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 "sysemu/hostmem.h"
  18 #include "sysemu/sysemu.h"
  19 #include "qom/object_interfaces.h"
  20
  21 #define MEMORY_BACKEND_FILE(obj) \
  22     OBJECT_CHECK(HostMemoryBackendFile, (obj), TYPE_MEMORY_BACKEND_FILE)
  23
  24 typedef struct HostMemoryBackendFile HostMemoryBackendFile;
  25
  26 struct HostMemoryBackendFile {
  27     HostMemoryBackend parent_obj;
  28
  29     char *mem_path;
  30     uint64_t align;
  31     bool discard_data;
  32     bool is_pmem;
  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     gchar *name;
  44
  45     if (!backend->size) {
  46         error_setg(errp, "can't create backend with size 0");
  47         return;
  48     }
  49     if (!fb->mem_path) {
  50         error_setg(errp, "mem-path property not set");
  51         return;
  52     }
  53
  54     backend->force_prealloc = mem_prealloc;
  55     name = host_memory_backend_get_name(backend);
  56     memory_region_init_ram_from_file(&backend->mr, OBJECT(backend),
  57                                      name,
  58                                      backend->size, fb->align,
  59                                      (backend->share ? RAM_SHARED : 0) |
  60                                      (fb->is_pmem ? RAM_PMEM : 0),
  61                                      fb->mem_path, 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     Error *local_err = NULL;
 115     uint64_t val;
 116
 117     if (host_memory_backend_mr_inited(backend)) {
 118         error_setg(&local_err, "cannot change property '%s' of %s",
 119                    name, object_get_typename(o));
 120         goto out;
 121     }
 122
 123     visit_type_size(v, name, &val, &local_err);
 124     if (local_err) {
 125         goto out;
 126     }
 127     fb->align = val;
 128
 129  out:
 130     error_propagate(errp, local_err);
 131 }
 132
 133 static bool file_memory_backend_get_pmem(Object *o, Error **errp)
 134 {
 135     return MEMORY_BACKEND_FILE(o)->is_pmem;
 136 }
 137
 138 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp)
 139 {
 140     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 141     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 142
 143     if (host_memory_backend_mr_inited(backend)) {
 144
 145         error_setg(errp, "cannot change property 'pmem' of %s.",
 146                    object_get_typename(o));
 147         return;
 148     }
 149
 150 #ifndef CONFIG_LIBPMEM
 151     if (value) {
 152         Error *local_err = NULL;
 153
 154         error_setg(&local_err,
 155                    "Lack of libpmem support while setting the 'pmem=on'"
 156                    " of %s. We can't ensure data persistence.",
 157                    object_get_typename(o));
 158         error_propagate(errp, local_err);
 159         return;
 160     }
 161 #endif
 162
 163     fb->is_pmem = value;
 164 }
 165
 166 static void file_backend_unparent(Object *obj)
 167 {
 168     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 169     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 170
 171     if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
 172         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 173         uint64_t sz = memory_region_size(&backend->mr);
 174
 175         qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
 176     }
 177 }
 178
 179 static void
 180 file_backend_class_init(ObjectClass *oc, void *data)
 181 {
 182     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
 183
 184     bc->alloc = file_backend_memory_alloc;
 185     oc->unparent = file_backend_unparent;
 186
 187     object_class_property_add_bool(oc, "discard-data",
 188         file_memory_backend_get_discard_data, file_memory_backend_set_discard_data,
 189         &error_abort);
 190     object_class_property_add_str(oc, "mem-path",
 191         get_mem_path, set_mem_path,
 192         &error_abort);
 193     object_class_property_add(oc, "align", "int",
 194         file_memory_backend_get_align,
 195         file_memory_backend_set_align,
 196         NULL, NULL, &error_abort);
 197     object_class_property_add_bool(oc, "pmem",
 198         file_memory_backend_get_pmem, file_memory_backend_set_pmem,
 199         &error_abort);
 200 }
 201
 202 static void file_backend_instance_finalize(Object *o)
 203 {
 204     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 205
 206     g_free(fb->mem_path);
 207 }
 208
 209 static const TypeInfo file_backend_info = {
 210     .name = TYPE_MEMORY_BACKEND_FILE,
 211     .parent = TYPE_MEMORY_BACKEND,
 212     .class_init = file_backend_class_init,
 213     .instance_finalize = file_backend_instance_finalize,
 214     .instance_size = sizeof(HostMemoryBackendFile),
 215 };
 216
 217 static void register_types(void)
 218 {
 219     type_register_static(&file_backend_info);
 220 }
 221
 222 type_init(register_types);