To migrate virtio-net TAP device backend (including open fds) locally,
user should simply set migration parameter
fds = [virtio-net]
Why not simple boolean? To simplify migration to further versions,
when more devices will support fds migration.
Alternatively, we may add per-device option to disable fds-migration,
but still:
1. It's more comfortable to set same capabilities/parameters on both
source and target QEMU, than care about each device.
2. To not break the design, that machine-type + device options +
migration capabilites and parameters are fully define the resulting
migration stream. We'll break this if add in future more fds-passing
support in devices under same fds=true parameter.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
---
include/qapi/util.h | 17 +++++++++++++++++
migration/options.c | 30 +++++++++++++++++++++++++++++
migration/options.h | 2 ++
qapi/migration.json | 46 ++++++++++++++++++++++++++++++++++++---------
4 files changed, 86 insertions(+), 9 deletions(-)
diff --git a/include/qapi/util.h b/include/qapi/util.h
index 29bc4eb865..b953402416 100644
--- a/include/qapi/util.h
+++ b/include/qapi/util.h
@@ -69,4 +69,21 @@ int parse_qapi_name(const char *name, bool complete);
_len; \
})
+/*
+ * For any GenericList @list, return true if it contains specified
+ * element.
+ */
+#define QAPI_LIST_CONTAINS(list, el) \
+ ({ \
+ bool _found = false; \
+ typeof_strip_qual(list) _tail; \
+ for (_tail = list; _tail != NULL; _tail = _tail->next) { \
+ if (_tail->value == el) { \
+ _found = true; \
+ break; \
+ } \
+ } \
+ _found; \
+ })
+
#endif
diff --git a/migration/options.c b/migration/options.c
index 4e923a2e07..061a1b8eaf 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -13,6 +13,7 @@
#include "qemu/osdep.h"
#include "qemu/error-report.h"
+#include "qapi/util.h"
#include "exec/target_page.h"
#include "qapi/clone-visitor.h"
#include "qapi/error.h"
@@ -262,6 +263,13 @@ bool migrate_mapped_ram(void)
return s->capabilities[MIGRATION_CAPABILITY_MAPPED_RAM];
}
+bool migrate_fds_virtio_net(void)
+{
+ MigrationState *s = migrate_get_current();
+
+ return QAPI_LIST_CONTAINS(s->parameters.fds, FDS_TARGET_VIRTIO_NET);
+}
+
bool migrate_ignore_shared(void)
{
MigrationState *s = migrate_get_current();
@@ -960,6 +968,11 @@ MigrationParameters *qmp_query_migrate_parameters(Error
**errp)
params->has_direct_io = true;
params->direct_io = s->parameters.direct_io;
+ if (s->parameters.has_fds) {
+ params->has_fds = true;
+ params->fds = QAPI_CLONE(FdsTargetList, s->parameters.fds);
+ }
+
return params;
}
@@ -1179,6 +1192,11 @@ bool migrate_params_check(MigrationParameters *params,
Error **errp)
return false;
}
+ if (params->has_fds) {
+ error_setg(errp, "Not implemented");
+ return false;
+ }
+
return true;
}
@@ -1297,6 +1315,11 @@ static void
migrate_params_test_apply(MigrateSetParameters *params,
if (params->has_direct_io) {
dest->direct_io = params->direct_io;
}
+
+ if (params->has_fds) {
+ dest->has_fds = true;
+ dest->fds = params->fds;
+ }
}
static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
@@ -1429,6 +1452,13 @@ static void migrate_params_apply(MigrateSetParameters
*params, Error **errp)
if (params->has_direct_io) {
s->parameters.direct_io = params->direct_io;
}
+
+ if (params->has_fds) {
+ qapi_free_FdsTargetList(s->parameters.fds);
+
+ s->parameters.has_fds = true;
+ s->parameters.fds = QAPI_CLONE(FdsTargetList, params->fds);
+ }
}
void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp)
diff --git a/migration/options.h b/migration/options.h
index 82d839709e..a79472a235 100644
--- a/migration/options.h
+++ b/migration/options.h
@@ -87,6 +87,8 @@ const char *migrate_tls_hostname(void);
uint64_t migrate_xbzrle_cache_size(void);
ZeroPageDetection migrate_zero_page_detection(void);
+bool migrate_fds_virtio_net(void);
+
/* parameters helpers */
bool migrate_params_check(MigrationParameters *params, Error **errp);
diff --git a/qapi/migration.json b/qapi/migration.json
index 2387c21e9c..6ef9629c6d 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -747,6 +747,19 @@
'*transform': 'BitmapMigrationBitmapAliasTransform'
} }
+##
+# @FdsTarget:
+#
+# @virtio-net: Enable live backend migration for virtio-net.
+# The only supported backend is TAP device. When enabled, TAP fds
+# and all related state is passed to target QEMU through migration
+# channel (which should be unix socket).
+#
+# Since: 10.2
+##
+{ 'enum': 'FdsTarget',
+ 'data': [ 'virtio-net' ] }
+
##
# @BitmapMigrationNodeAlias:
#
@@ -924,10 +937,14 @@
# only has effect if the @mapped-ram capability is enabled.
# (Since 9.1)
#
+# @fds: List of targets to enable live-backend migration for. This
+# requires migration channel to be a unix socket (to pass fds
+# through). (Since 10.2)
+#
# Features:
#
-# @unstable: Members @x-checkpoint-delay and
-# @x-vcpu-dirty-limit-period are experimental.
+# @unstable: Members @x-checkpoint-delay,
+# @x-vcpu-dirty-limit-period and @fds are experimental.
#
# Since: 2.4
##
@@ -950,7 +967,8 @@
'vcpu-dirty-limit',
'mode',
'zero-page-detection',
- 'direct-io'] }
+ 'direct-io',
+ 'fds' ] }
##
# @MigrateSetParameters:
@@ -1105,10 +1123,14 @@
# only has effect if the @mapped-ram capability is enabled.
# (Since 9.1)
#
+# @fds: List of targets to enable live-backend migration for. This
+# requires migration channel to be a unix socket (to pass fds
+# through). (Since 10.2)
+#
# Features:
#
-# @unstable: Members @x-checkpoint-delay and
-# @x-vcpu-dirty-limit-period are experimental.
+# @unstable: Members @x-checkpoint-delay,
+# @x-vcpu-dirty-limit-period and @fds are experimental.
#
# TODO: either fuse back into `MigrationParameters`, or make
# `MigrationParameters` members mandatory
@@ -1146,7 +1168,8 @@
'*vcpu-dirty-limit': 'uint64',
'*mode': 'MigMode',
'*zero-page-detection': 'ZeroPageDetection',
- '*direct-io': 'bool' } }
+ '*direct-io': 'bool',
+ '*fds': { 'type': [ 'FdsTarget' ], 'features': [ 'unstable' ] } } }
##
# @migrate-set-parameters:
@@ -1315,10 +1338,14 @@
# only has effect if the @mapped-ram capability is enabled.
# (Since 9.1)
#
+# @fds: List of targets to enable live-backend migration for. This
+# requires migration channel to be a unix socket (to pass fds
+# through). (Since 10.2)
+#
# Features:
#
-# @unstable: Members @x-checkpoint-delay and
-# @x-vcpu-dirty-limit-period are experimental.
+# @unstable: Members @x-checkpoint-delay,
+# @x-vcpu-dirty-limit-period and @fds are experimental.
#
# Since: 2.4
##
@@ -1353,7 +1380,8 @@
'*vcpu-dirty-limit': 'uint64',
'*mode': 'MigMode',
'*zero-page-detection': 'ZeroPageDetection',
- '*direct-io': 'bool' } }
+ '*direct-io': 'bool',
+ '*fds': { 'type': [ 'FdsTarget' ], 'features': [ 'unstable' ] } } }
##
# @query-migrate-parameters:
--
2.48.1
