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     ram_flags |= RAM_NAMED_FILE;
  61     memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name,
  62                                      backend->size, fb->align, ram_flags,
  63                                      fb->mem_path, fb->offset, fb->readonly,
  64                                      errp);
  65     g_free(name);
  66 #endif
  67 }
  68
  69 static char *get_mem_path(Object *o, Error **errp)
  70 {
  71     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  72
  73     return g_strdup(fb->mem_path);
  74 }
  75
  76 static void set_mem_path(Object *o, const char *str, Error **errp)
  77 {
  78     HostMemoryBackend *backend = MEMORY_BACKEND(o);
  79     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  80
  81     if (host_memory_backend_mr_inited(backend)) {
  82         error_setg(errp, "cannot change property 'mem-path' of %s",
  83                    object_get_typename(o));
  84         return;
  85     }
  86     g_free(fb->mem_path);
  87     fb->mem_path = g_strdup(str);
  88 }
  89
  90 static bool file_memory_backend_get_discard_data(Object *o, Error **errp)
  91 {
  92     return MEMORY_BACKEND_FILE(o)->discard_data;
  93 }
  94
  95 static void file_memory_backend_set_discard_data(Object *o, bool value,
  96                                                Error **errp)
  97 {
  98     MEMORY_BACKEND_FILE(o)->discard_data = value;
  99 }
 100
 101 static void file_memory_backend_get_align(Object *o, Visitor *v,
 102                                           const char *name, void *opaque,
 103                                           Error **errp)
 104 {
 105     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 106     uint64_t val = fb->align;
 107
 108     visit_type_size(v, name, &val, errp);
 109 }
 110
 111 static void file_memory_backend_set_align(Object *o, Visitor *v,
 112                                           const char *name, void *opaque,
 113                                           Error **errp)
 114 {
 115     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 116     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 117     uint64_t val;
 118
 119     if (host_memory_backend_mr_inited(backend)) {
 120         error_setg(errp, "cannot change property '%s' of %s", name,
 121                    object_get_typename(o));
 122         return;
 123     }
 124
 125     if (!visit_type_size(v, name, &val, errp)) {
 126         return;
 127     }
 128     fb->align = val;
 129 }
 130
 131 static void file_memory_backend_get_offset(Object *o, Visitor *v,
 132                                           const char *name, void *opaque,
 133                                           Error **errp)
 134 {
 135     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 136     uint64_t val = fb->offset;
 137
 138     visit_type_size(v, name, &val, errp);
 139 }
 140
 141 static void file_memory_backend_set_offset(Object *o, Visitor *v,
 142                                           const char *name, void *opaque,
 143                                           Error **errp)
 144 {
 145     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 146     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 147     uint64_t val;
 148
 149     if (host_memory_backend_mr_inited(backend)) {
 150         error_setg(errp, "cannot change property '%s' of %s", name,
 151                    object_get_typename(o));
 152         return;
 153     }
 154
 155     if (!visit_type_size(v, name, &val, errp)) {
 156         return;
 157     }
 158     fb->offset = val;
 159 }
 160
 161 #ifdef CONFIG_LIBPMEM
 162 static bool file_memory_backend_get_pmem(Object *o, Error **errp)
 163 {
 164     return MEMORY_BACKEND_FILE(o)->is_pmem;
 165 }
 166
 167 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp)
 168 {
 169     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 170     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 171
 172     if (host_memory_backend_mr_inited(backend)) {
 173         error_setg(errp, "cannot change property 'pmem' of %s.",
 174                    object_get_typename(o));
 175         return;
 176     }
 177
 178     fb->is_pmem = value;
 179 }
 180 #endif /* CONFIG_LIBPMEM */
 181
 182 static bool file_memory_backend_get_readonly(Object *obj, Error **errp)
 183 {
 184     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 185
 186     return fb->readonly;
 187 }
 188
 189 static void file_memory_backend_set_readonly(Object *obj, bool value,
 190                                              Error **errp)
 191 {
 192     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 193     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 194
 195     if (host_memory_backend_mr_inited(backend)) {
 196         error_setg(errp, "cannot change property 'readonly' of %s.",
 197                    object_get_typename(obj));
 198         return;
 199     }
 200
 201     fb->readonly = value;
 202 }
 203
 204 static void file_backend_unparent(Object *obj)
 205 {
 206     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 207     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 208
 209     if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
 210         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 211         uint64_t sz = memory_region_size(&backend->mr);
 212
 213         qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
 214     }
 215 }
 216
 217 static void
 218 file_backend_class_init(ObjectClass *oc, void *data)
 219 {
 220     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
 221
 222     bc->alloc = file_backend_memory_alloc;
 223     oc->unparent = file_backend_unparent;
 224
 225     object_class_property_add_bool(oc, "discard-data",
 226         file_memory_backend_get_discard_data, file_memory_backend_set_discard_data);
 227     object_class_property_add_str(oc, "mem-path",
 228         get_mem_path, set_mem_path);
 229     object_class_property_add(oc, "align", "int",
 230         file_memory_backend_get_align,
 231         file_memory_backend_set_align,
 232         NULL, NULL);
 233     object_class_property_add(oc, "offset", "int",
 234         file_memory_backend_get_offset,
 235         file_memory_backend_set_offset,
 236         NULL, NULL);
 237     object_class_property_set_description(oc, "offset",
 238         "Offset into the target file (ex: 1G)");
 239 #ifdef CONFIG_LIBPMEM
 240     object_class_property_add_bool(oc, "pmem",
 241         file_memory_backend_get_pmem, file_memory_backend_set_pmem);
 242 #endif
 243     object_class_property_add_bool(oc, "readonly",
 244         file_memory_backend_get_readonly,
 245         file_memory_backend_set_readonly);
 246 }
 247
 248 static void file_backend_instance_finalize(Object *o)
 249 {
 250     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 251
 252     g_free(fb->mem_path);
 253 }
 254
 255 static const TypeInfo file_backend_info = {
 256     .name = TYPE_MEMORY_BACKEND_FILE,
 257     .parent = TYPE_MEMORY_BACKEND,
 258     .class_init = file_backend_class_init,
 259     .instance_finalize = file_backend_instance_finalize,
 260     .instance_size = sizeof(HostMemoryBackendFile),
 261 };
 262
 263 static void register_types(void)
 264 {
 265     type_register_static(&file_backend_info);
 266 }
 267
 268 type_init(register_types);