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     bool discard_data;
  31     bool is_pmem;
  32     bool readonly;
  33 };
  34
  35 static void
  36 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
  37 {
  38 #ifndef CONFIG_POSIX
  39     error_setg(errp, "backend '%s' not supported on this host",
  40                object_get_typename(OBJECT(backend)));
  41 #else
  42     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);
  43     uint32_t ram_flags;
  44     gchar *name;
  45
  46     if (!backend->size) {
  47         error_setg(errp, "can't create backend with size 0");
  48         return;
  49     }
  50     if (!fb->mem_path) {
  51         error_setg(errp, "mem-path property not set");
  52         return;
  53     }
  54
  55     name = host_memory_backend_get_name(backend);
  56     ram_flags = backend->share ? RAM_SHARED : 0;
  57     ram_flags |= backend->reserve ? 0 : RAM_NORESERVE;
  58     ram_flags |= fb->is_pmem ? RAM_PMEM : 0;
  59     memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name,
  60                                      backend->size, fb->align, ram_flags,
  61                                      fb->mem_path, fb->readonly, errp);
  62     g_free(name);
  63 #endif
  64 }
  65
  66 static char *get_mem_path(Object *o, Error **errp)
  67 {
  68     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  69
  70     return g_strdup(fb->mem_path);
  71 }
  72
  73 static void set_mem_path(Object *o, const char *str, Error **errp)
  74 {
  75     HostMemoryBackend *backend = MEMORY_BACKEND(o);
  76     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  77
  78     if (host_memory_backend_mr_inited(backend)) {
  79         error_setg(errp, "cannot change property 'mem-path' of %s",
  80                    object_get_typename(o));
  81         return;
  82     }
  83     g_free(fb->mem_path);
  84     fb->mem_path = g_strdup(str);
  85 }
  86
  87 static bool file_memory_backend_get_discard_data(Object *o, Error **errp)
  88 {
  89     return MEMORY_BACKEND_FILE(o)->discard_data;
  90 }
  91
  92 static void file_memory_backend_set_discard_data(Object *o, bool value,
  93                                                Error **errp)
  94 {
  95     MEMORY_BACKEND_FILE(o)->discard_data = value;
  96 }
  97
  98 static void file_memory_backend_get_align(Object *o, Visitor *v,
  99                                           const char *name, void *opaque,
 100                                           Error **errp)
 101 {
 102     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 103     uint64_t val = fb->align;
 104
 105     visit_type_size(v, name, &val, errp);
 106 }
 107
 108 static void file_memory_backend_set_align(Object *o, Visitor *v,
 109                                           const char *name, void *opaque,
 110                                           Error **errp)
 111 {
 112     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 113     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 114     uint64_t val;
 115
 116     if (host_memory_backend_mr_inited(backend)) {
 117         error_setg(errp, "cannot change property '%s' of %s", name,
 118                    object_get_typename(o));
 119         return;
 120     }
 121
 122     if (!visit_type_size(v, name, &val, errp)) {
 123         return;
 124     }
 125     fb->align = val;
 126 }
 127
 128 #ifdef CONFIG_LIBPMEM
 129 static bool file_memory_backend_get_pmem(Object *o, Error **errp)
 130 {
 131     return MEMORY_BACKEND_FILE(o)->is_pmem;
 132 }
 133
 134 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp)
 135 {
 136     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 137     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 138
 139     if (host_memory_backend_mr_inited(backend)) {
 140         error_setg(errp, "cannot change property 'pmem' of %s.",
 141                    object_get_typename(o));
 142         return;
 143     }
 144
 145     fb->is_pmem = value;
 146 }
 147 #endif /* CONFIG_LIBPMEM */
 148
 149 static bool file_memory_backend_get_readonly(Object *obj, Error **errp)
 150 {
 151     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 152
 153     return fb->readonly;
 154 }
 155
 156 static void file_memory_backend_set_readonly(Object *obj, bool value,
 157                                              Error **errp)
 158 {
 159     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 160     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 161
 162     if (host_memory_backend_mr_inited(backend)) {
 163         error_setg(errp, "cannot change property 'readonly' of %s.",
 164                    object_get_typename(obj));
 165         return;
 166     }
 167
 168     fb->readonly = value;
 169 }
 170
 171 static void file_backend_unparent(Object *obj)
 172 {
 173     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 174     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 175
 176     if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
 177         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 178         uint64_t sz = memory_region_size(&backend->mr);
 179
 180         qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
 181     }
 182 }
 183
 184 static void
 185 file_backend_class_init(ObjectClass *oc, void *data)
 186 {
 187     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
 188
 189     bc->alloc = file_backend_memory_alloc;
 190     oc->unparent = file_backend_unparent;
 191
 192     object_class_property_add_bool(oc, "discard-data",
 193         file_memory_backend_get_discard_data, file_memory_backend_set_discard_data);
 194     object_class_property_add_str(oc, "mem-path",
 195         get_mem_path, set_mem_path);
 196     object_class_property_add(oc, "align", "int",
 197         file_memory_backend_get_align,
 198         file_memory_backend_set_align,
 199         NULL, NULL);
 200 #ifdef CONFIG_LIBPMEM
 201     object_class_property_add_bool(oc, "pmem",
 202         file_memory_backend_get_pmem, file_memory_backend_set_pmem);
 203 #endif
 204     object_class_property_add_bool(oc, "readonly",
 205         file_memory_backend_get_readonly,
 206         file_memory_backend_set_readonly);
 207 }
 208
 209 static void file_backend_instance_finalize(Object *o)
 210 {
 211     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 212
 213     g_free(fb->mem_path);
 214 }
 215
 216 static const TypeInfo file_backend_info = {
 217     .name = TYPE_MEMORY_BACKEND_FILE,
 218     .parent = TYPE_MEMORY_BACKEND,
 219     .class_init = file_backend_class_init,
 220     .instance_finalize = file_backend_instance_finalize,
 221     .instance_size = sizeof(HostMemoryBackendFile),
 222 };
 223
 224 static void register_types(void)
 225 {
 226     type_register_static(&file_backend_info);
 227 }
 228
 229 type_init(register_types);