_finalize,
 230     .interfaces = (InterfaceInfo[]) {
 231         { TYPE_USER_CREATABLE },
 232         { }
 233     }
 234 };
 235
 236 static void register_types(void)
 237 {
 238     type_register_static(&host_memory_backend_info);
 239 }
 240
 241 type_init(register_types);