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 "qom/object_interfaces.h"
  19 #include "qom/object.h"
  20
  21 OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendFile, MEMORY_BACKEND_FILE)
  22
  23
  24 struct HostMemoryBackendFile {
  25     HostMemoryBackend parent_obj;
  26
  27     char *mem_path;
  28     uint64_t align;
  29     bool discard_data;
  30     bool is_pmem;
  31     bool readonly;
  32 };
  33
  34 static void
  35 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
  36 {
  37 #ifndef CONFIG_POSIX
  38     error_setg(errp, "backend '%s' not supported on this host",
  39                object_get_typename(OBJECT(backend)));
  40 #else
  41     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);
  42     gchar *name;
  43
  44     if (!backend->size) {
  45         error_setg(errp, "can't create backend with size 0");
  46         return;
  47     }
  48     if (!fb->mem_path) {
  49         error_setg(errp, "mem-path property not set");
  50         return;
  51     }
  52
  53     name = host_memory_backend_get_name(backend);
  54     memory_region_init_ram_from_file(&backend->mr, OBJECT(backend),
  55                                      name,
  56                                      backend->size, fb->align,
  57                                      (backend->share ? RAM_SHARED : 0) |
  58                                      (fb->is_pmem ? RAM_PMEM : 0),
  59                                      fb->mem_path, fb->readonly, errp);
  60     g_free(name);
  61 #endif
  62 }
  63
  64 static char *get_mem_path(Object *o, Error **errp)
  65 {
  66     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  67
  68     return g_strdup(fb->mem_path);
  69 }
  70
  71 static void set_mem_path(Object *o, const char *str, Error **errp)
  72 {
  73     HostMemoryBackend *backend = MEMORY_BACKEND(o);
  74     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  75
  76     if (host_memory_backend_mr_inited(backend)) {
  77         error_setg(errp, "cannot change property 'mem-path' of %s",
  78                    object_get_typename(o));
  79         return;
  80     }
  81     g_free(fb->mem_path);
  82     fb->mem_path = g_strdup(str);
  83 }
  84
  85 static bool file_memory_backend_get_discard_data(Object *o, Error **errp)
  86 {
  87     return MEMORY_BACKEND_FILE(o)->discard_data;
  88 }
  89
  90 static void file_memory_backend_set_discard_data(Object *o, bool value,
  91                                                Error **errp)
  92 {
  93     MEMORY_BACKEND_FILE(o)->discard_data = value;
  94 }
  95
  96 static void file_memory_backend_get_align(Object *o, Visitor *v,
  97                                           const char *name, void *opaque,
  98                                           Error **errp)
  99 {
 100     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 101     uint64_t val = fb->align;
 102
 103     visit_type_size(v, name, &val, errp);
 104 }
 105
 106 static void file_memory_backend_set_align(Object *o, Visitor *v,
 107                                           const char *name, void *opaque,
 108                                           Error **errp)
 109 {
 110     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 111     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 112     uint64_t val;
 113
 114     if (host_memory_backend_mr_inited(backend)) {
 115         error_setg(errp, "cannot change property '%s' of %s", name,
 116                    object_get_typename(o));
 117         return;
 118     }
 119
 120     if (!visit_type_size(v, name, &val, errp)) {
 121         return;
 122     }
 123     fb->align = val;
 124 }
 125
 126 #ifdef CONFIG_LIBPMEM
 127 static bool file_memory_backend_get_pmem(Object *o, Error **errp)
 128 {
 129     return MEMORY_BACKEND_FILE(o)->is_pmem;
 130 }
 131
 132 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp)
 133 {
 134     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 135     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 136
 137     if (host_memory_backend_mr_inited(backend)) {
 138         error_setg(errp, "cannot change property 'pmem' of %s.",
 139                    object_get_typename(o));
 140         return;
 141     }
 142
 143     fb->is_pmem = value;
 144 }
 145 #endif /* CONFIG_LIBPMEM */
 146
 147 static bool file_memory_backend_get_readonly(Object *obj, Error **errp)
 148 {
 149     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 150
 151     return fb->readonly;
 152 }
 153
 154 static void file_memory_backend_set_readonly(Object *obj, bool value,
 155                                              Error **errp)
 156 {
 157     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 158     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 159
 160     if (host_memory_backend_mr_inited(backend)) {
 161         error_setg(errp, "cannot change property 'readonly' of %s.",
 162                    object_get_typename(obj));
 163         return;
 164     }
 165
 166     fb->readonly = value;
 167 }
 168
 169 static void file_backend_unparent(Object *obj)
 170 {
 171     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 172     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 173
 174     if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
 175         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 176         uint64_t sz = memory_region_size(&backend->mr);
 177
 178         qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
 179     }
 180 }
 181
 182 static void
 183 file_backend_class_init(ObjectClass *oc, void *data)
 184 {
 185     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
 186
 187     bc->alloc = file_backend_memory_alloc;
 188     oc->unparent = file_backend_unparent;
 189
 190     object_class_property_add_bool(oc, "discard-data",
 191         file_memory_backend_get_discard_data, file_memory_backend_set_discard_data);
 192     object_class_property_add_str(oc, "mem-path",
 193         get_mem_path, set_mem_path);
 194     object_class_property_add(oc, "align", "int",
 195         file_memory_backend_get_align,
 196         file_memory_backend_set_align,
 197         NULL, NULL);
 198 #ifdef CONFIG_LIBPMEM
 199     object_class_property_add_bool(oc, "pmem",
 200         file_memory_backend_get_pmem, file_memory_backend_set_pmem);
 201 #endif
 202     object_class_property_add_bool(oc, "readonly",
 203         file_memory_backend_get_readonly,
 204         file_memory_backend_set_readonly);
 205 }
 206
 207 static void file_backend_instance_finalize(Object *o)
 208 {
 209     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 210
 211     g_free(fb->mem_path);
 212 }
 213
 214 static const TypeInfo file_backend_info = {
 215     .name = TYPE_MEMORY_BACKEND_FILE,
 216     .parent = TYPE_MEMORY_BACKEND,
 217     .class_init = file_backend_class_init,
 218     .instance_finalize = file_backend_instance_finalize,
 219     .instance_size = sizeof(HostMemoryBackendFile),
 220 };
 221
 222 static void register_types(void)
 223 {
 224     type_register_static(&file_backend_info);
 225 }
 226
 227 type_init(register_types);