From 2a9e2e595f2bc81c07e2f06ef9ba7d4c68897f1c Mon Sep 17 00:00:00 2001 From: Steve Sistare Date: Fri, 8 Sep 2023 07:22:10 -0700 Subject: [PATCH] migration: file URI MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Extend the migration URI to support file:. This can be used for any migration scenario that does not require a reverse path. It can be used as an alternative to 'exec:cat > file' in minimized containers that do not contain /bin/sh, and it is easier to use than the fd: URI. It can be used in HMP commands, and as a qemu command-line parameter. For best performance, guest ram should be shared and x-ignore-shared should be true, so guest pages are not written to the file, in which case the guest may remain running. If ram is not so configured, then the user is advised to stop the guest first. Otherwise, a busy guest may re-dirty the same page, causing it to be appended to the file multiple times, and the file may grow unboundedly. That issue is being addressed in the "fixed-ram" patch series. Signed-off-by: Steve Sistare Tested-by: Michael Galaxy Reviewed-by: Michael Galaxy Reviewed-by: Fabiano Rosas Reviewed-by: Peter Xu Reviewed-by: Daniel P. Berrangé Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela Message-ID: <1694182931-61390-2-git-send-email-steven.sistare@oracle.com> --- migration/file.c | 62 ++++++++++++++++++++++++++++++++++++++++++ migration/file.h | 14 ++++++++++ migration/meson.build | 1 + migration/migration.c | 5 ++++ migration/trace-events | 4 +++ qemu-options.hx | 6 +++- 6 files changed, 91 insertions(+), 1 deletion(-) create mode 100644 migration/file.c create mode 100644 migration/file.h diff --git a/migration/file.c b/migration/file.c new file mode 100644 index 0000000000..0a65c43fdd --- /dev/null +++ b/migration/file.c @@ -0,0 +1,62 @@ +/* + * Copyright (c) 2021-2023 Oracle and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "channel.h" +#include "file.h" +#include "migration.h" +#include "io/channel-file.h" +#include "io/channel-util.h" +#include "trace.h" + +void file_start_outgoing_migration(MigrationState *s, const char *filename, + Error **errp) +{ + g_autoptr(QIOChannelFile) fioc = NULL; + QIOChannel *ioc; + + trace_migration_file_outgoing(filename); + + fioc = qio_channel_file_new_path(filename, O_CREAT | O_WRONLY | O_TRUNC, + 0600, errp); + if (!fioc) { + return; + } + + ioc = QIO_CHANNEL(fioc); + qio_channel_set_name(ioc, "migration-file-outgoing"); + migration_channel_connect(s, ioc, NULL, NULL); +} + +static gboolean file_accept_incoming_migration(QIOChannel *ioc, + GIOCondition condition, + gpointer opaque) +{ + migration_channel_process_incoming(ioc); + object_unref(OBJECT(ioc)); + return G_SOURCE_REMOVE; +} + +void file_start_incoming_migration(const char *filename, Error **errp) +{ + QIOChannelFile *fioc = NULL; + QIOChannel *ioc; + + trace_migration_file_incoming(filename); + + fioc = qio_channel_file_new_path(filename, O_RDONLY, 0, errp); + if (!fioc) { + return; + } + + ioc = QIO_CHANNEL(fioc); + qio_channel_set_name(QIO_CHANNEL(ioc), "migration-file-incoming"); + qio_channel_add_watch_full(ioc, G_IO_IN, + file_accept_incoming_migration, + NULL, NULL, + g_main_context_get_thread_default()); +} diff --git a/migration/file.h b/migration/file.h new file mode 100644 index 0000000000..90fa4849e0 --- /dev/null +++ b/migration/file.h @@ -0,0 +1,14 @@ +/* + * Copyright (c) 2021-2023 Oracle and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#ifndef QEMU_MIGRATION_FILE_H +#define QEMU_MIGRATION_FILE_H +void file_start_incoming_migration(const char *filename, Error **errp); + +void file_start_outgoing_migration(MigrationState *s, const char *filename, + Error **errp); +#endif diff --git a/migration/meson.build b/migration/meson.build index 1ae28523a1..92b1cc4297 100644 --- a/migration/meson.build +++ b/migration/meson.build @@ -16,6 +16,7 @@ system_ss.add(files( 'dirtyrate.c', 'exec.c', 'fd.c', + 'file.c', 'global_state.c', 'migration-hmp-cmds.c', 'migration.c', diff --git a/migration/migration.c b/migration/migration.c index 6d3cf5d5cd..585d3c8f55 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -20,6 +20,7 @@ #include "migration/blocker.h" #include "exec.h" #include "fd.h" +#include "file.h" #include "socket.h" #include "sysemu/runstate.h" #include "sysemu/sysemu.h" @@ -449,6 +450,8 @@ static void qemu_start_incoming_migration(const char *uri, Error **errp) exec_start_incoming_migration(p, errp); } else if (strstart(uri, "fd:", &p)) { fd_start_incoming_migration(p, errp); + } else if (strstart(uri, "file:", &p)) { + file_start_incoming_migration(p, errp); } else { error_setg(errp, "unknown migration protocol: %s", uri); } @@ -1702,6 +1705,8 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk, exec_start_outgoing_migration(s, p, &local_err); } else if (strstart(uri, "fd:", &p)) { fd_start_outgoing_migration(s, p, &local_err); + } else if (strstart(uri, "file:", &p)) { + file_start_outgoing_migration(s, p, &local_err); } else { error_setg(&local_err, QERR_INVALID_PARAMETER_VALUE, "uri", "a valid migration protocol"); diff --git a/migration/trace-events b/migration/trace-events index 63483732ce..3e9649ab2a 100644 --- a/migration/trace-events +++ b/migration/trace-events @@ -311,6 +311,10 @@ migration_exec_incoming(const char *cmd) "cmd=%s" migration_fd_outgoing(int fd) "fd=%d" migration_fd_incoming(int fd) "fd=%d" +# file.c +migration_file_outgoing(const char *filename) "filename=%s" +migration_file_incoming(const char *filename) "filename=%s" + # socket.c migration_socket_incoming_accepted(void) "" migration_socket_outgoing_connected(const char *hostname) "hostname=%s" diff --git a/qemu-options.hx b/qemu-options.hx index 9ce8a5b957..93e638c097 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -4706,6 +4706,7 @@ DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ " prepare for incoming migration, listen on\n" \ " specified protocol and socket address\n" \ "-incoming fd:fd\n" \ + "-incoming file:filename\n" \ "-incoming exec:cmdline\n" \ " accept incoming migration on given file descriptor\n" \ " or from given external command\n" \ @@ -4722,7 +4723,10 @@ SRST Prepare for incoming migration, listen on a given unix socket. ``-incoming fd:fd`` - Accept incoming migration from a given filedescriptor. + Accept incoming migration from a given file descriptor. + +``-incoming file:filename`` + Accept incoming migration from a given file. ``-incoming exec:cmdline`` Accept incoming migration as an output from specified external