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 /* hostmem-file.c */ 22 /** 23 * @TYPE_MEMORY_BACKEND_FILE: 24 * name of backend that uses mmap on a file descriptor 25 */ 26 #define TYPE_MEMORY_BACKEND_FILE "memory-backend-file" 27 28 #define MEMORY_BACKEND_FILE(obj) \ 29 OBJECT_CHECK(HostMemoryBackendFile, (obj), TYPE_MEMORY_BACKEND_FILE) 30 31 typedef struct HostMemoryBackendFile HostMemoryBackendFile; 32 33 struct HostMemoryBackendFile { 34 HostMemoryBackend parent_obj; 35 36 char *mem_path; 37 uint64_t align; 38 bool discard_data; 39 bool is_pmem; 40 }; 41 42 static void 43 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 44 { 45 #ifndef CONFIG_POSIX 46 error_setg(errp, "backend '%s' not supported on this host", 47 object_get_typename(OBJECT(backend))); 48 #else 49 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend); 50 gchar *name; 51 52 if (!backend->size) { 53 error_setg(errp, "can't create backend with size 0"); 54 return; 55 } 56 if (!fb->mem_path) { 57 error_setg(errp, "mem-path property not set"); 58 return; 59 } 60 61 backend->force_prealloc = mem_prealloc; 62 name = host_memory_backend_get_name(backend); 63 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), 64 name, 65 backend->size, fb->align, 66 (backend->share ? RAM_SHARED : 0) | 67 (fb->is_pmem ? RAM_PMEM : 0), 68 fb->mem_path, errp); 69 g_free(name); 70 #endif 71 } 72 73 static char *get_mem_path(Object *o, Error **errp) 74 { 75 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 76 77 return g_strdup(fb->mem_path); 78 } 79 80 static void set_mem_path(Object *o, const char *str, Error **errp) 81 { 82 HostMemoryBackend *backend = MEMORY_BACKEND(o); 83 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 84 85 if (host_memory_backend_mr_inited(backend)) { 86 error_setg(errp, "cannot change property 'mem-path' of %s", 87 object_get_typename(o)); 88 return; 89 } 90 g_free(fb->mem_path); 91 fb->mem_path = g_strdup(str); 92 } 93 94 static bool file_memory_backend_get_discard_data(Object *o, Error **errp) 95 { 96 return MEMORY_BACKEND_FILE(o)->discard_data; 97 } 98 99 static void file_memory_backend_set_discard_data(Object *o, bool value, 100 Error **errp) 101 { 102 MEMORY_BACKEND_FILE(o)->discard_data = value; 103 } 104 105 static void file_memory_backend_get_align(Object *o, Visitor *v, 106 const char *name, void *opaque, 107 Error **errp) 108 { 109 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 110 uint64_t val = fb->align; 111 112 visit_type_size(v, name, &val, errp); 113 } 114 115 static void file_memory_backend_set_align(Object *o, Visitor *v, 116 const char *name, void *opaque, 117 Error **errp) 118 { 119 HostMemoryBackend *backend = MEMORY_BACKEND(o); 120 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 121 Error *local_err = NULL; 122 uint64_t val; 123 124 if (host_memory_backend_mr_inited(backend)) { 125 error_setg(&local_err, "cannot change property '%s' of %s", 126 name, object_get_typename(o)); 127 goto out; 128 } 129 130 visit_type_size(v, name, &val, &local_err); 131 if (local_err) { 132 goto out; 133 } 134 fb->align = val; 135 136 out: 137 error_propagate(errp, local_err); 138 } 139 140 static bool file_memory_backend_get_pmem(Object *o, Error **errp) 141 { 142 return MEMORY_BACKEND_FILE(o)->is_pmem; 143 } 144 145 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp) 146 { 147 HostMemoryBackend *backend = MEMORY_BACKEND(o); 148 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 149 150 if (host_memory_backend_mr_inited(backend)) { 151 152 error_setg(errp, "cannot change property 'pmem' of %s.", 153 object_get_typename(o)); 154 return; 155 } 156 157 #ifndef CONFIG_LIBPMEM 158 if (value) { 159 Error *local_err = NULL; 160 161 error_setg(&local_err, 162 "Lack of libpmem support while setting the 'pmem=on'" 163 " of %s. We can't ensure data persistence.", 164 object_get_typename(o)); 165 error_propagate(errp, local_err); 166 return; 167 } 168 #endif 169 170 fb->is_pmem = value; 171 } 172 173 static void file_backend_unparent(Object *obj) 174 { 175 HostMemoryBackend *backend = MEMORY_BACKEND(obj); 176 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj); 177 178 if (host_memory_backend_mr_inited(backend) && fb->discard_data) { 179 void *ptr = memory_region_get_ram_ptr(&backend->mr); 180 uint64_t sz = memory_region_size(&backend->mr); 181 182 qemu_madvise(ptr, sz, QEMU_MADV_REMOVE); 183 } 184 } 185 186 static void 187 file_backend_class_init(ObjectClass *oc, void *data) 188 { 189 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 190 191 bc->alloc = file_backend_memory_alloc; 192 oc->unparent = file_backend_unparent; 193 194 object_class_property_add_bool(oc, "discard-data", 195 file_memory_backend_get_discard_data, file_memory_backend_set_discard_data, 196 &error_abort); 197 object_class_property_add_str(oc, "mem-path", 198 get_mem_path, set_mem_path, 199 &error_abort); 200 object_class_property_add(oc, "align", "int", 201 file_memory_backend_get_align, 202 file_memory_backend_set_align, 203 NULL, NULL, &error_abort); 204 object_class_property_add_bool(oc, "pmem", 205 file_memory_backend_get_pmem, file_memory_backend_set_pmem, 206 &error_abort); 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