1 /* 2 * QEMU I/O channels block driver 3 * 4 * Copyright (c) 2022 Red Hat, Inc. 5 * 6 * This library is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * This library is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with this library; if not, see <http://www.gnu.org/licenses/>. 18 * 19 */ 20 21 #include "qemu/osdep.h" 22 #include "migration/channel-block.h" 23 #include "qapi/error.h" 24 #include "block/block.h" 25 #include "trace.h" 26 27 QIOChannelBlock * 28 qio_channel_block_new(BlockDriverState *bs) 29 { 30 QIOChannelBlock *ioc; 31 32 ioc = QIO_CHANNEL_BLOCK(object_new(TYPE_QIO_CHANNEL_BLOCK)); 33 34 bdrv_ref(bs); 35 ioc->bs = bs; 36 37 return ioc; 38 } 39 40 41 static void 42 qio_channel_block_finalize(Object *obj) 43 { 44 QIOChannelBlock *ioc = QIO_CHANNEL_BLOCK(obj); 45 46 g_clear_pointer(&ioc->bs, bdrv_unref); 47 } 48 49 50 static ssize_t 51 qio_channel_block_readv(QIOChannel *ioc, 52 const struct iovec *iov, 53 size_t niov, 54 int **fds, 55 size_t *nfds, 56 int flags, 57 Error **errp) 58 { 59 QIOChannelBlock *bioc = QIO_CHANNEL_BLOCK(ioc); 60 QEMUIOVector qiov; 61 int ret; 62 63 qemu_iovec_init_external(&qiov, (struct iovec *)iov, niov); 64 ret = bdrv_readv_vmstate(bioc->bs, &qiov, bioc->offset); 65 if (ret < 0) { 66 error_setg_errno(errp, -ret, "bdrv_readv_vmstate failed"); 67 return -1; 68 } 69 70 bioc->offset += qiov.size; 71 return qiov.size; 72 } 73 74 75 static ssize_t 76 qio_channel_block_writev(QIOChannel *ioc, 77 const struct iovec *iov, 78 size_t niov, 79 int *fds, 80 size_t nfds, 81 int flags, 82 Error **errp) 83 { 84 QIOChannelBlock *bioc = QIO_CHANNEL_BLOCK(ioc); 85 QEMUIOVector qiov; 86 int ret; 87 88 qemu_iovec_init_external(&qiov, (struct iovec *)iov, niov); 89 ret = bdrv_writev_vmstate(bioc->bs, &qiov, bioc->offset); 90 if (ret < 0) { 91 error_setg_errno(errp, -ret, "bdrv_writev_vmstate failed"); 92 return -1; 93 } 94 95 bioc->offset += qiov.size; 96 return qiov.size; 97 } 98 99 100 static int 101 qio_channel_block_set_blocking(QIOChannel *ioc, 102 bool enabled, 103 Error **errp) 104 { 105 if (!enabled) { 106 error_setg(errp, "Non-blocking mode not supported for block devices"); 107 return -1; 108 } 109 return 0; 110 } 111 112 113 static off_t 114 qio_channel_block_seek(QIOChannel *ioc, 115 off_t offset, 116 int whence, 117 Error **errp) 118 { 119 QIOChannelBlock *bioc = QIO_CHANNEL_BLOCK(ioc); 120 121 switch (whence) { 122 case SEEK_SET: 123 bioc->offset = offset; 124 break; 125 case SEEK_CUR: 126 bioc->offset += whence; 127 break; 128 case SEEK_END: 129 error_setg(errp, "Size of VMstate region is unknown"); 130 return (off_t)-1; 131 default: 132 g_assert_not_reached(); 133 } 134 135 return bioc->offset; 136 } 137 138 139 static int 140 qio_channel_block_close(QIOChannel *ioc, 141 Error **errp) 142 { 143 QIOChannelBlock *bioc = QIO_CHANNEL_BLOCK(ioc); 144 int rv = bdrv_flush(bioc->bs); 145 146 if (rv < 0) { 147 error_setg_errno(errp, -rv, 148 "Unable to flush VMState"); 149 return -1; 150 } 151 152 g_clear_pointer(&bioc->bs, bdrv_unref); 153 bioc->offset = 0; 154 155 return 0; 156 } 157 158 159 static void 160 qio_channel_block_set_aio_fd_handler(QIOChannel *ioc, 161 AioContext *read_ctx, 162 IOHandler *io_read, 163 AioContext *write_ctx, 164 IOHandler *io_write, 165 void *opaque) 166 { 167 /* XXX anything we can do here ? */ 168 } 169 170 171 static void 172 qio_channel_block_class_init(ObjectClass *klass, 173 void *class_data G_GNUC_UNUSED) 174 { 175 QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass); 176 177 ioc_klass->io_writev = qio_channel_block_writev; 178 ioc_klass->io_readv = qio_channel_block_readv; 179 ioc_klass->io_set_blocking = qio_channel_block_set_blocking; 180 ioc_klass->io_seek = qio_channel_block_seek; 181 ioc_klass->io_close = qio_channel_block_close; 182 ioc_klass->io_set_aio_fd_handler = qio_channel_block_set_aio_fd_handler; 183 } 184 185 static const TypeInfo qio_channel_block_info = { 186 .parent = TYPE_QIO_CHANNEL, 187 .name = TYPE_QIO_CHANNEL_BLOCK, 188 .instance_size = sizeof(QIOChannelBlock), 189 .instance_finalize = qio_channel_block_finalize, 190 .class_init = qio_channel_block_class_init, 191 }; 192 193 static void 194 qio_channel_block_register_types(void) 195 { 196 type_register_static(&qio_channel_block_info); 197 } 198 199 type_init(qio_channel_block_register_types); 200