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 "qemu/madvise.h" 18 #include "sysemu/hostmem.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 bool readonly; 33 }; 34 35 static void 36 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 37 { 38 #ifndef CONFIG_POSIX 39 error_setg(errp, "backend '%s' not supported on this host", 40 object_get_typename(OBJECT(backend))); 41 #else 42 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend); 43 uint32_t ram_flags; 44 gchar *name; 45 46 if (!backend->size) { 47 error_setg(errp, "can't create backend with size 0"); 48 return; 49 } 50 if (!fb->mem_path) { 51 error_setg(errp, "mem-path property not set"); 52 return; 53 } 54 55 name = host_memory_backend_get_name(backend); 56 ram_flags = backend->share ? RAM_SHARED : 0; 57 ram_flags |= backend->reserve ? 0 : RAM_NORESERVE; 58 ram_flags |= fb->is_pmem ? RAM_PMEM : 0; 59 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name, 60 backend->size, fb->align, ram_flags, 61 fb->mem_path, fb->readonly, errp); 62 g_free(name); 63 #endif 64 } 65 66 static char *get_mem_path(Object *o, Error **errp) 67 { 68 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 69 70 return g_strdup(fb->mem_path); 71 } 72 73 static void set_mem_path(Object *o, const char *str, Error **errp) 74 { 75 HostMemoryBackend *backend = MEMORY_BACKEND(o); 76 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 77 78 if (host_memory_backend_mr_inited(backend)) { 79 error_setg(errp, "cannot change property 'mem-path' of %s", 80 object_get_typename(o)); 81 return; 82 } 83 g_free(fb->mem_path); 84 fb->mem_path = g_strdup(str); 85 } 86 87 static bool file_memory_backend_get_discard_data(Object *o, Error **errp) 88 { 89 return MEMORY_BACKEND_FILE(o)->discard_data; 90 } 91 92 static void file_memory_backend_set_discard_data(Object *o, bool value, 93 Error **errp) 94 { 95 MEMORY_BACKEND_FILE(o)->discard_data = value; 96 } 97 98 static void file_memory_backend_get_align(Object *o, Visitor *v, 99 const char *name, void *opaque, 100 Error **errp) 101 { 102 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 103 uint64_t val = fb->align; 104 105 visit_type_size(v, name, &val, errp); 106 } 107 108 static void file_memory_backend_set_align(Object *o, Visitor *v, 109 const char *name, void *opaque, 110 Error **errp) 111 { 112 HostMemoryBackend *backend = MEMORY_BACKEND(o); 113 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 114 uint64_t val; 115 116 if (host_memory_backend_mr_inited(backend)) { 117 error_setg(errp, "cannot change property '%s' of %s", name, 118 object_get_typename(o)); 119 return; 120 } 121 122 if (!visit_type_size(v, name, &val, errp)) { 123 return; 124 } 125 fb->align = val; 126 } 127 128 #ifdef CONFIG_LIBPMEM 129 static bool file_memory_backend_get_pmem(Object *o, Error **errp) 130 { 131 return MEMORY_BACKEND_FILE(o)->is_pmem; 132 } 133 134 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp) 135 { 136 HostMemoryBackend *backend = MEMORY_BACKEND(o); 137 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 138 139 if (host_memory_backend_mr_inited(backend)) { 140 error_setg(errp, "cannot change property 'pmem' of %s.", 141 object_get_typename(o)); 142 return; 143 } 144 145 fb->is_pmem = value; 146 } 147 #endif /* CONFIG_LIBPMEM */ 148 149 static bool file_memory_backend_get_readonly(Object *obj, Error **errp) 150 { 151 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 152 153 return fb->readonly; 154 } 155 156 static void file_memory_backend_set_readonly(Object *obj, bool value, 157 Error **errp) 158 { 159 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 160 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 161 162 if (host_memory_backend_mr_inited(backend)) { 163 error_setg(errp, "cannot change property 'readonly' of %s.", 164 object_get_typename(obj)); 165 return; 166 } 167 168 fb->readonly = value; 169 } 170 171 static void file_backend_unparent(Object *obj) 172 { 173 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 174 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 175 176 if (host_memory_backend_mr_inited(backend) && fb->discard_data) { 177 void *ptr = memory_region_get_ram_ptr(&backend->mr); 178 uint64_t sz = memory_region_size(&backend->mr); 179 180 qemu_madvise(ptr, sz, QEMU_MADV_REMOVE); 181 } 182 } 183 184 static void 185 file_backend_class_init(ObjectClass *oc, void *data) 186 { 187 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 188 189 bc->alloc = file_backend_memory_alloc; 190 oc->unparent = file_backend_unparent; 191 192 object_class_property_add_bool(oc, "discard-data", 193 file_memory_backend_get_discard_data, file_memory_backend_set_discard_data); 194 object_class_property_add_str(oc, "mem-path", 195 get_mem_path, set_mem_path); 196 object_class_property_add(oc, "align", "int", 197 file_memory_backend_get_align, 198 file_memory_backend_set_align, 199 NULL, NULL); 200 #ifdef CONFIG_LIBPMEM 201 object_class_property_add_bool(oc, "pmem", 202 file_memory_backend_get_pmem, file_memory_backend_set_pmem); 203 #endif 204 object_class_property_add_bool(oc, "readonly", 205 file_memory_backend_get_readonly, 206 file_memory_backend_set_readonly); 207 } 208 209 static void file_backend_instance_finalize(Object *o) 210 { 211 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 212 213 g_free(fb->mem_path); 214 } 215 216 static const TypeInfo file_backend_info = { 217 .name = TYPE_MEMORY_BACKEND_FILE, 218 .parent = TYPE_MEMORY_BACKEND, 219 .class_init = file_backend_class_init, 220 .instance_finalize = file_backend_instance_finalize, 221 .instance_size = sizeof(HostMemoryBackendFile), 222 }; 223 224 static void register_types(void) 225 { 226 type_register_static(&file_backend_info); 227 } 228 229 type_init(register_types); 230