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 #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 };
  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, 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 static bool file_memory_backend_get_pmem(Object *o, Error **errp)
 127 {
 128     return MEMORY_BACKEND_FILE(o)->is_pmem;
 129 }
 130
 131 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp)
 132 {
 133     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 134     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 135
 136     if (host_memory_backend_mr_inited(backend)) {
 137         error_setg(errp, "cannot change property 'pmem' of %s.",
 138                    object_get_typename(o));
 139         return;
 140     }
 141
 142 #ifndef CONFIG_LIBPMEM
 143     if (value) {
 144         error_setg(errp, "Lack of libpmem support while setting the 'pmem=on'"
 145                    " of %s. We can't ensure data persistence.",
 146                    object_get_typename(o));
 147         return;
 148     }
 149 #endif
 150
 151     fb->is_pmem = value;
 152 }
 153
 154 static void file_backend_unparent(Object *obj)
 155 {
 156     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 157     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 158
 159     if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
 160         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 161         uint64_t sz = memory_region_size(&backend->mr);
 162
 163         qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
 164     }
 165 }
 166
 167 static void
 168 file_backend_class_init(ObjectClass *oc, void *data)
 169 {
 170     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
 171
 172     bc->alloc = file_backend_memory_alloc;
 173     oc->unparent = file_backend_unparent;
 174
 175     object_class_property_add_bool(oc, "discard-data",
 176         file_memory_backend_get_discard_data, file_memory_backend_set_discard_data);
 177     object_class_property_add_str(oc, "mem-path",
 178         get_mem_path, set_mem_path);
 179     object_class_property_add(oc, "align", "int",
 180         file_memory_backend_get_align,
 181         file_memory_backend_set_align,
 182         NULL, NULL);
 183     object_class_property_add_bool(oc, "pmem",
 184         file_memory_backend_get_pmem, file_memory_backend_set_pmem);
 185 }
 186
 187 static void file_backend_instance_finalize(Object *o)
 188 {
 189     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 190
 191     g_free(fb->mem_path);
 192 }
 193
 194 static const TypeInfo file_backend_info = {
 195     .name = TYPE_MEMORY_BACKEND_FILE,
 196     .parent = TYPE_MEMORY_BACKEND,
 197     .class_init = file_backend_class_init,
 198     .instance_finalize = file_backend_instance_finalize,
 199     .instance_size = sizeof(HostMemoryBackendFile),
 200 };
 201
 202 static void register_types(void)
 203 {
 204     type_register_static(&file_backend_info);
 205 }
 206
 207 type_init(register_types);