LXR qemu/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#include "qemu/osdep.h"
  13#include "qapi/error.h"
  14#include "qemu-common.h"
  15#include "sysemu/hostmem.h"
  16#include "sysemu/sysemu.h"
  17#include "qom/object_interfaces.h"
  18
  19/* hostmem-file.c */
  20/**
  21 * @TYPE_MEMORY_BACKEND_FILE:
  22 * name of backend that uses mmap on a file descriptor
  23 */
  24#define TYPE_MEMORY_BACKEND_FILE "memory-backend-file"
  25
  26#define MEMORY_BACKEND_FILE(obj) \
  27    OBJECT_CHECK(HostMemoryBackendFile, (obj), TYPE_MEMORY_BACKEND_FILE)
  28
  29typedef struct HostMemoryBackendFile HostMemoryBackendFile;
  30
  31struct HostMemoryBackendFile {
  32    HostMemoryBackend parent_obj;
  33
  34    bool share;
  35    char *mem_path;
  36};
  37
  38static void
  39file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
  40{
  41    HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);
  42
  43    if (!backend->size) {
  44        error_setg(errp, "can't create backend with size 0");
  45        return;
  46    }
  47    if (!fb->mem_path) {
  48        error_setg(errp, "mem-path property not set");
  49        return;
  50    }
  51#ifndef CONFIG_LINUX
  52    error_setg(errp, "-mem-path not supported on this host");
  53#else
  54    if (!memory_region_size(&backend->mr)) {
  55        gchar *path;
  56        backend->force_prealloc = mem_prealloc;
  57        path = object_get_canonical_path(OBJECT(backend));
  58        memory_region_init_ram_from_file(&backend->mr, OBJECT(backend),
  59                                 path,
  60                                 backend->size, fb->share,
  61                                 fb->mem_path, errp);
  62        g_free(path);
  63    }
  64#endif
  65}
  66
  67static void
  68file_backend_class_init(ObjectClass *oc, void *data)
  69{
  70    HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
  71
  72    bc->alloc = file_backend_memory_alloc;
  73}
  74
  75static char *get_mem_path(Object *o, Error **errp)
  76{
  77    HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  78
  79    return g_strdup(fb->mem_path);
  80}
  81
  82static void set_mem_path(Object *o, const char *str, Error **errp)
  83{
  84    HostMemoryBackend *backend = MEMORY_BACKEND(o);
  85    HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  86
  87    if (memory_region_size(&backend->mr)) {
  88        error_setg(errp, "cannot change property value");
  89        return;
  90    }
  91    g_free(fb->mem_path);
  92    fb->mem_path = g_strdup(str);
  93}
  94
  95static bool file_memory_backend_get_share(Object *o, Error **errp)
  96{
  97    HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  98
  99    return fb->share;
 100}
 101
 102static void file_memory_backend_set_share(Object *o, bool value, Error **errp)
 103{
 104    HostMemoryBackend *backend = MEMORY_BACKEND(o);
 105    HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 106
 107    if (memory_region_size(&backend->mr)) {
 108        error_setg(errp, "cannot change property value");
 109        return;
 110    }
 111    fb->share = value;
 112}
 113
 114static void
 115file_backend_instance_init(Object *o)
 116{
 117    object_property_add_bool(o, "share",
 118                        file_memory_backend_get_share,
 119                        file_memory_backend_set_share, NULL);
 120    object_property_add_str(o, "mem-path", get_mem_path,
 121                            set_mem_path, NULL);
 122}
 123
 124static const TypeInfo file_backend_info = {
 125    .name = TYPE_MEMORY_BACKEND_FILE,
 126    .parent = TYPE_MEMORY_BACKEND,
 127    .class_init = file_backend_class_init,
 128    .instance_init = file_backend_instance_init,
 129    .instance_size = sizeof(HostMemoryBackendFile),
 130};
 131
 132static void register_types(void)
 133{
 134    type_register_static(&file_backend_info);
 135}
 136
 137type_init(register_types);
 138