1 /* 2 * QEMU host memfd memory backend 3 * 4 * Copyright (C) 2018 Red Hat Inc 5 * 6 * Authors: 7 * Marc-André Lureau <marcandre.lureau@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 "sysemu/hostmem.h" 15 #include "sysemu/sysemu.h" 16 #include "qom/object_interfaces.h" 17 #include "qemu/memfd.h" 18 #include "qemu/module.h" 19 #include "qapi/error.h" 20 21 #define TYPE_MEMORY_BACKEND_MEMFD "memory-backend-memfd" 22 23 #define MEMORY_BACKEND_MEMFD(obj) \ 24 OBJECT_CHECK(HostMemoryBackendMemfd, (obj), TYPE_MEMORY_BACKEND_MEMFD) 25 26 typedef struct HostMemoryBackendMemfd HostMemoryBackendMemfd; 27 28 struct HostMemoryBackendMemfd { 29 HostMemoryBackend parent_obj; 30 31 bool hugetlb; 32 uint64_t hugetlbsize; 33 bool seal; 34 }; 35 36 static void 37 memfd_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) 38 { 39 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(backend); 40 char *name; 41 int fd; 42 43 if (!backend->size) { 44 error_setg(errp, "can't create backend with size 0"); 45 return; 46 } 47 48 fd = qemu_memfd_create(TYPE_MEMORY_BACKEND_MEMFD, backend->size, 49 m->hugetlb, m->hugetlbsize, m->seal ? 50 F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL : 0, 51 errp); 52 if (fd == -1) { 53 return; 54 } 55 56 name = host_memory_backend_get_name(backend); 57 memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend), 58 name, backend->size, 59 backend->share, fd, errp); 60 g_free(name); 61 } 62 63 static bool 64 memfd_backend_get_hugetlb(Object *o, Error **errp) 65 { 66 return MEMORY_BACKEND_MEMFD(o)->hugetlb; 67 } 68 69 static void 70 memfd_backend_set_hugetlb(Object *o, bool value, Error **errp) 71 { 72 MEMORY_BACKEND_MEMFD(o)->hugetlb = value; 73 } 74 75 static void 76 memfd_backend_set_hugetlbsize(Object *obj, Visitor *v, const char *name, 77 void *opaque, Error **errp) 78 { 79 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); 80 Error *local_err = NULL; 81 uint64_t value; 82 83 if (host_memory_backend_mr_inited(MEMORY_BACKEND(obj))) { 84 error_setg(&local_err, "cannot change property value"); 85 goto out; 86 } 87 88 if (!visit_type_size(v, name, &value, &local_err)) { 89 goto out; 90 } 91 if (!value) { 92 error_setg(&local_err, "Property '%s.%s' doesn't take value '%" 93 PRIu64 "'", object_get_typename(obj), name, value); 94 goto out; 95 } 96 m->hugetlbsize = value; 97 out: 98 error_propagate(errp, local_err); 99 } 100 101 static void 102 memfd_backend_get_hugetlbsize(Object *obj, Visitor *v, const char *name, 103 void *opaque, Error **errp) 104 { 105 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); 106 uint64_t value = m->hugetlbsize; 107 108 visit_type_size(v, name, &value, errp); 109 } 110 111 static bool 112 memfd_backend_get_seal(Object *o, Error **errp) 113 { 114 return MEMORY_BACKEND_MEMFD(o)->seal; 115 } 116 117 static void 118 memfd_backend_set_seal(Object *o, bool value, Error **errp) 119 { 120 MEMORY_BACKEND_MEMFD(o)->seal = value; 121 } 122 123 static void 124 memfd_backend_instance_init(Object *obj) 125 { 126 HostMemoryBackendMemfd *m = MEMORY_BACKEND_MEMFD(obj); 127 128 /* default to sealed file */ 129 m->seal = true; 130 MEMORY_BACKEND(m)->share = true; 131 } 132 133 static void 134 memfd_backend_class_init(ObjectClass *oc, void *data) 135 { 136 HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc); 137 138 bc->alloc = memfd_backend_memory_alloc; 139 140 if (qemu_memfd_check(MFD_HUGETLB)) { 141 object_class_property_add_bool(oc, "hugetlb", 142 memfd_backend_get_hugetlb, 143 memfd_backend_set_hugetlb); 144 object_class_property_set_description(oc, "hugetlb", 145 "Use huge pages"); 146 object_class_property_add(oc, "hugetlbsize", "int", 147 memfd_backend_get_hugetlbsize, 148 memfd_backend_set_hugetlbsize, 149 NULL, NULL); 150 object_class_property_set_description(oc, "hugetlbsize", 151 "Huge pages size (ex: 2M, 1G)"); 152 } 153 object_class_property_add_bool(oc, "seal", 154 memfd_backend_get_seal, 155 memfd_backend_set_seal); 156 object_class_property_set_description(oc, "seal", 157 "Seal growing & shrinking"); 158 } 159 160 static const TypeInfo memfd_backend_info = { 161 .name = TYPE_MEMORY_BACKEND_MEMFD, 162 .parent = TYPE_MEMORY_BACKEND, 163 .instance_init = memfd_backend_instance_init, 164 .class_init = memfd_backend_class_init, 165 .instance_size = sizeof(HostMemoryBackendMemfd), 166 }; 167 168 static void register_types(void) 169 { 170 if (qemu_memfd_check(MFD_ALLOW_SEALING)) { 171 type_register_static(&memfd_backend_info); 172 } 173 } 174 175 type_init(register_types); 176