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 21 #define MEMORY_BACKEND_FILE(obj) \ 22 OBJECT_CHECK(HostMemoryBackendFile, (obj), TYPE_MEMORY_BACKEND_FILE) 23 24 typedef struct HostMemoryBackendFile HostMemoryBackendFile; 25 26 struct HostMemoryBackendFile { 27 HostMemoryBackend parent_obj; 28 29 char *mem_path; 30 uint64_t align; 31 bool discard_data; 32 bool is_pmem; 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 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 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), 56 name, 57 backend->size, fb->align, 58 (backend->share ? RAM_SHARED : 0) | 59 (fb->is_pmem ? RAM_PMEM : 0), 60 fb->mem_path, 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 Error *local_err = NULL; 114 uint64_t val; 115 116 if (host_memory_backend_mr_inited(backend)) { 117 error_setg(&local_err, "cannot change property '%s' of %s", 118 name, object_get_typename(o)); 119 goto out; 120 } 121 122 visit_type_size(v, name, &val, &local_err); 123 if (local_err) { 124 goto out; 125 } 126 fb->align = val; 127 128 out: 129 error_propagate(errp, local_err); 130 } 131 132 static bool file_memory_backend_get_pmem(Object *o, Error **errp) 133 { 134 return MEMORY_BACKEND_FILE(o)->is_pmem; 135 } 136 137 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp) 138 { 139 HostMemoryBackend *backend = MEMORY_BACKEND(o); 140 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 141 142 if (host_memory_backend_mr_inited(backend)) { 143 144 error_setg(errp, "cannot change property 'pmem' of %s.", 145 object_get_typename(o)); 146 return; 147 } 148 149 #ifndef CONFIG_LIBPMEM 150 if (value) { 151 Error *local_err = NULL; 152 153 error_setg(&local_err, 154 "Lack of libpmem support while setting the 'pmem=on'" 155 " of %s. We can't ensure data persistence.", 156 object_get_typename(o)); 157 error_propagate(errp, local_err); 158 return; 159 } 160 #endif 161 162 fb->is_pmem = value; 163 } 164 165 static void file_backend_unparent(Object *obj) 166 { 167 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 168 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 169 170 if (host_memory_backend_mr_inited(backend) && fb->discard_data) { 171 void *ptr = memory_region_get_ram_ptr(&backend->mr); 172 uint64_t sz = memory_region_size(&backend->mr); 173 174 qemu_madvise(ptr, sz, QEMU_MADV_REMOVE); 175 } 176 } 177 178 static void 179 file_backend_class_init(ObjectClass *oc, void *data) 180 { 181 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 182 183 bc->alloc = file_backend_memory_alloc; 184 oc->unparent = file_backend_unparent; 185 186 object_class_property_add_bool(oc, "discard-data", 187 file_memory_backend_get_discard_data, file_memory_backend_set_discard_data, 188 &error_abort); 189 object_class_property_add_str(oc, "mem-path", 190 get_mem_path, set_mem_path, 191 &error_abort); 192 object_class_property_add(oc, "align", "int", 193 file_memory_backend_get_align, 194 file_memory_backend_set_align, 195 NULL, NULL, &error_abort); 196 object_class_property_add_bool(oc, "pmem", 197 file_memory_backend_get_pmem, file_memory_backend_set_pmem, 198 &error_abort); 199 } 200 201 static void file_backend_instance_finalize(Object *o) 202 { 203 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 204 205 g_free(fb->mem_path); 206 } 207 208 static const TypeInfo file_backend_info = { 209 .name = TYPE_MEMORY_BACKEND_FILE, 210 .parent = TYPE_MEMORY_BACKEND, 211 .class_init = file_backend_class_init, 212 .instance_finalize = file_backend_instance_finalize, 213 .instance_size = sizeof(HostMemoryBackendFile), 214 }; 215 216 static void register_types(void) 217 { 218 type_register_static(&file_backend_info); 219 } 220 221 type_init(register_types); 222