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 char *mem_path; 36 }; 37 38 static void 39 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 40 { 41 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend); 42 43 if (!backend->size) { 44 error_setg(errp, "can't create backend with size 0"); 45 return; 46 } 47 if (!fb->mem_path) { 48 error_setg(errp, "mem-path property not set"); 49 return; 50 } 51 #ifndef CONFIG_LINUX 52 error_setg(errp, "-mem-path not supported on this host"); 53 #else 54 if (!memory_region_size(&backend->mr)) { 55 gchar *path; 56 backend->force_prealloc = mem_prealloc; 57 path = object_get_canonical_path(OBJECT(backend)); 58 memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), 59 path, 60 backend->size, fb->share, 61 fb->mem_path, errp); 62 g_free(path); 63 } 64 #endif 65 } 66 67 static char *get_mem_path(Object *o, Error **errp) 68 { 69 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 70 71 return g_strdup(fb->mem_path); 72 } 73 74 static void set_mem_path(Object *o, const char *str, Error **errp) 75 { 76 HostMemoryBackend *backend = MEMORY_BACKEND(o); 77 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 78 79 if (memory_region_size(&backend->mr)) { 80 error_setg(errp, "cannot change property value"); 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_share(Object *o, Error **errp) 88 { 89 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 90 91 return fb->share; 92 } 93 94 static void file_memory_backend_set_share(Object *o, bool value, Error **errp) 95 { 96 HostMemoryBackend *backend = MEMORY_BACKEND(o); 97 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 98 99 if (memory_region_size(&backend->mr)) { 100 error_setg(errp, "cannot change property value"); 101 return; 102 } 103 fb->share = value; 104 } 105 106 static void 107 file_backend_class_init(ObjectClass *oc, void *data) 108 { 109 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 110 111 bc->alloc = file_backend_memory_alloc; 112 113 object_class_property_add_bool(oc, "share", 114 file_memory_backend_get_share, file_memory_backend_set_share, 115 &error_abort); 116 object_class_property_add_str(oc, "mem-path", 117 get_mem_path, set_mem_path, 118 &error_abort); 119 } 120 121 static void file_backend_instance_finalize(Object *o) 122 { 123 HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o); 124 125 g_free(fb->mem_path); 126 } 127 128 static const TypeInfo file_backend_info = { 129 .name = TYPE_MEMORY_BACKEND_FILE, 130 .parent = TYPE_MEMORY_BACKEND, 131 .class_init = file_backend_class_init, 132 .instance_finalize = file_backend_instance_finalize, 133 .instance_size = sizeof(HostMemoryBackendFile), 134 }; 135 136 static void register_types(void) 137 { 138 type_register_static(&file_backend_info); 139 } 140 141 type_init(register_types); 142