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 uint32_t ram_flags; 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 name = host_memory_backend_get_name(backend); 55 ram_flags = backend->share ? RAM_SHARED : 0; 56 ram_flags |= backend->reserve ? 0 : RAM_NORESERVE; 57 ram_flags |= fb->is_pmem ? RAM_PMEM : 0; 58 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name, 59 backend->size, fb->align, ram_flags, 60 fb->mem_path, fb->readonly, errp); 61 g_free(name); 62 #endif 63 } 64 65 static char *get_mem_path(Object *o, Error **errp) 66 { 67 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 68 69 return g_strdup(fb->mem_path); 70 } 71 72 static void set_mem_path(Object *o, const char *str, Error **errp) 73 { 74 HostMemoryBackend *backend = MEMORY_BACKEND(o); 75 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 76 77 if (host_memory_backend_mr_inited(backend)) { 78 error_setg(errp, "cannot change property 'mem-path' of %s", 79 object_get_typename(o)); 80 return; 81 } 82 g_free(fb->mem_path); 83 fb->mem_path = g_strdup(str); 84 } 85 86 static bool file_memory_backend_get_discard_data(Object *o, Error **errp) 87 { 88 return MEMORY_BACKEND_FILE(o)->discard_data; 89 } 90 91 static void file_memory_backend_set_discard_data(Object *o, bool value, 92 Error **errp) 93 { 94 MEMORY_BACKEND_FILE(o)->discard_data = value; 95 } 96 97 static void file_memory_backend_get_align(Object *o, Visitor *v, 98 const char *name, void *opaque, 99 Error **errp) 100 { 101 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 102 uint64_t val = fb->align; 103 104 visit_type_size(v, name, &val, errp); 105 } 106 107 static void file_memory_backend_set_align(Object *o, Visitor *v, 108 const char *name, void *opaque, 109 Error **errp) 110 { 111 HostMemoryBackend *backend = MEMORY_BACKEND(o); 112 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 113 uint64_t val; 114 115 if (host_memory_backend_mr_inited(backend)) { 116 error_setg(errp, "cannot change property '%s' of %s", name, 117 object_get_typename(o)); 118 return; 119 } 120 121 if (!visit_type_size(v, name, &val, errp)) { 122 return; 123 } 124 fb->align = val; 125 } 126 127 #ifdef CONFIG_LIBPMEM 128 static bool file_memory_backend_get_pmem(Object *o, Error **errp) 129 { 130 return MEMORY_BACKEND_FILE(o)->is_pmem; 131 } 132 133 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp) 134 { 135 HostMemoryBackend *backend = MEMORY_BACKEND(o); 136 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 137 138 if (host_memory_backend_mr_inited(backend)) { 139 error_setg(errp, "cannot change property 'pmem' of %s.", 140 object_get_typename(o)); 141 return; 142 } 143 144 fb->is_pmem = value; 145 } 146 #endif /* CONFIG_LIBPMEM */ 147 148 static bool file_memory_backend_get_readonly(Object *obj, Error **errp) 149 { 150 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 151 152 return fb->readonly; 153 } 154 155 static void file_memory_backend_set_readonly(Object *obj, bool value, 156 Error **errp) 157 { 158 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 159 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 160 161 if (host_memory_backend_mr_inited(backend)) { 162 error_setg(errp, "cannot change property 'readonly' of %s.", 163 object_get_typename(obj)); 164 return; 165 } 166 167 fb->readonly = value; 168 } 169 170 static void file_backend_unparent(Object *obj) 171 { 172 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 173 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 174 175 if (host_memory_backend_mr_inited(backend) && fb->discard_data) { 176 void *ptr = memory_region_get_ram_ptr(&backend->mr); 177 uint64_t sz = memory_region_size(&backend->mr); 178 179 qemu_madvise(ptr, sz, QEMU_MADV_REMOVE); 180 } 181 } 182 183 static void 184 file_backend_class_init(ObjectClass *oc, void *data) 185 { 186 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 187 188 bc->alloc = file_backend_memory_alloc; 189 oc->unparent = file_backend_unparent; 190 191 object_class_property_add_bool(oc, "discard-data", 192 file_memory_backend_get_discard_data, file_memory_backend_set_discard_data); 193 object_class_property_add_str(oc, "mem-path", 194 get_mem_path, set_mem_path); 195 object_class_property_add(oc, "align", "int", 196 file_memory_backend_get_align, 197 file_memory_backend_set_align, 198 NULL, NULL); 199 #ifdef CONFIG_LIBPMEM 200 object_class_property_add_bool(oc, "pmem", 201 file_memory_backend_get_pmem, file_memory_backend_set_pmem); 202 #endif 203 object_class_property_add_bool(oc, "readonly", 204 file_memory_backend_get_readonly, 205 file_memory_backend_set_readonly); 206 } 207 208 static void file_backend_instance_finalize(Object *o) 209 { 210 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 211 212 g_free(fb->mem_path); 213 } 214 215 static const TypeInfo file_backend_info = { 216 .name = TYPE_MEMORY_BACKEND_FILE, 217 .parent = TYPE_MEMORY_BACKEND, 218 .class_init = file_backend_class_init, 219 .instance_finalize = file_backend_instance_finalize, 220 .instance_size = sizeof(HostMemoryBackendFile), 221 }; 222 223 static void register_types(void) 224 { 225 type_register_static(&file_backend_info); 226 } 227 228 type_init(register_types); 229