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 29 typedef struct HostMemoryBackendFile HostMemoryBackendFile; 30 31 struct HostMemoryBackendFile { 32 HostMemoryBackend parent_obj; 33 34 bool share; 35 bool discard_data; 36 char *mem_path; 37 uint64_t align; 38 }; 39 40 static void 41 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 42 { 43 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend); 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 #ifndef CONFIG_LINUX 54 error_setg(errp, "-mem-path not supported on this host"); 55 #else 56 if (!host_memory_backend_mr_inited(backend)) { 57 gchar *path; 58 backend->force_prealloc = mem_prealloc; 59 path = object_get_canonical_path(OBJECT(backend)); 60 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), 61 path, 62 backend->size, fb->align, fb->share, 63 fb->mem_path, errp); 64 g_free(path); 65 } 66 #endif 67 } 68 69 static char *get_mem_path(Object *o, Error **errp) 70 { 71 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 72 73 return g_strdup(fb->mem_path); 74 } 75 76 static void set_mem_path(Object *o, const char *str, Error **errp) 77 { 78 HostMemoryBackend *backend = MEMORY_BACKEND(o); 79 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 80 81 if (host_memory_backend_mr_inited(backend)) { 82 error_setg(errp, "cannot change property value"); 83 return; 84 } 85 g_free(fb->mem_path); 86 fb->mem_path = g_strdup(str); 87 } 88 89 static bool file_memory_backend_get_share(Object *o, Error **errp) 90 { 91 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 92 93 return fb->share; 94 } 95 96 static void file_memory_backend_set_share(Object *o, bool value, Error **errp) 97 { 98 HostMemoryBackend *backend = MEMORY_BACKEND(o); 99 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 100 101 if (host_memory_backend_mr_inited(backend)) { 102 error_setg(errp, "cannot change property value"); 103 return; 104 } 105 fb->share = value; 106 } 107 108 static bool file_memory_backend_get_discard_data(Object *o, Error **errp) 109 { 110 return MEMORY_BACKEND_FILE(o)->discard_data; 111 } 112 113 static void file_memory_backend_set_discard_data(Object *o, bool value, 114 Error **errp) 115 { 116 MEMORY_BACKEND_FILE(o)->discard_data = value; 117 } 118 119 static void file_memory_backend_get_align(Object *o, Visitor *v, 120 const char *name, void *opaque, 121 Error **errp) 122 { 123 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 124 uint64_t val = fb->align; 125 126 visit_type_size(v, name, &val, errp); 127 } 128 129 static void file_memory_backend_set_align(Object *o, Visitor *v, 130 const char *name, void *opaque, 131 Error **errp) 132 { 133 HostMemoryBackend *backend = MEMORY_BACKEND(o); 134 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 135 Error *local_err = NULL; 136 uint64_t val; 137 138 if (host_memory_backend_mr_inited(backend)) { 139 error_setg(&local_err, "cannot change property value"); 140 goto out; 141 } 142 143 visit_type_size(v, name, &val, &local_err); 144 if (local_err) { 145 goto out; 146 } 147 fb->align = val; 148 149 out: 150 error_propagate(errp, local_err); 151 } 152 153 static void file_backend_unparent(Object *obj) 154 { 155 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 156 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 157 158 if (host_memory_backend_mr_inited(backend) && fb->discard_data) { 159 void *ptr = memory_region_get_ram_ptr(&backend->mr); 160 uint64_t sz = memory_region_size(&backend->mr); 161 162 qemu_madvise(ptr, sz, QEMU_MADV_REMOVE); 163 } 164 } 165 166 static void 167 file_backend_class_init(ObjectClass *oc, void *data) 168 { 169 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 170 171 bc->alloc = file_backend_memory_alloc; 172 oc->unparent = file_backend_unparent; 173 174 object_class_property_add_bool(oc, "share", 175 file_memory_backend_get_share, file_memory_backend_set_share, 176 &error_abort); 177 object_class_property_add_bool(oc, "discard-data", 178 file_memory_backend_get_discard_data, file_memory_backend_set_discard_data, 179 &error_abort); 180 object_class_property_add_str(oc, "mem-path", 181 get_mem_path, set_mem_path, 182 &error_abort); 183 object_class_property_add(oc, "align", "int", 184 file_memory_backend_get_align, 185 file_memory_backend_set_align, 186 NULL, NULL, &error_abort); 187 } 188 189 static void file_backend_instance_finalize(Object *o) 190 { 191 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 192 193 g_free(fb->mem_path); 194 } 195 196 static const TypeInfo file_backend_info = { 197 .name = TYPE_MEMORY_BACKEND_FILE, 198 .parent = TYPE_MEMORY_BACKEND, 199 .class_init = file_backend_class_init, 200 .instance_finalize = file_backend_instance_finalize, 201 .instance_size = sizeof(HostMemoryBackendFile), 202 }; 203 204 static void register_types(void) 205 { 206 type_register_static(&file_backend_info); 207 } 208 209 type_init(register_types); 210