This commit introduces a possibility to migrate open chardev
socket fd through migration channel without reconnecting.
For this, user should:
- enable new migration capability local-char-socket
- mark the socket by an option support-local-migration=true
- on target add local-incoming=true option to the socket
Motivation for the API:
1. We don't want to migrate all sockets. For example, QMP-connection is
bad candidate, as it is separate on source and target. So, we need
@support-local-migration option to mark sockets, which we want to
migrate (after this series, we'll want to migrate chardev used to
connect with vhost-user-server).
2. Still, for remote migration, we can't migrate any sockets, so, we
need a capability, to enable/disable the whole feature.
3. And finally, we need a sign for the socket to not open a connection
on initialization, but wait for incoming migration. We can't use
@support-local-migration option for it, as it may be enabled, but we
are in incoming-remote migration. Also, we can't rely on the
migration capability, as user is free to setup capabilities before or
after chardev creation, and it would be a bad precedent to create
relations here.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
---
chardev/char-socket.c | 101 +++++++++++++++++++++++++++++++++-
include/chardev/char-socket.h | 3 +
migration/options.c | 7 +++
migration/options.h | 1 +
qapi/char.json | 16 +++++-
qapi/migration.json | 8 ++-
stubs/meson.build | 1 +
stubs/qemu_file.c | 15 +++++
stubs/vmstate.c | 6 ++
tests/qtest/meson.build | 2 +-
tests/unit/meson.build | 4 +-
11 files changed, 158 insertions(+), 6 deletions(-)
create mode 100644 stubs/qemu_file.c
diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index 1e8313915b..db6616e2f2 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -24,6 +24,7 @@
#include "qemu/osdep.h"
#include "chardev/char.h"
+#include "qapi-types-char.h"
#include "io/channel-socket.h"
#include "io/channel-websock.h"
#include "qemu/error-report.h"
@@ -34,6 +35,10 @@
#include "qapi/qapi-visit-sockets.h"
#include "qemu/yank.h"
#include "trace.h"
+#include "migration/vmstate.h"
+#include "migration/qemu-file.h"
+#include "migration/migration.h"
+#include "hw/vmstate-if.h"
#include "chardev/char-io.h"
#include "chardev/char-socket.h"
@@ -1118,6 +1123,7 @@ static void char_socket_finalize(Object *obj)
object_unref(OBJECT(s->tls_creds));
}
g_free(s->tls_authz);
+ g_free(s->vmstate_name);
if (s->registered_yank) {
/*
* In the chardev-change special-case, we shouldn't unregister the yank
@@ -1276,8 +1282,15 @@ static int qmp_chardev_open_socket_client(Chardev *chr,
{
SocketChardev *s = SOCKET_CHARDEV(chr);
+ s->reconnect_time_ms = reconnect_ms;
+
+ if (s->local_incoming) {
+ /* We'll get fd at migreation load. This field works once */
+ s->local_incoming = false;
+ return 0;
+ }
+
if (reconnect_ms > 0) {
- s->reconnect_time_ms = reconnect_ms;
tcp_chr_connect_client_async(chr);
return 0;
} else {
@@ -1367,6 +1380,52 @@ static bool qmp_chardev_validate_socket(ChardevSocket
*sock,
return true;
}
+static int char_socket_save(QEMUFile *f, void *opaque, size_t size,
+ const VMStateField *field, JSONWriter *vmdesc)
+{
+ SocketChardev *s = opaque;
+
+ warn_report("%s", __func__);
+ return qemu_file_put_fd(f, s->sioc->fd);
+}
+
+static int char_socket_load(QEMUFile *f, void *opaque, size_t size,
+ const VMStateField *field)
+{
+ Chardev *chr = opaque;
+
+ int fd = qemu_file_get_fd(f);
+ warn_report("%s %d", __func__, fd);
+ if (fd < 0) {
+ return fd;
+ }
+ return tcp_chr_add_client(chr, fd);
+}
+
+static bool char_socket_needed(void *opaque)
+{
+ SocketChardev *s = opaque;
+
+ return !!s->vmstate_name;
+}
+
+const VMStateDescription vmstate_char_socket = {
+ .name = "char_socket",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = char_socket_needed,
+ .fields = (VMStateField[]) {
+ {
+ .name = "fd",
+ .info = &(const VMStateInfo) {
+ .name = "fd",
+ .get = char_socket_load,
+ .put = char_socket_save,
+ },
+ },
+ VMSTATE_END_OF_LIST()
+ },
+};
static void qmp_chardev_open_socket(Chardev *chr,
ChardevBackend *backend,
@@ -1381,14 +1440,36 @@ static void qmp_chardev_open_socket(Chardev *chr,
bool is_tn3270 = sock->has_tn3270 ? sock->tn3270 : false;
bool is_waitconnect = sock->has_wait ? sock->wait : false;
bool is_websock = sock->has_websocket ? sock->websocket : false;
+ bool support_local_mig = sock->has_support_local_migration
+ ? sock->support_local_migration
+ : false;
+ bool local_incoming = sock->local_incoming;
int64_t reconnect_ms = 0;
SocketAddress *addr;
+ if (support_local_mig && is_listen) {
+ error_setg(errp,
+ "local migration is not supported for listening sockets");
+ return;
+ }
+
+ if (support_local_mig && !(chr->label && chr->label[0])) {
+ error_setg(errp,
+ "local migration is not supported for unnamed chardevs");
+ return;
+ }
+
s->is_listen = is_listen;
s->is_telnet = is_telnet;
s->is_tn3270 = is_tn3270;
s->is_websock = is_websock;
s->do_nodelay = do_nodelay;
+ s->local_incoming = local_incoming;
+
+ if (support_local_mig) {
+ s->vmstate_name = g_strdup_printf("__yc-chardev-%s", chr->label);
+ }
+
if (sock->tls_creds) {
Object *creds;
creds = object_resolve_path_component(
@@ -1448,6 +1529,7 @@ static void qmp_chardev_open_socket(Chardev *chr,
update_disconnected_filename(s);
if (s->is_listen) {
+ assert(!s->vmstate_name);
if (qmp_chardev_open_socket_server(chr, is_telnet || is_tn3270,
is_waitconnect, errp) < 0) {
return;
@@ -1463,6 +1545,8 @@ static void qmp_chardev_open_socket(Chardev *chr,
return;
}
}
+
+ vmstate_register(VMSTATE_IF(s), -1, &vmstate_char_socket, s);
}
static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend,
@@ -1581,9 +1665,20 @@ char_socket_get_connected(Object *obj, Error **errp)
return s->state == TCP_CHARDEV_STATE_CONNECTED;
}
+static char *
+char_socket_if_get_id(VMStateIf *obj)
+{
+ SocketChardev *s = SOCKET_CHARDEV(obj);
+
+ return s->vmstate_name;
+}
+
static void char_socket_class_init(ObjectClass *oc, const void *data)
{
ChardevClass *cc = CHARDEV_CLASS(oc);
+ VMStateIfClass *vc = VMSTATE_IF_CLASS(oc);
+
+ vc->get_id = char_socket_if_get_id;
cc->supports_yank = true;
@@ -1613,6 +1708,10 @@ static const TypeInfo char_socket_type_info = {
.instance_size = sizeof(SocketChardev),
.instance_finalize = char_socket_finalize,
.class_init = char_socket_class_init,
+ .interfaces = (InterfaceInfo[]) {
+ { TYPE_VMSTATE_IF },
+ { }
+ }
};
static void register_types(void)
diff --git a/include/chardev/char-socket.h b/include/chardev/char-socket.h
index d6d13ad37f..69b9609215 100644
--- a/include/chardev/char-socket.h
+++ b/include/chardev/char-socket.h
@@ -78,6 +78,9 @@ struct SocketChardev {
bool connect_err_reported;
QIOTask *connect_task;
+
+ char *vmstate_name;
+ bool local_incoming;
};
typedef struct SocketChardev SocketChardev;
diff --git a/migration/options.c b/migration/options.c
index 4e923a2e07..dffb6910f4 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -262,6 +262,13 @@ bool migrate_mapped_ram(void)
return s->capabilities[MIGRATION_CAPABILITY_MAPPED_RAM];
}
+bool migrate_local_char_socket(void)
+{
+ MigrationState *s = migrate_get_current();
+
+ return s->capabilities[MIGRATION_CAPABILITY_LOCAL_CHAR_SOCKET];
+}
+
bool migrate_ignore_shared(void)
{
MigrationState *s = migrate_get_current();
diff --git a/migration/options.h b/migration/options.h
index 82d839709e..40971f0aa0 100644
--- a/migration/options.h
+++ b/migration/options.h
@@ -30,6 +30,7 @@ bool migrate_colo(void);
bool migrate_dirty_bitmaps(void);
bool migrate_events(void);
bool migrate_mapped_ram(void);
+bool migrate_local_char_socket(void);
bool migrate_ignore_shared(void);
bool migrate_late_block_activate(void);
bool migrate_multifd(void);
diff --git a/qapi/char.json b/qapi/char.json
index f0a53f742c..5b535c196a 100644
--- a/qapi/char.json
+++ b/qapi/char.json
@@ -280,11 +280,23 @@
# mutually exclusive with @reconnect.
# (default: 0) (Since: 9.2)
#
+# @support-local-migration: The socket open file descriptor will
+# migrate if this field is true and local-char-socket migration
+# capability enabled (default: false) (Since: 10.2)
+#
+# @local-incoming: Do load open file descriptor for the socket
+# on incoming migration. May be used only if QEMU is started
+# for incoming migration and only together with local-char-socket
+# migration capability (default: false) (Since: 10.2)
+#
# Features:
#
# @deprecated: Member @reconnect is deprecated. Use @reconnect-ms
# instead.
#
+# @unstable: Members @support-local-migration and @local-incoming
+# are experimental
+#
# Since: 1.4
##
{ 'struct': 'ChardevSocket',
@@ -298,7 +310,9 @@
'*tn3270': 'bool',
'*websocket': 'bool',
'*reconnect': { 'type': 'int', 'features': [ 'deprecated' ] },
- '*reconnect-ms': 'int' },
+ '*reconnect-ms': 'int',
+ '*support-local-migration': { 'type': 'bool', 'features': [
'unstable' ] },
+ '*local-incoming': { 'type': 'bool', 'features': [ 'unstable' ] }
},
'base': 'ChardevCommon' }
##
diff --git a/qapi/migration.json b/qapi/migration.json
index 2387c21e9c..4f282d168e 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -517,6 +517,11 @@
# each RAM page. Requires a migration URI that supports seeking,
# such as a file. (since 9.0)
#
+# @local-char-socket: Migrate socket chardevs open file descriptors.
+# Only may be used when migration channel is unix socket. Only
+# involves socket chardevs with "support-local-migration" option
+# enabled. (since 10.2)
+#
# Features:
#
# @unstable: Members @x-colo and @x-ignore-shared are experimental.
@@ -536,7 +541,8 @@
{ 'name': 'x-ignore-shared', 'features': [ 'unstable' ] },
'validate-uuid', 'background-snapshot',
'zero-copy-send', 'postcopy-preempt', 'switchover-ack',
- 'dirty-limit', 'mapped-ram'] }
+ 'dirty-limit', 'mapped-ram',
+ { 'name': 'local-char-socket', 'features': [ 'unstable' ] } ] }
##
# @MigrationCapabilityStatus:
diff --git a/stubs/meson.build b/stubs/meson.build
index cef046e685..7855483639 100644
--- a/stubs/meson.build
+++ b/stubs/meson.build
@@ -50,6 +50,7 @@ if have_block or have_user
stub_ss.add(files('qtest.c'))
stub_ss.add(files('vm-stop.c'))
stub_ss.add(files('vmstate.c'))
+ stub_ss.add(files('qemu_file.c'))
endif
if have_user
diff --git a/stubs/qemu_file.c b/stubs/qemu_file.c
new file mode 100644
index 0000000000..854d4c13cd
--- /dev/null
+++ b/stubs/qemu_file.c
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "qemu/osdep.h"
+#include "migration/qemu-file.h"
+
+
+int qemu_file_get_fd(QEMUFile *f)
+{
+ return -1;
+}
+
+int qemu_file_put_fd(QEMUFile *f, int fd)
+{
+ return -1;
+}
diff --git a/stubs/vmstate.c b/stubs/vmstate.c
index c190762d7c..f345edf3c9 100644
--- a/stubs/vmstate.c
+++ b/stubs/vmstate.c
@@ -2,6 +2,7 @@
#include "migration/vmstate.h"
#include "qapi/qapi-types-migration.h"
#include "migration/client-options.h"
+#include "migration/options.h"
int vmstate_register_with_alias_id(VMStateIf *obj,
uint32_t instance_id,
@@ -28,3 +29,8 @@ MigMode migrate_mode(void)
{
return MIG_MODE_NORMAL;
}
+
+bool migrate_local_char_socket(void)
+{
+ return false;
+}
diff --git a/tests/qtest/meson.build b/tests/qtest/meson.build
index 669d07c06b..8be0c1dc7c 100644
--- a/tests/qtest/meson.build
+++ b/tests/qtest/meson.build
@@ -381,7 +381,7 @@ qtests = {
'pxe-test': files('boot-sector.c'),
'pnv-xive2-test': files('pnv-xive2-common.c', 'pnv-xive2-flush-sync.c',
'pnv-xive2-nvpg_bar.c'),
- 'qos-test': [chardev, io, qos_test_ss.apply({}).sources()],
+ 'qos-test': [chardev, io, qos_test_ss.apply({}).sources(),
'../../hw/core/vmstate-if.c'],
'tpm-crb-swtpm-test': [io, tpmemu_files],
'tpm-crb-test': [io, tpmemu_files],
'tpm-tis-swtpm-test': [io, tpmemu_files, 'tpm-tis-util.c'],
diff --git a/tests/unit/meson.build b/tests/unit/meson.build
index d5248ae51d..b96f4dcabe 100644
--- a/tests/unit/meson.build
+++ b/tests/unit/meson.build
@@ -139,7 +139,7 @@ if have_system
'test-bufferiszero': [],
'test-smp-parse': [qom, meson.project_source_root() /
'hw/core/machine-smp.c'],
'test-vmstate': [migration, io],
- 'test-yank': ['socket-helpers.c', qom, io, chardev]
+ 'test-yank': ['socket-helpers.c', qom, io, chardev,
'../../hw/core/vmstate-if.c']
}
if config_host_data.get('CONFIG_INOTIFY1')
tests += {'test-util-filemonitor': []}
@@ -151,7 +151,7 @@ if have_system
if not get_option('tsan')
if host_os != 'windows'
tests += {
- 'test-char': ['socket-helpers.c', qom, io, chardev]
+ 'test-char': ['socket-helpers.c', qom, io, chardev,
'../../hw/core/vmstate-if.c']
}
endif
--
2.48.1
