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migration: introduce a QIOChannel impl for BlockDriverState VMState
Introduce a QIOChannelBlock class that exposes the BlockDriverState VMState region for I/O. This is kept in the migration/ directory rather than io/, to avoid a mutual dependancy between block/ <-> io/ directories. Also the VMState should only be used by the migration code. Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> dgilbert: Fixed coding style in qio_channel_block_close
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/* | ||
* QEMU I/O channels block driver | ||
* | ||
* Copyright (c) 2022 Red Hat, Inc. | ||
* | ||
* This library is free software; you can redistribute it and/or | ||
* modify it under the terms of the GNU Lesser General Public | ||
* License as published by the Free Software Foundation; either | ||
* version 2.1 of the License, or (at your option) any later version. | ||
* | ||
* This library is distributed in the hope that it will be useful, | ||
* but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
* Lesser General Public License for more details. | ||
* | ||
* You should have received a copy of the GNU Lesser General Public | ||
* License along with this library; if not, see <http://www.gnu.org/licenses/>. | ||
* | ||
*/ | ||
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#include "qemu/osdep.h" | ||
#include "migration/channel-block.h" | ||
#include "qapi/error.h" | ||
#include "block/block.h" | ||
#include "trace.h" | ||
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QIOChannelBlock * | ||
qio_channel_block_new(BlockDriverState *bs) | ||
{ | ||
QIOChannelBlock *ioc; | ||
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ioc = QIO_CHANNEL_BLOCK(object_new(TYPE_QIO_CHANNEL_BLOCK)); | ||
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bdrv_ref(bs); | ||
ioc->bs = bs; | ||
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return ioc; | ||
} | ||
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static void | ||
qio_channel_block_finalize(Object *obj) | ||
{ | ||
QIOChannelBlock *ioc = QIO_CHANNEL_BLOCK(obj); | ||
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g_clear_pointer(&ioc->bs, bdrv_unref); | ||
} | ||
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static ssize_t | ||
qio_channel_block_readv(QIOChannel *ioc, | ||
const struct iovec *iov, | ||
size_t niov, | ||
int **fds, | ||
size_t *nfds, | ||
Error **errp) | ||
{ | ||
QIOChannelBlock *bioc = QIO_CHANNEL_BLOCK(ioc); | ||
QEMUIOVector qiov; | ||
int ret; | ||
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qemu_iovec_init_external(&qiov, (struct iovec *)iov, niov); | ||
ret = bdrv_readv_vmstate(bioc->bs, &qiov, bioc->offset); | ||
if (ret < 0) { | ||
return ret; | ||
} | ||
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bioc->offset += qiov.size; | ||
return qiov.size; | ||
} | ||
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static ssize_t | ||
qio_channel_block_writev(QIOChannel *ioc, | ||
const struct iovec *iov, | ||
size_t niov, | ||
int *fds, | ||
size_t nfds, | ||
int flags, | ||
Error **errp) | ||
{ | ||
QIOChannelBlock *bioc = QIO_CHANNEL_BLOCK(ioc); | ||
QEMUIOVector qiov; | ||
int ret; | ||
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qemu_iovec_init_external(&qiov, (struct iovec *)iov, niov); | ||
ret = bdrv_writev_vmstate(bioc->bs, &qiov, bioc->offset); | ||
if (ret < 0) { | ||
return ret; | ||
} | ||
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bioc->offset += qiov.size; | ||
return qiov.size; | ||
} | ||
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static int | ||
qio_channel_block_set_blocking(QIOChannel *ioc, | ||
bool enabled, | ||
Error **errp) | ||
{ | ||
if (!enabled) { | ||
error_setg(errp, "Non-blocking mode not supported for block devices"); | ||
return -1; | ||
} | ||
return 0; | ||
} | ||
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static off_t | ||
qio_channel_block_seek(QIOChannel *ioc, | ||
off_t offset, | ||
int whence, | ||
Error **errp) | ||
{ | ||
QIOChannelBlock *bioc = QIO_CHANNEL_BLOCK(ioc); | ||
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switch (whence) { | ||
case SEEK_SET: | ||
bioc->offset = offset; | ||
break; | ||
case SEEK_CUR: | ||
bioc->offset += whence; | ||
break; | ||
case SEEK_END: | ||
error_setg(errp, "Size of VMstate region is unknown"); | ||
return (off_t)-1; | ||
default: | ||
g_assert_not_reached(); | ||
} | ||
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return bioc->offset; | ||
} | ||
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static int | ||
qio_channel_block_close(QIOChannel *ioc, | ||
Error **errp) | ||
{ | ||
QIOChannelBlock *bioc = QIO_CHANNEL_BLOCK(ioc); | ||
int rv = bdrv_flush(bioc->bs); | ||
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if (rv < 0) { | ||
error_setg_errno(errp, -rv, | ||
"Unable to flush VMState"); | ||
return -1; | ||
} | ||
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g_clear_pointer(&bioc->bs, bdrv_unref); | ||
bioc->offset = 0; | ||
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return 0; | ||
} | ||
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static void | ||
qio_channel_block_set_aio_fd_handler(QIOChannel *ioc, | ||
AioContext *ctx, | ||
IOHandler *io_read, | ||
IOHandler *io_write, | ||
void *opaque) | ||
{ | ||
/* XXX anything we can do here ? */ | ||
} | ||
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static void | ||
qio_channel_block_class_init(ObjectClass *klass, | ||
void *class_data G_GNUC_UNUSED) | ||
{ | ||
QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass); | ||
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ioc_klass->io_writev = qio_channel_block_writev; | ||
ioc_klass->io_readv = qio_channel_block_readv; | ||
ioc_klass->io_set_blocking = qio_channel_block_set_blocking; | ||
ioc_klass->io_seek = qio_channel_block_seek; | ||
ioc_klass->io_close = qio_channel_block_close; | ||
ioc_klass->io_set_aio_fd_handler = qio_channel_block_set_aio_fd_handler; | ||
} | ||
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static const TypeInfo qio_channel_block_info = { | ||
.parent = TYPE_QIO_CHANNEL, | ||
.name = TYPE_QIO_CHANNEL_BLOCK, | ||
.instance_size = sizeof(QIOChannelBlock), | ||
.instance_finalize = qio_channel_block_finalize, | ||
.class_init = qio_channel_block_class_init, | ||
}; | ||
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static void | ||
qio_channel_block_register_types(void) | ||
{ | ||
type_register_static(&qio_channel_block_info); | ||
} | ||
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type_init(qio_channel_block_register_types); |
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,59 @@ | ||
/* | ||
* QEMU I/O channels block driver | ||
* | ||
* Copyright (c) 2022 Red Hat, Inc. | ||
* | ||
* This library is free software; you can redistribute it and/or | ||
* modify it under the terms of the GNU Lesser General Public | ||
* License as published by the Free Software Foundation; either | ||
* version 2.1 of the License, or (at your option) any later version. | ||
* | ||
* This library is distributed in the hope that it will be useful, | ||
* but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
* Lesser General Public License for more details. | ||
* | ||
* You should have received a copy of the GNU Lesser General Public | ||
* License along with this library; if not, see <http://www.gnu.org/licenses/>. | ||
* | ||
*/ | ||
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#ifndef QIO_CHANNEL_BLOCK_H | ||
#define QIO_CHANNEL_BLOCK_H | ||
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#include "io/channel.h" | ||
#include "qom/object.h" | ||
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#define TYPE_QIO_CHANNEL_BLOCK "qio-channel-block" | ||
OBJECT_DECLARE_SIMPLE_TYPE(QIOChannelBlock, QIO_CHANNEL_BLOCK) | ||
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/** | ||
* QIOChannelBlock: | ||
* | ||
* The QIOChannelBlock object provides a channel implementation | ||
* that is able to perform I/O on the BlockDriverState objects | ||
* to the VMState region. | ||
*/ | ||
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struct QIOChannelBlock { | ||
QIOChannel parent; | ||
BlockDriverState *bs; | ||
off_t offset; | ||
}; | ||
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/** | ||
* qio_channel_block_new: | ||
* @bs: the block driver state | ||
* | ||
* Create a new IO channel object that can perform | ||
* I/O on a BlockDriverState object to the VMState | ||
* region | ||
* | ||
* Returns: the new channel object | ||
*/ | ||
QIOChannelBlock * | ||
qio_channel_block_new(BlockDriverState *bs); | ||
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#endif /* QIO_CHANNEL_BLOCK_H */ |
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