To migrate virtio-net TAP device backend (including open fds) locally, user should simply set migration parameter
backend-transfer = ["virtio-net-tap"] Why not simple boolean? To simplify migration to further versions, when more devices will support backend-transfer migration. Alternatively, we may add per-device option to disable backend-transfer 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 capabilities and parameters are fully define the resulting migration stream. We'll break this if add in future more backend-transfer support in devices under same backend-transfer=true parameter. Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]> --- include/qapi/util.h | 17 ++++++++++++++++ migration/options.c | 32 ++++++++++++++++++++++++++++++ migration/options.h | 2 ++ qapi/migration.json | 47 ++++++++++++++++++++++++++++++++++++--------- 4 files changed, 89 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..137ca2147e 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 +263,14 @@ bool migrate_mapped_ram(void) return s->capabilities[MIGRATION_CAPABILITY_MAPPED_RAM]; } +bool migrate_virtio_net_tap(void) +{ + MigrationState *s = migrate_get_current(); + + return QAPI_LIST_CONTAINS(s->parameters.backend_transfer, + BACKEND_TRANSFER_VIRTIO_NET_TAP); +} + bool migrate_ignore_shared(void) { MigrationState *s = migrate_get_current(); @@ -960,6 +969,12 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp) params->has_direct_io = true; params->direct_io = s->parameters.direct_io; + if (s->parameters.backend_transfer) { + params->has_backend_transfer = true; + params->backend_transfer = QAPI_CLONE(BackendTransferList, + s->parameters.backend_transfer); + } + return params; } @@ -993,6 +1008,7 @@ void migrate_params_init(MigrationParameters *params) params->has_mode = true; params->has_zero_page_detection = true; params->has_direct_io = true; + params->has_backend_transfer = true; } /* @@ -1179,6 +1195,11 @@ bool migrate_params_check(MigrationParameters *params, Error **errp) return false; } + if (params->has_backend_transfer) { + error_setg(errp, "Not implemented"); + return false; + } + return true; } @@ -1297,6 +1318,10 @@ static void migrate_params_test_apply(MigrateSetParameters *params, if (params->has_direct_io) { dest->direct_io = params->direct_io; } + + if (params->has_backend_transfer) { + dest->backend_transfer = params->backend_transfer; + } } static void migrate_params_apply(MigrateSetParameters *params, Error **errp) @@ -1429,6 +1454,13 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp) if (params->has_direct_io) { s->parameters.direct_io = params->direct_io; } + + if (params->has_backend_transfer) { + qapi_free_BackendTransferList(s->parameters.backend_transfer); + + s->parameters.backend_transfer = QAPI_CLONE(BackendTransferList, + params->backend_transfer); + } } void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp) diff --git a/migration/options.h b/migration/options.h index 82d839709e..55c0345433 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_virtio_net_tap(void); + /* parameters helpers */ bool migrate_params_check(MigrationParameters *params, Error **errp); diff --git a/qapi/migration.json b/qapi/migration.json index 2387c21e9c..e39785dc07 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -747,6 +747,18 @@ '*transform': 'BitmapMigrationBitmapAliasTransform' } } +## +# @BackendTransfer: +# +# @virtio-net-tap: Enable backend-transfer migration for virtio-net/tap. 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': 'BackendTransfer', + 'data': [ 'virtio-net-tap' ] } + ## # @BitmapMigrationNodeAlias: # @@ -924,10 +936,14 @@ # only has effect if the @mapped-ram capability is enabled. # (Since 9.1) # +# @backend-transfer: List of targets to enable backend-transfer +# 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 @backend-transfer are experimental. # # Since: 2.4 ## @@ -950,7 +966,8 @@ 'vcpu-dirty-limit', 'mode', 'zero-page-detection', - 'direct-io'] } + 'direct-io', + 'backend-transfer' ] } ## # @MigrateSetParameters: @@ -1105,10 +1122,14 @@ # only has effect if the @mapped-ram capability is enabled. # (Since 9.1) # +# @backend-transfer: List of targets to enable backend-transfer +# 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 @backend-transfer are experimental. # # TODO: either fuse back into `MigrationParameters`, or make # `MigrationParameters` members mandatory @@ -1146,7 +1167,9 @@ '*vcpu-dirty-limit': 'uint64', '*mode': 'MigMode', '*zero-page-detection': 'ZeroPageDetection', - '*direct-io': 'bool' } } + '*direct-io': 'bool', + '*backend-transfer': { 'type': [ 'BackendTransfer' ], + 'features': [ 'unstable' ] } } } ## # @migrate-set-parameters: @@ -1315,10 +1338,14 @@ # only has effect if the @mapped-ram capability is enabled. # (Since 9.1) # +# @backend-transfer: List of targets to enable backend-transfer +# 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 @backend-transfer are experimental. # # Since: 2.4 ## @@ -1353,7 +1380,9 @@ '*vcpu-dirty-limit': 'uint64', '*mode': 'MigMode', '*zero-page-detection': 'ZeroPageDetection', - '*direct-io': 'bool' } } + '*direct-io': 'bool', + '*backend-transfer': { 'type': [ 'BackendTransfer' ], + 'features': [ 'unstable' ] } } } ## # @query-migrate-parameters: -- 2.48.1
