From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: "Daniel P. Berrange" <berrange@redhat.com>
Cc: Amit Shah <amit.shah@redhat.com>,
qemu-devel@nongnu.org, Juan Quintela <quintela@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v1 07/22] migration: introduce a new QEMUFile impl based on QIOChannel
Date: Tue, 2 Feb 2016 17:06:24 +0000 [thread overview]
Message-ID: <20160202170623.GA4498@work-vm> (raw)
In-Reply-To: <1452599056-27357-8-git-send-email-berrange@redhat.com>
* Daniel P. Berrange (berrange@redhat.com) wrote:
> Introduce a new QEMUFile implementation that is based on
> the QIOChannel objects. This impl is different from existing
> impls in that there is no file descriptor that can be made
> available, as some channels may be based on higher level
> protocols such as TLS.
>
> Although the QIOChannel based implementation can trivially
> provide a bi-directional stream, initially we have separate
> functions for opening input & output directions to fit with
> the expectation of the current QEMUFile interface.
>
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
> include/migration/qemu-file.h | 4 +
> migration/Makefile.objs | 1 +
> migration/qemu-file-channel.c | 201 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 206 insertions(+)
> create mode 100644 migration/qemu-file-channel.c
>
> diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
> index 072bb38..cb79311 100644
> --- a/include/migration/qemu-file.h
> +++ b/include/migration/qemu-file.h
> @@ -23,7 +23,9 @@
> */
> #ifndef QEMU_FILE_H
> #define QEMU_FILE_H 1
> +#include "qemu-common.h"
> #include "exec/cpu-common.h"
> +#include "io/channel.h"
>
> #include <stdint.h>
>
> @@ -136,6 +138,8 @@ QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
> QEMUFile *qemu_fopen(const char *filename, const char *mode);
> QEMUFile *qemu_fdopen(int fd, const char *mode);
> QEMUFile *qemu_fopen_socket(int fd, const char *mode);
> +QEMUFile *qemu_fopen_channel_input(QIOChannel *ioc);
> +QEMUFile *qemu_fopen_channel_output(QIOChannel *ioc);
> QEMUFile *qemu_popen_cmd(const char *command, const char *mode);
> QEMUFile *qemu_bufopen(const char *mode, QEMUSizedBuffer *input);
> void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks);
> diff --git a/migration/Makefile.objs b/migration/Makefile.objs
> index 0cac6d7..b357e2f 100644
> --- a/migration/Makefile.objs
> +++ b/migration/Makefile.objs
> @@ -1,6 +1,7 @@
> common-obj-y += migration.o tcp.o
> common-obj-y += vmstate.o
> common-obj-y += qemu-file.o qemu-file-buf.o qemu-file-unix.o qemu-file-stdio.o
> +common-obj-y += qemu-file-channel.o
> common-obj-y += xbzrle.o postcopy-ram.o
>
> common-obj-$(CONFIG_RDMA) += rdma.o
> diff --git a/migration/qemu-file-channel.c b/migration/qemu-file-channel.c
> new file mode 100644
> index 0000000..09a7170
> --- /dev/null
> +++ b/migration/qemu-file-channel.c
> @@ -0,0 +1,201 @@
> +/*
> + * QEMUFile backend for QIOChannel objects
> + *
> + * Copyright (c) 2015 Red Hat, Inc
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to deal
> + * in the Software without restriction, including without limitation the rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +#include "migration/qemu-file.h"
> +#include "io/channel-socket.h"
> +#include "qemu/iov.h"
> +
> +
> +/**
> + * @skip: number of bytes to advance head of @iov
> + * @iov: pointer to iov array, updated on success
> + * @iovcnt: number of elements in @iov, updated on success
> + * @oldiov: pointer single element to hold old info from @iov
> + *
> + * This will update @iov so that its head is advanced
> + * by @skip bytes. To do this, zero or more complete
> + * elements of @iov will be skipped over. The new head
> + * of @iov will then have its base & len updated to
> + * skip the remaining number of bytes. @oldiov will
> + * hold the original data from the new head of @iov.
> + */
> +static void channel_skip_iov(size_t skip,
> + struct iovec **iov,
> + int *iovcnt,
> + struct iovec *oldiov)
> +{
> + ssize_t done = 0;
> + size_t i;
> + for (i = 0; i < *iovcnt; i++) {
> + if ((*iov)[i].iov_len <= skip) {
> + done += (*iov)[i].iov_len;
> + skip -= (*iov)[i].iov_len;
> + } else {
> + done += skip;
> + oldiov->iov_base = (*iov)[i].iov_base;
> + oldiov->iov_len = (*iov)[i].iov_len;
> + (*iov)[i].iov_len -= skip;
> + (*iov)[i].iov_base += skip;
> + *iov = *iov + i;
> + *iovcnt = *iovcnt - i;
> + break;
> + }
> + }
> +}
> +
> +static ssize_t channel_writev_buffer(void *opaque,
> + struct iovec *iov,
> + int iovcnt,
> + int64_t pos)
> +{
> + QIOChannel *ioc = QIO_CHANNEL(opaque);
> + ssize_t done = 0;
> + ssize_t want = iov_size(iov, iovcnt);
> + struct iovec oldiov = { NULL, 0 };
> +
> + while (done < want) {
> + ssize_t len;
> + struct iovec *cur = iov;
> + int curcnt = iovcnt;
> +
> + channel_skip_iov(done, &cur, &curcnt, &oldiov);
> +
> + len = qio_channel_writev(ioc, cur, curcnt, NULL);
> + if (oldiov.iov_base) {
> + /* Restore original caller's info in @iov */
> + cur[0].iov_base = oldiov.iov_base;
> + cur[0].iov_len = oldiov.iov_len;
> + oldiov.iov_base = NULL;
> + oldiov.iov_len = 0;
> + }
> + if (len == QIO_CHANNEL_ERR_BLOCK) {
> + qio_channel_wait(ioc, G_IO_OUT);
> + continue;
> + }
> + if (len < 0) {
> + /* XXX handle Error objects */
> + return -EIO;
It's best to return 'len' rather than lose what little
error information you had (similarly below).
> + }
> +
> + done += len;
> + }
> + return done;
> +}
> +
> +
> +static ssize_t channel_get_buffer(void *opaque,
> + uint8_t *buf,
> + int64_t pos,
> + size_t size)
> +{
> + QIOChannel *ioc = QIO_CHANNEL(opaque);
> + ssize_t ret;
> +
> + reread:
> + ret = qio_channel_read(ioc, (char *)buf, size, NULL);
> + if (ret < 0) {
> + if (ret == QIO_CHANNEL_ERR_BLOCK) {
> + qio_channel_yield(ioc, G_IO_IN);
> + goto reread;
> + } else {
> + /* XXX handle Error * object */
> + return -EIO;
> + }
> + }
> + return ret;
I'd prefer a loop to a goto; generally the only places we
use goto is an error exit.
do {
ret = qio_channel_read(ioc, (char *)buf, size, NULL);
if (ret == QIO_CHANNEL_ERR_BLOCK) {
qio_channel_yield(ioc, G_IO_IN);
}
} while (ret == QIO_CHANNEL_ERR_BLOCK);
return ret;
and IMHO the loop is clearer.
> +}
> +
> +
> +static int channel_close(void *opaque)
> +{
> + QIOChannel *ioc = QIO_CHANNEL(opaque);
> + qio_channel_close(ioc, NULL);
> + object_unref(OBJECT(ioc));
> + return 0;
> +}
> +
> +
> +static int channel_shutdown(void *opaque,
> + bool rd,
> + bool wr)
> +{
> + QIOChannel *ioc = QIO_CHANNEL(opaque);
> +
> + if (qio_channel_has_feature(ioc,
> + QIO_CHANNEL_FEATURE_SHUTDOWN)) {
> + QIOChannelShutdown mode;
> + if (rd && wr) {
> + mode = QIO_CHANNEL_SHUTDOWN_BOTH;
> + } else if (rd) {
> + mode = QIO_CHANNEL_SHUTDOWN_READ;
> + } else {
> + mode = QIO_CHANNEL_SHUTDOWN_WRITE;
> + }
> + if (qio_channel_shutdown(ioc, mode, NULL) < 0) {
> + /* XXX handler Error * object */
> + return -EIO;
> + }
> + }
> + return 0;
> +}
> +
> +
> +static int channel_set_blocking(void *opaque,
> + bool enabled)
> +{
> + QIOChannel *ioc = QIO_CHANNEL(opaque);
> +
> + if (qio_channel_set_blocking(ioc, enabled, NULL) < 0) {
> + return -1;
> + }
> + return 0;
> +}
> +
> +
> +static const QEMUFileOps channel_input_ops = {
> + .get_buffer = channel_get_buffer,
> + .close = channel_close,
> + .shut_down = channel_shutdown,
> + .set_blocking = channel_set_blocking,
> +};
> +
> +
> +static const QEMUFileOps channel_output_ops = {
> + .writev_buffer = channel_writev_buffer,
> + .close = channel_close,
> + .shut_down = channel_shutdown,
> + .set_blocking = channel_set_blocking,
> +};
> +
> +
> +QEMUFile *qemu_fopen_channel_input(QIOChannel *ioc)
> +{
> + object_ref(OBJECT(ioc));
> + return qemu_fopen_ops(ioc, &channel_input_ops);
> +}
> +
> +QEMUFile *qemu_fopen_channel_output(QIOChannel *ioc)
> +{
> + object_ref(OBJECT(ioc));
> + return qemu_fopen_ops(ioc, &channel_output_ops);
> +}
Dave
> --
> 2.5.0
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
next prev parent reply other threads:[~2016-02-02 17:06 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-12 11:43 [Qemu-devel] [PATCH v1 00/22] Convert migration to QIOChannel & support TLS Daniel P. Berrange
2016-01-12 11:43 ` [Qemu-devel] [PATCH v1 01/22] s390: use FILE instead of QEMUFile for creating text file Daniel P. Berrange
2016-01-12 11:58 ` Cornelia Huck
2016-01-12 12:01 ` Daniel P. Berrange
2016-01-12 12:05 ` Cornelia Huck
2016-02-12 17:19 ` Dr. David Alan Gilbert
2016-01-12 11:43 ` [Qemu-devel] [PATCH v1 02/22] migration: remove use of qemu_bufopen from vmstate tests Daniel P. Berrange
2016-01-28 17:45 ` Dr. David Alan Gilbert
2016-01-12 11:43 ` [Qemu-devel] [PATCH v1 03/22] migration: ensure qemu_fflush() always writes full data amount Daniel P. Berrange
2016-01-28 17:53 ` Dr. David Alan Gilbert
2016-02-03 13:31 ` Daniel P. Berrange
2016-01-12 11:43 ` [Qemu-devel] [PATCH v1 04/22] migration: split migration hooks out of QEMUFileOps Daniel P. Berrange
2016-01-28 17:57 ` Dr. David Alan Gilbert
2016-01-12 11:43 ` [Qemu-devel] [PATCH v1 05/22] migration: introduce set_blocking function in QEMUFileOps Daniel P. Berrange
2016-01-28 18:00 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 06/22] migration: force QEMUFile to blocking mode for outgoing migration Daniel P. Berrange
2016-01-28 18:17 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 07/22] migration: introduce a new QEMUFile impl based on QIOChannel Daniel P. Berrange
2016-02-02 17:06 ` Dr. David Alan Gilbert [this message]
2016-02-03 13:37 ` Daniel P. Berrange
2016-02-12 17:16 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 08/22] migration: convert post-copy to use QIOChannelBuffer Daniel P. Berrange
2016-01-25 19:38 ` Dr. David Alan Gilbert
2016-01-25 22:15 ` Daniel P. Berrange
2016-01-26 18:59 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 09/22] migration: convert unix socket protocol to use QIOChannel Daniel P. Berrange
2016-02-02 18:02 ` Dr. David Alan Gilbert
2016-02-03 11:25 ` Daniel P. Berrange
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 10/22] migration: convert tcp " Daniel P. Berrange
2016-02-02 18:19 ` Dr. David Alan Gilbert
2016-02-03 10:02 ` Daniel P. Berrange
2016-02-03 10:33 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 11/22] migration: convert fd " Daniel P. Berrange
2016-02-02 18:46 ` Dr. David Alan Gilbert
2016-02-03 10:05 ` Daniel P. Berrange
2016-02-03 10:29 ` Dr. David Alan Gilbert
2016-02-03 10:39 ` Daniel P. Berrange
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 12/22] migration: convert exec " Daniel P. Berrange
2016-02-02 18:53 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 13/22] migration: convert RDMA to use QIOChannel interface Daniel P. Berrange
2016-02-02 20:01 ` Dr. David Alan Gilbert
2016-02-03 11:37 ` Daniel P. Berrange
2016-02-03 13:23 ` Dr. David Alan Gilbert
2016-02-03 13:25 ` Daniel P. Berrange
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 14/22] migration: convert savevm to use QIOChannel for writing to files Daniel P. Berrange
2016-02-03 9:52 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 15/22] migration: delete QEMUFile buffer implementation Daniel P. Berrange
2016-02-03 9:54 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 16/22] migration: delete QEMUSizedBuffer struct Daniel P. Berrange
2016-02-03 9:55 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 17/22] migration: delete QEMUFile sockets implementation Daniel P. Berrange
2016-02-03 9:56 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 18/22] migration: delete QEMUFile stdio implementation Daniel P. Berrange
2016-02-03 9:58 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 19/22] migration: move definition of struct QEMUFile back into qemu-file.c Daniel P. Berrange
2016-02-05 18:32 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 20/22] migration: support TLS encryption with TCP migration backend Daniel P. Berrange
2016-02-12 17:09 ` Dr. David Alan Gilbert
2016-02-12 17:25 ` Daniel P. Berrange
2016-02-15 11:00 ` Daniel P. Berrange
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 21/22] migration: remove support for non-iovec based write handlers Daniel P. Berrange
2016-02-12 15:48 ` Dr. David Alan Gilbert
2016-01-12 11:44 ` [Qemu-devel] [PATCH v1 22/22] migration: remove qemu_get_fd method from QEMUFile Daniel P. Berrange
2016-02-12 15:51 ` Dr. David Alan Gilbert
2016-01-12 11:59 ` [Qemu-devel] [PATCH v1 00/22] Convert migration to QIOChannel & support TLS Daniel P. Berrange
2016-01-20 18:01 ` Daniel P. Berrange
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