backends/hostmem-file.c

   1 /*
   2  * QEMU Host Memory Backend for hugetlbfs
   3  *
   4  * Copyright (C) 2013-2014 Red Hat Inc
   5  *
   6  * Authors:
   7  *   Paolo Bonzini <pbonzini@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
  13 #include "qemu/osdep.h"
  14 #include "qapi/error.h"
  15 #include "qemu/error-report.h"
  16 #include "qemu/module.h"
  17 #include "qemu/madvise.h"
  18 #include "sysemu/hostmem.h"
  19 #include "qom/object_interfaces.h"
  20 #include "qom/object.h"
  21
  22 OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendFile, MEMORY_BACKEND_FILE)
  23
  24
  25 struct HostMemoryBackendFile {
  26     HostMemoryBackend parent_obj;
  27
  28     char *mem_path;
  29     uint64_t align;
  30     uint64_t offset;
  31     bool discard_data;
  32     bool is_pmem;
  33     bool readonly;
  34 };
  35
  36 static void
  37 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
  38 {
  39 #ifndef CONFIG_POSIX
  40     error_setg(errp, "backend '%s' not supported on this host",
  41                object_get_typename(OBJECT(backend)));
  42 #else
  43     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);
  44     uint32_t ram_flags;
  45     gchar *name;
  46
  47     if (!backend->size) {
  48         error_setg(errp, "can't create backend with size 0");
  49         return;
  50     }
  51     if (!fb->mem_path) {
  52         error_setg(errp, "mem-path property not set");
  53         return;
  54     }
  55
  56     name = host_memory_backend_get_name(backend);
  57     ram_flags = backend->share ? RAM_SHARED : 0;
  58     ram_flags |= backend->reserve ? 0 : RAM_NORESERVE;
  59     ram_flags |= fb->is_pmem ? RAM_PMEM : 0;
  60     memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name,
  61                                      backend->size, fb->align, ram_flags,
  62                                      fb->mem_path, fb->offset, fb->readonly,
  63                                      errp);
  64     g_free(name);
  65 #endif
  66 }
  67
  68 static char *get_mem_path(Object *o, Error **errp)
  69 {
  70     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  71
  72     return g_strdup(fb->mem_path);
  73 }
  74
  75 static void set_mem_path(Object *o, const char *str, Error **errp)
  76 {
  77     HostMemoryBackend *backend = MEMORY_BACKEND(o);
  78     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  79
  80     if (host_memory_backend_mr_inited(backend)) {
  81         error_setg(errp, "cannot change property 'mem-path' of %s",
  82                    object_get_typename(o));
  83         return;
  84     }
  85     g_free(fb->mem_path);
  86     fb->mem_path = g_strdup(str);
  87 }
  88
  89 static bool file_memory_backend_get_discard_data(Object *o, Error **errp)
  90 {
  91     return MEMORY_BACKEND_FILE(o)->discard_data;
  92 }
  93
  94 static void file_memory_backend_set_discard_data(Object *o, bool value,
  95                                                Error **errp)
  96 {
  97     MEMORY_BACKEND_FILE(o)->discard_data = value;
  98 }
  99
 100 static void file_memory_backend_get_align(Object *o, Visitor *v,
 101                                           const char *name, void *opaque,
 102                                           Error **errp)
 103 {
 104     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 105     uint64_t val = fb->align;
 106
 107     visit_type_size(v, name, &val, errp);
 108 }
 109
 110 static void file_memory_backend_set_align(Object *o, Visitor *v,
 111                                           const char *name, void *opaque,
 112                                           Error **errp)
 113 {
 114     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 115     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 116     uint64_t val;
 117
 118     if (host_memory_backend_mr_inited(backend)) {
 119         error_setg(errp, "cannot change property '%s' of %s", name,
 120                    object_get_typename(o));
 121         return;
 122     }
 123
 124     if (!visit_type_size(v, name, &val, errp)) {
 125         return;
 126     }
 127     fb->align = val;
 128 }
 129
 130 static void file_memory_backend_get_offset(Object *o, Visitor *v,
 131                                           const char *name, void *opaque,
 132                                           Error **errp)
 133 {
 134     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 135     uint64_t val = fb->offset;
 136
 137     visit_type_size(v, name, &val, errp);
 138 }
 139
 140 static void file_memory_backend_set_offset(Object *o, Visitor *v,
 141                                           const char *name, void *opaque,
 142                                           Error **errp)
 143 {
 144     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 145     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 146     uint64_t val;
 147
 148     if (host_memory_backend_mr_inited(backend)) {
 149         error_setg(errp, "cannot change property '%s' of %s", name,
 150                    object_get_typename(o));
 151         return;
 152     }
 153
 154     if (!visit_type_size(v, name, &val, errp)) {
 155         return;
 156     }
 157     fb->offset = val;
 158 }
 159
 160 #ifdef CONFIG_LIBPMEM
 161 static bool file_memory_backend_get_pmem(Object *o, Error **errp)
 162 {
 163     return MEMORY_BACKEND_FILE(o)->is_pmem;
 164 }
 165
 166 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp)
 167 {
 168     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 169     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 170
 171     if (host_memory_backend_mr_inited(backend)) {
 172         error_setg(errp, "cannot change property 'pmem' of %s.",
 173                    object_get_typename(o));
 174         return;
 175     }
 176
 177     fb->is_pmem = value;
 178 }
 179 #endif /* CONFIG_LIBPMEM */
 180
 181 static bool file_memory_backend_get_readonly(Object *obj, Error **errp)
 182 {
 183     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 184
 185     return fb->readonly;
 186 }
 187
 188 static void file_memory_backend_set_readonly(Object *obj, bool value,
 189                                              Error **errp)
 190 {
 191     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 192     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 193
 194     if (host_memory_backend_mr_inited(backend)) {
 195         error_setg(errp, "cannot change property 'readonly' of %s.",
 196                    object_get_typename(obj));
 197         return;
 198     }
 199
 200     fb->readonly = value;
 201 }
 202
 203 static void file_backend_unparent(Object *obj)
 204 {
 205     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 206     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 207
 208     if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
 209         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 210         uint64_t sz = memory_region_size(&backend->mr);
 211
 212         qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
 213     }
 214 }
 215
 216 static void
 217 file_backend_class_init(ObjectClass *oc, void *data)
 218 {
 219     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
 220
 221     bc->alloc = file_backend_memory_alloc;
 222     oc->unparent = file_backend_unparent;
 223
 224     object_class_property_add_bool(oc, "discard-data",
 225         file_memory_backend_get_discard_data, file_memory_backend_set_discard_data);
 226     object_class_property_add_str(oc, "mem-path",
 227         get_mem_path, set_mem_path);
 228     object_class_property_add(oc, "align", "int",
 229         file_memory_backend_get_align,
 230         file_memory_backend_set_align,
 231         NULL, NULL);
 232     object_class_property_add(oc, "offset", "int",
 233         file_memory_backend_get_offset,
 234         file_memory_backend_set_offset,
 235         NULL, NULL);
 236     object_class_property_set_description(oc, "offset",
 237         "Offset into the target file (ex: 1G)");
 238 #ifdef CONFIG_LIBPMEM
 239     object_class_property_add_bool(oc, "pmem",
 240         file_memory_backend_get_pmem, file_memory_backend_set_pmem);
 241 #endif
 242     object_class_property_add_bool(oc, "readonly",
 243         file_memory_backend_get_readonly,
 244         file_memory_backend_set_readonly);
 245 }
 246
 247 static void file_backend_instance_finalize(Object *o)
 248 {
 249     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 250
 251     g_free(fb->mem_path);
 252 }
 253
 254 static const TypeInfo file_backend_info = {
 255     .name = TYPE_MEMORY_BACKEND_FILE,
 256     .parent = TYPE_MEMORY_BACKEND,
 257     .class_init = file_backend_class_init,
 258     .instance_finalize = file_backend_instance_finalize,
 259     .instance_size = sizeof(HostMemoryBackendFile),
 260 };
 261
 262 static void register_types(void)
 263 {
 264     type_register_static(&file_backend_info);
 265 }
 266
 267 type_init(register_types);